Detect the exists of methods in golang

Suppose we are trying to process a few interfaces, but not sure does a specific function exists.

A simple way is to declare a small interface, and try to cast into it.

Here is a simple example:

package main

import (
    "fmt"
)

func TryExecFunc(in interface{}) {
    type iFoo interface {
        Foo() string
    }

    if in != nil {
        if foo, ok := in.(iFoo); ok {
            fmt.Println("implemented, result: ", foo.Foo())
        } else {
            fmt.Println("not implemented")
        }
    } else {
        fmt.Println("in is nil")
    }
}

type MyFoo struct {
    Key string
}

func (f *MyFoo) Foo() string {
    return fmt.Sprintf("MyFoo: %v", f.Key)
}

func main() {
    TryExecFunc(nil)
    TryExecFunc("abc")
    f := &MyFoo{"my key"}
    TryExecFunc(f)
}

The output would seems as follow:

in is nil
not implemented
implemented, result:  MyFoo: my key