by Josh Bussdieker (jbuss, jaja, jbussdieker)

GVM provides an interface to manage Go versions.

• Install/Uninstall Go versions with gvm install [tag] where tag is "60.3", "go1", "weekly.2011-11-08", or "tip"
• List added/removed files in GOROOT with gvm diff
• Manage GOPATHs with gvm pkgset [create/use/delete] [name]. Use --local as name to manage repository under local path (/path/to/repo/.gvm_local).
• List latest release tags with gvm listall. Use --all to list weekly as well.
• Cache a clean copy of the latest Go source for multiple version installs.

When we started developing in Go mismatched dependencies and API changes plauged our build process and made it extremely difficult to merge with other peoples changes.

After nuking my entire GOROOT several times and rebuilding I decided to come up with a tool to oversee the process. It eventually evolved into what gvm is today.

To install:

bash < <(curl -s https://raw.github.com/moovweb/gvm/master/binscripts/gvm-installer)

gvm install go1
gvm use go1 [--default]

Once this is done Go will be in the path and ready to use. $GOROOT and $GOPATH are set automatically.

Additional options can be specified when installing Go:

Usage: gvm install [version] [options]
    -s,  --source=SOURCE      Install Go from specified source.
    -n,  --name=NAME          Override the default name for this version.
    -pb, --with-protobuf      Install Go protocol buffers.
    -b,  --with-build-tools   Install package build tools.
    -h,  --help               Display this message.

To list all installed Go versions (The current version is prefixed with "=>"):

gvm list

To completely remove gvm and all installed Go versions and packages:

gvm implode

Install mercurial from http://mercurial.berkwood.com/

sudo apt-get install curl
sudo apt-get install git
sudo apt-get install mercurial
sudo apt-get install make
sudo apt-get install binutils
sudo apt-get install bison
sudo apt-get install gcc

sudo pkg_add -r bash
sudo pkg_add -r git
sudo pkg_add -r mercurial

GVM supports vendoring package set-specific native code and related dependencies, which is useful if you need to qualify a new configuration or version of one of these dependencies against a last-known-good version in an isolated manner. Such behavior is critical to maintaining good release engineering and production environment hygiene.

As a convenience matter, GVM will furnish the following environment variables to aid in this manner if you want to decouple your work from what the operating system provides:

1. ${GVM_OVERLAY_PREFIX} functions in a manner akin to a root directory hierarchy suitable for auto{conf,make,tools} where it could be passed in to ./configure --prefix=${GVM_OVERLAY_PREFIX} and not conflict with any existing operating system artifacts and hermetically be used by your workspace. This is suitable to use with C{PP,XX}FLAGS and LDFLAGS, but you will have to manage these yourself, since each tool that uses them is different.

2. ${PATH} includes ${GVM_OVERLAY_PREFIX}/bin so that any tools you manually install will reside there, available for you.

3. ${LD_LIBRARY_PATH} includes ${GVM_OVERLAY_PREFIX}/lib so that any runtime library searching can be fulfilled there on FreeBSD and Linux.

4. ${DYLD_LIBRARY_PATH} includes ${GVM_OVERLAY_PREFIX}/lib so that any runtime library searching can be fulfilled there on Mac OS X.

5. ${PKG_CONFIG_PATH} includes ${GVM_OVERLAY_PREFIX}/lib/pkgconfig so that pkg-config can automatically resolve any vendored dependencies.

Recipe for success:

gvm use go1.1
gvm pkgset use current-known-good
# Let's assume that this includes some C headers and native libraries, which
# Go's CGO facility wraps for us.  Let's assume that these native
# dependencies are at version V.
gvm pkgset create trial-next-version
# Let's assume that V+1 has come along and you want to safely trial it in
# your workspace.
gvm pkgset use trial-next-version
# Do your work here replicating current-known-good from above, but install
# V+1 into ${GVM_OVERLAY_PREFIX}.

See examples/native for a working example.

Sometimes especially during upgrades the state of gvm's files can get mixed up. This is mostly true for upgrade from older version than 0.0.8. Changes are slowing down and a LTR is imminent. But for now rm -rf ~/.gvm will always remove gvm. Stay tuned!