Travis CI¶
For many use cases, the Travis caching section of the user guide will be sufficient.
This page documents how to use Stack on Travis CI. We assume you have basic familiarity with Travis.
Note: both Travis and Stack infrastructures are actively developed. We try to document best practices at the moment.
Container infrastructure¶
For Stack on Travis to be practical, we must use caching. Otherwise build times will take an incredibly long time, about 30 minutes versus 3-5. Caching is currently available only for container-based Travis infrastructure. Shortly we have to add
sudo: false # Caching so the next build will be fast too. cache: directories: - $HOME/.stack
To the .travis.yml
. This however restricts how we can install GHC and Stack on
the Travis machines.
Installing Stack¶
Currently there is only one reasonable way to install Stack: fetch precompiled binary from the Github.
before_install: # Download and unpack the stack executable - mkdir -p ~/.local/bin - export PATH=$HOME/.local/bin:$PATH - travis_retry curl -L https://www.stackage.org/stack/linux-x86_64 | tar xz --wildcards --strip-components=1 -C ~/.local/bin '*/stack'
Once Travis whitelists the stack .deb files, we’ll be able to simply include
stack in the addons
section, and automatically use the newest version of
stack, avoiding that complicated before_install
section This is being
tracked in the
apt-source-whitelist
and
apt-package-whitelist
issue trackers.
Installing GHC¶
There are two ways to install GHC:
- Let Stack download GHC
- Install GHC using apt plugin
See the Travis caching section of the user guide for an example of the first option (letting Stack download GHC). Here, we will explain the second option. With single GHC the situation is simple:
before_install: - export PATH=/opt/ghc/7.8.4/bin:$PATH addons: apt: sources: - hvr-ghc packages: - ghc-7.10.2
Multiple GHC - parametrised builds¶
Travis apt plugin doesn’t yet support installing apt packages dynamically
(https://github.com/travis-ci/travis-ci/issues/4291). That for we need to write
a bit repetetive .travis.yml
.
Also for different GHC versions, you probably want to use different stack.yaml
files.
# N.B. No top-level env: declaration! matrix: include: - env: GHCVER=7.8.4 STACK_YAML=stack.yaml addons: apt: sources: - hvr-ghc packages: - ghc-7.8.4 - env: GHCVER=7.10.1 STACK_YAML=stack-7.10.yaml addons: apt: sources: - hvr-ghc packages: - ghc-7.10.1 - env: GHCVER=head STACK_YAML=stack-head.yaml addons: apt: sources: - hvr-ghc packages: - ghc-head allow_failures: - env: GHCVER=head STACK_YAML=stack-head.yaml before_install: # ghc - export PATH=/opt/ghc/$GHCVER/bin:$PATH
Especially to use ghc HEAD
you need to pass --skip-ghc-check
option to Stack.
Running tests¶
After the environment setup, actual test running is simple:
script: - stack --no-terminal --skip-ghc-check test
Other details¶
Some Stack commands will run for long time (when cache is cold) without producing any output. For Travis not to timeout, one can wrap commands in a simple script.
install: - ./travis_long stack --no-terminal --skip-ghc-check setup - ./travis_long stack --no-terminal --skip-ghc-check test --only-snapshot