maxim-ge/godif

Go Dependency Injection For Functions

godif

Inject Functions

Usage

1. Declare Functions

package decl

// Declare function types explicitly, otherwise functions are matched by signature
type Func1Type func(x int, y int)
type Func2Type func(s string)

var Func1 Func1Type
var Func2 Func2Type

2. Provide Functions

package prov

func Declare() {
    godif.Provide(decl.func1, MyFunc1)
    godif.Provide(decl.func2, MyFunc2)
}

func MyFunc1(x int, y int) {
...
}

func MyFunc2(s string) {
...
}

3. Require Functions

package req

func Declare() {
    godif.Require(&decl.Func1)
    godif.Require(&decl.Func2)
}

4. Build App

package main

func main(){
    prov.Declare()
    req.Declare()

    errs := godif.ResolveAll()
    if len(errs) != 0{
        // Non-assignalble Requirements
        // Cyclic dependencies
        // Unresolved dependencies
        // Multiple implementations
        log.Panic(errs)
    }

    // All implementors of godif.InitFunc will be called
    // Dependency defines the order of init
    errs = godif.Init()
    defer godif.Finit()

    if len(errs) != 0{
        log.Panic(errs)
    } 

    // Do something
    declare.Func1(1, 2)
    declare.Func2("Hello")

}

Under the Hood

• All registration functions works with default instance of godif.ContainerDeclaration
• ResolveAll creates default instance of godif.ContainerInstance which is used to init/finit/start/stop