Continuous Integration

We have a Jenkins instance running at ci.bit-bots.de which automatically builds the current documentation located at doku.bit-bots.de.

Note

If you only want to know what to do with your package and don’t care about Jenkins internals you only need Enable CI for a Repository and Make Package resolvable in CI.

Enable CI for a Repository

CI is enabled on a per-repository basis and not per-package. Each repository which uses CI contains a configuration-as-code file called Jenkinsfile. This file is located at the repository root and is written in Jenkins-DSL (domain specific language) which is based on Groovy which is based on Java. All our Jenkinsfiles mostly look the same and utilizes common logic defined in our Pipeline Library:

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@Library('bitbots_jenkins_library') import de.bitbots.jenkins.*;

defineProperties()

def pipeline = new BitbotsPipeline(this, env, currentBuild, scm)
pipeline.configurePipelineForPackage(new PackagePipelineSettings(new PackageDefinition("bitbots_docs")))
pipeline.execute()

Explained line by line:

  1. First we use the Jenkins Library bitbots_jenkins_library and import everything from it.
  1. We call defineProperties() to set properties of this pipeline like when it is triggered and whether it may run concurrently.
  1. We create a pipeline variable of type BitbotsPipeline. This class contains most of the pipeline logic and is the main content of this library.

    By default, the pipeline restricts documentation publishing to only happen on the primary branch of a repository. Since we don’t want to change the default behavior, we don’t explicitly define the last argument.

  2. We configure the pipeline to run for the package named bitbots_docs. See PackagePipelineSettings which configures what the pipeline should do and PackageDefinition which defines a packages name and where it is defined in the repo.

    In this case, the pipeline should run for the package bitbots_docs which is located in a folder with the same name. The pipeline should build the package, document the package and publish the package which are the default settings so they are not explicitly given.

Make Package resolvable in CI

When package a is used as a dependency by package b and package b is supposed to have CI enabled, a needs to be resolvable via rosdep. This section assumes you are the maintainer of package a and want to make your package resolvable.

  1. Create .rdmanifest file in your package (not repository) root by calling the script gen_rdmanifest.py in bitbots_meta. It’s options should be self-explanatory when calling with –help.

    .rdmanifest syntax reference

  2. Define the package in our own rosdep definition by creating an entry like the following:

    bitbots_docs:
      ubuntu: &bitbots_docs
        source:
          uri: 'https://raw.githubusercontent.com/bit-bots/bitbots_tools/master/bitbots_docs/.rdmanifest'
      debian: *bitbots_docs
      fedora: *bitbots_docs
    

Jenkins System Configuration

The System-Configuration is done via the Web-UI or via configuration-as-code from ansible. In short it contains:

System Configuration:
 Only contains Security-Settings, which Github server to use, Jenkins base-url and user authentication setup.
Credentials:Passwords, SSH-Keys and Api-Tokens to access source control
bitbots_jenkins_library:
 This is a Jenkins Library (a collection of Groovy files) which can be loaded into a pipeline definition to provide common tasks. Its code is contained in bit-bots/bitbots_jenkins_library and it must be registered in the Jenkins configuration so that it is loadable in pipelines.

Jenkins is composed of a very small core and a ton of plugins. One of these plugins is the Github Plugin which lets Jenkins scan our Organisation for repositories with a valid configuration and automatically registers it in Jenkins.

Build triggers

Some builds are run periodically while most GitHub builds are triggered via webhooks as well.

These webhooks should be managed by the Github Plugin but in case that fails, Github must be configured as follows:

Payload URL:

http://ci.bit-bots.de/github-webhook/

Content Type:

application/json

Secret:

Ask Finn or someone else who can see the current settings in Github.

If that is not possible update the credential github-webhook-secret in Jenkins to a new value and set that in the webhook as well.

Which events?:

Send everything

Dependency Resolution Explained

Most of our packages have dependencies which are not normally resolvable via rosdep because they are our own packages. For example, bitbots_msgs depends on bitbots_docs in order to build documentation. To be able to resolve these dependencies while staying recent in their versions, a rosdep definition has been created which defines our packages as being installable via the source package manager. Each package also has a .rdmanifest file in its package directory which then teaches rosdep how exactly that package can be installed. The bitbots_builder docker image (used by our CI) has this rosdep definition configured and is thus able to resolve our packages as dependencies.

See REP 111 and REP 112 for more documentation about rosdep.