Files
cc-backend/internal/metricstore/api.go
2026-01-16 08:27:46 +01:00

306 lines
9.9 KiB
Go

// 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.
// This file contains the API types and data fetching logic for querying metric data
// from the in-memory metric store. It provides structures for building complex queries
// with support for aggregation, scaling, padding, and statistics computation.
package metricstore
import (
"errors"
"fmt"
"math"
"github.com/ClusterCockpit/cc-lib/v2/schema"
"github.com/ClusterCockpit/cc-lib/v2/util"
)
var (
// ErrInvalidTimeRange is returned when a query has 'from' >= 'to'
ErrInvalidTimeRange = errors.New("[METRICSTORE]> invalid time range: 'from' must be before 'to'")
// ErrEmptyCluster is returned when a query with ForAllNodes has no cluster specified
ErrEmptyCluster = errors.New("[METRICSTORE]> cluster name cannot be empty")
)
// APIMetricData represents the response data for a single metric query.
//
// It contains both the time-series data points and computed statistics (avg, min, max).
// If an error occurred during data retrieval, the Error field will be set and other
// fields may be incomplete.
type APIMetricData struct {
Error *string `json:"error,omitempty"`
Data schema.FloatArray `json:"data,omitempty"`
From int64 `json:"from"`
To int64 `json:"to"`
Resolution int64 `json:"resolution"`
Avg schema.Float `json:"avg"`
Min schema.Float `json:"min"`
Max schema.Float `json:"max"`
}
// APIQueryRequest represents a batch query request for metric data.
//
// It supports two modes of operation:
// 1. Explicit queries via the Queries field
// 2. Automatic query generation via ForAllNodes (queries all specified metrics for all nodes in the cluster)
//
// The request can be customized with flags to include/exclude statistics, raw data, and padding.
type APIQueryRequest struct {
Cluster string `json:"cluster"`
Queries []APIQuery `json:"queries"`
ForAllNodes []string `json:"for-all-nodes"`
From int64 `json:"from"`
To int64 `json:"to"`
WithStats bool `json:"with-stats"`
WithData bool `json:"with-data"`
WithPadding bool `json:"with-padding"`
}
// APIQueryResponse represents the response to an APIQueryRequest.
//
// Results is a 2D array where each outer element corresponds to a query,
// and each inner element corresponds to a selector within that query
// (e.g., multiple CPUs or cores).
type APIQueryResponse struct {
Queries []APIQuery `json:"queries,omitempty"`
Results [][]APIMetricData `json:"results"`
}
// APIQuery represents a single metric query with optional hierarchical selectors.
//
// The hierarchical selection works as follows:
// - Hostname: The node to query
// - Type + TypeIds: First level of hierarchy (e.g., "cpu" + ["0", "1", "2"])
// - SubType + SubTypeIds: Second level of hierarchy (e.g., "core" + ["0", "1"])
//
// If Aggregate is true, data from multiple type/subtype IDs will be aggregated according
// to the metric's aggregation strategy. Otherwise, separate results are returned for each combination.
type APIQuery struct {
Type *string `json:"type,omitempty"`
SubType *string `json:"subtype,omitempty"`
Metric string `json:"metric"`
Hostname string `json:"host"`
Resolution int64 `json:"resolution"`
TypeIds []string `json:"type-ids,omitempty"`
SubTypeIds []string `json:"subtype-ids,omitempty"`
ScaleFactor schema.Float `json:"scale-by,omitempty"`
Aggregate bool `json:"aggreg"`
}
// AddStats computes and populates the Avg, Min, and Max fields from the Data array.
//
// NaN values in the data are ignored during computation. If all values are NaN,
// the statistics fields will be set to NaN.
//
// TODO: Optimize this, just like the stats endpoint!
func (data *APIMetricData) AddStats() {
n := 0
sum, min, max := 0.0, math.MaxFloat64, -math.MaxFloat64
for _, x := range data.Data {
if x.IsNaN() {
continue
}
n += 1
sum += float64(x)
min = math.Min(min, float64(x))
max = math.Max(max, float64(x))
}
if n > 0 {
avg := sum / float64(n)
data.Avg = schema.Float(avg)
data.Min = schema.Float(min)
data.Max = schema.Float(max)
} else {
data.Avg, data.Min, data.Max = schema.NaN, schema.NaN, schema.NaN
}
}
// ScaleBy multiplies all data points and statistics by the given factor.
//
// This is commonly used for unit conversion (e.g., bytes to gigabytes).
// Scaling by 0 or 1 is a no-op for performance reasons.
func (data *APIMetricData) ScaleBy(f schema.Float) {
if f == 0 || f == 1 {
return
}
data.Avg *= f
data.Min *= f
data.Max *= f
for i := 0; i < len(data.Data); i++ {
data.Data[i] *= f
}
}
// PadDataWithNull pads the beginning of the data array with NaN values if needed.
//
// This ensures that the data aligns with the requested 'from' timestamp, even if
// the metric store doesn't have data for the earliest time points. This is useful
// for maintaining consistent array indexing across multiple queries.
//
// Parameters:
// - ms: MemoryStore instance to lookup metric configuration
// - from: The requested start timestamp
// - to: The requested end timestamp (unused but kept for API consistency)
// - metric: The metric name to lookup frequency information
func (data *APIMetricData) PadDataWithNull(ms *MemoryStore, from, to int64, metric string) {
minfo, ok := ms.Metrics[metric]
if !ok {
return
}
if (data.From / minfo.Frequency) > (from / minfo.Frequency) {
padfront := int((data.From / minfo.Frequency) - (from / minfo.Frequency))
ndata := make([]schema.Float, 0, padfront+len(data.Data))
for range padfront {
ndata = append(ndata, schema.NaN)
}
for j := 0; j < len(data.Data); j++ {
ndata = append(ndata, data.Data[j])
}
data.Data = ndata
}
}
// FetchData executes a batch metric query request and returns the results.
//
// This is the primary API for retrieving metric data from the memory store. It supports:
// - Individual queries via req.Queries
// - Batch queries for all nodes via req.ForAllNodes
// - Hierarchical selector construction (cluster → host → type → subtype)
// - Optional statistics computation (avg, min, max)
// - Optional data scaling
// - Optional data padding with NaN values
//
// The function constructs selectors based on the query parameters and calls MemoryStore.Read()
// for each selector. If a query specifies Aggregate=false with multiple type/subtype IDs,
// separate results are returned for each combination.
//
// Parameters:
// - req: The query request containing queries, time range, and options
//
// Returns:
// - APIQueryResponse containing results for each query, or error if validation fails
//
// Errors:
// - ErrInvalidTimeRange if req.From > req.To
// - ErrEmptyCluster if req.ForAllNodes is used without specifying a cluster
// - Error if MemoryStore is not initialized
// - Individual query errors are stored in APIMetricData.Error field
func FetchData(req APIQueryRequest) (*APIQueryResponse, error) {
if req.From > req.To {
return nil, ErrInvalidTimeRange
}
if req.Cluster == "" && req.ForAllNodes != nil {
return nil, ErrEmptyCluster
}
req.WithData = true
ms := GetMemoryStore()
if ms == nil {
return nil, fmt.Errorf("[METRICSTORE]> memorystore not initialized")
}
response := APIQueryResponse{
Results: make([][]APIMetricData, 0, len(req.Queries)),
}
if req.ForAllNodes != nil {
nodes := ms.ListChildren([]string{req.Cluster})
for _, node := range nodes {
for _, metric := range req.ForAllNodes {
q := APIQuery{
Metric: metric,
Hostname: node,
}
req.Queries = append(req.Queries, q)
response.Queries = append(response.Queries, q)
}
}
}
for _, query := range req.Queries {
sels := make([]util.Selector, 0, 1)
if query.Aggregate || query.Type == nil {
sel := util.Selector{{String: req.Cluster}, {String: query.Hostname}}
if query.Type != nil {
if len(query.TypeIds) == 1 {
sel = append(sel, util.SelectorElement{String: *query.Type + query.TypeIds[0]})
} else {
ids := make([]string, len(query.TypeIds))
for i, id := range query.TypeIds {
ids[i] = *query.Type + id
}
sel = append(sel, util.SelectorElement{Group: ids})
}
if query.SubType != nil {
if len(query.SubTypeIds) == 1 {
sel = append(sel, util.SelectorElement{String: *query.SubType + query.SubTypeIds[0]})
} else {
ids := make([]string, len(query.SubTypeIds))
for i, id := range query.SubTypeIds {
ids[i] = *query.SubType + id
}
sel = append(sel, util.SelectorElement{Group: ids})
}
}
}
sels = append(sels, sel)
} else {
for _, typeID := range query.TypeIds {
if query.SubType != nil {
for _, subTypeID := range query.SubTypeIds {
sels = append(sels, util.Selector{
{String: req.Cluster},
{String: query.Hostname},
{String: *query.Type + typeID},
{String: *query.SubType + subTypeID},
})
}
} else {
sels = append(sels, util.Selector{
{String: req.Cluster},
{String: query.Hostname},
{String: *query.Type + typeID},
})
}
}
}
var err error
res := make([]APIMetricData, 0, len(sels))
for _, sel := range sels {
data := APIMetricData{}
data.Data, data.From, data.To, data.Resolution, err = ms.Read(sel, query.Metric, req.From, req.To, query.Resolution)
if err != nil {
msg := err.Error()
data.Error = &msg
res = append(res, data)
continue
}
if req.WithStats {
data.AddStats()
}
if query.ScaleFactor != 0 {
data.ScaleBy(query.ScaleFactor)
}
if req.WithPadding {
data.PadDataWithNull(ms, req.From, req.To, query.Metric)
}
if !req.WithData {
data.Data = nil
}
res = append(res, data)
}
response.Results = append(response.Results, res)
}
return &response, nil
}