Conditional Tasks¶

Introduction¶

Conditional tasks allow you to run certain tasks when the defined condition evaluates to true only. At the moment you can use such conditions on each task: shell, docker(container), docker(image) and python.

Data sources¶

There are three sources of information that can be used the moment (via Jinja templating):

model variables - constant definition in the yaml file.

task variables - see different type of tasks using the field variable

environment variables - see the env entry usable on matrix, pipeline, stage and tasks

Rules¶

You have to comply some rules when using conditions. Following variants of conditions are intended:

{{ variables.cpu_count }} == 1 - comparison of two integers to be equal

not {{ variables.cpu_count }} == 1 - comparison of two integers to be not equal

{{ variables.cpu_count }} > 1 - comparison of one integer to be greater than another

{{ variables.cpu_count }} >= 1 - comparison of one integer to be greater or equal than another

{{ variables.cpu_count }} < 2 - comparison of one integer to be less than another

{{ variables.cpu_count }} <= 2 - comparison of one integer to be less or equal than another

“{{ env.BRANCH_NAME }}” == “master” - comparison of two strings to be equal

not “{{ env.BRANCH_NAME }}” == “master” - comparison of two strings to be not equal

{{ variables.cpu_count }} in [1, 2] - integer contained in a list of integers

{{ variables.cpu_count }} not in [1, 2] - integer not ontained in a list of integers

“{{ env.BRANCH_NAME }}” in [“master”, “release”] - comparison contained in a list of strings

“{{ env.BRANCH_NAME }}” not in [“master”, “release”] - comparison not contained in a list of strings

Please note: all other combination that might work should not be considered. Future versions of the spline tool will improve the condition checks to be more strict.

Please note: When the jinja templating finally produces a condition with wrong syntax each thrown exception will evaluate the related condition to false. Please check the logs for details then.

Examples¶

You can see examples in the file conditions.yaml of the tool repository; here is an extract of it:

- shell:
    script: echo "integer in integer list comparison"
    when: "{{ model.intval }} in [1234, 4321]"
- shell:
    # task output should not be shown
    script: echo "integer not in integer list comparison"
    when: "{{ model.intval }} not in [1234, 4321]"