如何使用 Gin 上下文创建的请求 ID 记录 HTTP 客户端的请求

Question

想法：我想用唯一的请求 ID 将传入和传出请求记录到我的 Gin 服务器。此外，我想使用与路由相同的请求 ID 在我的 Gin 路由中记录所有 HTTP 客户端的请求。

所有这些都应该使用中间件在后台工作。

将请求记录到我的服务器（和响应）

为了将每个请求记录到我的服务器，我编写了这个中间件：

import (
    "bytes"
    "context"
    "github.com/gin-contrib/requestid"
    "github.com/gin-gonic/gin"
    "github.com/rs/zerolog/log"
    "io/ioutil"
    "net/http"
    "time"
)

type responseBodyWriter struct {
    gin.ResponseWriter
    body *bytes.Buffer
}

func (r responseBodyWriter) Write(b []byte) (int, error) {
    r.body.Write(b)
    return r.ResponseWriter.Write(b)
}

func LoggerMiddleware() gin.HandlerFunc {
    return func(c *gin.Context) {

        start := time.Now()

        w := &responseBodyWriter{body: &bytes.Buffer{}, ResponseWriter: c.Writer}
        c.Writer = w

        msg := "Input:"
        path := c.Request.URL.Path
        raw := c.Request.URL.RawQuery
        if raw != "" {
            path = path + "?" + raw
        }

        // Read from body and write here again.
        var bodyBytes []byte
        if c.Request.Body != nil {
            bodyBytes, _ = ioutil.ReadAll(c.Request.Body)
        }
        c.Request.Body = ioutil.NopCloser(bytes.NewBuffer(bodyBytes))

        inputLogger := log.With().
            Str("method", c.Request.Method).
            Str("path", path).
            Str("requestId", requestid.Get(c)).
            Logger()

        if len(bodyBytes) > 0 {
            inputLogger.Info().RawJSON("body", bodyBytes).Msg(msg)
        } else {
            inputLogger.Info().Msg(msg)
        }

        c.Next()

        end := time.Now()
        latency := end.Sub(start)

        msg = "Output:"
        outputLogger := log.With().
            Str("method", c.Request.Method).
            Str("path", path).
            Str("requestId", requestid.Get(c)).
            RawJSON("body", w.body.Bytes()).
            Int("status", c.Writer.Status()).
            Dur("latency", latency).
            Logger()

        switch {
        case c.Writer.Status() >= http.StatusBadRequest && c.Writer.Status() < http.StatusInternalServerError:
            {
                outputLogger.Warn().Msg(msg)
            }
        case c.Writer.Status() >= http.StatusInternalServerError:
            {
                outputLogger.Error().Msg(msg)
            }
        default:
            outputLogger.Info().Msg(msg)
        }

    }
}

记录在我的服务器路由中发出的请求

问题是：我不知道如何将由 Gin 的中间件创建的请求 ID（或 Gin 的上下文）传递给 RoundTrip 函数：

type Transport struct {
    Transport  http.RoundTripper
}

var defaultTransport = Transport{
    Transport: http.DefaultTransport,
}

func init() {
    http.DefaultTransport = &defaultTransport
}

func (t *Transport) RoundTrip(req *http.Request) (*http.Response, error) {
    ctx := context.WithValue(req.Context(), ContextKeyRequestStart, time.Now())
    req = req.WithContext(ctx)
    t.logRequest(req)

    resp, err := t.transport().RoundTrip(req)
    if err != nil {
        return resp, err
    }

    t.logResponse(resp)

    return resp, err
}

func (t *Transport) logRequest(req *http.Request) {
    log.Info().
        Str("method", req.Method).
        Str("path", req.URL.String()).
        Str("requestId", "how can I get request id here???").
        Msg("Api request: ")
}

func (t *Transport) logResponse(resp *http.Response) {
    var bodyBytes []byte
    if resp.Body != nil {
        bodyBytes, _ = ioutil.ReadAll(resp.Body)
    }
    resp.Body = ioutil.NopCloser(bytes.NewBuffer(bodyBytes))

    ctx := resp.Request.Context()
    log.Info().
        Str("method", resp.Request.Method).
        Str("path", resp.Request.URL.String()).
        Str("requestId", "how can I get request id here???").
        RawJSON("body", bodyBytes).
        Int("status", resp.StatusCode).
        Dur("latency", time.Now().Sub(ctx.Value(ContextKeyRequestStart).(time.Time))).
        Msg("API response: ")
}

func (t *Transport) transport() http.RoundTripper {
    if t.Transport != nil {
        return t.Transport
    }

    return http.DefaultTransport
}

Answer 1

Transport.RoundTrip 函数采用 *http.Request 参数，因此您应该能够通过在处理程序中创建请求来传递 Gin 上下文：

func MyHandler(c *gin.Context) {
        // passing context to the request
        req := http.NewRequestWithContext(c, "GET", "http://localhost:8080", nil)
        resp, err := http.DefaultClient.Do(req)
}

请注意，为了能够使用您在不进行额外初始化的情况下覆盖的默认RoundTripper，您应该使用http.DefaultClient。

Answer 2

你可以使用这个：
https://github.com/sumit-tembe/gin-requestid

package main

import (
    "net/http"

    "github.com/gin-gonic/gin"
    requestid "github.com/sumit-tembe/gin-requestid"
)

func main() {
    // without any middlewares
    router := gin.New()

    // Middlewares
    {
        //recovery middleware
        router.Use(gin.Recovery())
        //middleware which injects a 'RequestID' into the context and header of each request.
        router.Use(requestid.RequestID(nil))
        //middleware which enhance Gin request logger to include 'RequestID'
        router.Use(gin.LoggerWithConfig(requestid.GetLoggerConfig(nil, nil, nil)))
    }

    router.GET("/", func(c *gin.Context) {
        c.String(http.StatusOK, "Hello world!")
    })

    router.Run(":8080")
}

输出：

[GIN-debug] 2019-12-16T18:50:49+05:30 [bzQg6wTpL4cdZ9bM] - "GET /"
[GIN-debug] 2019-12-16T18:50:49+05:30 [bzQg6wTpL4cdZ9bM] - [::1] "GET / HTTP/1.1 200 22.415µs" Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/78.0.3904.108 Safari/537.36

它还支持自定义请求ID生成器，您可以根据需要设计。