Go实战--实现一个自己的网络请求日志httplogger(The way to go)

生命不止，继续go go go~~~

之前我们简要介绍了go语言中的log package 和 net／http package，那么我们今天就干点实事儿，将二者结合，实现我们自己的日志记录网络请求。

另外，我们还没有跟你介绍time package，但是也可以看懂的。

首先，我默认你了解go语言的组织结构。

导入需要的package

我们需要 log net/http time三个包

package httplogger

import (
"log"
"net/http"
"time"
)

实现一个结构体

type loggedRoundTripper struct {
rt  http.RoundTripper
log HTTPLogger
}

其中http.RoudTripper:

RoundTripper is an interface representing the ability to execute a single HTTP transaction, obtaining the Response for a given Request.

实现一个接口HTTPLogger

type HTTPLogger interface {
LogRequest(*http.Request)
LogResponse(*http.Request, *http.Response, error, time.Duration)
}

实现函数：

type DefaultLogger struct {
}

func (dl DefaultLogger) LogRequest(*http.Request) {
}

func (dl DefaultLogger) LogResponse(req *http.Request, res *http.Response, err error, duration time.Duration) {
duration /= time.Millisecond
if err != nil {
log.Printf("HTTP Request method=%s host=%s path=%s status=error durationMs=%d error=%q", req.Method, req.Host, req.URL.Path, duration, err.Error())
} else {
log.Printf("HTTP Request method=%s host=%s path=%s status=%d durationMs=%d", req.Method, req.Host, req.URL.Path, res.StatusCode, duration)
}
}

完整代码

package httplogger

import (
"log"
"net/http"
"time"
)

type loggedRoundTripper struct {
rt  http.RoundTripper
log HTTPLogger
}

func (c *loggedRoundTripper) RoundTrip(request *http.Request) (*http.Response, error) {
c.log.LogRequest(request)
startTime := time.Now()
response, err := c.rt.RoundTrip(request)
duration := time.Since(startTime)
c.log.LogResponse(request, response, err, duration)
return response, err
}

// NewLoggedTransport takes an http.RoundTripper and returns a new one that logs requests and responses
func NewLoggedTransport(rt http.RoundTripper, log HTTPLogger) http.RoundTripper {
return &loggedRoundTripper{rt: rt, log: log}
}

// HTTPLogger defines the interface to log http request and responses
type HTTPLogger interface {
LogRequest(*http.Request)
LogResponse(*http.Request, *http.Response, error, time.Duration)
}

// DefaultLogger is an http logger that will use the standard logger in the log package to provide basic information about http responses
type DefaultLogger struct {
}

// LogRequest doens't do anything since we'll be logging replies only
func (dl DefaultLogger) LogRequest(*http.Request) {
}

// LogResponse logs path, host, status code and duration in milliseconds
func (dl DefaultLogger) LogResponse(req *http.Request, res *http.Response, err error, duration time.Duration) {
duration /= time.Millisecond
if err != nil {
log.Printf("HTTP Request method=%s host=%s path=%s status=error durationMs=%d error=%q", req.Method, req.Host, req.URL.Path, duration, err.Error())
} else {
log.Printf("HTTP Request method=%s host=%s path=%s status=%d durationMs=%d", req.Method, req.Host, req.URL.Path, res.StatusCode, duration)
}
}

// DefaultLoggedTransport wraps http.DefaultTransport to log using DefaultLogger
var DefaultLoggedTransport = NewLoggedTransport(http.DefaultTransport, DefaultLogger{})

使用

实现接口：

type httpLogger struct {
log *log.Logger
}

func newLogger() *httpLogger {
return &httpLogger{
log: log.New(os.Stderr, "log - ", log.LstdFlags),
}
}

func (l *httpLogger) LogRequest(req *http.Request) {
l.log.Printf(
"Request %s %s",
req.Method,
req.URL.String(),
)
}

func (l *httpLogger) LogResponse(req *http.Request, res *http.Response, err error, duration time.Duration) {
duration /= time.Millisecond
if err != nil {
l.log.Println(err)
} else {
l.log.Printf(
"Response method=%s status=%d durationMs=%d %s",
req.Method,
res.StatusCode,
duration,
req.URL.String(),
)
}
}

完整代码：

package main

import (
"log"
"net/http"
"os"
"time"

"httplogger/httplogger"
)

func main() {
client := http.Client{
Transport: httplogger.NewLoggedTransport(http.DefaultTransport, newLogger()),
}

client.Get("https://www.baidu.com")
}

type httpLogger struct {
log *log.Logger
}

func newLogger() *httpLogger {
return &httpLogger{
log: log.New(os.Stderr, "log - ", log.LstdFlags),
}
}

func (l *httpLogger) LogRequest(req *http.Request) {
l.log.Printf(
"Request %s %s",
req.Method,
req.URL.String(),
)
}

func (l *httpLogger) LogResponse(req *http.Request, res *http.Response, err error, duration time.Duration) {
duration /= time.Millisecond
if err != nil {
l.log.Println(err)
} else {
l.log.Printf(
"Response method=%s status=%d durationMs=%d %s",
req.Method,
res.StatusCode,
duration,
req.URL.String(),
)
}
}

结果：

log - 2017/04/18 23:39:41 Request GET https://www.baidu.com

log - 2017/04/18 23:39:42 Response method=GET status=200 durationMs=614 https://www.baidu.com