How to create a basic Go plugin in Golang?

To create a basic Go plugin in Golang, follow these steps:

Create a Go package with the desired functionality that you want to export as a plugin. For example, create a file called plugin.go with the following content:

package main

import "fmt"

// Exported function to be used as a plugin
func ExportedFunction() {
    fmt.Println("Exported function called")
}

// Exported variable to be used as a plugin
var ExportedVariable = 42

Build the package as a shared library or a plugin using the -buildmode flag. Use either plugin (for Linux and macOS) or --buildmode=plugin (for Windows). For example, to build the plugin for Linux:

go build -buildmode=plugin -o myplugin.so plugin.go

This will create a shared library file called myplugin.so that contains your exported functionality.

Use the plugin in another Go program. Create a new file called main.go with the following content:

package main

import (
    "fmt"
    "plugin"
)

func main() {
    // Open the plugin
    p, err := plugin.Open("myplugin.so")
    if err != nil {
        fmt.Println("Error opening plugin:", err)
        return
    }

    // Look up the exported function
    f, err := p.Lookup("ExportedFunction")
    if err != nil {
        fmt.Println("Error looking up function:", err)
        return
    }

    // Call the exported function
    f.(func())()

    // Look up the exported variable
    v, err := p.Lookup("ExportedVariable")
    if err != nil {
        fmt.Println("Error looking up variable:", err)
        return
    }

    // Print the value of the exported variable
    fmt.Println("Exported variable:", v.(int))
}

Build and run the program:

go run main.go

This will load the plugin, call the exported function ExportedFunction, and print the value of the exported variable ExportedVariable.