go-plugin.md

go plugin

The golang official plugin is only supported on Linux, FreeBSD, and macOS. And this solution also has many drawbacks.

create plugin functions

Firstly, you need to define your plugin functions. The functions can be very flexible, only the following restrictions should be complied with.

• plugin package name must be main.
• function names must be capitalized.
• function should return at most one value and one error.

Here is some plugin functions as example.

package main

func SumTwoInt(a, b int) int {
	return a + b
}

func SumInts(args ...int) int {
	var sum int
	for _, arg := range args {
		sum += arg
	}
	return sum
}

func Sum(args ...interface{}) (interface{}, error) {
	var sum float64
	for _, arg := range args {
		switch v := arg.(type) {
		case int:
			sum += float64(v)
		case float64:
			sum += v
		default:
			return nil, fmt.Errorf("unexpected type: %T", arg)
		}
	}
	return sum, nil
}

You can get more examples at fungo/examples/debugtalk.go

build plugin

Then you can build your go plugin with -buildmode=plugin flag to binary file xxx.so. The file suffix of .so is by convention and should not be changed.

$ go build -buildmode=plugin -o=fungo/examples/xxx.so fungo/examples/debugtalk.go

use plugin functions

Finally, you can use Init to initialize plugin via the xxx.so path, and you can call the plugin API to handle plugin functionality.

Notice: you should use the original function name.