A pipeline is a repeatable sequence of tasks that produces an expected output. For cloud-native services, it automates work needed to build and run services, reducing the manual effort of adding or refactoring them. A pipeline definition describes the tasks; a pipeline engine creates an instance that executes them and reports their status. section 3.1
A pipeline can run tests, copy code, deploy software, provision virtual machines, or create users. Its steps depend on the objective, but the definition should be reusable so repeated executions can produce the same results. Organizations still need to choose tools and mature workflows around their own applications and operating constraints. section 3.1 section 1.1.2
Run a service pipeline with Tekton
A Tekton Pipeline sequences three tasks: fetch a file with a reusable wget task, read it with an inline cat task, and pass the content to a Hello World task. Install the wget task, then apply the Pipeline definition with kubectl apply -f hello-world-pipeline.yaml. Create and apply a separate PipelineRun for each execution. Use kubectl get taskrun to check task results and kubectl logs on the final task’s pod to inspect its output. section 3.5.2
Listing 3.6 Pipeline definition
apiVersion: tekton.dev/v1
kind: Pipeline
metadata:
name: hello-world-pipeline
annotations:
description: |
Fetch resource from internet, cat content and then say hello
spec:
results: #1
- name: message
type: string
value: $(tasks.cat.results.messageFromFile)
params: #2
- name: url
description: resource that we want to fetch
type: string
default: ""
workspaces: #3
- name: files
tasks:
- name: wget
taskRef: #4
name: wget
params:
- name: url
value: "$(params.url)"
- name: diroptions
value:
- "-P"
workspaces:
- name: wget-workspace
workspace: files
- name: cat
runAfter: [wget]
workspaces:
- name: wget-workspace
workspace: files
taskSpec: #5
workspaces:
- name: wget-workspace
results:
- name: messageFromFile
description: the message obtained from the file
steps:
- name: cat
image: bash:latest
script: |
#!/usr/bin/env bash
cat $(workspaces.wget-workspace.path)/welcome.md |
> kubectl get pods
NAME READY STATUS AGE
tee /tekton/results/messageFromFile
- name: hello-world
runAfter: [cat]
taskRef:
name: hello-world-task #6
params:
- name: name
value: "$(tasks.cat.results.messageFromFile)" #7
The Tekton definition shows how parameters, a workspace, task references, and task ordering fit into one Pipeline resource. section 3.5.2
Pipelines can also process operational data rather than build services. A metrics pipeline collects events from multiple systems, transforms them into a standardized model, calculates DORA metrics, stores the results, and makes them available for a dashboard. Event sources must supply CloudEvents or be adapted to that format before entering this pipeline. section 9.2.2
