Minimum Viable Go Dependency Manager

checkit.go

package main

import (
	"fmt"
	"os"
	"os/exec"
	"strings"
)

func main() {
	if len(os.Args) < 3 {
		fmt.Println("Usage: checkit <import path> <ref>")
		os.Exit(1)
	}

	imp := os.Args[1]
	ref := os.Args[2]

	fmt.Println("checkit: checking out", imp, "@", ref)

	paths := strings.Split(os.Getenv("GOPATH"), ":")

	var path string
	for _, p := range paths {
		full := strings.Join([]string{p, "/src/", imp}, "")
		if _, err := os.Stat(full); err == nil {
			path = full
			break
		}
	}

	if path == "" {
		fmt.Println("checkit: could not find", imp)
		os.Exit(1)
	}

	cmd := exec.Command("git", "checkout", ref)
	cmd.Dir = path

	if err := cmd.Run(); err != nil {
		fmt.Println("checkit:", err)
		os.Exit(1)
	}
}

Makefile

build:
	# get all the deps
	go get -d -v -t ./...
	# check out the library to the right ref
	checkit github.com/myaccount/mylib abc123
	# build stuff!
	go build ./...