Vendors a set of go dependencies using 'gb-vendor', by reading the gb vendor manifest from another project.

gb2gb.go

// aids in moving deps from one gb project to another gb project:
//
// reads a gb vendor/manifest and uses the 'gb-vendor' plugin to vendor the
// same revision of each dependency into another gb-based project.
//
// Example:
//   To vendor all the dependencies of the project at /go/src/github.com/username/foo
//   into the new project at /path/to/gb/proj, run the following:
//
//    $ go run gb2gb.go -src-manifest=/go/src/github.com/username/foo/vendor/manifest -dest=/path/to/gb/proj
//
package main

import (
	"encoding/json"
	"flag"
	"fmt"
	"io/ioutil"
	"os/exec"
)

var (
	gbSrcManifest string
	gbDest        string
)

type Dep struct {
	ImportPath string `json:"importpath"`
	Revision   string `json:"revision"`
	Repo       string `json:"repository"`
}

func main() {
	flag.StringVar(&gbSrcManifest, "src-manifest", "", "the path to the gb manifest to copy from")
	flag.StringVar(&gbDest, "dest", "", "the project root for the gb project to copy to")
	flag.Parse()

	file, err := ioutil.ReadFile(gbSrcManifest)
	if err != nil {
		panic(err)
	}

	var manifest struct {
		Deps []Dep `json:"dependencies"`
	}

	if err := json.Unmarshal(file, &manifest); err != nil {
		panic(err)
	}

	for _, dep := range manifest.Deps {
		fmt.Printf("vendoring pkg %s, rev %s...\n", dep.ImportPath, dep.Revision)

		cmd := exec.Command("gb", "vendor", "fetch", "--revision", dep.Revision, dep.ImportPath)
		cmd.Dir = gbDest
		byts, err := cmd.CombinedOutput()
		if err != nil {
			fmt.Printf("ERROR: %s\n", string(byts))
			// don't panic or exit; just keep going if the dep was already vendored
		}
		fmt.Println(string(byts))
	}
}