Core Concepts for Beginners
Welcome to Travis CI! This page provides some contexts and terminologies used throughout the platform and documentation, which might be helpful if you are new here or new to Continuous Integration (CI).
What is Continuous Integration (CI)?
Continuous Integration is the practice of merging in small code changes frequently - rather than merging in a large change at the end of a development cycle. The goal is to build healthier software by developing and testing in smaller increments. This is where Travis CI comes in.
As a continuous integration platform, Travis CI supports your development process by automatically building and testing code changes, providing immediate feedback on the success of the change. Travis CI can also automate other parts of your development process by managing deployments and notifications.
CI builds and automation: building, testing, deploying
When you run a build, Travis CI clones your GitHub repository into a brand new virtual environment, and carries out a series of tasks to build and test your code. If one or more of those tasks fails, the build is considered broken. If none of the tasks fail, the build is considered passed, and Travis CI can deploy your code to a web server, or application host.
CI builds can also automate other parts of your delivery workflow. This means you can have jobs depend on each other with Build Stages, setup notifications, prepare deployments after builds, and many other tasks.
Builds, Jobs, Stages and Phases
In the Travis CI documentation, some common words have specific meanings:
- job - an automated process that clones your repository into a virtual
environment and then carries out a series of phases such as compiling your
code, running tests, etc. A job fails if the return code of the
scriptphase is non zero.
- phase - the sequential steps
of a job. For example, the
installphase, comes before the
scriptphase, which comes before the optional
- build - a group of jobs. For example, a build might have two jobs, each of which tests a project with a different version of a programming language. A build finishes when all of its jobs are finished.
- stage - a group of jobs that run in parallel as part of sequential build process composed of multiple stages.
travis-ci.org vs travis-ci.com
Travis CI was originally developed for open-source projects before being expanded to support closed-source projects at a later date. As a result:
- open-source projects are hosted on travis-ci.org.
- closed-source projects are hosted on travis-ci.com, also known as Travis Pro.
Breaking the Build
The build is considered broken when one or more of its jobs completes with a state that is not passed:
- errored - a command in the
before_scriptphase returned a non-zero exit code. The job stops immediately.
- failed - a command in the
scriptphase returned a non-zero exit code. The job continues to run until it completes.
- canceled - a user cancels the job before it completes.
Our Common Builds Problems page is a good place to start troubleshooting why your build is broken.
Infrastructure and environment notes
Travis CI offers a few different infrastructure environments, so you can select the setup that suits your project best:
- Container-based - is the default for new projects. It is a Linux Ubuntu environment running in a container. It starts faster than the sudo-enabled environment, but has less resources and does not support the use of
- Sudo-enabled - this Linux Ubuntu environment runs on full virtual machine. It starts a little slower, but it has more computational resources, and supports the use of
- OS X - uses one of several versions of the OS X operating system. This environment is useful for building projects that require the OS X software, such as projects written in Swift. It is not a requirement to use the OS X environment if you develop on a macOS machine.
More details are on our environments are available in our CI Environment documentation.
Now you’ve read the basics, head over to our Getting Started guide for details on setting up your first build!