Install go, yay!

gimme is a shell script that knows how to install go. Fancy! 🎉

Install from github:

# assumes ~/bin exists and is in $PATH, so adjust accordingly!

curl -sL -o ~/bin/gimme https://raw.githubusercontent.com/travis-ci/gimme/master/gimme
chmod +x ~/bin/gimme

Homebrew (OS X):

brew install gimme

Arch AUR (Arch Linux), substituting yaourt with however you prefer to install from AUR:

# latest released version
yaourt -S gimme

# current git HEAD revision
yaourt -S gimme-git

Then check the help text a la:

gimme -h

# or

gimme --help

# or

gimme help

# or

gimme wat

To install and use version 1.4, for example:

eval "$(GIMME_GO_VERSION=1.4 gimme)"

# or:

eval "$(gimme 1.4)"

# or if you can't stand the thought of using `eval`:

gimme 1.4
source ~/.gimme/envs/go1.4.env

Or run without installing gimme:

eval "$(curl -sL https://raw.githubusercontent.com/travis-ci/gimme/master/gimme | GIMME_GO_VERSION=1.4 bash)"

To install and use the current stable release of Go:

gimme stable

Or to install and use the development version (master branch) of Go:

gimme master

To list installed versions of Go:

gimme -l

# or

gimme --list

# or

gimme list

To force re-installation of an existing Go version:

gimme --force 1.4.1

# or

gimme -f 1.4.1

# or even

gimme force 1.4.1

To get the version of gimme:

gimme -V

# or

gimme --version

# or even

gimme version

The original goal of this project was trivial cross-compilation within Travis. The following is an example .travis.yml file to accomplish this for a normal Go project:

language: go

env:
    - GIMME_OS=linux GIMME_ARCH=amd64
    - GIMME_OS=darwin GIMME_ARCH=amd64
    - GIMME_OS=windows GIMME_ARCH=amd64

install:
    - go get -d -v ./...

script:
    - go build -v ./...

Gimme only supports downloading versions which the Go developers make available. If a version of Go is withdrawn, then Gimme has no logic to go look elsewhere for that version. Thus as the Go Maintainers withdraw old releases, they'll stop being available for Gimme to fetch.

Because Gimme caches builds, a testing framework which preserves that cache might still have older releases available, leading to sporadic failures. The only fix is to switch to only requesting currently available versions of Go.

The environment variable $GIMME_DOWNLOAD_BASE can be used to point Gimme at another location, so if you need to keep working with older Go releases, then you can maintain your own software artifact mirror which preserves those versions and point Gimme at that instead.

Invoke gimme -k or gimme --known to have Gimme report the versions which can be installed; invoking gimme stable installs the version which the Go Maintainers have declared to be stable. Both of these involve making network requests to retrieve this information, although the --known output is cached. (Use --force-known-update to ignore the cache).

The stable request retrieves https://golang.org/VERSION?m=text and reports that.

The known request retrieves https://golang.org/dl and parses the page to find releases. This is not the same as the location where the images are retrieved from, thus it's possible for known to know about more or fewer versions than are actually available. We proceed on the basis that the documented releases are suitable and undocumented releases no longer are.

This known list also includes any versions locally known.

Gimme now supports the concept of .x, as a version suffix; eg, 1.10.x might be 1.10 before the release of 1.10.1 but become 1.10.1 once that's available.

To make this easier, and reduce duplicate invocations, Gimme now supports a "query" which, instead of producing normal output, just prints the resolution of a version specifier. This is the --resolve option. It handles the .x suffix and the stable string; all other inputs are passed through unchanged, although unknown names will be accompanied by an error message and an exit code of 2. A valid version identifier, even if not currently downloadable from upstream, will resolve successfully. "Can resolve" is not "exists".

Thus given a list of versions to invoke against, tooling might do a first pass to use --resolve on each and de-duplicate, so that if an alias and a hard-coded version map to the same version, then only one invocation needs to happen.

Gimme only supports .x at the end of a version specifier.
The --resolve option must be given a version on the command-line afterwards, not by any other means.
The --resolve option and mechanism ignores any installed versions and relies solely upon upstream-exposed lists of available versions and resolvable tags.
A git tag named ending .x will never be found.
Use of .x will not find release candidates, alphas, betas or other non-release versions: it's only for finding the last stable release.
Use of ${GIMME_TYPE} to override auto and prevent git will affect --resolve by inhibiting use of git tags as valid names. This is a feature.

Note that because Gimme supports version identifiers which are git tags, --resolve defaults to handling this too. This means that --resolve can be heavy-weight: without the Go repo cloned, first the entire Go repo must be cloned. We default to "correct". To avoid this, export GIMME_TYPE=binary and disable the git resolution mechanism.