To load and use a Go plugin in a Golang application, you can follow these steps:
Create a plugin package: Start by creating a separate Go package for your plugin. This package should contain the functions or variables that you want to expose and use from your main application.
Build the plugin: Build the plugin package as a shared library using the -buildmode=plugin flag with the go build command. For example:
$ go build -buildmode=plugin -o plugin.so plugin.go
This command will generate a plugin.so file in the current directory. Make sure that the package name matches the filename (plugin.go in this case) to ensure compatibility.
Import and load the plugin: In your main application, import the plugin package from the standard library and load the plugin using the plugin.Open() function. For example:
package main
import (
"plugin"
)
func main() {
p, err := plugin.Open("plugin.so")
if err != nil {
panic(err)
}
// Use the loaded plugin...
}
Here, the plugin.Open() function is used to load the shared library. You need to provide the path to the generated plugin.so file as an argument.
Access and use plugin functions: Once you've loaded the plugin, you can access its functions and variables using the Lookup() function from the loaded plugin object. For example:
func main() {
// ...
greetSym, err := p.Lookup("Greet")
if err != nil {
panic(err)
}
greetFunc, ok := greetSym.(func(string) string)
if !ok {
panic("Invalid symbol type")
}
result := greetFunc("John")
fmt.Println(result)
}
Here, we use the Lookup("Greet") function to retrieve a symbol (function or variable) named "Greet" from the loaded plugin. Then, we assert the symbol to a function type and use it to invoke the function.
That's it! You have successfully loaded and used the plugin in your Golang application. Remember to handle errors appropriately and close the loaded plugin when you're done using it.