640 lines
24 KiB
Go
640 lines
24 KiB
Go
// Copyright 2014 The Prometheus Authors
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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 prometheus_test
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import (
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"bytes"
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"errors"
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"fmt"
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"math"
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"net/http"
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"runtime"
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"strings"
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"time"
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dto "github.com/prometheus/client_model/go"
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"github.com/prometheus/common/expfmt"
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"github.com/prometheus/client_golang/prometheus"
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"github.com/prometheus/client_golang/prometheus/promhttp"
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)
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func ExampleGauge() {
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opsQueued := prometheus.NewGauge(prometheus.GaugeOpts{
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Namespace: "our_company",
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Subsystem: "blob_storage",
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Name: "ops_queued",
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Help: "Number of blob storage operations waiting to be processed.",
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})
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prometheus.MustRegister(opsQueued)
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// 10 operations queued by the goroutine managing incoming requests.
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opsQueued.Add(10)
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// A worker goroutine has picked up a waiting operation.
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opsQueued.Dec()
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// And once more...
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opsQueued.Dec()
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}
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func ExampleGaugeVec() {
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opsQueued := prometheus.NewGaugeVec(
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prometheus.GaugeOpts{
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Namespace: "our_company",
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Subsystem: "blob_storage",
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Name: "ops_queued",
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Help: "Number of blob storage operations waiting to be processed, partitioned by user and type.",
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},
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[]string{
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// Which user has requested the operation?
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"user",
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// Of what type is the operation?
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"type",
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},
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)
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prometheus.MustRegister(opsQueued)
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// Increase a value using compact (but order-sensitive!) WithLabelValues().
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opsQueued.WithLabelValues("bob", "put").Add(4)
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// Increase a value with a map using WithLabels. More verbose, but order
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// doesn't matter anymore.
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opsQueued.With(prometheus.Labels{"type": "delete", "user": "alice"}).Inc()
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}
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func ExampleGaugeFunc_simple() {
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if err := prometheus.Register(prometheus.NewGaugeFunc(
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prometheus.GaugeOpts{
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Subsystem: "runtime",
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Name: "goroutines_count",
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Help: "Number of goroutines that currently exist.",
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},
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func() float64 { return float64(runtime.NumGoroutine()) },
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)); err == nil {
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fmt.Println("GaugeFunc 'goroutines_count' registered.")
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}
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// Note that the count of goroutines is a gauge (and not a counter) as
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// it can go up and down.
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// Output:
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// GaugeFunc 'goroutines_count' registered.
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}
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func ExampleGaugeFunc_constLabels() {
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// primaryDB and secondaryDB represent two example *sql.DB connections we want to instrument.
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var primaryDB, secondaryDB interface {
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Stats() struct{ OpenConnections int }
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}
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if err := prometheus.Register(prometheus.NewGaugeFunc(
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prometheus.GaugeOpts{
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Namespace: "mysql",
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Name: "connections_open",
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Help: "Number of mysql connections open.",
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ConstLabels: prometheus.Labels{"destination": "primary"},
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},
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func() float64 { return float64(primaryDB.Stats().OpenConnections) },
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)); err == nil {
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fmt.Println(`GaugeFunc 'connections_open' for primary DB connection registered with labels {destination="primary"}`)
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}
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if err := prometheus.Register(prometheus.NewGaugeFunc(
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prometheus.GaugeOpts{
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Namespace: "mysql",
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Name: "connections_open",
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Help: "Number of mysql connections open.",
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ConstLabels: prometheus.Labels{"destination": "secondary"},
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},
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func() float64 { return float64(secondaryDB.Stats().OpenConnections) },
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)); err == nil {
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fmt.Println(`GaugeFunc 'connections_open' for secondary DB connection registered with labels {destination="secondary"}`)
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}
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// Note that we can register more than once GaugeFunc with same metric name
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// as long as their const labels are consistent.
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// Output:
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// GaugeFunc 'connections_open' for primary DB connection registered with labels {destination="primary"}
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// GaugeFunc 'connections_open' for secondary DB connection registered with labels {destination="secondary"}
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}
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func ExampleCounterVec() {
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httpReqs := prometheus.NewCounterVec(
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prometheus.CounterOpts{
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Name: "http_requests_total",
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Help: "How many HTTP requests processed, partitioned by status code and HTTP method.",
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},
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[]string{"code", "method"},
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)
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prometheus.MustRegister(httpReqs)
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httpReqs.WithLabelValues("404", "POST").Add(42)
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// If you have to access the same set of labels very frequently, it
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// might be good to retrieve the metric only once and keep a handle to
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// it. But beware of deletion of that metric, see below!
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m := httpReqs.WithLabelValues("200", "GET")
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for i := 0; i < 1000000; i++ {
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m.Inc()
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}
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// Delete a metric from the vector. If you have previously kept a handle
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// to that metric (as above), future updates via that handle will go
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// unseen (even if you re-create a metric with the same label set
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// later).
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httpReqs.DeleteLabelValues("200", "GET")
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// Same thing with the more verbose Labels syntax.
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httpReqs.Delete(prometheus.Labels{"method": "GET", "code": "200"})
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}
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func ExampleRegister() {
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// Imagine you have a worker pool and want to count the tasks completed.
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taskCounter := prometheus.NewCounter(prometheus.CounterOpts{
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Subsystem: "worker_pool",
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Name: "completed_tasks_total",
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Help: "Total number of tasks completed.",
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})
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// This will register fine.
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if err := prometheus.Register(taskCounter); err != nil {
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fmt.Println(err)
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} else {
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fmt.Println("taskCounter registered.")
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}
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// Don't forget to tell the HTTP server about the Prometheus handler.
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// (In a real program, you still need to start the HTTP server...)
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http.Handle("/metrics", promhttp.Handler())
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// Now you can start workers and give every one of them a pointer to
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// taskCounter and let it increment it whenever it completes a task.
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taskCounter.Inc() // This has to happen somewhere in the worker code.
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// But wait, you want to see how individual workers perform. So you need
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// a vector of counters, with one element for each worker.
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taskCounterVec := prometheus.NewCounterVec(
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prometheus.CounterOpts{
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Subsystem: "worker_pool",
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Name: "completed_tasks_total",
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Help: "Total number of tasks completed.",
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},
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[]string{"worker_id"},
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)
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// Registering will fail because we already have a metric of that name.
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if err := prometheus.Register(taskCounterVec); err != nil {
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fmt.Println("taskCounterVec not registered:", err)
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} else {
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fmt.Println("taskCounterVec registered.")
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}
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// To fix, first unregister the old taskCounter.
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if prometheus.Unregister(taskCounter) {
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fmt.Println("taskCounter unregistered.")
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}
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// Try registering taskCounterVec again.
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if err := prometheus.Register(taskCounterVec); err != nil {
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fmt.Println("taskCounterVec not registered:", err)
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} else {
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fmt.Println("taskCounterVec registered.")
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}
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// Bummer! Still doesn't work.
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// Prometheus will not allow you to ever export metrics with
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// inconsistent help strings or label names. After unregistering, the
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// unregistered metrics will cease to show up in the /metrics HTTP
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// response, but the registry still remembers that those metrics had
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// been exported before. For this example, we will now choose a
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// different name. (In a real program, you would obviously not export
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// the obsolete metric in the first place.)
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taskCounterVec = prometheus.NewCounterVec(
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prometheus.CounterOpts{
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Subsystem: "worker_pool",
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Name: "completed_tasks_by_id",
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Help: "Total number of tasks completed.",
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},
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[]string{"worker_id"},
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)
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if err := prometheus.Register(taskCounterVec); err != nil {
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fmt.Println("taskCounterVec not registered:", err)
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} else {
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fmt.Println("taskCounterVec registered.")
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}
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// Finally it worked!
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// The workers have to tell taskCounterVec their id to increment the
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// right element in the metric vector.
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taskCounterVec.WithLabelValues("42").Inc() // Code from worker 42.
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// Each worker could also keep a reference to their own counter element
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// around. Pick the counter at initialization time of the worker.
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myCounter := taskCounterVec.WithLabelValues("42") // From worker 42 initialization code.
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myCounter.Inc() // Somewhere in the code of that worker.
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// Note that something like WithLabelValues("42", "spurious arg") would
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// panic (because you have provided too many label values). If you want
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// to get an error instead, use GetMetricWithLabelValues(...) instead.
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notMyCounter, err := taskCounterVec.GetMetricWithLabelValues("42", "spurious arg")
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if err != nil {
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fmt.Println("Worker initialization failed:", err)
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}
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if notMyCounter == nil {
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fmt.Println("notMyCounter is nil.")
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}
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// A different (and somewhat tricky) approach is to use
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// ConstLabels. ConstLabels are pairs of label names and label values
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// that never change. Each worker creates and registers an own Counter
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// instance where the only difference is in the value of the
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// ConstLabels. Those Counters can all be registered because the
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// different ConstLabel values guarantee that each worker will increment
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// a different Counter metric.
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counterOpts := prometheus.CounterOpts{
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Subsystem: "worker_pool",
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Name: "completed_tasks",
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Help: "Total number of tasks completed.",
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ConstLabels: prometheus.Labels{"worker_id": "42"},
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}
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taskCounterForWorker42 := prometheus.NewCounter(counterOpts)
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if err := prometheus.Register(taskCounterForWorker42); err != nil {
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fmt.Println("taskCounterVForWorker42 not registered:", err)
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} else {
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fmt.Println("taskCounterForWorker42 registered.")
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}
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// Obviously, in real code, taskCounterForWorker42 would be a member
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// variable of a worker struct, and the "42" would be retrieved with a
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// GetId() method or something. The Counter would be created and
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// registered in the initialization code of the worker.
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// For the creation of the next Counter, we can recycle
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// counterOpts. Just change the ConstLabels.
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counterOpts.ConstLabels = prometheus.Labels{"worker_id": "2001"}
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taskCounterForWorker2001 := prometheus.NewCounter(counterOpts)
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if err := prometheus.Register(taskCounterForWorker2001); err != nil {
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fmt.Println("taskCounterVForWorker2001 not registered:", err)
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} else {
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fmt.Println("taskCounterForWorker2001 registered.")
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}
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taskCounterForWorker2001.Inc()
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taskCounterForWorker42.Inc()
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taskCounterForWorker2001.Inc()
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// Yet another approach would be to turn the workers themselves into
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// Collectors and register them. See the Collector example for details.
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// Output:
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// taskCounter registered.
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// taskCounterVec not registered: a previously registered descriptor with the same fully-qualified name as Desc{fqName: "worker_pool_completed_tasks_total", help: "Total number of tasks completed.", constLabels: {}, variableLabels: {worker_id}} has different label names or a different help string
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// taskCounter unregistered.
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// taskCounterVec not registered: a previously registered descriptor with the same fully-qualified name as Desc{fqName: "worker_pool_completed_tasks_total", help: "Total number of tasks completed.", constLabels: {}, variableLabels: {worker_id}} has different label names or a different help string
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// taskCounterVec registered.
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// Worker initialization failed: inconsistent label cardinality: expected 1 label values but got 2 in []string{"42", "spurious arg"}
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// notMyCounter is nil.
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// taskCounterForWorker42 registered.
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// taskCounterForWorker2001 registered.
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}
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func ExampleSummary() {
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temps := prometheus.NewSummary(prometheus.SummaryOpts{
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Name: "pond_temperature_celsius",
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Help: "The temperature of the frog pond.",
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Objectives: map[float64]float64{0.5: 0.05, 0.9: 0.01, 0.99: 0.001},
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})
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// Simulate some observations.
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for i := 0; i < 1000; i++ {
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temps.Observe(30 + math.Floor(120*math.Sin(float64(i)*0.1))/10)
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}
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// Just for demonstration, let's check the state of the summary by
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// (ab)using its Write method (which is usually only used by Prometheus
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// internally).
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metric := &dto.Metric{}
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temps.Write(metric)
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printlnNormalized(metric)
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// Output:
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// {"summary":{"sampleCount":"1000","sampleSum":29969.50000000001,"quantile":[{"quantile":0.5,"value":31.1},{"quantile":0.9,"value":41.3},{"quantile":0.99,"value":41.9}]}}
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}
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func ExampleSummaryVec() {
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temps := prometheus.NewSummaryVec(
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prometheus.SummaryOpts{
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Name: "pond_temperature_celsius",
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Help: "The temperature of the frog pond.",
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Objectives: map[float64]float64{0.5: 0.05, 0.9: 0.01, 0.99: 0.001},
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},
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[]string{"species"},
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)
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// Simulate some observations.
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for i := 0; i < 1000; i++ {
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temps.WithLabelValues("litoria-caerulea").Observe(30 + math.Floor(120*math.Sin(float64(i)*0.1))/10)
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temps.WithLabelValues("lithobates-catesbeianus").Observe(32 + math.Floor(100*math.Cos(float64(i)*0.11))/10)
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}
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// Create a Summary without any observations.
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temps.WithLabelValues("leiopelma-hochstetteri")
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// Just for demonstration, let's check the state of the summary vector
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// by registering it with a custom registry and then let it collect the
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// metrics.
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reg := prometheus.NewRegistry()
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reg.MustRegister(temps)
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metricFamilies, err := reg.Gather()
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if err != nil || len(metricFamilies) != 1 {
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panic("unexpected behavior of custom test registry")
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}
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printlnNormalized(metricFamilies[0])
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// Output:
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// {"name":"pond_temperature_celsius","help":"The temperature of the frog pond.","type":"SUMMARY","metric":[{"label":[{"name":"species","value":"leiopelma-hochstetteri"}],"summary":{"sampleCount":"0","sampleSum":0,"quantile":[{"quantile":0.5,"value":"NaN"},{"quantile":0.9,"value":"NaN"},{"quantile":0.99,"value":"NaN"}]}},{"label":[{"name":"species","value":"lithobates-catesbeianus"}],"summary":{"sampleCount":"1000","sampleSum":31956.100000000017,"quantile":[{"quantile":0.5,"value":32.4},{"quantile":0.9,"value":41.4},{"quantile":0.99,"value":41.9}]}},{"label":[{"name":"species","value":"litoria-caerulea"}],"summary":{"sampleCount":"1000","sampleSum":29969.50000000001,"quantile":[{"quantile":0.5,"value":31.1},{"quantile":0.9,"value":41.3},{"quantile":0.99,"value":41.9}]}}]}
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}
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func ExampleNewConstSummary() {
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desc := prometheus.NewDesc(
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"http_request_duration_seconds",
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"A summary of the HTTP request durations.",
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[]string{"code", "method"},
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prometheus.Labels{"owner": "example"},
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)
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// Create a constant summary from values we got from a 3rd party telemetry system.
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s := prometheus.MustNewConstSummary(
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desc,
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4711, 403.34,
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map[float64]float64{0.5: 42.3, 0.9: 323.3},
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"200", "get",
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)
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// Just for demonstration, let's check the state of the summary by
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// (ab)using its Write method (which is usually only used by Prometheus
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// internally).
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metric := &dto.Metric{}
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s.Write(metric)
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printlnNormalized(metric)
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// Output:
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// {"label":[{"name":"code","value":"200"},{"name":"method","value":"get"},{"name":"owner","value":"example"}],"summary":{"sampleCount":"4711","sampleSum":403.34,"quantile":[{"quantile":0.5,"value":42.3},{"quantile":0.9,"value":323.3}]}}
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}
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func ExampleHistogram() {
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temps := prometheus.NewHistogram(prometheus.HistogramOpts{
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Name: "pond_temperature_celsius",
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Help: "The temperature of the frog pond.", // Sorry, we can't measure how badly it smells.
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Buckets: prometheus.LinearBuckets(20, 5, 5), // 5 buckets, each 5 centigrade wide.
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})
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// Simulate some observations.
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for i := 0; i < 1000; i++ {
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temps.Observe(30 + math.Floor(120*math.Sin(float64(i)*0.1))/10)
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}
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// Just for demonstration, let's check the state of the histogram by
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// (ab)using its Write method (which is usually only used by Prometheus
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// internally).
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metric := &dto.Metric{}
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temps.Write(metric)
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printlnNormalized(metric)
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// Output:
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// {"histogram":{"sampleCount":"1000","sampleSum":29969.50000000001,"bucket":[{"cumulativeCount":"192","upperBound":20},{"cumulativeCount":"366","upperBound":25},{"cumulativeCount":"501","upperBound":30},{"cumulativeCount":"638","upperBound":35},{"cumulativeCount":"816","upperBound":40}]}}
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}
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func ExampleNewConstHistogram() {
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desc := prometheus.NewDesc(
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"http_request_duration_seconds",
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"A histogram of the HTTP request durations.",
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[]string{"code", "method"},
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prometheus.Labels{"owner": "example"},
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)
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// Create a constant histogram from values we got from a 3rd party telemetry system.
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h := prometheus.MustNewConstHistogram(
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desc,
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4711, 403.34,
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map[float64]uint64{25: 121, 50: 2403, 100: 3221, 200: 4233},
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"200", "get",
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)
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// Just for demonstration, let's check the state of the histogram by
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// (ab)using its Write method (which is usually only used by Prometheus
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// internally).
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metric := &dto.Metric{}
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h.Write(metric)
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printlnNormalized(metric)
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// Output:
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// {"label":[{"name":"code","value":"200"},{"name":"method","value":"get"},{"name":"owner","value":"example"}],"histogram":{"sampleCount":"4711","sampleSum":403.34,"bucket":[{"cumulativeCount":"121","upperBound":25},{"cumulativeCount":"2403","upperBound":50},{"cumulativeCount":"3221","upperBound":100},{"cumulativeCount":"4233","upperBound":200}]}}
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}
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func ExampleNewConstHistogram_WithExemplar() {
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desc := prometheus.NewDesc(
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"http_request_duration_seconds",
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"A histogram of the HTTP request durations.",
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[]string{"code", "method"},
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prometheus.Labels{"owner": "example"},
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)
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// Create a constant histogram from values we got from a 3rd party telemetry system.
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h := prometheus.MustNewConstHistogram(
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desc,
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4711, 403.34,
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map[float64]uint64{25: 121, 50: 2403, 100: 3221, 200: 4233},
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"200", "get",
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)
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// Wrap const histogram with exemplars for each bucket.
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exemplarTs, _ := time.Parse(time.RFC850, "Monday, 02-Jan-06 15:04:05 GMT")
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exemplarLabels := prometheus.Labels{"testName": "testVal"}
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h = prometheus.MustNewMetricWithExemplars(
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h,
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|
prometheus.Exemplar{Labels: exemplarLabels, Timestamp: exemplarTs, Value: 24.0},
|
|
prometheus.Exemplar{Labels: exemplarLabels, Timestamp: exemplarTs, Value: 42.0},
|
|
prometheus.Exemplar{Labels: exemplarLabels, Timestamp: exemplarTs, Value: 89.0},
|
|
prometheus.Exemplar{Labels: exemplarLabels, Timestamp: exemplarTs, Value: 157.0},
|
|
)
|
|
|
|
// Just for demonstration, let's check the state of the histogram by
|
|
// (ab)using its Write method (which is usually only used by Prometheus
|
|
// internally).
|
|
metric := &dto.Metric{}
|
|
h.Write(metric)
|
|
printlnNormalized(metric)
|
|
|
|
// Output:
|
|
// {"label":[{"name":"code","value":"200"},{"name":"method","value":"get"},{"name":"owner","value":"example"}],"histogram":{"sampleCount":"4711","sampleSum":403.34,"bucket":[{"cumulativeCount":"121","upperBound":25,"exemplar":{"label":[{"name":"testName","value":"testVal"}],"value":24,"timestamp":"2006-01-02T15:04:05Z"}},{"cumulativeCount":"2403","upperBound":50,"exemplar":{"label":[{"name":"testName","value":"testVal"}],"value":42,"timestamp":"2006-01-02T15:04:05Z"}},{"cumulativeCount":"3221","upperBound":100,"exemplar":{"label":[{"name":"testName","value":"testVal"}],"value":89,"timestamp":"2006-01-02T15:04:05Z"}},{"cumulativeCount":"4233","upperBound":200,"exemplar":{"label":[{"name":"testName","value":"testVal"}],"value":157,"timestamp":"2006-01-02T15:04:05Z"}}]}}
|
|
}
|
|
|
|
func ExampleAlreadyRegisteredError() {
|
|
reqCounter := prometheus.NewCounter(prometheus.CounterOpts{
|
|
Name: "requests_total",
|
|
Help: "The total number of requests served.",
|
|
})
|
|
if err := prometheus.Register(reqCounter); err != nil {
|
|
are := &prometheus.AlreadyRegisteredError{}
|
|
if errors.As(err, are) {
|
|
// A counter for that metric has been registered before.
|
|
// Use the old counter from now on.
|
|
reqCounter = are.ExistingCollector.(prometheus.Counter)
|
|
} else {
|
|
// Something else went wrong!
|
|
panic(err)
|
|
}
|
|
}
|
|
reqCounter.Inc()
|
|
}
|
|
|
|
func ExampleGatherers() {
|
|
reg := prometheus.NewRegistry()
|
|
temp := prometheus.NewGaugeVec(
|
|
prometheus.GaugeOpts{
|
|
Name: "temperature_kelvin",
|
|
Help: "Temperature in Kelvin.",
|
|
},
|
|
[]string{"location"},
|
|
)
|
|
reg.MustRegister(temp)
|
|
temp.WithLabelValues("outside").Set(273.14)
|
|
temp.WithLabelValues("inside").Set(298.44)
|
|
|
|
var parser expfmt.TextParser
|
|
|
|
text := `
|
|
# TYPE humidity_percent gauge
|
|
# HELP humidity_percent Humidity in %.
|
|
humidity_percent{location="outside"} 45.4
|
|
humidity_percent{location="inside"} 33.2
|
|
# TYPE temperature_kelvin gauge
|
|
# HELP temperature_kelvin Temperature in Kelvin.
|
|
temperature_kelvin{location="somewhere else"} 4.5
|
|
`
|
|
|
|
parseText := func() ([]*dto.MetricFamily, error) {
|
|
parsed, err := parser.TextToMetricFamilies(strings.NewReader(text))
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
var result []*dto.MetricFamily
|
|
for _, mf := range parsed {
|
|
result = append(result, mf)
|
|
}
|
|
return result, nil
|
|
}
|
|
|
|
gatherers := prometheus.Gatherers{
|
|
reg,
|
|
prometheus.GathererFunc(parseText),
|
|
}
|
|
|
|
gathering, err := gatherers.Gather()
|
|
if err != nil {
|
|
fmt.Println(err)
|
|
}
|
|
|
|
out := &bytes.Buffer{}
|
|
for _, mf := range gathering {
|
|
if _, err := expfmt.MetricFamilyToText(out, mf); err != nil {
|
|
panic(err)
|
|
}
|
|
}
|
|
fmt.Print(out.String())
|
|
fmt.Println("----------")
|
|
|
|
// Note how the temperature_kelvin metric family has been merged from
|
|
// different sources. Now try
|
|
text = `
|
|
# TYPE humidity_percent gauge
|
|
# HELP humidity_percent Humidity in %.
|
|
humidity_percent{location="outside"} 45.4
|
|
humidity_percent{location="inside"} 33.2
|
|
# TYPE temperature_kelvin gauge
|
|
# HELP temperature_kelvin Temperature in Kelvin.
|
|
# Duplicate metric:
|
|
temperature_kelvin{location="outside"} 265.3
|
|
# Missing location label (note that this is undesirable but valid):
|
|
temperature_kelvin 4.5
|
|
`
|
|
|
|
gathering, err = gatherers.Gather()
|
|
if err != nil {
|
|
// We expect error collected metric "temperature_kelvin" { label:<name:"location" value:"outside" > gauge:<value:265.3 > } was collected before with the same name and label values
|
|
// We cannot assert it because of https://github.com/golang/protobuf/issues/1121
|
|
if strings.HasPrefix(err.Error(), `collected metric "temperature_kelvin" `) {
|
|
fmt.Println("Found duplicated metric `temperature_kelvin`")
|
|
} else {
|
|
fmt.Print(err)
|
|
}
|
|
}
|
|
// Note that still as many metrics as possible are returned:
|
|
out.Reset()
|
|
for _, mf := range gathering {
|
|
if _, err := expfmt.MetricFamilyToText(out, mf); err != nil {
|
|
panic(err)
|
|
}
|
|
}
|
|
fmt.Print(out.String())
|
|
|
|
// Output:
|
|
// # HELP humidity_percent Humidity in %.
|
|
// # TYPE humidity_percent gauge
|
|
// humidity_percent{location="inside"} 33.2
|
|
// humidity_percent{location="outside"} 45.4
|
|
// # HELP temperature_kelvin Temperature in Kelvin.
|
|
// # TYPE temperature_kelvin gauge
|
|
// temperature_kelvin{location="inside"} 298.44
|
|
// temperature_kelvin{location="outside"} 273.14
|
|
// temperature_kelvin{location="somewhere else"} 4.5
|
|
// ----------
|
|
// Found duplicated metric `temperature_kelvin`
|
|
// # HELP humidity_percent Humidity in %.
|
|
// # TYPE humidity_percent gauge
|
|
// humidity_percent{location="inside"} 33.2
|
|
// humidity_percent{location="outside"} 45.4
|
|
// # HELP temperature_kelvin Temperature in Kelvin.
|
|
// # TYPE temperature_kelvin gauge
|
|
// temperature_kelvin 4.5
|
|
// temperature_kelvin{location="inside"} 298.44
|
|
// temperature_kelvin{location="outside"} 273.14
|
|
}
|
|
|
|
func ExampleNewMetricWithTimestamp() {
|
|
desc := prometheus.NewDesc(
|
|
"temperature_kelvin",
|
|
"Current temperature in Kelvin.",
|
|
nil, nil,
|
|
)
|
|
|
|
// Create a constant gauge from values we got from an external
|
|
// temperature reporting system. Those values are reported with a slight
|
|
// delay, so we want to add the timestamp of the actual measurement.
|
|
temperatureReportedByExternalSystem := 298.15
|
|
timeReportedByExternalSystem := time.Date(2009, time.November, 10, 23, 0, 0, 12345678, time.UTC)
|
|
s := prometheus.NewMetricWithTimestamp(
|
|
timeReportedByExternalSystem,
|
|
prometheus.MustNewConstMetric(
|
|
desc, prometheus.GaugeValue, temperatureReportedByExternalSystem,
|
|
),
|
|
)
|
|
|
|
// Just for demonstration, let's check the state of the gauge by
|
|
// (ab)using its Write method (which is usually only used by Prometheus
|
|
// internally).
|
|
metric := &dto.Metric{}
|
|
s.Write(metric)
|
|
printlnNormalized(metric)
|
|
|
|
// Output:
|
|
// {"gauge":{"value":298.15},"timestampMs":"1257894000012"}
|
|
}
|