In this section we are going to use Travis CI as our continuous-integration service. Travis CI is mostly used for building and running tests for projects hosted at GitHub. It supports different programming languages and for our particular case, it supports the Crystal language.
If you are new to continuous integration (or you want to refresh the basic concepts) we may start reading the core concepts guide.
Now let's see some examples!
Build and run specs¶
A first (and very basic) Travis CI config file could be:
That's it! With this config file, Travis CI by default will run
Now, we just need to go to Travis CI dashboard to add the GitHub repository.
Let's see another example:
language: crystal crystal: - latest - nightly script: - crystal spec - crystal tool format --check ``` With this configuration, Travis CI will run the tests using both Crystal `latest` and `nightly` releases on every push to a branch on your Github repository. !!!note When [creating a Crystal project](../../using_the_compiler/README.md#creating-a-crystal-project) using `crystal init`, Crystal creates a `.travis.yml` file for us. ### Using a specific Crystal release Let's suppose we want to pin a specific Crystal release (maybe we want to make sure the shard compiles and works with that version) for example [Crystal 0.31.1](https://github.com/crystal-lang/crystal/releases/tag/0.31.1). Travis CI only provides _runners_ to `latest` and `nightly` releases directly and so, we need to install the requested Crystal release manually. For this we are going to use [Docker](https://www.docker.com/). First we need to add Docker as a service in `.travis.yml`, and then we can use `docker` commands in our build steps, like this: !!!example ".travis.yml" ```yaml language: minimal services: - docker script: - docker run -v $PWD:/src -w /src crystallang/crystal:0.31.1 crystal spec ``` !!!note We may read about different [languages](https://docs.travis-ci.com/user/languages/) supported by Travis CI, included [minimal](https://docs.travis-ci.com/user/languages/minimal-and-generic/). !!!note A list with the different official [Crystal docker images](https://hub.docker.com/r/crystallang/crystal/tags) is available at [DockerHub](https://hub.docker.com/r/crystallang/crystal). ### Using `latest`, `nightly` and a specific Crystal release all together! Supported _runners_ can be combined with Docker-based _runners_ using a [Build Matrix](https://docs.travis-ci.com/user/customizing-the-build#build-matrix). This will allow us to run tests against `latest` and `nightly` and pinned releases. Here is the example: !!!example ".travis.yml" ```yaml matrix: include: - language: crystal crystal: - latest script: - crystal spec - language: crystal crystal: - nightly script: - crystal spec - language: bash services: - docker script: - docker run -v $PWD:/src -w /src crystallang/crystal:0.31.1 crystal spec ``` ## Installing shards packages In native _runners_ (`language: crystal`), Travis CI already automatically installs shards dependencies using `shards install`. To improve build performance we may add [caching](#caching) on top of that. ### Using Docker In a Docker-based _runner_ we need to run `shards install` explicitly, like this: !!!example ".travis.yml" ```yaml language: bash services: - docker script: - docker run -v $PWD:/src -w /src crystallang/crystal:0.31.1 shards install - docker run -v $PWD:/src -w /src crystallang/crystal:0.31.1 crystal spec ``` !!!note Since the shards will be installed in `./lib/` folder, it will be preserved for the second docker run command. ## Installing binary dependencies Our application or maybe some shards may required libraries and packages. This binary dependencies may be installed using different methods. Here we are going to show an example using the [Apt](https://help.ubuntu.com/lts/serverguide/apt.html) command (since the Docker image we are using is based on Ubuntu) Here is a first example installing the `libsqlite3` development package using the [APT addon](https://docs.travis-ci.com/user/installing-dependencies/#installing-packages-with-the-apt-addon): !!!example ".travis.yml" ```yaml language: crystal crystal: - latest before_install: - sudo apt-get -y install libsqlite3-dev addons: apt: update: true script: - crystal spec ``` ### Using Docker We are going to build a new docker image based on [crystallang/crystal](https://hub.docker.com/r/crystallang/crystal/), and in this new image we will be installing the binary dependencies. To accomplish this we are going to use a [Dockerfile](https://docs.docker.com/engine/reference/builder/): !!!example "Dockerfile" ```dockerfile FROM crystallang/crystal:latest # install binary dependencies: RUN apt-get update && apt-get install -y libsqlite3-dev ``` And here is the Travis CI configuration file: !!!example ".travis.yml" ```yaml language: bash services: - docker before_install: # build image using Dockerfile: - docker build -t testing . script: # run specs in the container - docker run -v $PWD:/src -w /src testing crystal spec ``` !!!note Dockerfile arguments can be used to use the same Dockerfile for latest, nightly or a specific version. ## Using services Travis CI may start [services](https://docs.travis-ci.com/user/database-setup/) as requested. For example, we can start a [MySQL](https://docs.travis-ci.com/user/database-setup/#mysql) database service by adding a `services:` section to our `.travis.yml`: !!!example ".travis.yml" ```yaml language: crystal crystal: - latest services: - mysql script: - crystal spec ``` Here is the new test file for testing against the database: !!!example "spec/simple_db_spec.cr" ```crystal require "./spec_helper" require "mysql" it "connects to the database" do DB.connect ENV["DATABASE_URL"] do |cnn| cnn.query_one("SELECT 'foo'", as: String).should eq "foo" end end ``` When pushing this changes Travis CI will report the following error: `Unknown database 'test' (Exception)`, showing that we need to configure the MySQL service **and also setup the database**: !!!example ".travis.yml" ```yaml language: crystal crystal: - latest env: global: - DATABASE_NAME=test - DATABASE_URL=mysql://root@localhost/$DATABASE_NAME services: - mysql before_install: - mysql -e "CREATE DATABASE IF NOT EXISTS $DATABASE_NAME;" - mysql -u root --password="" $DATABASE_NAME < db/schema.sql script: - crystal spec ``` We are [using a `schema.sql` script](https://andidittrich.de/2017/06/travisci-setup-mysql-tablesdata-before-running-tests.html) to create a more readable `.travis.yml`. The file `./db/schema.sql` looks like this: !!!example "schema.sql" ```sql CREATE TABLE ... etc ...
Pushing these changes will trigger Travis CI and the build should be successful!
If we read Travis CI job log, we will find that every time the job runs, Travis CI needs to fetch the libraries needed to run the application:
Fetching https://github.com/crystal-lang/crystal-mysql.git Fetching https://github.com/crystal-lang/crystal-db.git
This takes time and, on the other hand, these libraries might not change as often as our application, so it looks like we may cache them and save time.
Travis CI uses caching to improve some parts of the building path. Here is the new configuration file with cache enabled:
```yaml language: crystal crystal: - latest
cache: shards script: - crystal spec ```
Let's push these changes. Travis CI will run, and it will install dependencies, but then it will cache the shards cache folder which, usually, is
~/.cache/shards. The following runs will use the cached dependencies.