prometheus/web/api/query.go

189 lines
5.7 KiB
Go

// Copyright 2013 The Prometheus Authors
// 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")
}
func httpJSONError(w http.ResponseWriter, err error, code int) {
w.Header().Set("Content-Type", "application/json")
w.WriteHeader(code)
fmt.Fprintln(w, ast.ErrorToJSON(err))
}
func parseTimestampOrNow(t string, now clientmodel.Timestamp) (clientmodel.Timestamp, error) {
if t == "" {
return now, nil
}
tFloat, err := strconv.ParseFloat(t, 64)
if err != nil {
return 0, err
}
return clientmodel.TimestampFromUnixNano(int64(tFloat * float64(time.Second/time.Nanosecond))), nil
}
func parseDuration(d string) (time.Duration, error) {
dFloat, err := strconv.ParseFloat(d, 64)
if err != nil {
return 0, err
}
return time.Duration(dFloat * float64(time.Second/time.Nanosecond)), nil
}
// Query handles the /api/query endpoint.
func (serv MetricsService) Query(w http.ResponseWriter, r *http.Request) {
setAccessControlHeaders(w)
w.Header().Set("Content-Type", "application/json")
params := httputils.GetQueryParams(r)
expr := params.Get("expr")
timestamp, err := parseTimestampOrNow(params.Get("timestamp"), serv.Now())
if err != nil {
httpJSONError(w, fmt.Errorf("invalid query timestamp %s", err), http.StatusBadRequest)
return
}
exprNode, err := rules.LoadExprFromString(expr)
if err != nil {
fmt.Fprint(w, ast.ErrorToJSON(err))
return
}
queryStats := stats.NewTimerGroup()
result := ast.EvalToString(exprNode, timestamp, ast.JSON, 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")
duration, err := parseDuration(params.Get("range"))
if err != nil {
httpJSONError(w, fmt.Errorf("invalid query range: %s", err), http.StatusBadRequest)
return
}
step, err := parseDuration(params.Get("step"))
if err != nil {
httpJSONError(w, fmt.Errorf("invalid query resolution: %s", err), http.StatusBadRequest)
return
}
end, err := parseTimestampOrNow(params.Get("end"), serv.Now())
if err != nil {
httpJSONError(w, fmt.Errorf("invalid query timestamp: %s", err), http.StatusBadRequest)
return
}
// TODO(julius): Remove this special-case handling a while after PromDash and
// other API consumers have been changed to no longer set "end=0" for setting
// the current time as the end time. Instead, the "end" parameter should
// simply be omitted or set to an empty string for that case.
if end == 0 {
end = serv.Now()
}
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
}
// 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.Add(-time.Duration(end.UnixNano() % int64(step)))
queryStats := stats.NewTimerGroup()
matrix, err := ast.EvalVectorRange(
exprNode.(ast.VectorNode),
end.Add(-duration),
end,
step,
serv.Storage,
queryStats)
if err != nil {
fmt.Fprint(w, ast.ErrorToJSON(err))
return
}
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)
w.Header().Set("Content-Type", "application/json")
metricNames := serv.Storage.GetLabelValuesForLabelName(clientmodel.MetricNameLabel)
sort.Sort(metricNames)
resultBytes, err := json.Marshal(metricNames)
if err != nil {
glog.Error("Error marshalling metric names: ", err)
httpJSONError(w, fmt.Errorf("Error marshalling metric names: %s", err), http.StatusInternalServerError)
return
}
w.Write(resultBytes)
}