基础包

net

pprof

golang 提供的 pprof 工具可以很方便的分析性能上的问题比如cpu的使用情况，堆内存分配，goroutine 死锁情况等。

mux := http.NewServeMux()
mux.HandleFunc("/debug/pprof/", pprof.Index)
mux.HandleFunc("/debug/pprof/cmdline", pprof.Cmdline)
mux.HandleFunc("/debug/pprof/profile", pprof.Profile)
mux.HandleFunc("/debug/pprof/symbol", pprof.Symbol)
mux.HandleFunc("/debug/pprof/trace", pprof.Trace)

pprofServer := http.Server{
    Addr:    pprofAddr,
    Handler: mux,
}
setupLog.Info("Starting pprof HTTP server", "pprof server address", pprofServer.Addr)

go func() {
    go func() {
        ctx := context.Background()
        <-ctx.Done()

        ctx, cancelFunc := context.WithTimeout(context.Background(), 60*time.Minute)
        defer cancelFunc()

        if err := pprofServer.Shutdown(ctx); err != nil {
            setupLog.Error(err, "Failed to shutdown debug HTTP server")
        }
    }()

    if err := pprofServer.ListenAndServe(); !errors.Is(http.ErrServerClosed, err) {
        setupLog.Error(err, "Failed to start debug HTTP server")
        panic(err)
    }
}()

json

json包是通过反射机制来实现编解码的，因此结构体必须导出所转换的字段，不导出的字段不会被json包解析。

type DebugInfo struct {
   Level  string `json:"level,omitempty"` // Level解析为level,忽略空值
   Msg    string `json:"message"`     // Msg解析为message
   Author string `json:"-"`        // 忽略Author
}

log

Zap logging

zap是uber开源的一款高性能日志组件框架

github.com/golang/glog

github.com/go-logr/logr

A simple logging interface for Go

Log 门面实现（类似slf4j）

log.V(1).Info("job count", "active jobs", len(activeJobs), "successful jobs", len(successfulJobs), "failed jobs", len(failedJobs))

github.com/go-logr/glogr

An implementation of logr (Go logging) with glog

github.com/go-logr/zapr

A logr implementation using Zap

使用

import (
    "fmt"

    "go.uber.org/zap"
    "github.com/go-logr/logr"
    "github.com/go-logr/zapr"
)

func main() {
    var log logr.Logger

    zapLog, err := zap.NewDevelopment()
    if err != nil {
        panic(fmt.Sprintf("who watches the watchmen (%v)?", err))
    }
    log = zapr.NewLogger(zapLog)

    log.Info("Logr in action!", "the answer", 42)
}

CLI（Cobra）

CLI：A Commander for modern Go CLI interactions

• Easy subcommand-based CLIs: app server, app fetch, etc.
• Fully POSIX-compliant flags (including short & long versions)
• Nested subcommands
• Global, local and cascading flags
• Easy generation of applications & commands with cobra init & cobra add cmdname
• Intelligent suggestions (app srver... did you mean app server?)
• Automatic help generation for commands and flags
• Automatic help flag recognition of -h, --help, etc.
• Automatically generated shell autocomplete for your application (bash, zsh, fish, powershell)
• Automatically generated man pages for your application
• Command aliases so you can change things without breaking them
• The flexibility to define your own help, usage, etc.
• Optional seamless integration with viper for 12-factor apps

原理

Commands represent actions

Args are things

Flags are modifiers for those actions.

# server is a command, and port is a flag
$ hugo server --port=1313

demo

import ( "github.com/spf13/cobra" )
var (
    short                bool
    metricsAddr          string
    enableLeaderElection bool
    development          bool
    pprofAddr            string
)
var cmd = &cobra.Command{
    Use:   "dataset-controller",
    Short: "controller for dataset",
}
var startCmd = &cobra.Command{
    Use:   "start",
    Short: "start dataset-controller in Kubernetes",
    Run: func(cmd *cobra.Command, args []string) {
        handle()
    }
}

func init() {
    startCmd.Flags().StringVarP(&metricsAddr, "metrics-addr", "", ":8080", "The address the metric endpoint binds to.")
    startCmd.Flags().BoolVarP(&enableLeaderElection, "enable-leader-election", "", false, "Enable leader election for controller manager. Enabling this will ensure there is only one active controller manager.")
    startCmd.Flags().BoolVarP(&development, "development", "", true, "Enable development mode for fluid controller.")
    startCmd.Flags().StringVarP(&pprofAddr, "pprof-addr", "", "", "The address for pprof to use while exporting profiling results")
    cmd.AddCommand(startCmd)
}

func main() {
    if err := cmd.Execute(); err != nil {
        fmt.Fprintf(os.Stderr, "%s", err.Error())
        os.Exit(1)
    }
}

Template

https://golang.google.cn/pkg/text/template/

模板引擎

viper（配置读写）

go get github.com/spf13/viper

读

viper.SetConfigName("config") // name of config file (without extension)
viper.SetConfigType("yaml") // REQUIRED if the config file does not have the extension in the name
viper.AddConfigPath("/etc/appname/")   // path to look for the config file in
viper.AddConfigPath("$HOME/.appname")  // call multiple times to add many search paths
viper.AddConfigPath(".")               // optionally look for config in the working directory
err := viper.ReadInConfig() // Find and read the config file
if err != nil { // Handle errors reading the config file
    panic(fmt.Errorf("fatal error config file: %w", err))
}