Plugin库介绍

Package plugin implements loading and symbol resolution of Go plugins.

A plugin is a Go main package with exported functions and variables that has been built with:

go build -buildmode=plugin
When a plugin is first opened, the init functions of all packages not already part of the program are called. The main function is not run. A plugin is only initialized once, and cannot be closed.

Currently plugins are only supported on Linux, FreeBSD, and macOS. Please report any issues.

type Plugin
    func Open(path string) (*Plugin, error)
    func (p *Plugin) Lookup(symName string) (Symbol, error)
type Symbol

通过概览，了解到这个库提供了插件化开发的模式，符合unix设计哲学。

使用

废话不多说，先撸起代码：

写一个plugin的源文件：

然后写一个主程序：

/**
* @file main.go
* @brief 主程序入口
* @author DongChaofeng <s654632396@hotmail.com>
* @version 0.0.1
* @date 2021-07-14
 */

package main

import (
  "fmt"
  "os"
  "plugin"
)

// Plugins 全局插件变量
var Plugins map[string]*plugin.Plugin

/**
* @brief init 程序初始化
*
* @return
 */
func init() {
  fmt.Println("main initialize..")
  fmt.Println("init Plugins Mapper...")
  // 初始化我们的全局插件变量mapper
  Plugins = make(map[string]*plugin.Plugin)
  // 调用加载插件的函数
  if err := loadPlugs(); err != nil {
       fmt.Errorf("[loading plugins] %s\n", err)
       os.Exit(1)
  }
}

/**
* @brief loadPlugs 加载默认so插件的函数
*
* @param
*
* @return error
 */
func loadPlugs() (err error) {
  // 从本地加载动态链接库, 注册到全局插件变量里
  Plugins["plug_1"], err = plugin.Open("./plug_1.so")
  if err != nil {
       return err
  }
  fmt.Println("plugs loaded.")
  return
}

func main() {

  // 使用Lookup函数,从 plug_1 这个so库中查找 TestPlug 这个symbol
  funcTest, err := Plugins["plug_1"].Lookup("TestPlug")
  if err != nil {
       fmt.Println(err)
       os.Exit(1)
  }

  // 然后使用断言， 断言这个symbol的类型, 这里是断言的 type func(string)
  if PfuncTestPlug, ok := funcTest.(func(string)); ok {
       // 现在可以调用函数了
       PfuncTestPlug("abc")
  }
}

编写我们的makefile

BUILD_PATH?=build
MAIN_OUTPUT_FILE=test
MAIN_PROGRAM=${BUILD_PATH}/${MAIN_OUTPUT_FILE}


# make run
run:  plug_1.so
  go build  -o=${MAIN_PROGRAM} main.go
  [ -f "${MAIN_PROGRAM}" ] && cd ${BUILD_PATH} && sh -c ./${MAIN_OUTPUT_FILE}; cd -

plug_1.so: clean
  go build -buildmode=plugin -o=${BUILD_PATH}/plug_1.so plug_1.go

pre_build:
  ([ ! -d "${BUILD_PATH}" ] && mkdir ${BUILD_PATH}) || echo "ok."


clean: pre_build
  [ -d "${BUILD_PATH}" ] && rm -rf ${BUILD_PATH}/{*.so,${MAIN_OUTPUT_FILE}}

.Phony: run clean pre_build

好，现在目录如下：

执行

完美运行！

参考阅读

• Go进阶25:Go插件plugin教程