gdm is a lightweight package manager for Go written in Go. It does not copy dependencies in-repo and does not require that people (users and developers) use gdm to build your project. In this way, people can still simply go get your project and build it.

This tool assumes you are working in a standard Go workspace, as described in http://golang.org/doc/code.html.

$ go get github.com/sparrc/gdm

Assuming your Go workspace is setup, so you can build your project with go install or go install ./..., it's one command to start using:

src/github.com/sparrc/gdm $ gdm save

This will create a new file in your repo directory called Godeps, which specifies project dependencies and their revisions. This file is identical to the file used by gpm.

Godeps is a simple text file of repo roots and revisions:

  collectd.org/api 9fc824c70f713ea0f058a07b49a4c563ef2a3b98
  collectd.org/network 9fc824c70f713ea0f058a07b49a4c563ef2a3b98
  github.com/BurntSushi/toml 056c9bc7be7190eaa7715723883caffa5f8fa3e4
  ...

The file supports comments using the # character.

The gdm restore command is the opposite of gdm save. It will checkout the package versions specified in Godeps to your $GOPATH. This modifies the state of packages in your $GOPATH.

To add a new package github.com/foo/bar, do this:

1. Run gdm restore
2. Run go get github.com/foo/bar
3. Run gdm save

To update a package from your $GOPATH, do this:

1. Run gdm restore
2. Run go get -u github.com/foo/bar
3. Run gdm save

Before committing the change, you'll probably want to inspect the changes to Godeps, for example with git diff, and make sure it looks reasonable.

To update all dependencies from your $GOPATH, do this:

1. Run go get -u ./...
2. Run gdm save

Building a project managed by gdm looks like this:

1. Run go get github.com/foo/bar/...
2. Run cd $GOPATH/src/github.com/foo/bar
3. Run gdm restore
4. Build: go install or go install ./...

To help make a homebrew formula for your Go project, gdm supports a gdm brew command, which will print out your dependencies to stdout in the homebrew go_resource format, like this:

$ gdm brew # in directory $GOPATH/src/github.com/influxdb/influxdb
======= Go Dependency Manager =======
= working dir: /Users/csparr/ws/go/src/github.com/influxdb/influxdb
= GOPATH:      /Users/csparr/ws/go
=====================================

  go_resource "collectd.org/api" do
    url "https://github.com/collectd/go-collectd.git",
    :revision => "9fc824c70f713ea0f058a07b49a4c563ef2a3b98"
  end

  go_resource "collectd.org/network" do
    url "https://github.com/collectd/go-collectd.git",
    :revision => "9fc824c70f713ea0f058a07b49a4c563ef2a3b98"
  end

  go_resource "github.com/BurntSushi/toml" do
    url "https://github.com/BurntSushi/toml.git",
    :revision => "056c9bc7be7190eaa7715723883caffa5f8fa3e4"
  end

  ...

If you're familiar with Go dependency management, you can probably see the similarities with gpm and godep. This tool could not have existed without their influence!