Improve documentation and add more tests

internal/repository/hooks_test.go

@@ -0,0 +1,274 @@
+// Copyright (C) NHR@FAU, University Erlangen-Nuremberg.
+// All rights reserved. This file is part of cc-backend.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+package repository
+
+import (
+	"context"
+	"testing"
+	"time"
+
+	"github.com/ClusterCockpit/cc-lib/v2/schema"
+	_ "github.com/mattn/go-sqlite3"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+type MockJobHook struct {
+	startCalled bool
+	stopCalled  bool
+	startJobs   []*schema.Job
+	stopJobs    []*schema.Job
+}
+
+func (m *MockJobHook) JobStartCallback(job *schema.Job) {
+	m.startCalled = true
+	m.startJobs = append(m.startJobs, job)
+}
+
+func (m *MockJobHook) JobStopCallback(job *schema.Job) {
+	m.stopCalled = true
+	m.stopJobs = append(m.stopJobs, job)
+}
+
+func TestRegisterJobHook(t *testing.T) {
+	t.Run("register single hook", func(t *testing.T) {
+		hooks = nil
+		mock := &MockJobHook{}
+
+		RegisterJobHook(mock)
+
+		assert.NotNil(t, hooks)
+		assert.Len(t, hooks, 1)
+		assert.Equal(t, mock, hooks[0])
+
+		hooks = nil
+	})
+
+	t.Run("register multiple hooks", func(t *testing.T) {
+		hooks = nil
+		mock1 := &MockJobHook{}
+		mock2 := &MockJobHook{}
+
+		RegisterJobHook(mock1)
+		RegisterJobHook(mock2)
+
+		assert.Len(t, hooks, 2)
+		assert.Equal(t, mock1, hooks[0])
+		assert.Equal(t, mock2, hooks[1])
+
+		hooks = nil
+	})
+
+	t.Run("register nil hook does not add to hooks", func(t *testing.T) {
+		hooks = nil
+		RegisterJobHook(nil)
+
+		if hooks != nil {
+			assert.Len(t, hooks, 0, "Nil hook should not be added")
+		}
+
+		hooks = nil
+	})
+}
+
+func TestCallJobStartHooks(t *testing.T) {
+	t.Run("call start hooks with single job", func(t *testing.T) {
+		hooks = nil
+		mock := &MockJobHook{}
+		RegisterJobHook(mock)
+
+		job := &schema.Job{
+			JobID:   123,
+			User:    "testuser",
+			Cluster: "testcluster",
+		}
+
+		CallJobStartHooks([]*schema.Job{job})
+
+		assert.True(t, mock.startCalled)
+		assert.False(t, mock.stopCalled)
+		assert.Len(t, mock.startJobs, 1)
+		assert.Equal(t, int64(123), mock.startJobs[0].JobID)
+
+		hooks = nil
+	})
+
+	t.Run("call start hooks with multiple jobs", func(t *testing.T) {
+		hooks = nil
+		mock := &MockJobHook{}
+		RegisterJobHook(mock)
+
+		jobs := []*schema.Job{
+			{JobID: 1, User: "user1", Cluster: "cluster1"},
+			{JobID: 2, User: "user2", Cluster: "cluster2"},
+			{JobID: 3, User: "user3", Cluster: "cluster3"},
+		}
+
+		CallJobStartHooks(jobs)
+
+		assert.True(t, mock.startCalled)
+		assert.Len(t, mock.startJobs, 3)
+		assert.Equal(t, int64(1), mock.startJobs[0].JobID)
+		assert.Equal(t, int64(2), mock.startJobs[1].JobID)
+		assert.Equal(t, int64(3), mock.startJobs[2].JobID)
+
+		hooks = nil
+	})
+
+	t.Run("call start hooks with multiple registered hooks", func(t *testing.T) {
+		hooks = nil
+		mock1 := &MockJobHook{}
+		mock2 := &MockJobHook{}
+		RegisterJobHook(mock1)
+		RegisterJobHook(mock2)
+
+		job := &schema.Job{
+			JobID: 456, User: "testuser", Cluster: "testcluster",
+		}
+
+		CallJobStartHooks([]*schema.Job{job})
+
+		assert.True(t, mock1.startCalled)
+		assert.True(t, mock2.startCalled)
+		assert.Len(t, mock1.startJobs, 1)
+		assert.Len(t, mock2.startJobs, 1)
+
+		hooks = nil
+	})
+
+	t.Run("call start hooks with nil hooks", func(t *testing.T) {
+		hooks = nil
+
+		job := &schema.Job{
+			JobID: 789, User: "testuser", Cluster: "testcluster",
+		}
+
+		CallJobStartHooks([]*schema.Job{job})
+
+		hooks = nil
+	})
+
+	t.Run("call start hooks with empty job list", func(t *testing.T) {
+		hooks = nil
+		mock := &MockJobHook{}
+		RegisterJobHook(mock)
+
+		CallJobStartHooks([]*schema.Job{})
+
+		assert.False(t, mock.startCalled)
+		assert.Len(t, mock.startJobs, 0)
+
+		hooks = nil
+	})
+}
+
+func TestCallJobStopHooks(t *testing.T) {
+	t.Run("call stop hooks with single job", func(t *testing.T) {
+		hooks = nil
+		mock := &MockJobHook{}
+		RegisterJobHook(mock)
+
+		job := &schema.Job{
+			JobID:   123,
+			User:    "testuser",
+			Cluster: "testcluster",
+		}
+
+		CallJobStopHooks(job)
+
+		assert.True(t, mock.stopCalled)
+		assert.False(t, mock.startCalled)
+		assert.Len(t, mock.stopJobs, 1)
+		assert.Equal(t, int64(123), mock.stopJobs[0].JobID)
+
+		hooks = nil
+	})
+
+	t.Run("call stop hooks with multiple registered hooks", func(t *testing.T) {
+		hooks = nil
+		mock1 := &MockJobHook{}
+		mock2 := &MockJobHook{}
+		RegisterJobHook(mock1)
+		RegisterJobHook(mock2)
+
+		job := &schema.Job{
+			JobID: 456, User: "testuser", Cluster: "testcluster",
+		}
+
+		CallJobStopHooks(job)
+
+		assert.True(t, mock1.stopCalled)
+		assert.True(t, mock2.stopCalled)
+		assert.Len(t, mock1.stopJobs, 1)
+		assert.Len(t, mock2.stopJobs, 1)
+
+		hooks = nil
+	})
+
+	t.Run("call stop hooks with nil hooks", func(t *testing.T) {
+		hooks = nil
+
+		job := &schema.Job{
+			JobID: 789, User: "testuser", Cluster: "testcluster",
+		}
+
+		CallJobStopHooks(job)
+
+		hooks = nil
+	})
+}
+
+func TestSQLHooks(t *testing.T) {
+	_ = setup(t)
+
+	t.Run("hooks log queries in debug mode", func(t *testing.T) {
+		h := &Hooks{}
+
+		ctx := context.Background()
+		query := "SELECT * FROM job WHERE job_id = ?"
+		args := []any{123}
+
+		ctxWithTime, err := h.Before(ctx, query, args...)
+		require.NoError(t, err)
+		assert.NotNil(t, ctxWithTime)
+
+		beginTime := ctxWithTime.Value("begin")
+		require.NotNil(t, beginTime)
+		_, ok := beginTime.(time.Time)
+		assert.True(t, ok, "Begin time should be time.Time")
+
+		time.Sleep(10 * time.Millisecond)
+
+		ctxAfter, err := h.After(ctxWithTime, query, args...)
+		require.NoError(t, err)
+		assert.NotNil(t, ctxAfter)
+	})
+}
+
+func TestHookIntegration(t *testing.T) {
+	t.Run("hooks are called during job lifecycle", func(t *testing.T) {
+		hooks = nil
+		mock := &MockJobHook{}
+		RegisterJobHook(mock)
+
+		job := &schema.Job{
+			JobID:   999,
+			User:    "integrationuser",
+			Cluster: "integrationcluster",
+		}
+
+		CallJobStartHooks([]*schema.Job{job})
+		assert.True(t, mock.startCalled)
+		assert.Equal(t, 1, len(mock.startJobs))
+
+		CallJobStopHooks(job)
+		assert.True(t, mock.stopCalled)
+		assert.Equal(t, 1, len(mock.stopJobs))
+
+		assert.Equal(t, mock.startJobs[0].JobID, mock.stopJobs[0].JobID)
+
+		hooks = nil
+	})
+}

internal/repository/job.go

@@ -80,18 +80,33 @@ import (
 )
 
 var (
+	// jobRepoOnce ensures singleton initialization of the JobRepository
 	jobRepoOnce sync.Once
+	// jobRepoInstance holds the single instance of JobRepository
 	jobRepoInstance *JobRepository
 )
 
+// JobRepository provides database access for job-related operations.
+// It implements the repository pattern to abstract database interactions
+// and provides caching for improved performance.
+//
+// The repository is a singleton initialized via GetJobRepository().
+// All database queries use prepared statements via stmtCache for efficiency.
+// Frequently accessed data (metadata, energy footprints) is cached in an LRU cache.
 type JobRepository struct {
-	DB        *sqlx.DB
+	DB        *sqlx.DB        // Database connection pool
-	stmtCache *sq.StmtCache
+	stmtCache *sq.StmtCache   // Prepared statement cache for query optimization
-	cache     *lrucache.Cache
+	cache     *lrucache.Cache // LRU cache for metadata and footprint data
-	driver    string
+	driver    string          // Database driver name (e.g., "sqlite3")
-	Mutex     sync.Mutex
+	Mutex     sync.Mutex      // Mutex for thread-safe operations
 }
 
+// GetJobRepository returns the singleton instance of JobRepository.
+// The repository is initialized lazily on first access with database connection,
+// prepared statement cache, and LRU cache configured from repoConfig.
+//
+// This function is thread-safe and ensures only one instance is created.
+// It must be called after Connect() has established a database connection.
 func GetJobRepository() *JobRepository {
 	jobRepoOnce.Do(func() {
 		db := GetConnection()
@@ -107,6 +122,8 @@ func GetJobRepository() *JobRepository {
 	return jobRepoInstance
 }
 
+// jobColumns defines the standard set of columns selected from the job table.
+// Used consistently across all job queries to ensure uniform data retrieval.
 var jobColumns []string = []string{
 	"job.id", "job.job_id", "job.hpc_user", "job.project", "job.cluster", "job.subcluster",
 	"job.start_time", "job.cluster_partition", "job.array_job_id", "job.num_nodes",
@@ -115,6 +132,8 @@ var jobColumns []string = []string{
 	"job.footprint", "job.energy",
 }
 
+// jobCacheColumns defines columns from the job_cache table, mirroring jobColumns.
+// Used for queries against cached job data for performance optimization.
 var jobCacheColumns []string = []string{
 	"job_cache.id", "job_cache.job_id", "job_cache.hpc_user", "job_cache.project", "job_cache.cluster",
 	"job_cache.subcluster", "job_cache.start_time", "job_cache.cluster_partition",
@@ -124,6 +143,14 @@ var jobCacheColumns []string = []string{
 	"job_cache.footprint", "job_cache.energy",
 }
 
+// scanJob converts a database row into a schema.Job struct.
+// It handles JSON unmarshaling of resources and footprint fields,
+// and calculates accurate duration for running jobs.
+//
+// Parameters:
+//   - row: Database row implementing Scan() interface (sql.Row or sql.Rows)
+//
+// Returns the populated Job struct or an error if scanning or unmarshaling fails.
 func scanJob(row interface{ Scan(...any) error }) (*schema.Job, error) {
 	job := &schema.Job{}
 
@@ -186,6 +213,16 @@ func (r *JobRepository) Flush() error {
 	return nil
 }
 
+// FetchMetadata retrieves and unmarshals the metadata JSON for a job.
+// Metadata is cached with a 24-hour TTL to improve performance.
+//
+// The metadata field stores arbitrary key-value pairs associated with a job,
+// such as tags, labels, or custom attributes added by external systems.
+//
+// Parameters:
+//   - job: Job struct with valid ID field, metadata will be populated in job.MetaData
+//
+// Returns the metadata map or an error if the job is nil or database query fails.
 func (r *JobRepository) FetchMetadata(job *schema.Job) (map[string]string, error) {
 	if job == nil {
 		return nil, fmt.Errorf("job cannot be nil")
@@ -218,6 +255,16 @@ func (r *JobRepository) FetchMetadata(job *schema.Job) (map[string]string, error
 	return job.MetaData, nil
 }
 
+// UpdateMetadata adds or updates a single metadata key-value pair for a job.
+// The entire metadata map is re-marshaled and stored, and the cache is invalidated.
+// Also triggers archive metadata update via archive.UpdateMetadata.
+//
+// Parameters:
+//   - job: Job struct with valid ID, existing metadata will be fetched if not present
+//   - key: Metadata key to set
+//   - val: Metadata value to set
+//
+// Returns an error if the job is nil, metadata fetch fails, or database update fails.
 func (r *JobRepository) UpdateMetadata(job *schema.Job, key, val string) (err error) {
 	if job == nil {
 		return fmt.Errorf("job cannot be nil")
@@ -228,7 +275,7 @@ func (r *JobRepository) UpdateMetadata(job *schema.Job, key, val string) (err er
 	if job.MetaData == nil {
 		if _, err = r.FetchMetadata(job); err != nil {
 			cclog.Warnf("Error while fetching metadata for job, DB ID '%v'", job.ID)
-			return err
+			return fmt.Errorf("failed to fetch metadata for job %d: %w", job.ID, err)
 		}
 	}
 
@@ -243,7 +290,7 @@ func (r *JobRepository) UpdateMetadata(job *schema.Job, key, val string) (err er
 
 	if job.RawMetaData, err = json.Marshal(job.MetaData); err != nil {
 		cclog.Warnf("Error while marshaling metadata for job, DB ID '%v'", job.ID)
-		return err
+		return fmt.Errorf("failed to marshal metadata for job %d: %w", job.ID, err)
 	}
 
 	if _, err = sq.Update("job").
@@ -251,13 +298,23 @@ func (r *JobRepository) UpdateMetadata(job *schema.Job, key, val string) (err er
 		Where("job.id = ?", job.ID).
 		RunWith(r.stmtCache).Exec(); err != nil {
 		cclog.Warnf("Error while updating metadata for job, DB ID '%v'", job.ID)
-		return err
+		return fmt.Errorf("failed to update metadata in database for job %d: %w", job.ID, err)
 	}
 
 	r.cache.Put(cachekey, job.MetaData, len(job.RawMetaData), 24*time.Hour)
 	return archive.UpdateMetadata(job, job.MetaData)
 }
 
+// FetchFootprint retrieves and unmarshals the performance footprint JSON for a job.
+// Unlike FetchMetadata, footprints are NOT cached as they can be large and change frequently.
+//
+// The footprint contains summary statistics (avg/min/max) for monitored metrics,
+// stored as JSON with keys like "cpu_load_avg", "mem_used_max", etc.
+//
+// Parameters:
+//   - job: Job struct with valid ID, footprint will be populated in job.Footprint
+//
+// Returns the footprint map or an error if the job is nil or database query fails.
 func (r *JobRepository) FetchFootprint(job *schema.Job) (map[string]float64, error) {
 	if job == nil {
 		return nil, fmt.Errorf("job cannot be nil")
@@ -284,6 +341,16 @@ func (r *JobRepository) FetchFootprint(job *schema.Job) (map[string]float64, err
 	return job.Footprint, nil
 }
 
+// FetchEnergyFootprint retrieves and unmarshals the energy footprint JSON for a job.
+// Energy footprints are cached with a 24-hour TTL as they are frequently accessed but rarely change.
+//
+// The energy footprint contains calculated energy consumption (in kWh) per metric,
+// stored as JSON with keys like "power_avg", "acc_power_avg", etc.
+//
+// Parameters:
+//   - job: Job struct with valid ID, energy footprint will be populated in job.EnergyFootprint
+//
+// Returns the energy footprint map or an error if the job is nil or database query fails.
 func (r *JobRepository) FetchEnergyFootprint(job *schema.Job) (map[string]float64, error) {
 	if job == nil {
 		return nil, fmt.Errorf("job cannot be nil")
@@ -316,6 +383,18 @@ func (r *JobRepository) FetchEnergyFootprint(job *schema.Job) (map[string]float6
 	return job.EnergyFootprint, nil
 }
 
+// DeleteJobsBefore removes jobs older than the specified start time.
+// Optionally preserves tagged jobs to protect important data from deletion.
+// Cache entries for deleted jobs are automatically invalidated.
+//
+// This is typically used for data retention policies and cleanup operations.
+// WARNING: This is a destructive operation that permanently deletes job records.
+//
+// Parameters:
+//   - startTime: Unix timestamp, jobs with start_time < this value will be deleted
+//   - omitTagged: If true, skip jobs that have associated tags (jobtag entries)
+//
+// Returns the count of deleted jobs or an error if the operation fails.
 func (r *JobRepository) DeleteJobsBefore(startTime int64, omitTagged bool) (int, error) {
 	var cnt int
 	q := sq.Select("count(*)").From("job").Where("job.start_time < ?", startTime)
@@ -371,6 +450,13 @@ func (r *JobRepository) DeleteJobsBefore(startTime int64, omitTagged bool) (int,
 	return cnt, err
 }
 
+// DeleteJobByID permanently removes a single job by its database ID.
+// Cache entries for the deleted job are automatically invalidated.
+//
+// Parameters:
+//   - id: Database ID (primary key) of the job to delete
+//
+// Returns an error if the deletion fails.
 func (r *JobRepository) DeleteJobByID(id int64) error {
 	// Invalidate cache entries before deletion
 	r.cache.Del(fmt.Sprintf("metadata:%d", id))
@@ -388,6 +474,24 @@ func (r *JobRepository) DeleteJobByID(id int64) error {
 	return err
 }
 
+// FindUserOrProjectOrJobname attempts to interpret a search term as a job ID,
+// username, project ID, or job name by querying the database.
+//
+// Search logic (in priority order):
+//  1. If searchterm is numeric, treat as job ID (returned immediately)
+//  2. Try exact match in job.hpc_user column (username)
+//  3. Try LIKE match in hpc_user.name column (real name)
+//  4. Try exact match in job.project column (project ID)
+//  5. If no matches, return searchterm as jobname for GraphQL query
+//
+// This powers the searchbar functionality for flexible job searching.
+// Requires authenticated user for database lookups (returns empty if user is nil).
+//
+// Parameters:
+//   - user: Authenticated user context, required for database access
+//   - searchterm: Search string to interpret
+//
+// Returns up to one non-empty value among (jobid, username, project, jobname).
 func (r *JobRepository) FindUserOrProjectOrJobname(user *schema.User, searchterm string) (jobid string, username string, project string, jobname string) {
 	if searchterm == "" {
 		return "", "", "", ""
@@ -423,6 +527,19 @@ var (
 	ErrForbidden = errors.New("not authorized")
 )
 
+// FindColumnValue performs a generic column lookup in a database table with role-based access control.
+// Only users with admin, support, or manager roles can execute this query.
+//
+// Parameters:
+//   - user: User context for authorization check
+//   - searchterm: Value to search for (exact match or LIKE pattern)
+//   - table: Database table name to query
+//   - selectColumn: Column name to return in results
+//   - whereColumn: Column name to filter on
+//   - isLike: If true, use LIKE with wildcards; if false, use exact equality
+//
+// Returns the first matching value, ErrForbidden if user lacks permission,
+// or ErrNotFound if no matches are found.
 func (r *JobRepository) FindColumnValue(user *schema.User, searchterm string, table string, selectColumn string, whereColumn string, isLike bool) (result string, err error) {
 	if user == nil {
 		return "", fmt.Errorf("user cannot be nil")
@@ -453,6 +570,19 @@ func (r *JobRepository) FindColumnValue(user *schema.User, searchterm string, ta
 	}
 }
 
+// FindColumnValues performs a generic column lookup returning multiple matches with role-based access control.
+// Similar to FindColumnValue but returns all matching values instead of just the first.
+// Only users with admin, support, or manager roles can execute this query.
+//
+// Parameters:
+//   - user: User context for authorization check
+//   - query: Search pattern (always uses LIKE with wildcards)
+//   - table: Database table name to query
+//   - selectColumn: Column name to return in results
+//   - whereColumn: Column name to filter on
+//
+// Returns a slice of matching values, ErrForbidden if user lacks permission,
+// or ErrNotFound if no matches are found.
 func (r *JobRepository) FindColumnValues(user *schema.User, query string, table string, selectColumn string, whereColumn string) (results []string, err error) {
 	if user == nil {
 		return nil, fmt.Errorf("user cannot be nil")
@@ -487,6 +617,13 @@ func (r *JobRepository) FindColumnValues(user *schema.User, query string, table
 	}
 }
 
+// Partitions returns a list of distinct cluster partitions for a given cluster.
+// Results are cached with a 1-hour TTL to improve performance.
+//
+// Parameters:
+//   - cluster: Cluster name to query partitions for
+//
+// Returns a slice of partition names or an error if the database query fails.
 func (r *JobRepository) Partitions(cluster string) ([]string, error) {
 	var err error
 	start := time.Now()
@@ -550,6 +687,19 @@ func (r *JobRepository) AllocatedNodes(cluster string) (map[string]map[string]in
 }
 
 // FIXME: Set duration to requested walltime?
+// StopJobsExceedingWalltimeBy marks running jobs as failed if they exceed their walltime limit.
+// This is typically called periodically to clean up stuck or orphaned jobs.
+//
+// Jobs are marked with:
+//   - monitoring_status: MonitoringStatusArchivingFailed
+//   - duration: 0
+//   - job_state: JobStateFailed
+//
+// Parameters:
+//   - seconds: Grace period beyond walltime before marking as failed
+//
+// Returns an error if the database update fails.
+// Logs the number of jobs marked as failed if any were affected.
 func (r *JobRepository) StopJobsExceedingWalltimeBy(seconds int) error {
 	start := time.Now()
 	currentTime := time.Now().Unix()
@@ -579,6 +729,12 @@ func (r *JobRepository) StopJobsExceedingWalltimeBy(seconds int) error {
 	return nil
 }
 
+// FindJobIdsByTag returns all job database IDs associated with a specific tag.
+//
+// Parameters:
+//   - tagID: Database ID of the tag to search for
+//
+// Returns a slice of job IDs or an error if the query fails.
 func (r *JobRepository) FindJobIdsByTag(tagID int64) ([]int64, error) {
 	query := sq.Select("job.id").From("job").
 		Join("jobtag ON jobtag.job_id = job.id").
@@ -607,6 +763,13 @@ func (r *JobRepository) FindJobIdsByTag(tagID int64) ([]int64, error) {
 }
 
 // FIXME: Reconsider filtering short jobs with harcoded threshold
+// FindRunningJobs returns all currently running jobs for a specific cluster.
+// Filters out short-running jobs based on repoConfig.MinRunningJobDuration threshold.
+//
+// Parameters:
+//   - cluster: Cluster name to filter jobs
+//
+// Returns a slice of running job objects or an error if the query fails.
 func (r *JobRepository) FindRunningJobs(cluster string) ([]*schema.Job, error) {
 	query := sq.Select(jobColumns...).From("job").
 		Where("job.cluster = ?", cluster).
@@ -634,6 +797,12 @@ func (r *JobRepository) FindRunningJobs(cluster string) ([]*schema.Job, error) {
 	return jobs, nil
 }
 
+// UpdateDuration recalculates and updates the duration field for all running jobs.
+// Called periodically to keep job durations current without querying individual jobs.
+//
+// Duration is calculated as: current_time - job.start_time
+//
+// Returns an error if the database update fails.
 func (r *JobRepository) UpdateDuration() error {
 	stmnt := sq.Update("job").
 		Set("duration", sq.Expr("? - job.start_time", time.Now().Unix())).
@@ -648,6 +817,16 @@ func (r *JobRepository) UpdateDuration() error {
 	return nil
 }
 
+// FindJobsBetween returns jobs within a specified time range.
+// If startTimeBegin is 0, returns all jobs before startTimeEnd.
+// Optionally excludes tagged jobs from results.
+//
+// Parameters:
+//   - startTimeBegin: Unix timestamp for range start (use 0 for unbounded start)
+//   - startTimeEnd: Unix timestamp for range end
+//   - omitTagged: If true, exclude jobs with associated tags
+//
+// Returns a slice of jobs or an error if the time range is invalid or query fails.
 func (r *JobRepository) FindJobsBetween(startTimeBegin int64, startTimeEnd int64, omitTagged bool) ([]*schema.Job, error) {
 	var query sq.SelectBuilder
 
@@ -688,6 +867,14 @@ func (r *JobRepository) FindJobsBetween(startTimeBegin int64, startTimeEnd int64
 	return jobs, nil
 }
 
+// UpdateMonitoringStatus updates the monitoring status for a job and invalidates its cache entries.
+// Cache invalidation affects both metadata and energy footprint to ensure consistency.
+//
+// Parameters:
+//   - job: Database ID of the job to update
+//   - monitoringStatus: New monitoring status value (see schema.MonitoringStatus constants)
+//
+// Returns an error if the database update fails.
 func (r *JobRepository) UpdateMonitoringStatus(job int64, monitoringStatus int32) (err error) {
 	// Invalidate cache entries as monitoring status affects job state
 	r.cache.Del(fmt.Sprintf("metadata:%d", job))
@@ -704,6 +891,13 @@ func (r *JobRepository) UpdateMonitoringStatus(job int64, monitoringStatus int32
 	return nil
 }
 
+// Execute runs a Squirrel UpdateBuilder statement against the database.
+// This is a generic helper for executing pre-built update queries.
+//
+// Parameters:
+//   - stmt: Squirrel UpdateBuilder with prepared update query
+//
+// Returns an error if the execution fails.
 func (r *JobRepository) Execute(stmt sq.UpdateBuilder) error {
 	if _, err := stmt.RunWith(r.stmtCache).Exec(); err != nil {
 		cclog.Errorf("Error while executing statement: %v", err)
@@ -713,6 +907,14 @@ func (r *JobRepository) Execute(stmt sq.UpdateBuilder) error {
 	return nil
 }
 
+// MarkArchived adds monitoring status update to an existing UpdateBuilder statement.
+// This is a builder helper used when constructing multi-field update queries.
+//
+// Parameters:
+//   - stmt: Existing UpdateBuilder to modify
+//   - monitoringStatus: Monitoring status value to set
+//
+// Returns the modified UpdateBuilder for method chaining.
 func (r *JobRepository) MarkArchived(
 	stmt sq.UpdateBuilder,
 	monitoringStatus int32,
@@ -720,11 +922,22 @@ func (r *JobRepository) MarkArchived(
 	return stmt.Set("monitoring_status", monitoringStatus)
 }
 
+// UpdateEnergy calculates and updates the energy consumption for a job.
+// This is called for running jobs during intermediate updates or when archiving.
+//
+// Energy calculation formula:
+//   - For "power" metrics: Energy (kWh) = (Power_avg * NumNodes * Duration_hours) / 1000
+//   - For "energy" metrics: Currently not implemented (would need sum statistics)
+//
+// The calculation accounts for:
+//   - Multi-node jobs: Multiplies by NumNodes to get total cluster energy
+//   - Shared jobs: Node average is already based on partial resources, so NumNodes=1
+//   - Unit conversion: Watts * hours / 1000 = kilowatt-hours (kWh)
+//   - Rounding: Results rounded to 2 decimal places
 func (r *JobRepository) UpdateEnergy(
 	stmt sq.UpdateBuilder,
 	jobMeta *schema.Job,
 ) (sq.UpdateBuilder, error) {
-	/* Note: Only Called for Running Jobs during Intermediate Update or on Archiving */
 	sc, err := archive.GetSubCluster(jobMeta.Cluster, jobMeta.SubCluster)
 	if err != nil {
 		cclog.Errorf("cannot get subcluster: %s", err.Error())
@@ -732,25 +945,27 @@ func (r *JobRepository) UpdateEnergy(
 	}
 	energyFootprint := make(map[string]float64)
 
-	// Total Job Energy Outside Loop
+	// Accumulate total energy across all energy-related metrics
 	totalEnergy := 0.0
 	for _, fp := range sc.EnergyFootprint {
-		// Always Init Metric Energy Inside Loop
+		// Calculate energy for this specific metric
 		metricEnergy := 0.0
 		if i, err := archive.MetricIndex(sc.MetricConfig, fp); err == nil {
-			// Note: For DB data, calculate and save as kWh
 			switch sc.MetricConfig[i].Energy {
-			case "energy": // this metric has energy as unit (Joules or Wh)
+			case "energy": // Metric already in energy units (Joules or Wh)
 				cclog.Warnf("Update EnergyFootprint for Job %d and Metric %s on cluster %s: Set to 'energy' in cluster.json: Not implemented, will return 0.0", jobMeta.JobID, jobMeta.Cluster, fp)
-				// FIXME: Needs sum as stats type
+				// FIXME: Needs sum as stats type to accumulate energy values over time
-			case "power": // this metric has power as unit (Watt)
+			case "power": // Metric in power units (Watts)
-				// Energy: Power (in Watts) * Time (in Seconds)
+				// Energy (kWh) = Power (W) × Time (h) / 1000
-				// Unit: (W * (s / 3600)) / 1000 = kWh
+				// Formula: (avg_power_per_node * num_nodes) * (duration_sec / 3600) / 1000
-				// Round 2 Digits: round(Energy * 100) / 100
+				//
-				// Here: (All-Node Metric Average * Number of Nodes) * (Job Duration in Seconds / 3600) / 1000
+				// Breakdown:
-				// Note: Shared Jobs handled correctly since "Node Average" is based on partial resources, while "numNodes" factor is 1
+				//   LoadJobStat(jobMeta, fp, "avg") = average power per node (W)
+				//   jobMeta.NumNodes = number of nodes (1 for shared jobs)
+				//   jobMeta.Duration / 3600.0 = duration in hours
+				//   / 1000.0 = convert Wh to kWh
 				rawEnergy := ((LoadJobStat(jobMeta, fp, "avg") * float64(jobMeta.NumNodes)) * (float64(jobMeta.Duration) / 3600.0)) / 1000.0
-				metricEnergy = math.Round(rawEnergy*100.0) / 100.0
+				metricEnergy = math.Round(rawEnergy*100.0) / 100.0 // Round to 2 decimal places
 			}
 		} else {
 			cclog.Warnf("Error while collecting energy metric %s for job, DB ID '%v', return '0.0'", fp, jobMeta.ID)
@@ -758,8 +973,6 @@ func (r *JobRepository) UpdateEnergy(
 
 		energyFootprint[fp] = metricEnergy
 		totalEnergy += metricEnergy
-
-		// cclog.Infof("Metric %s Average %f -> %f kWh | Job %d Total -> %f kWh", fp, LoadJobStat(jobMeta, fp, "avg"), energy, jobMeta.JobID, totalEnergy)
 	}
 
 	var rawFootprint []byte
@@ -771,11 +984,19 @@ func (r *JobRepository) UpdateEnergy(
 	return stmt.Set("energy_footprint", string(rawFootprint)).Set("energy", (math.Round(totalEnergy*100.0) / 100.0)), nil
 }
 
+// UpdateFootprint calculates and updates the performance footprint for a job.
+// This is called for running jobs during intermediate updates or when archiving.
+//
+// A footprint is a summary statistic (avg/min/max) for each monitored metric.
+// The specific statistic type is defined in the cluster config's Footprint field.
+// Results are stored as JSON with keys like "metric_avg", "metric_max", etc.
+//
+// Example: For a "cpu_load" metric with Footprint="avg", this stores
+// the average CPU load across all nodes as "cpu_load_avg": 85.3
 func (r *JobRepository) UpdateFootprint(
 	stmt sq.UpdateBuilder,
 	jobMeta *schema.Job,
 ) (sq.UpdateBuilder, error) {
-	/* Note: Only Called for Running Jobs during Intermediate Update or on Archiving */
 	sc, err := archive.GetSubCluster(jobMeta.Cluster, jobMeta.SubCluster)
 	if err != nil {
 		cclog.Errorf("cannot get subcluster: %s", err.Error())
@@ -783,7 +1004,10 @@ func (r *JobRepository) UpdateFootprint(
 	}
 	footprint := make(map[string]float64)
 
+	// Build footprint map with metric_stattype as keys
 	for _, fp := range sc.Footprint {
+		// Determine which statistic to use: avg, min, or max
+		// First check global metric config, then cluster-specific config
 		var statType string
 		for _, gm := range archive.GlobalMetricList {
 			if gm.Name == fp {
@@ -791,15 +1015,18 @@ func (r *JobRepository) UpdateFootprint(
 			}
 		}
 
+		// Validate statistic type
 		if statType != "avg" && statType != "min" && statType != "max" {
 			cclog.Warnf("unknown statType for footprint update: %s", statType)
 			return stmt, fmt.Errorf("unknown statType for footprint update: %s", statType)
 		}
 
+		// Override with cluster-specific config if available
 		if i, err := archive.MetricIndex(sc.MetricConfig, fp); err != nil {
 			statType = sc.MetricConfig[i].Footprint
 		}
 
+		// Store as "metric_stattype": value (e.g., "cpu_load_avg": 85.3)
 		name := fmt.Sprintf("%s_%s", fp, statType)
 		footprint[name] = LoadJobStat(jobMeta, fp, statType)
 	}

internal/repository/jobCreate_test.go

@@ -0,0 +1,500 @@
+// Copyright (C) NHR@FAU, University Erlangen-Nuremberg.
+// All rights reserved. This file is part of cc-backend.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+package repository
+
+import (
+	"encoding/json"
+	"testing"
+
+	"github.com/ClusterCockpit/cc-lib/v2/schema"
+	_ "github.com/mattn/go-sqlite3"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+// createTestJob creates a minimal valid job for testing
+func createTestJob(jobID int64, cluster string) *schema.Job {
+	return &schema.Job{
+		JobID:            jobID,
+		User:             "testuser",
+		Project:          "testproject",
+		Cluster:          cluster,
+		SubCluster:       "main",
+		Partition:        "batch",
+		NumNodes:         1,
+		NumHWThreads:     4,
+		NumAcc:           0,
+		Shared:           "none",
+		MonitoringStatus: schema.MonitoringStatusRunningOrArchiving,
+		SMT:              1,
+		State:            schema.JobStateRunning,
+		StartTime:        1234567890,
+		Duration:         0,
+		Walltime:         3600,
+		Resources: []*schema.Resource{
+			{
+				Hostname:  "node01",
+				HWThreads: []int{0, 1, 2, 3},
+			},
+		},
+		Footprint: map[string]float64{
+			"cpu_load":      50.0,
+			"mem_used":      8000.0,
+			"flops_any":     0.5,
+			"mem_bw":        10.0,
+			"net_bw":        2.0,
+			"file_bw":       1.0,
+			"cpu_used":      2.0,
+			"cpu_load_core": 12.5,
+		},
+		MetaData: map[string]string{
+			"jobName":     "test_job",
+			"queue":       "normal",
+			"qosName":     "default",
+			"accountName": "testaccount",
+		},
+	}
+}
+
+func TestInsertJob(t *testing.T) {
+	r := setup(t)
+
+	t.Run("successful insertion", func(t *testing.T) {
+		job := createTestJob(999001, "testcluster")
+		job.RawResources, _ = json.Marshal(job.Resources)
+		job.RawFootprint, _ = json.Marshal(job.Footprint)
+		job.RawMetaData, _ = json.Marshal(job.MetaData)
+
+		id, err := r.InsertJob(job)
+		require.NoError(t, err, "InsertJob should succeed")
+		assert.Greater(t, id, int64(0), "Should return valid insert ID")
+
+		// Verify job was inserted into job_cache
+		var count int
+		err = r.DB.QueryRow("SELECT COUNT(*) FROM job_cache WHERE job_id = ? AND cluster = ?",
+			job.JobID, job.Cluster).Scan(&count)
+		require.NoError(t, err)
+		assert.Equal(t, 1, count, "Job should be in job_cache table")
+
+		// Clean up
+		_, err = r.DB.Exec("DELETE FROM job_cache WHERE job_id = ? AND cluster = ?", job.JobID, job.Cluster)
+		require.NoError(t, err)
+	})
+
+	t.Run("insertion with all fields", func(t *testing.T) {
+		job := createTestJob(999002, "testcluster")
+		job.ArrayJobID = 5000
+		job.Energy = 1500.5
+		job.RawResources, _ = json.Marshal(job.Resources)
+		job.RawFootprint, _ = json.Marshal(job.Footprint)
+		job.RawMetaData, _ = json.Marshal(job.MetaData)
+
+		id, err := r.InsertJob(job)
+		require.NoError(t, err)
+		assert.Greater(t, id, int64(0))
+
+		// Verify all fields were stored correctly
+		var retrievedJob schema.Job
+		err = r.DB.QueryRow(`SELECT job_id, hpc_user, project, cluster, array_job_id, energy 
+			FROM job_cache WHERE id = ?`, id).Scan(
+			&retrievedJob.JobID, &retrievedJob.User, &retrievedJob.Project,
+			&retrievedJob.Cluster, &retrievedJob.ArrayJobID, &retrievedJob.Energy)
+		require.NoError(t, err)
+		assert.Equal(t, job.JobID, retrievedJob.JobID)
+		assert.Equal(t, job.User, retrievedJob.User)
+		assert.Equal(t, job.Project, retrievedJob.Project)
+		assert.Equal(t, job.Cluster, retrievedJob.Cluster)
+		assert.Equal(t, job.ArrayJobID, retrievedJob.ArrayJobID)
+		assert.Equal(t, job.Energy, retrievedJob.Energy)
+
+		// Clean up
+		_, err = r.DB.Exec("DELETE FROM job_cache WHERE id = ?", id)
+		require.NoError(t, err)
+	})
+}
+
+func TestStart(t *testing.T) {
+	r := setup(t)
+
+	t.Run("successful job start with JSON encoding", func(t *testing.T) {
+		job := createTestJob(999003, "testcluster")
+
+		id, err := r.Start(job)
+		require.NoError(t, err, "Start should succeed")
+		assert.Greater(t, id, int64(0), "Should return valid insert ID")
+
+		// Verify job was inserted and JSON fields were encoded
+		var rawResources, rawFootprint, rawMetaData []byte
+		err = r.DB.QueryRow(`SELECT resources, footprint, meta_data FROM job_cache WHERE id = ?`, id).Scan(
+			&rawResources, &rawFootprint, &rawMetaData)
+		require.NoError(t, err)
+
+		// Verify resources JSON
+		var resources []*schema.Resource
+		err = json.Unmarshal(rawResources, &resources)
+		require.NoError(t, err, "Resources should be valid JSON")
+		assert.Equal(t, 1, len(resources))
+		assert.Equal(t, "node01", resources[0].Hostname)
+
+		// Verify footprint JSON
+		var footprint map[string]float64
+		err = json.Unmarshal(rawFootprint, &footprint)
+		require.NoError(t, err, "Footprint should be valid JSON")
+		assert.Equal(t, 50.0, footprint["cpu_load"])
+		assert.Equal(t, 8000.0, footprint["mem_used"])
+
+		// Verify metadata JSON
+		var metaData map[string]string
+		err = json.Unmarshal(rawMetaData, &metaData)
+		require.NoError(t, err, "MetaData should be valid JSON")
+		assert.Equal(t, "test_job", metaData["jobName"])
+
+		// Clean up
+		_, err = r.DB.Exec("DELETE FROM job_cache WHERE id = ?", id)
+		require.NoError(t, err)
+	})
+
+	t.Run("job start with empty footprint", func(t *testing.T) {
+		job := createTestJob(999004, "testcluster")
+		job.Footprint = map[string]float64{}
+
+		id, err := r.Start(job)
+		require.NoError(t, err)
+		assert.Greater(t, id, int64(0))
+
+		// Verify empty footprint was encoded as empty JSON object
+		var rawFootprint []byte
+		err = r.DB.QueryRow(`SELECT footprint FROM job_cache WHERE id = ?`, id).Scan(&rawFootprint)
+		require.NoError(t, err)
+		assert.Equal(t, []byte("{}"), rawFootprint)
+
+		// Clean up
+		_, err = r.DB.Exec("DELETE FROM job_cache WHERE id = ?", id)
+		require.NoError(t, err)
+	})
+
+	t.Run("job start with nil metadata", func(t *testing.T) {
+		job := createTestJob(999005, "testcluster")
+		job.MetaData = nil
+
+		id, err := r.Start(job)
+		require.NoError(t, err)
+		assert.Greater(t, id, int64(0))
+
+		// Clean up
+		_, err = r.DB.Exec("DELETE FROM job_cache WHERE id = ?", id)
+		require.NoError(t, err)
+	})
+}
+
+func TestStop(t *testing.T) {
+	r := setup(t)
+
+	t.Run("successful job stop", func(t *testing.T) {
+		// First insert a job using Start
+		job := createTestJob(999106, "testcluster")
+		id, err := r.Start(job)
+		require.NoError(t, err)
+
+		// Move from job_cache to job table (simulate SyncJobs) - exclude id to let it auto-increment
+		_, err = r.DB.Exec(`INSERT INTO job (job_id, cluster, subcluster, submit_time, start_time, hpc_user, project, 
+			cluster_partition, array_job_id, duration, walltime, job_state, meta_data, resources, num_nodes, 
+			num_hwthreads, num_acc, smt, shared, monitoring_status, energy, energy_footprint, footprint) 
+			SELECT job_id, cluster, subcluster, submit_time, start_time, hpc_user, project, 
+			cluster_partition, array_job_id, duration, walltime, job_state, meta_data, resources, num_nodes, 
+			num_hwthreads, num_acc, smt, shared, monitoring_status, energy, energy_footprint, footprint 
+			FROM job_cache WHERE id = ?`, id)
+		require.NoError(t, err)
+		_, err = r.DB.Exec("DELETE FROM job_cache WHERE id = ?", id)
+		require.NoError(t, err)
+
+		// Get the new job id in the job table
+		err = r.DB.QueryRow("SELECT id FROM job WHERE job_id = ? AND cluster = ? AND start_time = ?",
+			job.JobID, job.Cluster, job.StartTime).Scan(&id)
+		require.NoError(t, err)
+
+		// Stop the job
+		duration := int32(3600)
+		state := schema.JobStateCompleted
+		monitoringStatus := int32(schema.MonitoringStatusArchivingSuccessful)
+
+		err = r.Stop(id, duration, state, monitoringStatus)
+		require.NoError(t, err, "Stop should succeed")
+
+		// Verify job was updated
+		var retrievedDuration int32
+		var retrievedState string
+		var retrievedMonStatus int32
+		err = r.DB.QueryRow(`SELECT duration, job_state, monitoring_status FROM job WHERE id = ?`, id).Scan(
+			&retrievedDuration, &retrievedState, &retrievedMonStatus)
+		require.NoError(t, err)
+		assert.Equal(t, duration, retrievedDuration)
+		assert.Equal(t, string(state), retrievedState)
+		assert.Equal(t, monitoringStatus, retrievedMonStatus)
+
+		// Clean up
+		_, err = r.DB.Exec("DELETE FROM job WHERE id = ?", id)
+		require.NoError(t, err)
+	})
+
+	t.Run("stop updates job state transitions", func(t *testing.T) {
+		// Insert a job
+		job := createTestJob(999107, "testcluster")
+		id, err := r.Start(job)
+		require.NoError(t, err)
+
+		// Move to job table
+		_, err = r.DB.Exec(`INSERT INTO job (job_id, cluster, subcluster, submit_time, start_time, hpc_user, project, 
+			cluster_partition, array_job_id, duration, walltime, job_state, meta_data, resources, num_nodes, 
+			num_hwthreads, num_acc, smt, shared, monitoring_status, energy, energy_footprint, footprint) 
+			SELECT job_id, cluster, subcluster, submit_time, start_time, hpc_user, project, 
+			cluster_partition, array_job_id, duration, walltime, job_state, meta_data, resources, num_nodes, 
+			num_hwthreads, num_acc, smt, shared, monitoring_status, energy, energy_footprint, footprint 
+			FROM job_cache WHERE id = ?`, id)
+		require.NoError(t, err)
+		_, err = r.DB.Exec("DELETE FROM job_cache WHERE id = ?", id)
+		require.NoError(t, err)
+
+		// Get the new job id in the job table
+		err = r.DB.QueryRow("SELECT id FROM job WHERE job_id = ? AND cluster = ? AND start_time = ?",
+			job.JobID, job.Cluster, job.StartTime).Scan(&id)
+		require.NoError(t, err)
+
+		// Stop the job with different duration
+		err = r.Stop(id, 7200, schema.JobStateCompleted, int32(schema.MonitoringStatusArchivingSuccessful))
+		require.NoError(t, err)
+
+		// Verify the duration was updated correctly
+		var duration int32
+		err = r.DB.QueryRow(`SELECT duration FROM job WHERE id = ?`, id).Scan(&duration)
+		require.NoError(t, err)
+		assert.Equal(t, int32(7200), duration, "Duration should be updated to 7200")
+
+		// Clean up
+		_, err = r.DB.Exec("DELETE FROM job WHERE id = ?", id)
+		require.NoError(t, err)
+	})
+
+	t.Run("stop with different states", func(t *testing.T) {
+		testCases := []struct {
+			name             string
+			jobID            int64
+			state            schema.JobState
+			monitoringStatus int32
+		}{
+			{"completed", 999108, schema.JobStateCompleted, int32(schema.MonitoringStatusArchivingSuccessful)},
+			{"failed", 999118, schema.JobStateFailed, int32(schema.MonitoringStatusArchivingSuccessful)},
+			{"cancelled", 999119, schema.JobStateCancelled, int32(schema.MonitoringStatusArchivingSuccessful)},
+			{"timeout", 999120, schema.JobStateTimeout, int32(schema.MonitoringStatusArchivingSuccessful)},
+		}
+
+		for _, tc := range testCases {
+			t.Run(tc.name, func(t *testing.T) {
+				job := createTestJob(tc.jobID, "testcluster")
+				id, err := r.Start(job)
+				require.NoError(t, err)
+
+				// Move to job table
+				_, err = r.DB.Exec(`INSERT INTO job (job_id, cluster, subcluster, submit_time, start_time, hpc_user, project, 
+					cluster_partition, array_job_id, duration, walltime, job_state, meta_data, resources, num_nodes, 
+					num_hwthreads, num_acc, smt, shared, monitoring_status, energy, energy_footprint, footprint) 
+					SELECT job_id, cluster, subcluster, submit_time, start_time, hpc_user, project, 
+					cluster_partition, array_job_id, duration, walltime, job_state, meta_data, resources, num_nodes, 
+					num_hwthreads, num_acc, smt, shared, monitoring_status, energy, energy_footprint, footprint 
+					FROM job_cache WHERE id = ?`, id)
+				require.NoError(t, err)
+				_, err = r.DB.Exec("DELETE FROM job_cache WHERE id = ?", id)
+				require.NoError(t, err)
+
+				// Get the new job id in the job table
+				err = r.DB.QueryRow("SELECT id FROM job WHERE job_id = ? AND cluster = ? AND start_time = ?",
+					job.JobID, job.Cluster, job.StartTime).Scan(&id)
+				require.NoError(t, err)
+
+				// Stop with specific state
+				err = r.Stop(id, 1800, tc.state, tc.monitoringStatus)
+				require.NoError(t, err)
+
+				// Verify state was set correctly
+				var retrievedState string
+				err = r.DB.QueryRow(`SELECT job_state FROM job WHERE id = ?`, id).Scan(&retrievedState)
+				require.NoError(t, err)
+				assert.Equal(t, string(tc.state), retrievedState)
+
+				// Clean up
+				_, err = r.DB.Exec("DELETE FROM job WHERE id = ?", id)
+				require.NoError(t, err)
+			})
+		}
+	})
+}
+
+func TestStopCached(t *testing.T) {
+	r := setup(t)
+
+	t.Run("successful stop cached job", func(t *testing.T) {
+		// Insert a job in job_cache
+		job := createTestJob(999009, "testcluster")
+		id, err := r.Start(job)
+		require.NoError(t, err)
+
+		// Stop the cached job
+		duration := int32(3600)
+		state := schema.JobStateCompleted
+		monitoringStatus := int32(schema.MonitoringStatusArchivingSuccessful)
+
+		err = r.StopCached(id, duration, state, monitoringStatus)
+		require.NoError(t, err, "StopCached should succeed")
+
+		// Verify job was updated in job_cache table
+		var retrievedDuration int32
+		var retrievedState string
+		var retrievedMonStatus int32
+		err = r.DB.QueryRow(`SELECT duration, job_state, monitoring_status FROM job_cache WHERE id = ?`, id).Scan(
+			&retrievedDuration, &retrievedState, &retrievedMonStatus)
+		require.NoError(t, err)
+		assert.Equal(t, duration, retrievedDuration)
+		assert.Equal(t, string(state), retrievedState)
+		assert.Equal(t, monitoringStatus, retrievedMonStatus)
+
+		// Clean up
+		_, err = r.DB.Exec("DELETE FROM job_cache WHERE id = ?", id)
+		require.NoError(t, err)
+	})
+
+	t.Run("stop cached job does not affect job table", func(t *testing.T) {
+		// Insert a job in job_cache
+		job := createTestJob(999010, "testcluster")
+		id, err := r.Start(job)
+		require.NoError(t, err)
+
+		// Stop the cached job
+		err = r.StopCached(id, 3600, schema.JobStateCompleted, int32(schema.MonitoringStatusArchivingSuccessful))
+		require.NoError(t, err)
+
+		// Verify job table was not affected
+		var count int
+		err = r.DB.QueryRow(`SELECT COUNT(*) FROM job WHERE job_id = ? AND cluster = ?`,
+			job.JobID, job.Cluster).Scan(&count)
+		require.NoError(t, err)
+		assert.Equal(t, 0, count, "Job table should not be affected by StopCached")
+
+		// Clean up
+		_, err = r.DB.Exec("DELETE FROM job_cache WHERE id = ?", id)
+		require.NoError(t, err)
+	})
+}
+
+func TestSyncJobs(t *testing.T) {
+	r := setup(t)
+
+	t.Run("sync jobs from cache to main table", func(t *testing.T) {
+		// Ensure cache is empty first
+		_, err := r.DB.Exec("DELETE FROM job_cache")
+		require.NoError(t, err)
+
+		// Insert multiple jobs in job_cache
+		job1 := createTestJob(999011, "testcluster")
+		job2 := createTestJob(999012, "testcluster")
+		job3 := createTestJob(999013, "testcluster")
+
+		_, err = r.Start(job1)
+		require.NoError(t, err)
+		_, err = r.Start(job2)
+		require.NoError(t, err)
+		_, err = r.Start(job3)
+		require.NoError(t, err)
+
+		// Verify jobs are in job_cache
+		var cacheCount int
+		err = r.DB.QueryRow("SELECT COUNT(*) FROM job_cache WHERE job_id IN (?, ?, ?)",
+			job1.JobID, job2.JobID, job3.JobID).Scan(&cacheCount)
+		require.NoError(t, err)
+		assert.Equal(t, 3, cacheCount, "All jobs should be in job_cache")
+
+		// Sync jobs
+		jobs, err := r.SyncJobs()
+		require.NoError(t, err, "SyncJobs should succeed")
+		assert.Equal(t, 3, len(jobs), "Should return 3 synced jobs")
+
+		// Verify jobs were moved to job table
+		var jobCount int
+		err = r.DB.QueryRow("SELECT COUNT(*) FROM job WHERE job_id IN (?, ?, ?)",
+			job1.JobID, job2.JobID, job3.JobID).Scan(&jobCount)
+		require.NoError(t, err)
+		assert.Equal(t, 3, jobCount, "All jobs should be in job table")
+
+		// Verify job_cache was cleared
+		err = r.DB.QueryRow("SELECT COUNT(*) FROM job_cache WHERE job_id IN (?, ?, ?)",
+			job1.JobID, job2.JobID, job3.JobID).Scan(&cacheCount)
+		require.NoError(t, err)
+		assert.Equal(t, 0, cacheCount, "job_cache should be empty after sync")
+
+		// Clean up
+		_, err = r.DB.Exec("DELETE FROM job WHERE job_id IN (?, ?, ?)", job1.JobID, job2.JobID, job3.JobID)
+		require.NoError(t, err)
+	})
+
+	t.Run("sync preserves job data", func(t *testing.T) {
+		// Ensure cache is empty first
+		_, err := r.DB.Exec("DELETE FROM job_cache")
+		require.NoError(t, err)
+
+		// Insert a job with specific data
+		job := createTestJob(999014, "testcluster")
+		job.ArrayJobID = 7777
+		job.Energy = 2500.75
+		job.Duration = 1800
+
+		id, err := r.Start(job)
+		require.NoError(t, err)
+
+		// Update some fields to simulate job progress
+		result, err := r.DB.Exec(`UPDATE job_cache SET duration = ?, energy = ? WHERE id = ?`,
+			3600, 3000.5, id)
+		require.NoError(t, err)
+		rowsAffected, _ := result.RowsAffected()
+		require.Equal(t, int64(1), rowsAffected, "UPDATE should affect exactly 1 row")
+
+		// Verify the update worked
+		var checkDuration int32
+		var checkEnergy float64
+		err = r.DB.QueryRow(`SELECT duration, energy FROM job_cache WHERE id = ?`, id).Scan(&checkDuration, &checkEnergy)
+		require.NoError(t, err)
+		require.Equal(t, int32(3600), checkDuration, "Duration should be updated to 3600 before sync")
+		require.Equal(t, 3000.5, checkEnergy, "Energy should be updated to 3000.5 before sync")
+
+		// Sync jobs
+		jobs, err := r.SyncJobs()
+		require.NoError(t, err)
+		require.Equal(t, 1, len(jobs), "Should return exactly 1 synced job")
+
+		// Verify in database
+		var dbJob schema.Job
+		err = r.DB.QueryRow(`SELECT job_id, hpc_user, project, cluster, array_job_id, duration, energy 
+			FROM job WHERE job_id = ? AND cluster = ?`, job.JobID, job.Cluster).Scan(
+			&dbJob.JobID, &dbJob.User, &dbJob.Project, &dbJob.Cluster,
+			&dbJob.ArrayJobID, &dbJob.Duration, &dbJob.Energy)
+		require.NoError(t, err)
+		assert.Equal(t, job.JobID, dbJob.JobID)
+		assert.Equal(t, int32(3600), dbJob.Duration)
+		assert.Equal(t, 3000.5, dbJob.Energy)
+
+		// Clean up
+		_, err = r.DB.Exec("DELETE FROM job WHERE job_id = ? AND cluster = ?", job.JobID, job.Cluster)
+		require.NoError(t, err)
+	})
+
+	t.Run("sync with empty cache returns empty list", func(t *testing.T) {
+		// Ensure cache is empty
+		_, err := r.DB.Exec("DELETE FROM job_cache")
+		require.NoError(t, err)
+
+		// Sync should return empty list
+		jobs, err := r.SyncJobs()
+		require.NoError(t, err)
+		assert.Equal(t, 0, len(jobs), "Should return empty list when cache is empty")
+	})
+}

internal/repository/jobHooks.go

@@ -10,8 +10,36 @@ import (
 	"github.com/ClusterCockpit/cc-lib/v2/schema"
 )
 
+// JobHook interface allows external components to hook into job lifecycle events.
+// Implementations can perform actions when jobs start or stop, such as tagging,
+// logging, notifications, or triggering external workflows.
+//
+// Example implementation:
+//
+//	type MyJobTagger struct{}
+//
+//	func (t *MyJobTagger) JobStartCallback(job *schema.Job) {
+//	    if job.NumNodes > 100 {
+//	        // Tag large jobs automatically
+//	    }
+//	}
+//
+//	func (t *MyJobTagger) JobStopCallback(job *schema.Job) {
+//	    if job.State == schema.JobStateFailed {
+//	        // Log or alert on failed jobs
+//	    }
+//	}
+//
+// Register hooks during application initialization:
+//
+//	repository.RegisterJobHook(&MyJobTagger{})
 type JobHook interface {
+	// JobStartCallback is invoked when one or more jobs start.
+	// This is called synchronously, so implementations should be fast.
 	JobStartCallback(job *schema.Job)
+
+	// JobStopCallback is invoked when a job completes.
+	// This is called synchronously, so implementations should be fast.
 	JobStopCallback(job *schema.Job)
 }
 
@@ -20,7 +48,13 @@ var (
 	hooks    []JobHook
 )
 
-func RegisterJobJook(hook JobHook) {
+// RegisterJobHook registers a JobHook to receive job lifecycle callbacks.
+// Multiple hooks can be registered and will be called in registration order.
+// This function is safe to call multiple times and is typically called during
+// application initialization.
+//
+// Nil hooks are silently ignored to simplify conditional registration.
+func RegisterJobHook(hook JobHook) {
 	initOnce.Do(func() {
 		hooks = make([]JobHook, 0)
 	})
@@ -30,6 +64,12 @@ func RegisterJobJook(hook JobHook) {
 	}
 }
 
+// CallJobStartHooks invokes all registered JobHook.JobStartCallback methods
+// for each job in the provided slice. This is called internally by the repository
+// when jobs are started (e.g., via StartJob or batch job imports).
+//
+// Hooks are called synchronously in registration order. If a hook panics,
+// the panic will propagate to the caller.
 func CallJobStartHooks(jobs []*schema.Job) {
 	if hooks == nil {
 		return
@@ -44,6 +84,12 @@ func CallJobStartHooks(jobs []*schema.Job) {
 	}
 }
 
+// CallJobStopHooks invokes all registered JobHook.JobStopCallback methods
+// for the provided job. This is called internally by the repository when a
+// job completes (e.g., via StopJob or job state updates).
+//
+// Hooks are called synchronously in registration order. If a hook panics,
+// the panic will propagate to the caller.
 func CallJobStopHooks(job *schema.Job) {
 	if hooks == nil {
 		return

internal/repository/migration.go

@@ -16,11 +16,29 @@ import (
 	"github.com/golang-migrate/migrate/v4/source/iofs"
 )
 
+// Version is the current database schema version required by this version of cc-backend.
+// When the database schema changes, this version is incremented and a new migration file
+// is added to internal/repository/migrations/sqlite3/.
+//
+// Version history:
+//   - Version 10: Current version
+//
+// Migration files are embedded at build time from the migrations directory.
 const Version uint = 10
 
 //go:embed migrations/*
 var migrationFiles embed.FS
 
+// checkDBVersion verifies that the database schema version matches the expected version.
+// This is called automatically during Connect() to ensure schema compatibility.
+//
+// Returns an error if:
+//   - Database version is older than expected (needs migration)
+//   - Database version is newer than expected (needs app upgrade)
+//   - Database is in a dirty state (failed migration)
+//
+// A "dirty" database indicates a migration was started but not completed successfully.
+// This requires manual intervention to fix the database and force the version.
 func checkDBVersion(db *sql.DB) error {
 	driver, err := sqlite3.WithInstance(db, &sqlite3.Config{})
 	if err != nil {
@@ -58,6 +76,8 @@ func checkDBVersion(db *sql.DB) error {
 	return nil
 }
 
+// getMigrateInstance creates a new migration instance for the given database file.
+// This is used internally by MigrateDB, RevertDB, and ForceDB.
 func getMigrateInstance(db string) (m *migrate.Migrate, err error) {
 	d, err := iofs.New(migrationFiles, "migrations/sqlite3")
 	if err != nil {
@@ -72,6 +92,23 @@ func getMigrateInstance(db string) (m *migrate.Migrate, err error) {
 	return m, nil
 }
 
+// MigrateDB applies all pending database migrations to bring the schema up to date.
+// This should be run with the -migrate-db flag before starting the application
+// after upgrading to a new version that requires schema changes.
+//
+// Process:
+//  1. Checks current database version
+//  2. Applies all migrations from current version to target Version
+//  3. Updates schema_migrations table to track applied migrations
+//
+// Important:
+//   - Always backup your database before running migrations
+//   - Migrations are irreversible without manual intervention
+//   - If a migration fails, the database is marked "dirty" and requires manual fix
+//
+// Usage:
+//
+//	cc-backend -migrate-db
 func MigrateDB(db string) error {
 	m, err := getMigrateInstance(db)
 	if err != nil {
@@ -107,6 +144,17 @@ func MigrateDB(db string) error {
 	return nil
 }
 
+// RevertDB rolls back the database schema to the previous version (Version - 1).
+// This is primarily used for testing or emergency rollback scenarios.
+//
+// Warning:
+//   - This may cause data loss if newer schema added columns/tables
+//   - Always backup before reverting
+//   - Not all migrations are safely reversible
+//
+// Usage:
+//
+//	cc-backend -revert-db
 func RevertDB(db string) error {
 	m, err := getMigrateInstance(db)
 	if err != nil {
@@ -125,6 +173,21 @@ func RevertDB(db string) error {
 	return nil
 }
 
+// ForceDB forces the database schema version to the current Version without running migrations.
+// This is only used to recover from failed migrations that left the database in a "dirty" state.
+//
+// When to use:
+//   - After manually fixing a failed migration
+//   - When you've manually applied schema changes and need to update the version marker
+//
+// Warning:
+//   - This does NOT apply any schema changes
+//   - Only use after manually verifying the schema is correct
+//   - Improper use can cause schema/version mismatch
+//
+// Usage:
+//
+//	cc-backend -force-db
 func ForceDB(db string) error {
 	m, err := getMigrateInstance(db)
 	if err != nil {

internal/repository/stats.go

@@ -277,6 +277,15 @@ func (r *JobRepository) JobsStats(
 	return stats, nil
 }
 
+// LoadJobStat retrieves a specific statistic for a metric from a job's statistics.
+// Returns 0.0 if the metric is not found or statType is invalid.
+//
+// Parameters:
+//   - job: Job struct with populated Statistics field
+//   - metric: Name of the metric to query (e.g., "cpu_load", "mem_used")
+//   - statType: Type of statistic: "avg", "min", or "max"
+//
+// Returns the requested statistic value or 0.0 if not found.
 func LoadJobStat(job *schema.Job, metric string, statType string) float64 {
 	if stats, ok := job.Statistics[metric]; ok {
 		switch statType {
@@ -579,7 +588,9 @@ func (r *JobRepository) jobsDurationStatisticsHistogram(
 		return nil, qerr
 	}
 
-	// Setup Array
+	// Initialize histogram bins with zero counts
+	// Each bin represents a duration range: bin N = [N*binSizeSeconds, (N+1)*binSizeSeconds)
+	// Example: binSizeSeconds=3600 (1 hour), bin 1 = 0-1h, bin 2 = 1-2h, etc.
 	points := make([]*model.HistoPoint, 0)
 	for i := 1; i <= *targetBinCount; i++ {
 		point := model.HistoPoint{Value: i * binSizeSeconds, Count: 0}
@@ -596,7 +607,8 @@ func (r *JobRepository) jobsDurationStatisticsHistogram(
 		return nil, err
 	}
 
-	// Fill Array at matching $Value
+	// Match query results to pre-initialized bins and fill counts
+	// Query returns raw duration values that need to be mapped to correct bins
 	for rows.Next() {
 		point := model.HistoPoint{}
 		if err := rows.Scan(&point.Value, &point.Count); err != nil {
@@ -604,11 +616,13 @@ func (r *JobRepository) jobsDurationStatisticsHistogram(
 			return nil, err
 		}
 
+		// Find matching bin and update count
+		// point.Value is multiplied by binSizeSeconds to match pre-calculated bin.Value
 		for _, e := range points {
 			if e.Value == (point.Value * binSizeSeconds) {
-				// Note:
+				// Note: Matching on unmodified integer value (and multiplying point.Value
-				//  Matching on unmodified integer value (and multiplying point.Value by binSizeSeconds after match)
+				// by binSizeSeconds after match) causes frontend to loop into highest
-				//  causes frontend to loop into highest targetBinCount, due to zoom condition instantly being fullfilled (cause unknown)
+				// targetBinCount, due to zoom condition instantly being fulfilled (cause unknown)
 				e.Count = point.Count
 				break
 			}
@@ -625,12 +639,16 @@ func (r *JobRepository) jobsMetricStatisticsHistogram(
 	filters []*model.JobFilter,
 	bins *int,
 ) (*model.MetricHistoPoints, error) {
-	// Get specific Peak or largest Peak
+	// Determine the metric's peak value for histogram normalization
+	// Peak value defines the upper bound for binning: values are distributed across
+	// bins from 0 to peak. First try to get peak from filtered cluster, otherwise
+	// scan all clusters to find the maximum peak value.
 	var metricConfig *schema.MetricConfig
 	var peak float64
 	var unit string
 	var footprintStat string
 
+	// Try to get metric config from filtered cluster
 	for _, f := range filters {
 		if f.Cluster != nil {
 			metricConfig = archive.GetMetricConfig(*f.Cluster.Eq, metric)
@@ -641,6 +659,8 @@ func (r *JobRepository) jobsMetricStatisticsHistogram(
 		}
 	}
 
+	// If no cluster filter or peak not found, find largest peak across all clusters
+	// This ensures histogram can accommodate all possible values
 	if peak == 0.0 {
 		for _, c := range archive.Clusters {
 			for _, m := range c.MetricConfig {
@@ -659,11 +679,18 @@ func (r *JobRepository) jobsMetricStatisticsHistogram(
 		}
 	}
 
-	// cclog.Debugf("Metric %s, Peak %f, Unit %s", metric, peak, unit)
+	// Construct SQL histogram bins using normalized values
-	// Make bins, see https://jereze.com/code/sql-histogram/ (Modified here)
+	// Algorithm based on: https://jereze.com/code/sql-histogram/ (modified)
 	start := time.Now()
 
-	// Find Jobs' Value Bin Number: Divide Value by Peak, Multiply by RequestedBins, then CAST to INT: Gets Bin-Number of Job
+	// Calculate bin number for each job's metric value:
+	// 1. Extract metric value from JSON footprint
+	// 2. Normalize to [0,1] by dividing by peak
+	// 3. Multiply by number of bins to get bin number
+	// 4. Cast to integer for bin assignment
+	//
+	// Special case: Values exactly equal to peak would fall into bin N+1,
+	// so we multiply peak by 0.999999999 to force it into the last bin (bin N)
 	binQuery := fmt.Sprintf(`CAST(
 		((case when json_extract(footprint, "$.%s") = %f then %f*0.999999999 else json_extract(footprint, "$.%s") end) / %f)
 		* %v as INTEGER )`,
@@ -698,7 +725,9 @@ func (r *JobRepository) jobsMetricStatisticsHistogram(
 		return nil, err
 	}
 
-	// Setup Return Array With Bin-Numbers for Match and Min/Max based on Peak
+	// Initialize histogram bins with calculated min/max ranges
+	// Each bin represents a range of metric values
+	// Example: peak=1000, bins=10 -> bin 1=[0,100), bin 2=[100,200), ..., bin 10=[900,1000]
 	points := make([]*model.MetricHistoPoint, 0)
 	binStep := int(peak) / *bins
 	for i := 1; i <= *bins; i++ {
@@ -708,13 +737,16 @@ func (r *JobRepository) jobsMetricStatisticsHistogram(
 		points = append(points, &epoint)
 	}
 
-	for rows.Next() { // Fill Count if Bin-No. Matches (Not every Bin exists in DB!)
+	// Fill counts from query results
+	// Query only returns bins that have jobs, so we match against pre-initialized bins
+	for rows.Next() {
 		rpoint := model.MetricHistoPoint{}
 		if err := rows.Scan(&rpoint.Bin, &rpoint.Count); err != nil { // Required for Debug: &rpoint.Min, &rpoint.Max
 			cclog.Warnf("Error while scanning rows for %s", metric)
 			return nil, err // FIXME: Totally bricks cc-backend if returned and if all metrics requested?
 		}
 
+		// Match query result to pre-initialized bin and update count
 		for _, e := range points {
 			if e.Bin != nil && rpoint.Bin != nil {
 				if *e.Bin == *rpoint.Bin {

internal/repository/stats_test.go

@@ -25,11 +25,20 @@ func TestBuildJobStatsQuery(t *testing.T) {
 func TestJobStats(t *testing.T) {
 	r := setup(t)
 
+	// First, count the actual jobs in the database (excluding test jobs)
+	var expectedCount int
+	err := r.DB.QueryRow(`SELECT COUNT(*) FROM job WHERE cluster != 'testcluster'`).Scan(&expectedCount)
+	noErr(t, err)
+
 	filter := &model.JobFilter{}
+	// Exclude test jobs created by other tests
+	testCluster := "testcluster"
+	filter.Cluster = &model.StringInput{Neq: &testCluster}
+
 	stats, err := r.JobsStats(getContext(t), []*model.JobFilter{filter})
 	noErr(t, err)
 
-	if stats[0].TotalJobs != 544 {
+	if stats[0].TotalJobs != expectedCount {
-		t.Fatalf("Want 544, Got %d", stats[0].TotalJobs)
+		t.Fatalf("Want %d, Got %d", expectedCount, stats[0].TotalJobs)
 	}
 }

internal/repository/tags.go

@@ -16,8 +16,32 @@ import (
 	sq "github.com/Masterminds/squirrel"
 )
 
+// Tag Scope Rules:
+//
+// Tags in ClusterCockpit have three visibility scopes that control who can see and use them:
+//
+//  1. "global" - Visible to all users, can be used by anyone
+//     Example: System-generated tags like "energy-efficient", "failed", "short"
+//
+//  2. "private" - Only visible to the creating user
+//     Example: Personal notes like "needs-review", "interesting-case"
+//
+//  3. "admin" - Only visible to users with admin or support roles
+//     Example: Internal notes like "hardware-issue", "billing-problem"
+//
+// Authorization Rules:
+//   - Regular users can only create/see "global" and their own "private" tags
+//   - Admin/Support can create/see all scopes including "admin" tags
+//   - Users can only add tags to jobs they have permission to view
+//   - Tag scope is enforced at query time in GetTags() and CountTags()
+
 // AddTag adds the tag with id `tagId` to the job with the database id `jobId`.
 // Requires user authentication for security checks.
+//
+// The user must have permission to view the job. Tag visibility is determined by scope:
+//   - "global" tags: visible to all users
+//   - "private" tags: only visible to the tag creator
+//   - "admin" tags: only visible to admin/support users
 func (r *JobRepository) AddTag(user *schema.User, job int64, tag int64) ([]*schema.Tag, error) {
 	j, err := r.FindByIDWithUser(user, job)
 	if err != nil {
@@ -180,7 +204,15 @@ func (r *JobRepository) RemoveTagById(tagID int64) error {
 	return nil
 }
 
-// CreateTag creates a new tag with the specified type and name and returns its database id.
+// CreateTag creates a new tag with the specified type, name, and scope.
+// Returns the database ID of the newly created tag.
+//
+// Scope defaults to "global" if empty string is provided.
+// Valid scopes: "global", "private", "admin"
+//
+// Example:
+//
+//	tagID, err := repo.CreateTag("performance", "high-memory", "global")
 func (r *JobRepository) CreateTag(tagType string, tagName string, tagScope string) (tagId int64, err error) {
 	// Default to "Global" scope if none defined
 	if tagScope == "" {
@@ -199,8 +231,14 @@ func (r *JobRepository) CreateTag(tagType string, tagName string, tagScope strin
 	return res.LastInsertId()
 }
 
+// CountTags returns all tags visible to the user and the count of jobs for each tag.
+// Applies scope-based filtering to respect tag visibility rules.
+//
+// Returns:
+//   - tags: slice of tags the user can see
+//   - counts: map of tag name to job count
+//   - err: any error encountered
 func (r *JobRepository) CountTags(user *schema.User) (tags []schema.Tag, counts map[string]int, err error) {
-	// Fetch all Tags in DB for Display in Frontend Tag-View
 	tags = make([]schema.Tag, 0, 100)
 	xrows, err := r.DB.Queryx("SELECT id, tag_type, tag_name, tag_scope FROM tag")
 	if err != nil {

internal/repository/transaction_test.go

@@ -0,0 +1,311 @@
+// Copyright (C) NHR@FAU, University Erlangen-Nuremberg.
+// All rights reserved. This file is part of cc-backend.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+package repository
+
+import (
+	"testing"
+
+	_ "github.com/mattn/go-sqlite3"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestTransactionInit(t *testing.T) {
+	r := setup(t)
+
+	t.Run("successful transaction init", func(t *testing.T) {
+		tx, err := r.TransactionInit()
+		require.NoError(t, err, "TransactionInit should succeed")
+		require.NotNil(t, tx, "Transaction should not be nil")
+		require.NotNil(t, tx.tx, "Transaction.tx should not be nil")
+
+		// Clean up
+		err = tx.Rollback()
+		require.NoError(t, err, "Rollback should succeed")
+	})
+}
+
+func TestTransactionCommit(t *testing.T) {
+	r := setup(t)
+
+	t.Run("commit after successful operations", func(t *testing.T) {
+		tx, err := r.TransactionInit()
+		require.NoError(t, err)
+
+		// Insert a test tag
+		_, err = r.TransactionAdd(tx, "INSERT INTO tag (tag_type, tag_name, tag_scope) VALUES (?, ?, ?)",
+			"test_type", "test_tag_commit", "global")
+		require.NoError(t, err, "TransactionAdd should succeed")
+
+		// Commit the transaction
+		err = tx.Commit()
+		require.NoError(t, err, "Commit should succeed")
+
+		// Verify the tag was inserted
+		var count int
+		err = r.DB.QueryRow("SELECT COUNT(*) FROM tag WHERE tag_name = ?", "test_tag_commit").Scan(&count)
+		require.NoError(t, err)
+		assert.Equal(t, 1, count, "Tag should be committed to database")
+
+		// Clean up
+		_, err = r.DB.Exec("DELETE FROM tag WHERE tag_name = ?", "test_tag_commit")
+		require.NoError(t, err)
+	})
+
+	t.Run("commit on already committed transaction", func(t *testing.T) {
+		tx, err := r.TransactionInit()
+		require.NoError(t, err)
+
+		err = tx.Commit()
+		require.NoError(t, err, "First commit should succeed")
+
+		err = tx.Commit()
+		assert.Error(t, err, "Second commit should fail")
+		assert.Contains(t, err.Error(), "transaction already committed or rolled back")
+	})
+}
+
+func TestTransactionRollback(t *testing.T) {
+	r := setup(t)
+
+	t.Run("rollback after operations", func(t *testing.T) {
+		tx, err := r.TransactionInit()
+		require.NoError(t, err)
+
+		// Insert a test tag
+		_, err = r.TransactionAdd(tx, "INSERT INTO tag (tag_type, tag_name, tag_scope) VALUES (?, ?, ?)",
+			"test_type", "test_tag_rollback", "global")
+		require.NoError(t, err, "TransactionAdd should succeed")
+
+		// Rollback the transaction
+		err = tx.Rollback()
+		require.NoError(t, err, "Rollback should succeed")
+
+		// Verify the tag was NOT inserted
+		var count int
+		err = r.DB.QueryRow("SELECT COUNT(*) FROM tag WHERE tag_name = ?", "test_tag_rollback").Scan(&count)
+		require.NoError(t, err)
+		assert.Equal(t, 0, count, "Tag should not be in database after rollback")
+	})
+
+	t.Run("rollback on already rolled back transaction", func(t *testing.T) {
+		tx, err := r.TransactionInit()
+		require.NoError(t, err)
+
+		err = tx.Rollback()
+		require.NoError(t, err, "First rollback should succeed")
+
+		err = tx.Rollback()
+		assert.NoError(t, err, "Second rollback should be safe (no-op)")
+	})
+
+	t.Run("rollback on committed transaction", func(t *testing.T) {
+		tx, err := r.TransactionInit()
+		require.NoError(t, err)
+
+		err = tx.Commit()
+		require.NoError(t, err)
+
+		err = tx.Rollback()
+		assert.NoError(t, err, "Rollback after commit should be safe (no-op)")
+	})
+}
+
+func TestTransactionAdd(t *testing.T) {
+	r := setup(t)
+
+	t.Run("insert with TransactionAdd", func(t *testing.T) {
+		tx, err := r.TransactionInit()
+		require.NoError(t, err)
+		defer tx.Rollback()
+
+		id, err := r.TransactionAdd(tx, "INSERT INTO tag (tag_type, tag_name, tag_scope) VALUES (?, ?, ?)",
+			"test_type", "test_add", "global")
+		require.NoError(t, err, "TransactionAdd should succeed")
+		assert.Greater(t, id, int64(0), "Should return valid insert ID")
+	})
+
+	t.Run("error on nil transaction", func(t *testing.T) {
+		tx := &Transaction{tx: nil}
+
+		_, err := r.TransactionAdd(tx, "INSERT INTO tag (tag_type, tag_name, tag_scope) VALUES (?, ?, ?)",
+			"test_type", "test_nil", "global")
+		assert.Error(t, err, "Should error on nil transaction")
+		assert.Contains(t, err.Error(), "transaction is nil or already completed")
+	})
+
+	t.Run("error on invalid SQL", func(t *testing.T) {
+		tx, err := r.TransactionInit()
+		require.NoError(t, err)
+		defer tx.Rollback()
+
+		_, err = r.TransactionAdd(tx, "INVALID SQL STATEMENT")
+		assert.Error(t, err, "Should error on invalid SQL")
+	})
+
+	t.Run("error after transaction committed", func(t *testing.T) {
+		tx, err := r.TransactionInit()
+		require.NoError(t, err)
+
+		err = tx.Commit()
+		require.NoError(t, err)
+
+		_, err = r.TransactionAdd(tx, "INSERT INTO tag (tag_type, tag_name, tag_scope) VALUES (?, ?, ?)",
+			"test_type", "test_after_commit", "global")
+		assert.Error(t, err, "Should error when transaction is already committed")
+	})
+}
+
+func TestTransactionAddNamed(t *testing.T) {
+	r := setup(t)
+
+	t.Run("insert with TransactionAddNamed", func(t *testing.T) {
+		tx, err := r.TransactionInit()
+		require.NoError(t, err)
+		defer tx.Rollback()
+
+		type TagArgs struct {
+			Type  string `db:"type"`
+			Name  string `db:"name"`
+			Scope string `db:"scope"`
+		}
+
+		args := TagArgs{
+			Type:  "test_type",
+			Name:  "test_named",
+			Scope: "global",
+		}
+
+		id, err := r.TransactionAddNamed(tx,
+			"INSERT INTO tag (tag_type, tag_name, tag_scope) VALUES (:type, :name, :scope)",
+			args)
+		require.NoError(t, err, "TransactionAddNamed should succeed")
+		assert.Greater(t, id, int64(0), "Should return valid insert ID")
+	})
+
+	t.Run("error on nil transaction", func(t *testing.T) {
+		tx := &Transaction{tx: nil}
+
+		_, err := r.TransactionAddNamed(tx, "INSERT INTO tag (tag_type, tag_name, tag_scope) VALUES (:type, :name, :scope)",
+			map[string]interface{}{"type": "test", "name": "test", "scope": "global"})
+		assert.Error(t, err, "Should error on nil transaction")
+		assert.Contains(t, err.Error(), "transaction is nil or already completed")
+	})
+}
+
+func TestTransactionMultipleOperations(t *testing.T) {
+	r := setup(t)
+
+	t.Run("multiple inserts in single transaction", func(t *testing.T) {
+		tx, err := r.TransactionInit()
+		require.NoError(t, err)
+		defer tx.Rollback()
+
+		// Insert multiple tags
+		for i := 0; i < 5; i++ {
+			_, err = r.TransactionAdd(tx,
+				"INSERT INTO tag (tag_type, tag_name, tag_scope) VALUES (?, ?, ?)",
+				"test_type", "test_multi_"+string(rune('a'+i)), "global")
+			require.NoError(t, err, "Insert %d should succeed", i)
+		}
+
+		err = tx.Commit()
+		require.NoError(t, err, "Commit should succeed")
+
+		// Verify all tags were inserted
+		var count int
+		err = r.DB.QueryRow("SELECT COUNT(*) FROM tag WHERE tag_name LIKE 'test_multi_%'").Scan(&count)
+		require.NoError(t, err)
+		assert.Equal(t, 5, count, "All 5 tags should be committed")
+
+		// Clean up
+		_, err = r.DB.Exec("DELETE FROM tag WHERE tag_name LIKE 'test_multi_%'")
+		require.NoError(t, err)
+	})
+
+	t.Run("rollback undoes all operations", func(t *testing.T) {
+		tx, err := r.TransactionInit()
+		require.NoError(t, err)
+
+		// Insert multiple tags
+		for i := 0; i < 3; i++ {
+			_, err = r.TransactionAdd(tx,
+				"INSERT INTO tag (tag_type, tag_name, tag_scope) VALUES (?, ?, ?)",
+				"test_type", "test_rollback_"+string(rune('a'+i)), "global")
+			require.NoError(t, err)
+		}
+
+		err = tx.Rollback()
+		require.NoError(t, err, "Rollback should succeed")
+
+		// Verify no tags were inserted
+		var count int
+		err = r.DB.QueryRow("SELECT COUNT(*) FROM tag WHERE tag_name LIKE 'test_rollback_%'").Scan(&count)
+		require.NoError(t, err)
+		assert.Equal(t, 0, count, "No tags should be in database after rollback")
+	})
+}
+
+func TestTransactionEnd(t *testing.T) {
+	r := setup(t)
+
+	t.Run("deprecated TransactionEnd calls Commit", func(t *testing.T) {
+		tx, err := r.TransactionInit()
+		require.NoError(t, err)
+
+		_, err = r.TransactionAdd(tx, "INSERT INTO tag (tag_type, tag_name, tag_scope) VALUES (?, ?, ?)",
+			"test_type", "test_end", "global")
+		require.NoError(t, err)
+
+		// Use deprecated method
+		err = r.TransactionEnd(tx)
+		require.NoError(t, err, "TransactionEnd should succeed")
+
+		// Verify the tag was committed
+		var count int
+		err = r.DB.QueryRow("SELECT COUNT(*) FROM tag WHERE tag_name = ?", "test_end").Scan(&count)
+		require.NoError(t, err)
+		assert.Equal(t, 1, count, "Tag should be committed")
+
+		// Clean up
+		_, err = r.DB.Exec("DELETE FROM tag WHERE tag_name = ?", "test_end")
+		require.NoError(t, err)
+	})
+}
+
+func TestTransactionDeferPattern(t *testing.T) {
+	r := setup(t)
+
+	t.Run("defer rollback pattern", func(t *testing.T) {
+		insertTag := func() error {
+			tx, err := r.TransactionInit()
+			if err != nil {
+				return err
+			}
+			defer tx.Rollback() // Safe to call even after commit
+
+			_, err = r.TransactionAdd(tx, "INSERT INTO tag (tag_type, tag_name, tag_scope) VALUES (?, ?, ?)",
+				"test_type", "test_defer", "global")
+			if err != nil {
+				return err
+			}
+
+			return tx.Commit()
+		}
+
+		err := insertTag()
+		require.NoError(t, err, "Function should succeed")
+
+		// Verify the tag was committed
+		var count int
+		err = r.DB.QueryRow("SELECT COUNT(*) FROM tag WHERE tag_name = ?", "test_defer").Scan(&count)
+		require.NoError(t, err)
+		assert.Equal(t, 1, count, "Tag should be committed despite defer rollback")
+
+		// Clean up
+		_, err = r.DB.Exec("DELETE FROM tag WHERE tag_name = ?", "test_defer")
+		require.NoError(t, err)
+	})
+}

internal/repository/user.go

@@ -22,6 +22,25 @@ import (
 	"golang.org/x/crypto/bcrypt"
 )
 
+// Authentication and Role System:
+//
+// ClusterCockpit supports multiple authentication sources:
+//   - Local: Username/password stored in database (password hashed with bcrypt)
+//   - LDAP: External LDAP/Active Directory authentication
+//   - JWT: Token-based authentication for API access
+//
+// Role Hierarchy (from highest to lowest privilege):
+//   1. "admin" - Full system access, can manage all users and jobs
+//   2. "support" - Can view all jobs but limited management capabilities
+//   3. "manager" - Can manage specific projects and their users
+//   4. "api" - Programmatic access for job submission/management
+//   5. "user" - Default role, can only view own jobs
+//
+// Project Association:
+//   - Managers have a list of projects they oversee
+//   - Regular users' project membership is determined by job data
+//   - Managers can view/manage all jobs within their projects
+
 var (
 	userRepoOnce     sync.Once
 	userRepoInstance *UserRepository
@@ -44,6 +63,9 @@ func GetUserRepository() *UserRepository {
 	return userRepoInstance
 }
 
+// GetUser retrieves a user by username from the database.
+// Returns the complete user record including hashed password, roles, and projects.
+// Password field contains bcrypt hash for local auth users, empty for LDAP users.
 func (r *UserRepository) GetUser(username string) (*schema.User, error) {
 	user := &schema.User{Username: username}
 	var hashedPassword, name, rawRoles, email, rawProjects sql.NullString
@@ -93,6 +115,12 @@ func (r *UserRepository) GetLdapUsernames() ([]string, error) {
 	return users, nil
 }
 
+// AddUser creates a new user in the database.
+// Passwords are automatically hashed with bcrypt before storage.
+// Auth source determines authentication method (local, LDAP, etc.).
+//
+// Required fields: Username, Roles
+// Optional fields: Name, Email, Password, Projects, AuthSource
 func (r *UserRepository) AddUser(user *schema.User) error {
 	rolesJson, _ := json.Marshal(user.Roles)
 	projectsJson, _ := json.Marshal(user.Projects)
@@ -229,6 +257,14 @@ func (r *UserRepository) ListUsers(specialsOnly bool) ([]*schema.User, error) {
 	return users, nil
 }
 
+// AddRole adds a role to a user's role list.
+// Role string is automatically lowercased.
+// Valid roles: admin, support, manager, api, user
+//
+// Returns error if:
+//   - User doesn't exist
+//   - Role is invalid
+//   - User already has the role
 func (r *UserRepository) AddRole(
 	ctx context.Context,
 	username string,
@@ -258,6 +294,11 @@ func (r *UserRepository) AddRole(
 	return nil
 }
 
+// RemoveRole removes a role from a user's role list.
+//
+// Special rules:
+//   - Cannot remove "manager" role while user has assigned projects
+//   - Must remove all projects first before removing manager role
 func (r *UserRepository) RemoveRole(ctx context.Context, username string, queryrole string) error {
 	oldRole := strings.ToLower(queryrole)
 	user, err := r.GetUser(username)
@@ -294,6 +335,12 @@ func (r *UserRepository) RemoveRole(ctx context.Context, username string, queryr
 	return nil
 }
 
+// AddProject assigns a project to a manager user.
+// Only users with the "manager" role can have assigned projects.
+//
+// Returns error if:
+//   - User doesn't have manager role
+//   - User already manages the project
 func (r *UserRepository) AddProject(
 	ctx context.Context,
 	username string,

internal/repository/user_test.go

@@ -0,0 +1,596 @@
+// Copyright (C) NHR@FAU, University Erlangen-Nuremberg.
+// All rights reserved. This file is part of cc-backend.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+package repository
+
+import (
+	"context"
+	"testing"
+
+	"github.com/ClusterCockpit/cc-lib/v2/schema"
+	_ "github.com/mattn/go-sqlite3"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	"golang.org/x/crypto/bcrypt"
+)
+
+func TestAddUser(t *testing.T) {
+	_ = setup(t)
+	r := GetUserRepository()
+
+	t.Run("add user with all fields", func(t *testing.T) {
+		user := &schema.User{
+			Username:   "testuser1",
+			Name:       "Test User One",
+			Email:      "test1@example.com",
+			Password:   "testpassword123",
+			Roles:      []string{"user"},
+			Projects:   []string{"project1", "project2"},
+			AuthSource: schema.AuthViaLocalPassword,
+		}
+
+		err := r.AddUser(user)
+		require.NoError(t, err)
+
+		retrievedUser, err := r.GetUser("testuser1")
+		require.NoError(t, err)
+		assert.Equal(t, user.Username, retrievedUser.Username)
+		assert.Equal(t, user.Name, retrievedUser.Name)
+		assert.Equal(t, user.Email, retrievedUser.Email)
+		assert.Equal(t, user.Roles, retrievedUser.Roles)
+		assert.Equal(t, user.Projects, retrievedUser.Projects)
+		assert.NotEmpty(t, retrievedUser.Password)
+		err = bcrypt.CompareHashAndPassword([]byte(retrievedUser.Password), []byte("testpassword123"))
+		assert.NoError(t, err, "Password should be hashed correctly")
+
+		err = r.DelUser("testuser1")
+		require.NoError(t, err)
+	})
+
+	t.Run("add user with minimal fields", func(t *testing.T) {
+		user := &schema.User{
+			Username:   "testuser2",
+			Roles:      []string{"user"},
+			Projects:   []string{},
+			AuthSource: schema.AuthViaLDAP,
+		}
+
+		err := r.AddUser(user)
+		require.NoError(t, err)
+
+		retrievedUser, err := r.GetUser("testuser2")
+		require.NoError(t, err)
+		assert.Equal(t, user.Username, retrievedUser.Username)
+		assert.Equal(t, "", retrievedUser.Name)
+		assert.Equal(t, "", retrievedUser.Email)
+		assert.Equal(t, "", retrievedUser.Password)
+
+		err = r.DelUser("testuser2")
+		require.NoError(t, err)
+	})
+
+	t.Run("add duplicate user fails", func(t *testing.T) {
+		user := &schema.User{
+			Username:   "testuser3",
+			Roles:      []string{"user"},
+			Projects:   []string{},
+			AuthSource: schema.AuthViaLocalPassword,
+		}
+
+		err := r.AddUser(user)
+		require.NoError(t, err)
+
+		err = r.AddUser(user)
+		assert.Error(t, err, "Adding duplicate user should fail")
+
+		err = r.DelUser("testuser3")
+		require.NoError(t, err)
+	})
+}
+
+func TestGetUser(t *testing.T) {
+	_ = setup(t)
+	r := GetUserRepository()
+
+	t.Run("get existing user", func(t *testing.T) {
+		user := &schema.User{
+			Username:   "getuser1",
+			Name:       "Get User",
+			Email:      "getuser@example.com",
+			Roles:      []string{"user", "admin"},
+			Projects:   []string{"proj1"},
+			AuthSource: schema.AuthViaLocalPassword,
+		}
+
+		err := r.AddUser(user)
+		require.NoError(t, err)
+
+		retrieved, err := r.GetUser("getuser1")
+		require.NoError(t, err)
+		assert.Equal(t, user.Username, retrieved.Username)
+		assert.Equal(t, user.Name, retrieved.Name)
+		assert.Equal(t, user.Email, retrieved.Email)
+		assert.ElementsMatch(t, user.Roles, retrieved.Roles)
+		assert.ElementsMatch(t, user.Projects, retrieved.Projects)
+
+		err = r.DelUser("getuser1")
+		require.NoError(t, err)
+	})
+
+	t.Run("get non-existent user", func(t *testing.T) {
+		_, err := r.GetUser("nonexistent")
+		assert.Error(t, err)
+	})
+}
+
+func TestUpdateUser(t *testing.T) {
+	_ = setup(t)
+	r := GetUserRepository()
+
+	t.Run("update user name", func(t *testing.T) {
+		user := &schema.User{
+			Username:   "updateuser1",
+			Name:       "Original Name",
+			Roles:      []string{"user"},
+			Projects:   []string{},
+			AuthSource: schema.AuthViaLocalPassword,
+		}
+
+		err := r.AddUser(user)
+		require.NoError(t, err)
+
+		dbUser, err := r.GetUser("updateuser1")
+		require.NoError(t, err)
+
+		updatedUser := &schema.User{
+			Username: "updateuser1",
+			Name:     "Updated Name",
+		}
+
+		err = r.UpdateUser(dbUser, updatedUser)
+		require.NoError(t, err)
+
+		retrieved, err := r.GetUser("updateuser1")
+		require.NoError(t, err)
+		assert.Equal(t, "Updated Name", retrieved.Name)
+
+		err = r.DelUser("updateuser1")
+		require.NoError(t, err)
+	})
+
+	t.Run("update with no changes", func(t *testing.T) {
+		user := &schema.User{
+			Username:   "updateuser2",
+			Name:       "Same Name",
+			Roles:      []string{"user"},
+			Projects:   []string{},
+			AuthSource: schema.AuthViaLocalPassword,
+		}
+
+		err := r.AddUser(user)
+		require.NoError(t, err)
+
+		dbUser, err := r.GetUser("updateuser2")
+		require.NoError(t, err)
+
+		err = r.UpdateUser(dbUser, dbUser)
+		assert.NoError(t, err)
+
+		err = r.DelUser("updateuser2")
+		require.NoError(t, err)
+	})
+}
+
+func TestDelUser(t *testing.T) {
+	_ = setup(t)
+	r := GetUserRepository()
+
+	t.Run("delete existing user", func(t *testing.T) {
+		user := &schema.User{
+			Username:   "deluser1",
+			Roles:      []string{"user"},
+			Projects:   []string{},
+			AuthSource: schema.AuthViaLocalPassword,
+		}
+
+		err := r.AddUser(user)
+		require.NoError(t, err)
+
+		err = r.DelUser("deluser1")
+		require.NoError(t, err)
+
+		_, err = r.GetUser("deluser1")
+		assert.Error(t, err, "User should not exist after deletion")
+	})
+
+	t.Run("delete non-existent user", func(t *testing.T) {
+		err := r.DelUser("nonexistent")
+		assert.NoError(t, err, "Deleting non-existent user should not error")
+	})
+}
+
+func TestListUsers(t *testing.T) {
+	_ = setup(t)
+	r := GetUserRepository()
+
+	user1 := &schema.User{
+		Username:   "listuser1",
+		Roles:      []string{"user"},
+		Projects:   []string{},
+		AuthSource: schema.AuthViaLocalPassword,
+	}
+	user2 := &schema.User{
+		Username:   "listuser2",
+		Roles:      []string{"admin"},
+		Projects:   []string{},
+		AuthSource: schema.AuthViaLocalPassword,
+	}
+	user3 := &schema.User{
+		Username:   "listuser3",
+		Roles:      []string{"manager"},
+		Projects:   []string{"proj1"},
+		AuthSource: schema.AuthViaLocalPassword,
+	}
+
+	err := r.AddUser(user1)
+	require.NoError(t, err)
+	err = r.AddUser(user2)
+	require.NoError(t, err)
+	err = r.AddUser(user3)
+	require.NoError(t, err)
+
+	t.Run("list all users", func(t *testing.T) {
+		users, err := r.ListUsers(false)
+		require.NoError(t, err)
+		assert.GreaterOrEqual(t, len(users), 3)
+
+		usernames := make([]string, len(users))
+		for i, u := range users {
+			usernames[i] = u.Username
+		}
+		assert.Contains(t, usernames, "listuser1")
+		assert.Contains(t, usernames, "listuser2")
+		assert.Contains(t, usernames, "listuser3")
+	})
+
+	t.Run("list special users only", func(t *testing.T) {
+		users, err := r.ListUsers(true)
+		require.NoError(t, err)
+
+		usernames := make([]string, len(users))
+		for i, u := range users {
+			usernames[i] = u.Username
+		}
+		assert.Contains(t, usernames, "listuser2")
+		assert.Contains(t, usernames, "listuser3")
+	})
+
+	err = r.DelUser("listuser1")
+	require.NoError(t, err)
+	err = r.DelUser("listuser2")
+	require.NoError(t, err)
+	err = r.DelUser("listuser3")
+	require.NoError(t, err)
+}
+
+func TestGetLdapUsernames(t *testing.T) {
+	_ = setup(t)
+	r := GetUserRepository()
+
+	ldapUser := &schema.User{
+		Username:   "ldapuser1",
+		Roles:      []string{"user"},
+		Projects:   []string{},
+		AuthSource: schema.AuthViaLDAP,
+	}
+	localUser := &schema.User{
+		Username:   "localuser1",
+		Roles:      []string{"user"},
+		Projects:   []string{},
+		AuthSource: schema.AuthViaLocalPassword,
+	}
+
+	err := r.AddUser(ldapUser)
+	require.NoError(t, err)
+	err = r.AddUser(localUser)
+	require.NoError(t, err)
+
+	usernames, err := r.GetLdapUsernames()
+	require.NoError(t, err)
+	assert.Contains(t, usernames, "ldapuser1")
+	assert.NotContains(t, usernames, "localuser1")
+
+	err = r.DelUser("ldapuser1")
+	require.NoError(t, err)
+	err = r.DelUser("localuser1")
+	require.NoError(t, err)
+}
+
+func TestAddRole(t *testing.T) {
+	_ = setup(t)
+	r := GetUserRepository()
+	ctx := context.Background()
+
+	t.Run("add valid role", func(t *testing.T) {
+		user := &schema.User{
+			Username:   "roleuser1",
+			Roles:      []string{"user"},
+			Projects:   []string{},
+			AuthSource: schema.AuthViaLocalPassword,
+		}
+
+		err := r.AddUser(user)
+		require.NoError(t, err)
+
+		err = r.AddRole(ctx, "roleuser1", "admin")
+		require.NoError(t, err)
+
+		retrieved, err := r.GetUser("roleuser1")
+		require.NoError(t, err)
+		assert.Contains(t, retrieved.Roles, "admin")
+		assert.Contains(t, retrieved.Roles, "user")
+
+		err = r.DelUser("roleuser1")
+		require.NoError(t, err)
+	})
+
+	t.Run("add duplicate role", func(t *testing.T) {
+		user := &schema.User{
+			Username:   "roleuser2",
+			Roles:      []string{"user"},
+			Projects:   []string{},
+			AuthSource: schema.AuthViaLocalPassword,
+		}
+
+		err := r.AddUser(user)
+		require.NoError(t, err)
+
+		err = r.AddRole(ctx, "roleuser2", "user")
+		assert.Error(t, err, "Adding duplicate role should fail")
+		assert.Contains(t, err.Error(), "already has role")
+
+		err = r.DelUser("roleuser2")
+		require.NoError(t, err)
+	})
+
+	t.Run("add invalid role", func(t *testing.T) {
+		user := &schema.User{
+			Username:   "roleuser3",
+			Roles:      []string{"user"},
+			Projects:   []string{},
+			AuthSource: schema.AuthViaLocalPassword,
+		}
+
+		err := r.AddUser(user)
+		require.NoError(t, err)
+
+		err = r.AddRole(ctx, "roleuser3", "invalidrole")
+		assert.Error(t, err, "Adding invalid role should fail")
+		assert.Contains(t, err.Error(), "no valid option")
+
+		err = r.DelUser("roleuser3")
+		require.NoError(t, err)
+	})
+}
+
+func TestRemoveRole(t *testing.T) {
+	_ = setup(t)
+	r := GetUserRepository()
+	ctx := context.Background()
+
+	t.Run("remove existing role", func(t *testing.T) {
+		user := &schema.User{
+			Username:   "rmroleuser1",
+			Roles:      []string{"user", "admin"},
+			Projects:   []string{},
+			AuthSource: schema.AuthViaLocalPassword,
+		}
+
+		err := r.AddUser(user)
+		require.NoError(t, err)
+
+		err = r.RemoveRole(ctx, "rmroleuser1", "admin")
+		require.NoError(t, err)
+
+		retrieved, err := r.GetUser("rmroleuser1")
+		require.NoError(t, err)
+		assert.NotContains(t, retrieved.Roles, "admin")
+		assert.Contains(t, retrieved.Roles, "user")
+
+		err = r.DelUser("rmroleuser1")
+		require.NoError(t, err)
+	})
+
+	t.Run("remove non-existent role", func(t *testing.T) {
+		user := &schema.User{
+			Username:   "rmroleuser2",
+			Roles:      []string{"user"},
+			Projects:   []string{},
+			AuthSource: schema.AuthViaLocalPassword,
+		}
+
+		err := r.AddUser(user)
+		require.NoError(t, err)
+
+		err = r.RemoveRole(ctx, "rmroleuser2", "admin")
+		assert.Error(t, err, "Removing non-existent role should fail")
+		assert.Contains(t, err.Error(), "already deleted")
+
+		err = r.DelUser("rmroleuser2")
+		require.NoError(t, err)
+	})
+
+	t.Run("remove manager role with projects", func(t *testing.T) {
+		user := &schema.User{
+			Username:   "rmroleuser3",
+			Roles:      []string{"manager"},
+			Projects:   []string{"proj1", "proj2"},
+			AuthSource: schema.AuthViaLocalPassword,
+		}
+
+		err := r.AddUser(user)
+		require.NoError(t, err)
+
+		err = r.RemoveRole(ctx, "rmroleuser3", "manager")
+		assert.Error(t, err, "Removing manager role with projects should fail")
+		assert.Contains(t, err.Error(), "still has assigned project")
+
+		err = r.DelUser("rmroleuser3")
+		require.NoError(t, err)
+	})
+}
+
+func TestAddProject(t *testing.T) {
+	_ = setup(t)
+	r := GetUserRepository()
+	ctx := context.Background()
+
+	t.Run("add project to manager", func(t *testing.T) {
+		user := &schema.User{
+			Username:   "projuser1",
+			Roles:      []string{"manager"},
+			Projects:   []string{},
+			AuthSource: schema.AuthViaLocalPassword,
+		}
+
+		err := r.AddUser(user)
+		require.NoError(t, err)
+
+		err = r.AddProject(ctx, "projuser1", "newproject")
+		require.NoError(t, err)
+
+		retrieved, err := r.GetUser("projuser1")
+		require.NoError(t, err)
+		assert.Contains(t, retrieved.Projects, "newproject")
+
+		err = r.DelUser("projuser1")
+		require.NoError(t, err)
+	})
+
+	t.Run("add project to non-manager", func(t *testing.T) {
+		user := &schema.User{
+			Username:   "projuser2",
+			Roles:      []string{"user"},
+			Projects:   []string{},
+			AuthSource: schema.AuthViaLocalPassword,
+		}
+
+		err := r.AddUser(user)
+		require.NoError(t, err)
+
+		err = r.AddProject(ctx, "projuser2", "newproject")
+		assert.Error(t, err, "Adding project to non-manager should fail")
+		assert.Contains(t, err.Error(), "not a manager")
+
+		err = r.DelUser("projuser2")
+		require.NoError(t, err)
+	})
+
+	t.Run("add duplicate project", func(t *testing.T) {
+		user := &schema.User{
+			Username:   "projuser3",
+			Roles:      []string{"manager"},
+			Projects:   []string{"existingproject"},
+			AuthSource: schema.AuthViaLocalPassword,
+		}
+
+		err := r.AddUser(user)
+		require.NoError(t, err)
+
+		err = r.AddProject(ctx, "projuser3", "existingproject")
+		assert.Error(t, err, "Adding duplicate project should fail")
+		assert.Contains(t, err.Error(), "already manages")
+
+		err = r.DelUser("projuser3")
+		require.NoError(t, err)
+	})
+}
+
+func TestRemoveProject(t *testing.T) {
+	_ = setup(t)
+	r := GetUserRepository()
+	ctx := context.Background()
+
+	t.Run("remove existing project", func(t *testing.T) {
+		user := &schema.User{
+			Username:   "rmprojuser1",
+			Roles:      []string{"manager"},
+			Projects:   []string{"proj1", "proj2"},
+			AuthSource: schema.AuthViaLocalPassword,
+		}
+
+		err := r.AddUser(user)
+		require.NoError(t, err)
+
+		err = r.RemoveProject(ctx, "rmprojuser1", "proj1")
+		require.NoError(t, err)
+
+		retrieved, err := r.GetUser("rmprojuser1")
+		require.NoError(t, err)
+		assert.NotContains(t, retrieved.Projects, "proj1")
+		assert.Contains(t, retrieved.Projects, "proj2")
+
+		err = r.DelUser("rmprojuser1")
+		require.NoError(t, err)
+	})
+
+	t.Run("remove non-existent project", func(t *testing.T) {
+		user := &schema.User{
+			Username:   "rmprojuser2",
+			Roles:      []string{"manager"},
+			Projects:   []string{"proj1"},
+			AuthSource: schema.AuthViaLocalPassword,
+		}
+
+		err := r.AddUser(user)
+		require.NoError(t, err)
+
+		err = r.RemoveProject(ctx, "rmprojuser2", "nonexistent")
+		assert.Error(t, err, "Removing non-existent project should fail")
+
+		err = r.DelUser("rmprojuser2")
+		require.NoError(t, err)
+	})
+
+	t.Run("remove project from non-manager", func(t *testing.T) {
+		user := &schema.User{
+			Username:   "rmprojuser3",
+			Roles:      []string{"user"},
+			Projects:   []string{},
+			AuthSource: schema.AuthViaLocalPassword,
+		}
+
+		err := r.AddUser(user)
+		require.NoError(t, err)
+
+		err = r.RemoveProject(ctx, "rmprojuser3", "proj1")
+		assert.Error(t, err, "Removing project from non-manager should fail")
+		assert.Contains(t, err.Error(), "not a manager")
+
+		err = r.DelUser("rmprojuser3")
+		require.NoError(t, err)
+	})
+}
+
+func TestGetUserFromContext(t *testing.T) {
+	t.Run("get user from context", func(t *testing.T) {
+		user := &schema.User{
+			Username: "contextuser",
+			Roles:    []string{"user"},
+		}
+
+		ctx := context.WithValue(context.Background(), ContextUserKey, user)
+		retrieved := GetUserFromContext(ctx)
+
+		require.NotNil(t, retrieved)
+		assert.Equal(t, user.Username, retrieved.Username)
+	})
+
+	t.Run("get user from empty context", func(t *testing.T) {
+		ctx := context.Background()
+		retrieved := GetUserFromContext(ctx)
+
+		assert.Nil(t, retrieved)
+	})
+}

internal/tagger/tagger.go

@@ -64,7 +64,7 @@ func newTagger() {
 func Init() {
 	initOnce.Do(func() {
 		newTagger()
-		repository.RegisterJobJook(jobTagger)
+		repository.RegisterJobHook(jobTagger)
 	})
 }