prometheus client_go为应用程序自定义监控指标

http.Handle("/metrics", promhttp.Handler())

go_gc_duration_seconds
go_goroutines
go_info
....

process_start_time_seconds
process_cpu_seconds_total
....

http.Handle("/metrics", promhttp.Handler())

// prometheus/client_golang/prometheus/promhttp/http.go
func Handler() http.Handler {
    return InstrumentMetricHandler(
        prometheus.DefaultRegisterer, HandlerFor(prometheus.DefaultGatherer, HandlerOpts{}),
    )
}

// prometheus/client_golang/prometheus/registry.go
var (
    defaultRegistry              = NewRegistry()
    DefaultRegisterer Registerer = defaultRegistry
    DefaultGatherer   Gatherer   = defaultRegistry
)
func init() {
    MustRegister(NewProcessCollector(ProcessCollectorOpts{}))    // 采集Proc指标
    MustRegister(NewGoCollector())                                // 采集Go指标
}
func MustRegister(cs ...Collector) {
    DefaultRegisterer.MustRegister(cs...)
}

import (
    "net/http"
    "github.com/prometheus/client_golang/prometheus"
    "github.com/prometheus/client_golang/prometheus/promhttp"
)
func main() {
    // 创建一个自定义的注册表
    registry := prometheus.NewRegistry()
    // 可选: 添加 process 和 Go 运行时指标到我们自定义的注册表中
    registry.MustRegister(prometheus.NewProcessCollector(prometheus.ProcessCollectorOpts{}))
    registry.MustRegister(prometheus.NewGoCollector())
    // 创建一个简单的 gauge 指标。
    temp := prometheus.NewGauge(prometheus.GaugeOpts{
        Name: "home_temperature_celsius",
        Help: "The current temperature in degrees Celsius.",
    })
    // 使用我们自定义的注册表注册 gauge
    registry.MustRegister(temp)
    // 设置 gague 的值为 39
    temp.Set(39)
    // 暴露自定义指标
    http.Handle("/metrics", promhttp.HandlerFor(registry, promhttp.HandlerOpts{Registry: registry}))
    http.ListenAndServe(":8080", nil)
}