Import inside of a function-CodePudding

As the title asks, is there any way to import a go file from inside of a function? I was thinking of using a loop for my discordgo(https://pkg.go.dev/github.com/bwmarrin/discordgo) program.

ex :

package main

import (
    ...
)

func main() {
    client, _ := disocrdgo.New("Bot "   mytoken)
    ...


    events, _ := ioutil.ReadDir("./events")
    for event, _ := range events {
        x, _ := import "MyApp/src/events/"   event // <---
        client.AddHandler(x.executor) // using type struct where executor is the function i want to use from the imported file
    }

    ...
}

I feel obligated to precise it so : Thanks for your SERIOUS answers.

CodePudding user response：

Imports are a compiler concept, so you cannot import packages at runtime (the source code doesn't even exist on the machine running your program, usually).

You can use the registry pattern to get close to what you're looking for.

In the events package, create a function that stores handlers. Call that function in the init function for each event handler package.
In the events package, create another function that adds the stored handlers to a client.
In the main package, import all event handler packages you need and call that second function.

This is more or less how the sql and image packages in the standard library work. See sql.Register and image.RegisterFormat.

// events/registry.go
package events

var handlers = map[string]interface{}{}

func Register(name string, h interface{}) {
    handlers[name] = h
}

func ConfigureClient(client *discordgo.Session) {
    for _, h := range handlers {
        client.AddHandler(h)
    }
}

// events/foo/foo.go
package foo

import "MyApp/src/events"

func init() {
    events.Register("foo", executor{})
}

type executor struct{}

// events/bar/bar.go
package bar

import "MyApp/src/events"

func init() {
    events.Register("bar", executor{})
}

type executor struct{}

// main.go
package main

import (
    _ "MyApp/src/events/foo"
    _ "MyApp/src/events/bar"
    // ...
)

func main() {
    client, _ := discordgo.New("Bot "   mytoken)
    events.ConfigureClient(client)
}

CodePudding user response：

You can precompile the go packages and use go plugins to load the lib, see https://pkg.go.dev/plugin for usage