Enabling Pipeline Resources to be marked as Optional

[pritidesai]

Changes

Pipeline inputs and outputs are considered required, there is no way
today to mark them optional. This change introduces a new field called
optional as part of the PipelineDeclaredResource similar to previous PR #1601,
by default optional is set to false and a resource is required.
To mark any resource optional, set optional to true:

apiVersion: tekton.dev/v1alpha1
kind: Pipeline
metadata:
 name: pipeline-build-image
spec:
 resources:
   - name: workspace
     type: git
     optional: true
 tasks:
   - name: check-workspace

Closes #1710

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Release Notes

Allowing any pipeline resource to be declared as optional.

apiVersion: tekton.dev/v1alpha1
kind: Pipeline
metadata:
 name: pipeline-build-image
spec:
 resources:
   - name: workspace
     type: git
     optional: true
 tasks:
   - name: check-workspace

[pritidesai]

/test pull-tekton-pipeline-integration-tests

[bobcatfish]

/test pull-tekton-pipeline-integration-tests

[afrittoli]

/kind feature

[ghost]

/lgtm

[ghost]

I was trying to figure out what would happen if a pipeline makes a resource optional but a task in the pipeline requires the resource. Would this manifest as a TaskRun error & fail the pipeline?

[pritidesai]

I was trying to figure out what would happen if a pipeline makes a resource optional but a task in the pipeline requires the resource. Would this manifest as a TaskRun error & fail the pipeline?

Hey @sbwsg it will fail with PipelineValidationFailed and will produce error message where source-repo is a resource marked as optional within pipeline but required as part of task: couldn''t resolve all references: couldn''t match referenced resources with declared resources: pipelineTask tried to use input resource source-repo not present in declared resources'

[ghost]

/approve

[tekton-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: sbwsg

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