Refactor package structure

Builds but not tested

internal/repository/user.go

@@ -0,0 +1,140 @@
+// Copyright (C) 2022 NHR@FAU, University Erlangen-Nuremberg.
+// All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+package repository
+
+import (
+	"context"
+	"encoding/json"
+	"log"
+	"net/http"
+	"sync"
+	"time"
+
+	"github.com/ClusterCockpit/cc-backend/internal/auth"
+	"github.com/ClusterCockpit/cc-backend/pkg/lrucache"
+	"github.com/jmoiron/sqlx"
+)
+
+var (
+	userCfgRepoOnce     sync.Once
+	userCfgRepoInstance *UserCfgRepo
+)
+
+type UserCfgRepo struct {
+	DB         *sqlx.DB
+	Lookup     *sqlx.Stmt
+	lock       sync.RWMutex
+	uiDefaults map[string]interface{}
+	cache      *lrucache.Cache
+}
+
+func GetUserCfgRepo() *UserCfgRepo {
+	userCfgRepoOnce.Do(func() {
+		db := GetConnection()
+
+		_, err := db.DB.Exec(`
+		CREATE TABLE IF NOT EXISTS configuration (
+			username varchar(255),
+			confkey  varchar(255),
+			value    varchar(255),
+			PRIMARY KEY (username, confkey),
+			FOREIGN KEY (username) REFERENCES user (username) ON DELETE CASCADE ON UPDATE NO ACTION);`)
+
+		if err != nil {
+			log.Fatal(err)
+		}
+
+		lookupConfigStmt, err := db.DB.Preparex(`SELECT confkey, value FROM configuration WHERE configuration.username = ?`)
+		if err != nil {
+			log.Fatal(err)
+		}
+
+		userCfgRepoInstance = &UserCfgRepo{
+			DB:     db.DB,
+			Lookup: lookupConfigStmt,
+			cache:  lrucache.New(1024),
+		}
+	})
+
+	return userCfgRepoInstance
+}
+
+// Return the personalised UI config for the currently authenticated
+// user or return the plain default config.
+func (uCfg *UserCfgRepo) GetUIConfig(r *http.Request) (map[string]interface{}, error) {
+	user := auth.GetUser(r.Context())
+	if user == nil {
+		uCfg.lock.RLock()
+		copy := make(map[string]interface{}, len(uCfg.uiDefaults))
+		for k, v := range uCfg.uiDefaults {
+			copy[k] = v
+		}
+		uCfg.lock.RUnlock()
+		return copy, nil
+	}
+
+	data := uCfg.cache.Get(user.Username, func() (interface{}, time.Duration, int) {
+		config := make(map[string]interface{}, len(uCfg.uiDefaults))
+		for k, v := range uCfg.uiDefaults {
+			config[k] = v
+		}
+
+		rows, err := uCfg.Lookup.Query(user.Username)
+		if err != nil {
+			return err, 0, 0
+		}
+
+		size := 0
+		defer rows.Close()
+		for rows.Next() {
+			var key, rawval string
+			if err := rows.Scan(&key, &rawval); err != nil {
+				return err, 0, 0
+			}
+
+			var val interface{}
+			if err := json.Unmarshal([]byte(rawval), &val); err != nil {
+				return err, 0, 0
+			}
+
+			size += len(key)
+			size += len(rawval)
+			config[key] = val
+		}
+
+		return config, 24 * time.Hour, size
+	})
+	if err, ok := data.(error); ok {
+		return nil, err
+	}
+
+	return data.(map[string]interface{}), nil
+}
+
+// If the context does not have a user, update the global ui configuration
+// without persisting it!  If there is a (authenticated) user, update only his
+// configuration.
+func (uCfg *UserCfgRepo) UpdateConfig(key, value string, ctx context.Context) error {
+	user := auth.GetUser(ctx)
+	if user == nil {
+		var val interface{}
+		if err := json.Unmarshal([]byte(value), &val); err != nil {
+			return err
+		}
+
+		uCfg.lock.Lock()
+		defer uCfg.lock.Unlock()
+		uCfg.uiDefaults[key] = val
+		return nil
+	}
+
+	if _, err := uCfg.DB.Exec(`REPLACE INTO configuration (username, confkey, value) VALUES (?, ?, ?)`,
+		user, key, value); err != nil {
+		return err
+	}
+
+	uCfg.cache.Del(user.Username)
+	return nil
+}