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// Copyright 2015 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 push provides functions to push metrics to a Pushgateway. It uses a
// builder approach. Create a Pusher with New and then add the various options
// by using its methods, finally calling Add or Push, like this:
//
// // Easy case:
// push.New("http://example.org/metrics", "my_job").Gatherer(myRegistry).Push()
//
// // Complex case:
// push.New("http://example.org/metrics", "my_job").
// Collector(myCollector1).
// Collector(myCollector2).
// Grouping("zone", "xy").
// Client(&myHTTPClient).
// BasicAuth("top", "secret").
// Add()
//
// See the examples section for more detailed examples.
//
// See the documentation of the Pushgateway to understand the meaning of
// the grouping key and the differences between Push and Add:
// https://github.com/prometheus/pushgateway
package push
import (
"bytes"
"fmt"
"io/ioutil"
"net/http"
"net/url"
"strings"
"github.com/prometheus/common/expfmt"
"github.com/prometheus/common/model"
"github.com/prometheus/client_golang/prometheus"
)
const contentTypeHeader = "Content-Type"
// HTTPDoer is an interface for the one method of http.Client that is used by Pusher
type HTTPDoer interface {
Do(*http.Request) (*http.Response, error)
}
// Pusher manages a push to the Pushgateway. Use New to create one, configure it
// with its methods, and finally use the Add or Push method to push.
type Pusher struct {
error error
url, job string
grouping map[string]string
gatherers prometheus.Gatherers
registerer prometheus.Registerer
client HTTPDoer
useBasicAuth bool
username, password string
expfmt expfmt.Format
}
// New creates a new Pusher to push to the provided URL with the provided job
// name. You can use just host:port or ip:port as url, in which case “http://”
// is added automatically. Alternatively, include the schema in the
// URL. However, do not include the “/metrics/jobs/…” part.
//
// Note that until https://github.com/prometheus/pushgateway/issues/97 is
// resolved, a “/” character in the job name is prohibited.
func New(url, job string) *Pusher {
var (
reg = prometheus.NewRegistry()
err error
)
if !strings.Contains(url, "://") {
url = "http://" + url
}
if strings.HasSuffix(url, "/") {
url = url[:len(url)-1]
}
if strings.Contains(job, "/") {
err = fmt.Errorf("job contains '/': %s", job)
}
return &Pusher{
error: err,
url: url,
job: job,
grouping: map[string]string{},
gatherers: prometheus.Gatherers{reg},
registerer: reg,
client: &http.Client{},
expfmt: expfmt.FmtProtoDelim,
}
}
// Push collects/gathers all metrics from all Collectors and Gatherers added to
// this Pusher. Then, it pushes them to the Pushgateway configured while
// creating this Pusher, using the configured job name and any added grouping
// labels as grouping key. All previously pushed metrics with the same job and
// other grouping labels will be replaced with the metrics pushed by this
// call. (It uses HTTP method “PUT” to push to the Pushgateway.)
//
// Push returns the first error encountered by any method call (including this
// one) in the lifetime of the Pusher.
func (p *Pusher) Push() error {
return p.push(http.MethodPut)
}
// Add works like push, but only previously pushed metrics with the same name
// (and the same job and other grouping labels) will be replaced. (It uses HTTP
// method “POST” to push to the Pushgateway.)
func (p *Pusher) Add() error {
return p.push(http.MethodPost)
}
// Gatherer adds a Gatherer to the Pusher, from which metrics will be gathered
// to push them to the Pushgateway. The gathered metrics must not contain a job
// label of their own.
//
// For convenience, this method returns a pointer to the Pusher itself.
func (p *Pusher) Gatherer(g prometheus.Gatherer) *Pusher {
p.gatherers = append(p.gatherers, g)
return p
}
// Collector adds a Collector to the Pusher, from which metrics will be
// collected to push them to the Pushgateway. The collected metrics must not
// contain a job label of their own.
//
// For convenience, this method returns a pointer to the Pusher itself.
func (p *Pusher) Collector(c prometheus.Collector) *Pusher {
if p.error == nil {
p.error = p.registerer.Register(c)
}
return p
}
// Grouping adds a label pair to the grouping key of the Pusher, replacing any
// previously added label pair with the same label name. Note that setting any
// labels in the grouping key that are already contained in the metrics to push
// will lead to an error.
//
// For convenience, this method returns a pointer to the Pusher itself.
//
// Note that until https://github.com/prometheus/pushgateway/issues/97 is
// resolved, this method does not allow a “/” character in the label value.
func (p *Pusher) Grouping(name, value string) *Pusher {
if p.error == nil {
if !model.LabelName(name).IsValid() {
p.error = fmt.Errorf("grouping label has invalid name: %s", name)
return p
}
if strings.Contains(value, "/") {
p.error = fmt.Errorf("value of grouping label %s contains '/': %s", name, value)
return p
}
p.grouping[name] = value
}
return p
}
// Client sets a custom HTTP client for the Pusher. For convenience, this method
// returns a pointer to the Pusher itself.
// Pusher only needs one method of the custom HTTP client: Do(*http.Request).
// Thus, rather than requiring a fully fledged http.Client,
// the provided client only needs to implement the HTTPDoer interface.
// Since *http.Client naturally implements that interface, it can still be used normally.
func (p *Pusher) Client(c HTTPDoer) *Pusher {
p.client = c
return p
}
// BasicAuth configures the Pusher to use HTTP Basic Authentication with the
// provided username and password. For convenience, this method returns a
// pointer to the Pusher itself.
func (p *Pusher) BasicAuth(username, password string) *Pusher {
p.useBasicAuth = true
p.username = username
p.password = password
return p
}
// Format configures the Pusher to use an encoding format given by the
// provided expfmt.Format. The default format is expfmt.FmtProtoDelim and
// should be used with the standard Prometheus Pushgateway. Custom
// implementations may require different formats. For convenience, this
// method returns a pointer to the Pusher itself.
func (p *Pusher) Format(format expfmt.Format) *Pusher {
p.expfmt = format
return p
}
// Delete sends a “DELETE” request to the Pushgateway configured while creating
// this Pusher, using the configured job name and any added grouping labels as
// grouping key. Any added Gatherers and Collectors added to this Pusher are
// ignored by this method.
//
// Delete returns the first error encountered by any method call (including this
// one) in the lifetime of the Pusher.
func (p *Pusher) Delete() error {
if p.error != nil {
return p.error
}
urlComponents := []string{url.QueryEscape(p.job)}
for ln, lv := range p.grouping {
urlComponents = append(urlComponents, ln, lv)
}
deleteURL := fmt.Sprintf("%s/metrics/job/%s", p.url, strings.Join(urlComponents, "/"))
req, err := http.NewRequest(http.MethodDelete, deleteURL, nil)
if err != nil {
return err
}
if p.useBasicAuth {
req.SetBasicAuth(p.username, p.password)
}
resp, err := p.client.Do(req)
if err != nil {
return err
}
defer resp.Body.Close()
if resp.StatusCode != 202 {
body, _ := ioutil.ReadAll(resp.Body) // Ignore any further error as this is for an error message only.
return fmt.Errorf("unexpected status code %d while deleting %s: %s", resp.StatusCode, deleteURL, body)
}
return nil
}
func (p *Pusher) push(method string) error {
if p.error != nil {
return p.error
}
urlComponents := []string{url.QueryEscape(p.job)}
for ln, lv := range p.grouping {
urlComponents = append(urlComponents, ln, lv)
}
pushURL := fmt.Sprintf("%s/metrics/job/%s", p.url, strings.Join(urlComponents, "/"))
mfs, err := p.gatherers.Gather()
if err != nil {
return err
}
buf := &bytes.Buffer{}
enc := expfmt.NewEncoder(buf, p.expfmt)
// Check for pre-existing grouping labels:
for _, mf := range mfs {
for _, m := range mf.GetMetric() {
for _, l := range m.GetLabel() {
if l.GetName() == "job" {
return fmt.Errorf("pushed metric %s (%s) already contains a job label", mf.GetName(), m)
}
if _, ok := p.grouping[l.GetName()]; ok {
return fmt.Errorf(
"pushed metric %s (%s) already contains grouping label %s",
mf.GetName(), m, l.GetName(),
)
}
}
}
enc.Encode(mf)
}
req, err := http.NewRequest(method, pushURL, buf)
if err != nil {
return err
}
if p.useBasicAuth {
req.SetBasicAuth(p.username, p.password)
}
req.Header.Set(contentTypeHeader, string(p.expfmt))
resp, err := p.client.Do(req)
if err != nil {
return err
}
defer resp.Body.Close()
if resp.StatusCode != 202 {
body, _ := ioutil.ReadAll(resp.Body) // Ignore any further error as this is for an error message only.
return fmt.Errorf("unexpected status code %d while pushing to %s: %s", resp.StatusCode, pushURL, body)
}
return nil
}
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