How to pass complex data structures (e.g., structs, maps) between a Golang application and plugins?

To pass complex data structures between a Golang application and plugins, you can use the plugin package provided by the standard library. Here's a step-by-step guide:

Define a common interface: Create an interface that defines the functions or methods you want to expose to plugins. This interface should include any necessary methods for accessing or manipulating the data structures.

type DataService interface {
    GetData() []structs.MyStruct
    SetData([]structs.MyStruct)
    // other methods...
}

Implement the interface in your main application: Create a struct that implements the defined interface and holds the complex data structures. This struct will serve as the shared data between your application and plugins.

type DataServiceImpl struct {
    data []structs.MyStruct
    // other fields...
}

func (d *DataServiceImpl) GetData() []structs.MyStruct {
    return d.data
}

func (d *DataServiceImpl) SetData(data []structs.MyStruct) {
    d.data = data
}

// other method implementations...

Load the plugin: In your main application, use the plugin.Open() function to load the plugin file. Make sure the plugin implements the same interface.

plugin, err := plugin.Open("plugin.so")
if err != nil {
    // handle error
}

Retrieve the exported symbol: Use the plugin.Lookup() function to get a reference to the symbol that implements the defined interface.

symbol, err := plugin.Lookup("DataPlugin")
if err != nil {
    // handle error
}

dataService, ok := symbol.(DataService)
if !ok {
    // handle type assertion error
}

Use the interface methods: Now, you can use the interface methods to interact with the complex data structures from your main application or plugin.

// Get data from the plugin
data := dataService.GetData()

// Modify the data and set it back to the plugin
data[0].Field = "NewValue"
dataService.SetData(data)

Build the plugin: The plugin code should implement the defined interface and build as a shared object (.so) file.

package main

import "C"

type DataPlugin struct{}

func (d *DataPlugin) GetData() []structs.MyStruct {
    // implement logic to retrieve data
    return data
}

func (d *DataPlugin) SetData(data []structs.MyStruct) {
    // implement logic to set data
}

// other method implementations...

// Export the symbol
var DataPluginExport = DataPlugin{}

Make sure to build the plugin using the -buildmode=plugin flag: go build -buildmode=plugin -o plugin.so plugin.go.

With these steps, you can pass complex data structures between your Golang application and plugins using a common interface.