Automatically Build Go Binaries via TravisCI & GitHub

Update: I’ve updated the travis.yml config to reflect Go 1.11.

GitHub has a great Releases feature that allows you surface—and users to download—tagged releases of your projects.

By default, Releases will provide links to a ZIP and a tarball of the source code for that tag. But for projects with binary releases, manually building and then uploading binaries (perhaps for multiple platforms!) is time-consuming and fragile. Making binary releases available automatically is great for the users of a project too: they can use it without having to deal with toolchains (e.g. installing Go) and environments. Making software usable by non-developer is an important goal for many projects.

We can use TravisCI + GitHub Releases to do all of the work for us with a fairly straightforward configuration, so let’s take a look at how to release Go binaries automatically.

Configuration

Here’s the full .travis.yml from a small utility library I wrote at my day job. This will:

• Always build on the latest Go version - “go: 1.x” and sets an env variable. We’ll use this to only build binaries using the latest Go version.
• Build as far back as 1.7
• Builds, but doesn’t fail the entire run, on “tip” (e.g. Go’s master branch, which breaks from time-to-time)

It then runs a fairly straightforward build script using Go’s existing tooling: gofmt (style), go vet (correctness), and then any tests with the race detector enabled.

The final step—and the reason why you’re probably reading this post!—is invoking gox to build binaries for Linux, Darwin (macOS) & Windows, and setting the “Rev” variable to the git commit it was built from. The latter is super useful for debugging or supporting users when combined with a –version command-line flag. We also only release on tagged commits via tags: true so that we’re only releasing binaries with intent. Tests are otherwise automatically run on every branch (inc. Pull Requests).

language: go
sudo: false
matrix:
  include:
    # "1.x" always refers to the latest Go version, inc. the patch release.
    # e.g. "1.x" is 1.11 until 1.11.1 is available.
    - go: 1.x
      env: LATEST=true
    - go: 1.7.x
    - go: 1.8.x
    - go: 1.9.x
    - go: 1.10.x
    - go: 1.11.x
    - go: tip
  allow_failures:
    - go: tip

before_install:
  # gox simplifies building for multiple architectures
  - go get github.com/mitchellh/gox

install:
  - # skip

script:
  - go get -t -v ./...
  - diff -u <(echo -n) <(gofmt -d .)
  - go vet $(go list ./... | grep -v /vendor/)
  - go test -v -race ./...
  # Only build binaries from the latest Go release.
  - if [ "${LATEST}" = "true" ]; then gox -os="linux darwin windows" -arch="amd64" -output="logshare.." -ldflags "-X main.Rev=`git rev-parse --short HEAD`" -verbose ./...; fi

deploy:
  provider: releases
  skip_cleanup: true
  api_key:
    # Your *encrypted* GitHub key, as the output of the Travis CI CLI tool.
    secure: 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
  file:
  # The names of the binaries to output, based on the -output template passed to gox.
  - logshare.windows.amd64.exe
  - logshare.darwin.amd64
  - logshare.linux.amd64
  on:
    # What to repository to build
    repo: username/reponame
    # Only build binaries for tagged commits
    tags: true
    condition: $LATEST = true

Note: It’s critical that you follow TravisCI’s documentation on how to securely encrypt your API key—e.g. don’t paste your raw key into this file, ever. TravisCI’s documentation and CLI tool make this straightforward.

Wrap

Pretty easy, right? If you’re already using Travis CI to test your Go projects, extending your configuration to release binaries on tagged versions is only a few minutes of work.

Further Reading

• In the wild: https://github.com/cloudflare/logshare
• Go on Travis: https://docs.travis-ci.com/user/languages/go/
• GitHub Releases Uploading: https://docs.travis-ci.com/user/deployment/releases/