1// Copyright 2014 The Prometheus Authors 2// Licensed under the Apache License, Version 2.0 (the "License"); 3// you may not use this file except in compliance with the License. 4// You may obtain a copy of the License at 5// 6// http://www.apache.org/licenses/LICENSE-2.0 7// 8// Unless required by applicable law or agreed to in writing, software 9// distributed under the License is distributed on an "AS IS" BASIS, 10// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 11// See the License for the specific language governing permissions and 12// limitations under the License. 13 14package prometheus_test 15 16import ( 17 "os" 18 19 "github.com/prometheus/client_golang/prometheus" 20) 21 22var ( 23 // If a function is called rarely (i.e. not more often than scrapes 24 // happen) or ideally only once (like in a batch job), it can make sense 25 // to use a Gauge for timing the function call. For timing a batch job 26 // and pushing the result to a Pushgateway, see also the comprehensive 27 // example in the push package. 28 funcDuration = prometheus.NewGauge(prometheus.GaugeOpts{ 29 Name: "example_function_duration_seconds", 30 Help: "Duration of the last call of an example function.", 31 }) 32) 33 34func run() error { 35 // The Set method of the Gauge is used to observe the duration. 36 timer := prometheus.NewTimer(prometheus.ObserverFunc(funcDuration.Set)) 37 defer timer.ObserveDuration() 38 39 // Do something. Return errors as encountered. The use of 'defer' above 40 // makes sure the function is still timed properly. 41 return nil 42} 43 44func ExampleTimer_gauge() { 45 if err := run(); err != nil { 46 os.Exit(1) 47 } 48} 49