Defining and creating pipeline tasks

Tasks are the building blocks of a Pipeline and consist of sequentially executed steps. steps are a series of commands that achieve a specific goal, for instance, build an image.

Every Task runs as a pod and each step runs in its own container within the same pod. Since they run within the same pod they have access to the same volumes to cache files, configmaps, and secrets. They use inputs parameters, for example, a git , and outputs parameters, for example, an image in a registry, to interact with other tasks.

Tasks are reusable and can be used in multiple Pipeline s. For this tutorial, you create a Maven Task with a single step to build a Maven based application, and then add two reusable Tasks from the catalog repository.

Procedure

  1. To create the Maven Task:

    1. Copy the contents of the following sample Task YAML file and save it:

      apiVersion: tekton.dev/v1alpha1
kind: Task
metadata:
  name: maven-build
spec:
  inputs:
    resources:
    - name: workspace-git
      targetPath: /
      type: git
  steps:
  - name: build
    image: maven:3.6.0-jdk-8-slim
    command:
    - /usr/bin/mvn
    args:
    - install

      This Task starts a pod and runs a container inside that pod using the maven:3.6.0-jdk-8-slim image to run the specified commands. It receives an input directory called workspace-git which contains the source code of the application.

      Only the requirement for a git repository is declared on the Task and not a specific git repository to be used. This allows Tasks to be reusable for multiple Pipeline s and purposes.

    2. Create the Task within your project:

      oc create -f maven-build-task.yaml

  2. Install the s2i-java and openshift-client reusable Tasks from the catalog repository, which contains a list of reusable Tasks for Pipeline s:

    $ oc create -f https://raw.githubusercontent.com/tektoncd/catalog/master/openshift-client/openshift-client-task.yaml
$ oc create -f https://raw.githubusercontent.com/openshift/pipelines-catalog/master/s2i-java8/s2i-java-8-task.yaml

  3. Verify the Tasks added to the Pipeline as follows:

    $ tkn task ls

NAME              AGE
maven-build       23 secs ago
openshift-client  10 secs ago
s2i-java          11 secs ago

Additional resources