You are viewing an old version of this page. View the current version.

Compare with Current View Page History

Version 24 Next »

从v2.0版本开始，glog组件提供了超级强大的、可自定义日志处理的Handler特性。Handler采用了中间件设计方式，开发者可以为日志对象注册多个处理Handler，也可以在Handler中覆盖默认的日志组件处理逻辑。

相关定义

Handler方法定义

// Handler is function handler for custom logging content outputs.
type Handler func(ctx context.Context, in *HandlerInput)

可以看到第二个参数为日志处理的日志信息，并且为指针类型，意味着在Handler中可以修改该参数的任意属性信息，并且修改后的内容将会传递给下一个Handler。

Handler参数定义

// HandlerInput is the input parameter struct for logging Handler.
type HandlerInput struct {
	Logger      *Logger       // Current Logger object.
	Buffer      *bytes.Buffer // Buffer for logging content outputs.
	Time        time.Time     // Logging time, which is the time that logging triggers.
	TimeFormat  string        // Formatted time string, like "2016-01-09 12:00:00".
	Color       int           // Using color, like COLOR_RED, COLOR_BLUE, etc. Eg: 34
	Level       int           // Using level, like LEVEL_INFO, LEVEL_ERRO, etc. Eg: 256
	LevelFormat string        // Formatted level string, like "DEBU", "ERRO", etc. Eg: ERRO
	CallerFunc  string        // The source function name that calls logging, only available if F_CALLER_FN set.
	CallerPath  string        // The source file path and its line number that calls logging, only available if F_FILE_SHORT or F_FILE_LONG set.
	CtxStr      string        // The retrieved context value string from context, only available if Config.CtxKeys configured.
	TraceId     string        // Trace id, only available if OpenTelemetry is enabled.
	Prefix      string        // Custom prefix string for logging content.
	Content     string        // Content is the main logging content without error stack string produced by logger.
	Values      []any         // The passed un-formatted values array to logger.
	Stack       string        // Stack string produced by logger, only available if Config.StStatus configured.
	IsAsync     bool          // IsAsync marks it is in asynchronous logging.
}

开发者有两种方式通过Handler自定义日志输出内容：

  • 一种是直接修改HandlerInput中的属性信息，然后继续执行in.Next()，默认的日志输出逻辑会将HandlerInput中的属性打印为字符串输出。
  • 另一种是将日志内容写入到Buffer缓冲对象中即可，默认的日志输出逻辑如果发现Buffer已经存在日志内容将会忽略默认日志输出逻辑。

Handler注册到Logger方法

// SetHandlers sets the logging handlers for current logger.
func (l *Logger) SetHandlers(handlers ...Handler)

使用示例

我们来看两个示例便于更快速了解Handler的使用。

示例1. 将日志输出转换为Json格式输出

在本示例中，我们采用了前置中间件的设计，通过自定义Handler将日志内容输出格式修改为了JSON格式。

package main

import (
	"context"
	"encoding/json"
	"os"

	"github.com/gogf/gf/v2/frame/g"
	"github.com/gogf/gf/v2/os/glog"
	"github.com/gogf/gf/v2/text/gstr"
)

// JsonOutputsForLogger is for JSON marshaling in sequence.
type JsonOutputsForLogger struct {
	Time    string `json:"time"`
	Level   string `json:"level"`
	Content string `json:"content"`
}

// LoggingJsonHandler is a example handler for logging JSON format content.
var LoggingJsonHandler glog.Handler = func(ctx context.Context, in *glog.HandlerInput) {
	jsonForLogger := JsonOutputsForLogger{
		Time:    in.TimeFormat,
		Level:   gstr.Trim(in.LevelFormat, "[]"),
		Content: gstr.Trim(in.Content),
	}
	jsonBytes, err := json.Marshal(jsonForLogger)
	if err != nil {
		_, _ = os.Stderr.WriteString(err.Error())
		return
	}
	in.Buffer.Write(jsonBytes)
	in.Buffer.WriteString("\n")
	in.Next(ctx)
}

func main() {
	g.Log().SetHandlers(LoggingJsonHandler)
	ctx := context.TODO()
	g.Log().Debug(ctx, "Debugging...")
	g.Log().Warning(ctx, "It is warning info")
	g.Log().Error(ctx, "Error occurs, please have a check")
}

可以看到，我们可以在Handler中通过Buffer属性操作来控制输出的日志内容。如果在所有的前置中间件Handler处理后Buffer内容为空，那么继续Next执行后将会执行日志中间件默认的Handler逻辑。执行本示例的代码后，终端输出：

{"time":"2021-12-31 11:03:25.438","level":"DEBU","content":"Debugging..."}
{"time":"2021-12-31 11:03:25.438","level":"WARN","content":"It is warning info"}
{"time":"2021-12-31 11:03:25.438","level":"ERRO","content":"Error occurs, please have a check \nStack:\n1.  main.main\n    C:/hailaz/test/main.go:42"}

示例2. 将内容输出到第三方日志搜集服务中

在本示例中，我们采用了后置中间件的设计，通过自定义Handler将日志内容输出一份到第三方graylog日志搜集服务中，并且不影响原有的日志输出处理。

Graylog 是与 ELK 可以相提并论的一款集中式日志管理方案，支持数据收集、检索、可视化 Dashboard。在本示例中使用到了一个简单的第三方graylog客户端组件。

package main

import (
	"context"

	"github.com/gogf/gf/v2/frame/g"
	"github.com/gogf/gf/v2/os/glog"
	gelf "github.com/robertkowalski/graylog-golang"
)

var grayLogClient = gelf.New(gelf.Config{
	GraylogPort:     80,
	GraylogHostname: "graylog-host.com",
	Connection:      "wan",
	MaxChunkSizeWan: 42,
	MaxChunkSizeLan: 1337,
})

// LoggingGrayLogHandler is an example handler for logging content to remote GrayLog service.
var LoggingGrayLogHandler glog.Handler = func(ctx context.Context, in *glog.HandlerInput) {
	in.Next()
	grayLogClient.Log(in.Buffer.String())
}

func main() {
	g.Log().SetHandlers(LoggingGrayLogHandler)
	ctx := context.TODO()
	g.Log().Debug(ctx, "Debugging...")
	g.Log().Warning(ctx, "It is warning info")
	g.Log().Error(ctx, "Error occurs, please have a check")
	glog.Print(ctx, "test log")
}

全局默认Handler

日志对象默认是没有设置任何的Handler，从v2.1版本开始，框架提供了可以设置全局默认Handler的功能特性。全局默认Handler将对所有的使用该日志组件，并且没有自定义Handler的日志打印功能生效。同时，全局默认Handler将会影响日志包方法的日志打印行为。

开发者可以通过以下两个方法来设置和获取全局默认的Handler。

// SetDefaultHandler sets default handler for package.
func SetDefaultHandler(handler Handler)

// GetDefaultHandler returns the default handler of package.
func GetDefaultHandler() Handler

需要注意，这种全局包配置的方法不是并发安全的，并且往往需要在项目启动逻辑最顶部执行。

使用示例，我们将项目所有的日志输出均采用JSON格式输出，以保证日志内容结构化并且每次日志输出都是单行，方便日志采集期采集日志：

package main

import (
	"context"
	"encoding/json"
	"os"

	"github.com/gogf/gf/v2/frame/g"
	"github.com/gogf/gf/v2/os/glog"
	"github.com/gogf/gf/v2/text/gstr"
)

// JsonOutputsForLogger is for JSON marshaling in sequence.
type JsonOutputsForLogger struct {
	Time    string `json:"time"`
	Level   string `json:"level"`
	Content string `json:"content"`
}

// LoggingJsonHandler is a example handler for logging JSON format content.
var LoggingJsonHandler glog.Handler = func(ctx context.Context, in *glog.HandlerInput) {
	jsonForLogger := JsonOutputsForLogger{
		Time:    in.TimeFormat,
		Level:   gstr.Trim(in.LevelFormat, "[]"),
		Content: gstr.Trim(in.Content),
	}
	jsonBytes, err := json.Marshal(jsonForLogger)
	if err != nil {
		_, _ = os.Stderr.WriteString(err.Error())
		return
	}
	in.Buffer.Write(jsonBytes)
	in.Buffer.WriteString("\n")
	in.Next(ctx)
}

func main() {
	ctx := context.TODO()
	glog.SetDefaultHandler(LoggingJsonHandler)

	g.Log().Debug(ctx, "Debugging...")
	glog.Warning(ctx, "It is warning info")
	glog.Error(ctx, "Error occurs, please have a check")
}

执行后，终端输出：

{"time":"2022-06-20 10:51:50.235","level":"DEBU","content":"Debugging..."}
{"time":"2022-06-20 10:51:50.235","level":"WARN","content":"It is warning info"}
{"time":"2022-06-20 10:51:50.235","level":"ERRO","content":"Error occurs, please have a check"}

组件通用Handler

组件提供了一些通用性的日志Handler，方便开发者使用，提高开发效率。

HandlerJson

该Handler可以将日志内容转换为Json格式打印。使用示例：

package main

import (
	"context"

	"github.com/gogf/gf/v2/frame/g"
	"github.com/gogf/gf/v2/os/glog"
)

func main() {
	ctx := context.TODO()
	glog.SetDefaultHandler(glog.HandlerJson)

	g.Log().Debug(ctx, "Debugging...")
	glog.Warning(ctx, "It is warning info")
	glog.Error(ctx, "Error occurs, please have a check")
}

执行后，终端输出：

{"Time":"2022-06-20 20:04:04.725","Level":"DEBU","Content":"Debugging..."}
{"Time":"2022-06-20 20:04:04.725","Level":"WARN","Content":"It is warning info"}
{"Time":"2022-06-20 20:04:04.725","Level":"ERRO","Content":"Error occurs, please have a check","Stack":"1.  main.main\n    /Users/john/Workspace/Go/GOPATH/src/github.com/gogf/gf/.test/main.go:16\n"}

HandlerStructure

该Handler可以将日志内容转换为结构化格式打印，主要是为了和Golang新版本的slog日志输出内容保持一致。使用示例：

package main

import (
	"context"
	"net"

	"github.com/gogf/gf/v2/frame/g"
	"github.com/gogf/gf/v2/os/glog"
)

func main() {
	ctx := context.TODO()
	glog.SetDefaultHandler(glog.HandlerStructure)

	g.Log().Info(ctx, "caution", "name", "admin")
	glog.Error(ctx, "oops", net.ErrClosed, "status", 500)
}

 执行后，终端输出：

Time="2023-11-23 21:00:08.671" Level=INFO Content=caution name=admin
Time="2023-11-23 21:00:08.671" Level=ERRO oops="use of closed network connection" status=500 Stack="1.  main.main\n    /Users/txqiangguo/Workspace/gogf/gf/example/.test/main.go:16\n"




Content Menu

  • No labels