gvt, the go vendoring tool

gvt is a simple Go vendoring tool made for the GO15VENDOREXPERIMENT, based on gb-vendor.

It lets you easily and "idiomatically" include external dependencies in your repository to get reproducible builds.

No need to learn a new tool or format!
You already know how to use gvt: just run gvt fetch when and like you would run go get. You can imagine what gvt update and gvt delete do.
No need to change how you build your project!
gvt downloads packages to ./vendor/.... With GO15VENDOREXPERIMENT=1 the stock Go compiler will find and use those dependencies automatically (without import path or GOPATH changes).
No need to manually chase, copy or cleanup dependencies!
gvt works recursively as you would expect, and lets you update vendored dependencies. It also writes a manifest to ./vendor/manifest and never touches your system GOPATH. Finally, it strips the VCS metadata so that you can commit the vendored source cleanly.
No need for your users and occasional contributors to install or even know about gvt!
Packages whose dependencies are vendored with gvt are go build-able and go get-able out of the box by Go 1.5 with GO15VENDOREXPERIMENT=1 set.

Note that projects must live within the GOPATH tree in order to be go buildable with the GO15VENDOREXPERIMENT flag.

If you use and like (or dislike!) gvt, it would definitely make my day better if you dropped a line at gvt -at- filippo.io :)

Installation

With a correctly configured Go installation:

GO15VENDOREXPERIMENT=1 go get -u github.com/FiloSottile/gvt

Usage

You know how to use go get? That's how you use gvt fetch.

# This will fetch the dependency into the ./vendor folder.
$ gvt fetch github.com/fatih/color
2015/09/05 02:38:06 fetching recursive dependency github.com/mattn/go-isatty
2015/09/05 02:38:07 fetching recursive dependency github.com/shiena/ansicolor

$ tree -d
.
└── vendor
    └── github.com
        ├── fatih
        │   └── color
        ├── mattn
        │   └── go-isatty
        └── shiena
            └── ansicolor
                └── ansicolor

9 directories

$ cat > main.go
package main
import "github.com/fatih/color"
func main() {
    color.Red("Hello, world!")
}

$ export GO15VENDOREXPERIMENT=1
$ go build .
$ ./hello
Hello, world!

$ git add main.go vendor/ && git commit

A full set of example usage can be found on GoDoc.

Alternative: not checking in vendored source

Some developers prefer not to check in the source of the vendored dependencies. In that case you can add lines like these to e.g. your .gitignore

vendor/**
!vendor/manifest

When you check out the source again, you can then run gvt restore to fetch all the dependencies at the revisions specified in the vendor/manifest file.

Please consider that this approach has the following consequences:

the package consumer will need gvt to fetch the dependencies
the dependencies will need to remain available from the source repositories: if the original repository goes down or rewrites history, build reproducibility is lost
go get won't work on your package

Troubleshooting

`fatal: Not a git repository [...]`

`error: tag 'fetch' not found.`

These errors can occur because you have an alias for gvt pointing to git verify-tag (default if using oh-my-zsh).

Recent versions of oh-my-zsh removed the alias. You can update with upgrade_oh_my_zsh.

Alternatively, run this, and preferably add it to your ~/.bashrc / ~/.zshrc: unalias gvt.

`go build` can't find the vendored package

Make sure you set GO15VENDOREXPERIMENT=1.

Also note that GO15VENDOREXPERIMENT does not apply when outside the GOPATH tree. That is, your project must be somewhere in a subfolder of $GOPATH.

License

MIT licensed. See the LICENSE file for details.

w4ngyi/gvt