prometheus/web/api/query.go
Julius Volz cc27fb8aab Rename remaining all-caps constants in AST layer.
Change-Id: Ibe97e30981969056ffcdb89e63c1468ea1ffa140
2014-12-25 01:30:47 +01:00

167 lines
4.9 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 (
"encoding/json"
"errors"
"fmt"
"net/http"
"sort"
"strconv"
"time"
"github.com/golang/glog"
clientmodel "github.com/prometheus/client_golang/model"
"github.com/prometheus/prometheus/rules"
"github.com/prometheus/prometheus/rules/ast"
"github.com/prometheus/prometheus/stats"
"github.com/prometheus/prometheus/web/httputils"
)
// Enables cross-site script calls.
func setAccessControlHeaders(w http.ResponseWriter) {
w.Header().Set("Access-Control-Allow-Headers", "Accept, Authorization, Content-Type, Origin")
w.Header().Set("Access-Control-Allow-Methods", "GET")
w.Header().Set("Access-Control-Allow-Origin", "*")
w.Header().Set("Access-Control-Expose-Headers", "Date")
}
// Query handles the /api/query endpoint.
func (serv MetricsService) Query(w http.ResponseWriter, r *http.Request) {
setAccessControlHeaders(w)
params := httputils.GetQueryParams(r)
expr := params.Get("expr")
asText := params.Get("asText")
var format ast.OutputFormat
// BUG(julius): Use Content-Type negotiation.
if asText == "" {
format = ast.JSON
w.Header().Set("Content-Type", "application/json")
} else {
format = ast.Text
w.Header().Set("Content-Type", "text/plain")
}
exprNode, err := rules.LoadExprFromString(expr)
if err != nil {
fmt.Fprint(w, ast.ErrorToJSON(err))
return
}
timestamp := clientmodel.TimestampFromTime(serv.time.Now())
queryStats := stats.NewTimerGroup()
result := ast.EvalToString(exprNode, timestamp, format, serv.Storage, queryStats)
glog.V(1).Infof("Instant query: %s\nQuery stats:\n%s\n", expr, queryStats)
fmt.Fprint(w, result)
}
// QueryRange handles the /api/query_range endpoint.
func (serv MetricsService) QueryRange(w http.ResponseWriter, r *http.Request) {
setAccessControlHeaders(w)
w.Header().Set("Content-Type", "application/json")
params := httputils.GetQueryParams(r)
expr := params.Get("expr")
// Input times and durations are in seconds and get converted to nanoseconds.
endFloat, _ := strconv.ParseFloat(params.Get("end"), 64)
durationFloat, _ := strconv.ParseFloat(params.Get("range"), 64)
stepFloat, _ := strconv.ParseFloat(params.Get("step"), 64)
nanosPerSecond := int64(time.Second / time.Nanosecond)
end := int64(endFloat) * nanosPerSecond
duration := int64(durationFloat) * nanosPerSecond
step := int64(stepFloat) * nanosPerSecond
exprNode, err := rules.LoadExprFromString(expr)
if err != nil {
fmt.Fprint(w, ast.ErrorToJSON(err))
return
}
if exprNode.Type() != ast.VectorType {
fmt.Fprint(w, ast.ErrorToJSON(errors.New("expression does not evaluate to vector type")))
return
}
if end == 0 {
end = clientmodel.Now().UnixNano()
}
if step <= 0 {
step = nanosPerSecond
}
if end-duration < 0 {
duration = end
}
// For safety, limit the number of returned points per timeseries.
// This is sufficient for 60s resolution for a week or 1h resolution for a year.
if duration/step > 11000 {
fmt.Fprint(w, ast.ErrorToJSON(errors.New("exceeded maximum resolution of 11,000 points per timeseries. Try decreasing the query resolution (?step=XX)")))
return
}
// 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),
clientmodel.TimestampFromUnixNano(end-duration),
clientmodel.TimestampFromUnixNano(end),
time.Duration(step),
serv.Storage,
queryStats)
if err != nil {
fmt.Fprint(w, ast.ErrorToJSON(err))
return
}
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()
glog.V(1).Infof("Range query: %s\nQuery stats:\n%s\n", expr, queryStats)
fmt.Fprint(w, result)
}
// Metrics handles the /api/metrics endpoint.
func (serv MetricsService) Metrics(w http.ResponseWriter, r *http.Request) {
setAccessControlHeaders(w)
metricNames := serv.Storage.GetLabelValuesForLabelName(clientmodel.MetricNameLabel)
sort.Sort(metricNames)
resultBytes, err := json.Marshal(metricNames)
if err != nil {
glog.Error("Error marshalling metric names: ", err)
http.Error(w, err.Error(), http.StatusInternalServerError)
return
}
w.Header().Set("Content-Type", "application/json")
w.Write(resultBytes)
}