Databases on Travis workers

What This Guide Covers

This guide covers data stores offered in the Travis CI environment and what users & settings projects hosted on travis-ci.org can rely on. Most of the content is applicable to any technology but there are subtle aspects in the behavior of some database drivers that this guide will try to cover. We recommend you start with the Getting Started and Build Configuration guides before reading this one.

Data Stores in the Travis CI Environment

Travis CI Environment has multiple popular data stores preinstalled. Some of the services available are:

  • MySQL
  • PostgreSQL
  • SQLite3
  • MongoDB
  • CouchDB
  • Redis
  • Riak
  • Memcached

All aforementioned data stores use mostly stock default settings, however, when it makes sense, new users are added and security settings are relaxed (because for continuous integration ease of use is more important): one example of such adaptation is PostgreSQL that has strict default access settings.

Configure Your Projects to Use Databases in Tests

Here is how to configure your project to use databases in its tests. This assumes you have already visited Build configuration documentation.

MySQL

MySQL on Travis CI binds to 127.0.0.1 and requires authentication. You can connect using "root" username and blank password.

If specify a blank username, keep in mind that for some clients, this is the same as "root" but for some it means "anonymous user". When in doubt, try switching to root username.

You do have to create the myapp_test database first. Run this as part of your build script:

# .travis.yml
before_script:
  - mysql -e 'create database myapp_test;'

config/database.yml Example

config/database.yml example for Ruby projects using ActiveRecord:

mysql:
  adapter: mysql2
  database: myapp_test
  username: root
  encoding: utf8

PostgreSQL

PostgreSQL binds to 127.0.0.1 and requires authentication with "postgres" user and no password.

You have to create the database as part of your build process:

# .travis.yml
before_script:
  - psql -c 'create database myapp_test;' -U postgres

config/database.yml Example

config/database.yml example for Ruby projects using ActiveRecord:

postgres:
  adapter: postgresql
  database: myapp_test
  username: postgres

SQLite3

Probably the easiest and simplest solution for your relation database needs. If you don't specifically want to test how your code behaves with other databases, in memory SQLite might be the best option.

Ruby Projects

For ruby projects, ensure that you have the sqlite3 ruby bindings in your bundle:

# Gemfile
# for CRuby, Rubinius, including Windows and RubyInstaller
gem "sqlite3", :platform => [:ruby, :mswin, :mingw]

# for JRuby
gem "jdbc-sqlite3", :platform => :jruby

config/database.yml example for projects that use ActiveRecord:

test:
  adapter: sqlite3
  database: ":memory:"
  timeout: 500

However, if your project is a general library or plugin, you need to handle connecting to the database yourself in tests. For example, connecting with ActiveRecord:

ActiveRecord::Base.establish_connection :adapter => 'sqlite3',
                                        :database => ':memory:'

MongoDB

MongoDB binds to 127.0.0.1, uses stock configuration and requires no authentication or database creation up front.

In cases you need to create users for your database, you can do it using a before_script in your .travis.yml file::

# .travis.yml
before_script:
  - mongo mydb_test --eval 'db.addUser("travis", "test");'

JVM-based projects

For JVM-based projects that use the official MongoDB Java driver, you'll have to use 127.0.0.1 instead of localhost to connect to work around this known MongoDB Java driver issue that affects Linux.

CouchDB

CouchDB binds to 127.0.0.1, uses stock configuration and requires no authentication (it runs in admin party).

You have to create the database as part of your build process:

# .travis.yml
before_script:
  - curl -X PUT localhost:5984/myapp_test

Riak

Riak uses stock configuration with one exception: it is configured to use LevelDB storage backend.

Redis

Redis uses stock configuration and is available on localhost.

Cassandra

Cassandra is available but not started by default. You can start it using before_install:

before_install:
  - sudo service cassandra start
  - sleep 3

Cassandra is provided via Datastax Community Edition and uses stock configuration (available on 127.0.0.1).

Neo4J

Neo4J Server Community Edition is available but not started by default. You can start it using before_install:

before_install:
  - which neo4j && sudo neo4j start
  - sleep 3

Neo4J Server uses default configuration (localhost, port 7474).

ElasticSearch

ElasticSearch is available but not started by default. You can start it using before_install:

before_install:
  - sudo service elasticsearch start
  - sleep 3

ElasticSearch is provided via official Debian packages and uses stock configuration (available on 127.0.0.1).

Multiple database systems

If your project's tests need to run multiple times using different databases, this can be configured on Travis CI in several ways.

Using ENV variables

Now you use the "DB" environment variable to specify the name of the database configuration you want to use. Locally, you would run this as:

$ DB=postgres [commands to run your tests]

On Travis CI you want to test against all 3 databases all the time, and for that you can use the "env" option:

# .travis.yml
env:
  - DB=sqlite
  - DB=mysql
  - DB=postgres

When doing this, please read and understand everything about the build matrix described in Build configuration.

Ruby

One approach you might take is put all database configurations in one YAML file, like ActiveRecord does:

# test/database.yml
sqlite:
  adapter: sqlite3
  database: ":memory:"
  timeout: 500
mysql:
  adapter: mysql2
  database: myapp_test
  username:
  encoding: utf8
postgres:
  adapter: postgresql
  database: myapp_test
  username: postgres

Then, in your test suite, read that data into a configurations hash:

configs = YAML.load_file('test/database.yml')
ActiveRecord::Base.configurations = configs

db_name = ENV['DB'] || 'sqlite'
ActiveRecord::Base.establish_connection(db_name)
ActiveRecord::Base.default_timezone = :utc

Conclusion

Travis CI Environment provides several popular open source data stores that hosted projects can use. In the majority of cases, said data stores use stock configuration. When it is not the case, the purpose of customizing the configuration is usually to minimize the amount of work developers have to do to use them. Often this means relaxing security settings, which is OK for continuous integration environments.