9.【go-kit教程】go-kit集成Prometheus

在 Go kit 中集成 Prometheus 进行 API 监控可以帮助开发人员更好地了解系统的性能和行为，提高系统的可观察性和可靠性。下面是一个简单的示例，演示如何在 Go kit 中集成 Prometheus 进行 API 监控：

package main

import (
        "net/http"

        "github.com/go-kit/kit/log"
        "github.com/go-kit/kit/metrics/prometheus"
        "github.com/go-kit/kit/metrics/provider"
        "github.com/go-kit/kit/transport"
        httptransport "github.com/go-kit/kit/transport/http"
        "github.com/prometheus/client_golang/prometheus/promhttp"
)

func main() {
        // 创建 Prometheus 监控器
        fieldKeys := []string{"method", "error"}
        requestCount := prometheus.NewCounterFrom(provider.NewProvider(), prometheus.CounterOpts{
                Namespace: "my_api",
                Name:      "request_count",
                Help:      "Number of requests received.",
        }, fieldKeys)
        requestLatency := prometheus.NewSummaryFrom(provider.NewProvider(), prometheus.SummaryOpts{
                Namespace: "my_api",
                Name:      "request_latency",
                Help:      "Total duration of requests in microseconds.",
        }, fieldKeys)

        // 创建 endpoint
        helloEndpoint := func() string {
                return "Hello, World!"
        }
        helloEndpoint = transport.NewServer(
                helloEndpoint,
                func(ctx context.Context, r *http.Request) (interface{}, error) {
                        return nil, nil
                },
                func(ctx context.Context, w http.ResponseWriter, response interface{}) error {
                        w.Header().Set("Content-Type", "text/plain; charset=utf-8")
                        fmt.Fprint(w, response.(string))
                        return nil
                },
                transport.ServerErrorLogger(log.NewNopLogger()),
                transport.ServerErrorEncoder(errorEncoder),
                transport.ServerBefore(prometheus.HTTPToContext()),
        ).Endpoint()

        // 创建 HTTP server
        r := mux.NewRouter()
        r.Handle("/hello", httptransport.NewServer(
                helloEndpoint,
                httpDecodeRequest,
                httpEncodeResponse,
                httptransport.ServerBefore(prometheus.HTTPToContext()),
                httptransport.ServerErrorLogger(log.NewNopLogger()),
                httptransport.ServerErrorEncoder(errorEncoder),
                httptransport.ServerBefore(prometheus.HTTPToContext()),
        )).Methods("GET")
        r.Handle("/metrics", promhttp.Handler())

        fmt.Println("listening on :8080...")
        http.ListenAndServe(":8080", r)
}

func httpDecodeRequest(_ context.Context, r *http.Request) (interface{}, error) {
        return nil, nil
}

func httpEncodeResponse(_ context.Context, w http.ResponseWriter, response interface{}) error {
        w.Header().Set("Content-Type", "text/plain; charset=utf-8")
        fmt.Fprint(w, response.(string))
        return nil
}

func errorEncoder(_ context.Context, err error, w http.ResponseWriter) {
        w.Header().Set("Content-Type", "text/plain; charset=utf-8")
        w.WriteHeader(http.StatusBadRequest)
        fmt.Fprint(w, err.Error())
}