jenkins-job-builder/doc/source/definition.rst

Job Definitions

The job definitions for Jenkins Job Builder are kept in any number of YAML files, in whatever way you would like to organize them. When you invoke jenkins-jobs you may specify either the path of a single YAML file, or a directory. If you choose a directory, all of the .yaml (or .yml) files in that directory will be read, and all the jobs they define will be created or updated.

Definitions

Jenkins Job Builder understands a few basic object types which are described in the next sections.

Job

The most straightforward way to create a job is simply to define a Job in YAML. It looks like this:

- job:
    name: job-name

That's not very useful, so you'll want to add some actions such as builders, and perhaps publishers. Those are described later.

jenkins_jobs.modules.general

Job Template

If you need several jobs defined that are nearly identical, except perhaps in their names, SCP targets, etc., then you may use a Job Template to specify the particulars of the job, and then use a Project to realize the job with appropriate variable substitution. Any variables not specified at the project level will be inherited from the Defaults.

A Job Template has the same syntax as a Job, but you may add variables anywhere in the definition. Variables are indicated by enclosing them in braces, e.g., {name} will substitute the variable name. When using a variable in a string field, it is good practice to wrap the entire string in quotes, even if the rules of YAML syntax don't require it because the value of the variable may require quotes after substitution. In the rare situation that you must encode braces within literals inside a template (for example a shell function definition in a builder), doubling the braces will prevent them from being interpreted as a template variable.

You must include a variable in the name field of a Job Template (otherwise, every instance would have the same name). For example:

- job-template:
    name: '{name}-unit-tests'

Will not cause any job to be created in Jenkins, however, it will define a template that you can use to create jobs with a Project definition. It's name will depend on what is supplied to the Project.

Project

The purpose of a project is to collect related jobs together, and provide values for the variables in a Job Template. It looks like this:

- project:
    name: project-name
    jobs:
      - '{name}-unit-tests'

Any number of arbitrarily named additional fields may be specified, and they will be available for variable substitution in the job template. Any job templates listed under jobs: will be realized with those values. The example above would create the job called 'project-name-unit-tests' in Jenkins.

The jobs: list can also allow for specifying job-specific substitutions as follows:

- project:
    name: project-name
    jobs:
      - '{name}-unit-tests':
          mail-to: developer@nowhere.net
      - '{name}-perf-tests':
          mail-to: projmanager@nowhere.net

If a variable is a list, the job template will be realized with the variable set to each value in the list. Multiple lists will lead to the template being realized with the cartesian product of those values. Example:

- project:
    name: project-name
    pyver:
      - 26
      - 27
    jobs:
      - '{name}-{pyver}'

If there are templates being realized that differ only in the variable used for its name (thus not a use case for job-specific substitutions), additional variables can be specified for project variables. Example:

/../../tests/yamlparser/fixtures/templates002.yaml

Job Group

If you have several Job Templates that should all be realized together, you can define a Job Group to collect them. Simply use the Job Group where you would normally use a Job Template and all of the Job Templates in the Job Group will be realized. For example:

/../../tests/yamlparser/fixtures/templates001.yaml

Would cause the jobs project-name-unit-tests and project-name-perf-tests to be created in Jenkins.

Macro

Many of the actions of a Job, such as builders or publishers, can be defined as a Macro, and then that Macro used in the Job description. Builders are described later, but let's introduce a simple one now to illustrate the Macro functionality. This snippet will instruct Jenkins to execute "make test" as part of the job:

- job:
    name: foo-test
    builders:
      - shell: 'make test'

If you wanted to define a macro (which won't save much typing in this case, but could still be useful to centralize the definition of a commonly repeated task), the configuration would look like:

- builder:
    name: make-test
    builders:
      - shell: 'make test'

- job:
    name: foo-test
    builders:
      - make-test

This allows you to create complex actions (and even sequences of actions) in YAML that look like first-class Jenkins Job Builder actions. Not every attribute supports Macros, check the documentation for the action before you try to use a Macro for it.

Macros can take parameters, letting you define a generic macro and more specific ones without having to duplicate code:

# The 'add' macro takes a 'number' parameter and will creates a
# job which prints 'Adding ' followed by the 'number' parameter:
- builder:
    name: add
    builders:
     - shell: "echo Adding {number}"

# A specialized macro 'addtwo' reusing the 'add' macro but with
# a 'number' parameter hardcoded to 'two':
- builder:
    name: addtwo
    builders:
     - add:
        number: "two"

# Glue to have Jenkins Job Builder to expand this YAML example:
- job:
    name: "testingjob"
    builders:
     # The specialized macro:
     - addtwo
     # Generic macro call with a parameter
     - add:
        number: "ZERO"
     # Generic macro called without a parameter. Never do this!
     # See below for the resulting wrong output :(
     - add

Then <builders /> section of the generated job show up as:

<builders>
  <hudson.tasks.Shell>
    <command>echo Adding two</command>
  </hudson.tasks.Shell>
  <hudson.tasks.Shell>
    <command>echo Adding ZERO</command>
  </hudson.tasks.Shell>
  <hudson.tasks.Shell>
    <command>echo Adding {number}</command>
  </hudson.tasks.Shell>
</builders>

As you can see, the specialized macro addtwo reused the definition from the generic macro add. Whenever you forget a parameter from a macro, it will not be expanded and left as is, which will most probably cause havoc in your Jenkins builds.

Defaults

Defaults collect job attributes (including actions) and will supply those values when the job is created, unless superseded by a value in the 'Job'_ definition. If a set of Defaults is specified with the name global, that will be used by all Job (and Job Template) definitions unless they specify a different Default object with the defaults attribute. For example:

- defaults:
    name: global
    description: 'Do not edit this job through the web!'

Will set the job description for every job created.

You can define variables that will be realized in a Job Template.

/../../tests/yamlparser/fixtures/template_honor_defaults.yaml

Would create jobs build-i386 and build-amd64.

Variable References

If you want to pass an object (boolean, list or dict) to templates you can use an {obj:key} variable in the job template. This triggers the use of code that retains the original object type.

For example:

/../../tests/yamlparser/fixtures/custom_distri.yaml

The yaml specification supports anchors and aliases which means that JJB definitions allow references to variables in templates.

For example:

/../../tests/yamlparser/fixtures/yaml_anchor.yaml

Custom Yaml Tags

jenkins_jobs.local_yaml

Modules

The bulk of the job definitions come from the following modules.

project_flow project_freestyle project_maven project_matrix builders hipchat metadata notifications parameters properties publishers reporters scm triggers wrappers zuul

Module Execution

The jenkins job builder modules are executed in sequence.

Generally the sequence is:

1. parameters/properties
2. scm
3. triggers
4. wrappers
5. prebuilders (maven only, configured like builders)
6. builders (maven, freestyle, matrix, etc..)
7. postbuilders (maven only, configured like builders)
8. publishers/reporters/notifications