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5e9447996b
By setting Access-Control headers, the Prometheus metrics API can be accessed by cross-origin javascript applications (e.g., an external dashboard pulling Prometheus metrics).
117 lines
3.1 KiB
Go
117 lines
3.1 KiB
Go
// Copyright 2013 Prometheus Team
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package api
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import (
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"code.google.com/p/gorest"
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"encoding/json"
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"errors"
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"github.com/prometheus/prometheus/model"
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"github.com/prometheus/prometheus/rules"
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"github.com/prometheus/prometheus/rules/ast"
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"log"
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"net/http"
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"sort"
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"time"
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)
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func (serv MetricsService) setAccessControlHeaders(rb *gorest.ResponseBuilder) {
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rb.AddHeader("Access-Control-Allow-Headers", "Accept, Authorization, Content-Type, Origin")
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rb.AddHeader("Access-Control-Allow-Methods", "GET")
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rb.AddHeader("Access-Control-Allow-Origin", "*")
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rb.AddHeader("Access-Control-Expose-Headers", "Date")
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}
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func (serv MetricsService) Query(expr string, formatJson string) (result string) {
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exprNode, err := rules.LoadExprFromString(expr)
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if err != nil {
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return ast.ErrorToJSON(err)
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}
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timestamp := serv.time.Now()
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rb := serv.ResponseBuilder()
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serv.setAccessControlHeaders(rb)
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var format ast.OutputFormat
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if formatJson != "" {
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format = ast.JSON
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rb.SetContentType(gorest.Application_Json)
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} else {
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format = ast.TEXT
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rb.SetContentType(gorest.Text_Plain)
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}
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return ast.EvalToString(exprNode, timestamp, format)
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}
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func (serv MetricsService) QueryRange(expr string, end int64, duration int64, step int64) string {
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exprNode, err := rules.LoadExprFromString(expr)
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if err != nil {
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return ast.ErrorToJSON(err)
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}
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if exprNode.Type() != ast.VECTOR {
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return ast.ErrorToJSON(errors.New("Expression does not evaluate to vector type"))
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}
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rb := serv.ResponseBuilder()
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serv.setAccessControlHeaders(rb)
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rb.SetContentType(gorest.Application_Json)
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if end == 0 {
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end = serv.time.Now().Unix()
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}
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if step < 1 {
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step = 1
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}
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if end-duration < 0 {
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duration = end
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}
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// Align the start to step "tick" boundary.
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end -= end % step
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matrix, err := ast.EvalVectorRange(
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exprNode.(ast.VectorNode),
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time.Unix(end-duration, 0),
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time.Unix(end, 0),
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time.Duration(step)*time.Second)
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if err != nil {
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return ast.ErrorToJSON(err)
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}
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sort.Sort(matrix)
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return ast.TypedValueToJSON(matrix, "matrix")
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}
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func (serv MetricsService) Metrics() string {
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metricNames, err := serv.appState.Storage.GetAllValuesForLabel(model.MetricNameLabel)
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rb := serv.ResponseBuilder()
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serv.setAccessControlHeaders(rb)
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rb.SetContentType(gorest.Application_Json)
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if err != nil {
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log.Printf("Error loading metric names: %v", err)
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rb.SetResponseCode(http.StatusInternalServerError)
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return err.Error()
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}
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sort.Sort(metricNames)
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resultBytes, err := json.Marshal(metricNames)
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if err != nil {
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log.Printf("Error marshalling metric names: %v", err)
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rb.SetResponseCode(http.StatusInternalServerError)
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return err.Error()
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}
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return string(resultBytes)
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}
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