prometheus/web/api/query.go
Julius Volz 51689d965d Add debug timers to instant and range queries.
This adds timers around several query-relevant code blocks. For now, the
query timer stats are only logged for queries initiated through the UI.
In other cases (rule evaluations), the stats are simply thrown away.

My hope is that this helps us understand where queries spend time,
especially in cases where they sometimes hang for unusual amounts of
time.
2013-06-05 18:32:54 +02:00

135 lines
3.7 KiB
Go

// Copyright 2013 Prometheus Team
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package api
import (
"code.google.com/p/gorest"
"encoding/json"
"errors"
"github.com/prometheus/prometheus/model"
"github.com/prometheus/prometheus/rules"
"github.com/prometheus/prometheus/rules/ast"
"github.com/prometheus/prometheus/stats"
"log"
"net/http"
"sort"
"time"
)
func (serv MetricsService) setAccessControlHeaders(rb *gorest.ResponseBuilder) {
rb.AddHeader("Access-Control-Allow-Headers", "Accept, Authorization, Content-Type, Origin")
rb.AddHeader("Access-Control-Allow-Methods", "GET")
rb.AddHeader("Access-Control-Allow-Origin", "*")
rb.AddHeader("Access-Control-Expose-Headers", "Date")
}
func (serv MetricsService) Query(expr string, formatJson string) string {
exprNode, err := rules.LoadExprFromString(expr)
if err != nil {
return ast.ErrorToJSON(err)
}
timestamp := serv.time.Now()
rb := serv.ResponseBuilder()
serv.setAccessControlHeaders(rb)
var format ast.OutputFormat
if formatJson != "" {
format = ast.JSON
rb.SetContentType(gorest.Application_Json)
} else {
format = ast.TEXT
rb.SetContentType(gorest.Text_Plain)
}
queryStats := stats.NewTimerGroup()
result := ast.EvalToString(exprNode, timestamp, format, serv.Storage, queryStats)
log.Printf("Instant query: %s\nQuery stats:\n%s\n", expr, queryStats)
return result
}
func (serv MetricsService) QueryRange(expr string, end int64, duration int64, step int64) string {
exprNode, err := rules.LoadExprFromString(expr)
if err != nil {
return ast.ErrorToJSON(err)
}
if exprNode.Type() != ast.VECTOR {
return ast.ErrorToJSON(errors.New("Expression does not evaluate to vector type"))
}
rb := serv.ResponseBuilder()
serv.setAccessControlHeaders(rb)
rb.SetContentType(gorest.Application_Json)
if end == 0 {
end = serv.time.Now().Unix()
}
if step < 1 {
step = 1
}
if end-duration < 0 {
duration = end
}
// Align the start to step "tick" boundary.
end -= end % step
queryStats := stats.NewTimerGroup()
evalTimer := queryStats.GetTimer(stats.TotalEvalTime).Start()
matrix, err := ast.EvalVectorRange(
exprNode.(ast.VectorNode),
time.Unix(end-duration, 0).UTC(),
time.Unix(end, 0).UTC(),
time.Duration(step)*time.Second,
serv.Storage,
queryStats)
if err != nil {
return ast.ErrorToJSON(err)
}
evalTimer.Stop()
sortTimer := queryStats.GetTimer(stats.ResultSortTime).Start()
sort.Sort(matrix)
sortTimer.Stop()
jsonTimer := queryStats.GetTimer(stats.JsonEncodeTime).Start()
result := ast.TypedValueToJSON(matrix, "matrix")
jsonTimer.Stop()
log.Printf("Range query: %s\nQuery stats:\n%s\n", expr, queryStats)
return result
}
func (serv MetricsService) Metrics() string {
metricNames, err := serv.Storage.GetAllValuesForLabel(model.MetricNameLabel)
rb := serv.ResponseBuilder()
serv.setAccessControlHeaders(rb)
rb.SetContentType(gorest.Application_Json)
if err != nil {
log.Printf("Error loading metric names: %v", err)
rb.SetResponseCode(http.StatusInternalServerError)
return err.Error()
}
sort.Sort(metricNames)
resultBytes, err := json.Marshal(metricNames)
if err != nil {
log.Printf("Error marshalling metric names: %v", err)
rb.SetResponseCode(http.StatusInternalServerError)
return err.Error()
}
return string(resultBytes)
}