Travis CI, Codecov, and vgo

Posted on Edited on

vgo is the (newest) official way to managed versioned dependencies in Go. In my most recent project, I’ve decided to use it instead of dep or glide, which I’ve used previously. Taking a leaf out of the recent work I’ve been doing at work, I’ve hooked that repository up to some free CI tools, including Travis CI.

Getting it all to work

The chief problem I had was getting vgo to play nice on Travis. You can’t tell now because I rebased my commit history, but I had a lot of trouble getting Travis to build and test what I actually wanted it to without throwing errors about Go dependencies and GitHub errors.

Getting vgo installed in the build

First off, getting vgo installed, as it doesn’t exist by default on Travis (obviously). Travis has an install step that I’m using to install vgo:

1
2
install:
  - go get -u golang.org/x/vgo

That should look very familiar - it’s just installing vgo like any other go get command would.

Testing via vgo

By default, Travis runs the test command against the go binary, so I’m overriding the script step to use vgo instead:

1
2
script:
  - vgo test -v -race -coverprofile=coverage.txt -covermode=atomic ./...

Note that command also runs the race condition checked (not actually needed for this library) and saves the coverage to a file called coverage.txt. That’s up in a bit.

If you have just this for your vgo test command, it’ll fail, citing the GitHub API rate limits for unauthorized requests. The way to get around this on your dev machine is to edit ~/.netrc with a generated GitHub Personal Access Token. Travis recommends doing this too in the build in their docs for private dependencies, and it can work for vgo’s problems with GitHub rate limits.

I didn’t want to put a key in a file in my repository, but I still needed that .netrc file to be created during my build, so I’m using an echo command and output redirection in the before_install step in Travis to echo that token into the .netrc file. I’m taking the token (and my GitHub login) as hidden environment variables in the job configuration so I don’t have to save them in plain text in the actual repo. The setup for the .netrc file looks like this:

1
2
3
before_install:
  - echo -e "machine api.github.com\n  login ${GITHUB_LOGIN}\n  password ${GITHUB_TOKEN}" > ~/.netrc
  - chmod 600 ~/.netrc

With this, vgo has the system configuration it needs to get past GitHub’s rate limits.

Coverage

If you just wanted to run unit tests in vgo, then the command would just be vgo test with any other parameters you want to supply, but I’m also calculating coverage, as http://codecov.io is free for open-source repositories (just like Travis) and I’d like to have my repo have a coverage percentage badge as well as a “build: passing” badge.

Codecov has an example repo for uploading public (or private) coverage metrics as part of the Travis build, so the end of my .travis.yml file looks like:

1
2
after_success:
  - bash <(curl -s https://codecov.io/bash)

Full config

My full .travis.yml file at time of writing is this:

1
2
3
4
5
6
7
8
9
10
11
12
language: go
go:
  - "1.10.x"
before_install:
  - echo -e "machine api.github.com\n  login ${GITHUB_LOGIN}\n  password ${GITHUB_TOKEN}" > ~/.netrc
  - chmod 600 ~/.netrc
install:
  - go get -u golang.org/x/vgo
script:
  - vgo test -v -race -coverprofile=coverage.txt -covermode=atomic ./...
after_success:
  - bash <(curl -s https://codecov.io/bash)

And my Travis repo settings has environment variables for CODECOV_TOKEN, GITHUB_LOGIN, and GITHUB_TOKEN.

Summary

vgo was annoying to get running properly, but Travis runs great and Codecov was a breeze. Now that both sites are configured, I get builds and coverage metrics whenever I push, all for free.