README.md

Developer docs

This document is aimed at helping maintainers/developers of project understand the complexity.

How are resources shared between tasks?

Pipelineruns uses PVC to share resources between tasks. PVC volume is mounted on path /pvc by Pipelinerun.

• If resource in a task is declared as output then taskun controllers add step to copy each output resource to directory path /pvc/task_name/resource_name.

• If input resource includes providedBy condition then container definition to copy from PVC to directory from /pvc/previous_task/resource_name.

How are inputs handled?

Input resources like source code(git) or artifacts are dumped at path /workspace/task_resource_name. Resource definition in task can have custom target directory. If targetPath is mentioned in task input then controllers have to be responsible for adding container definitions to create directories and also to fetch versioned artifacts into that directory.

How are outputs handled?

Output resources like source code(git) or artifacts(storage resource) are expected in directory path /workspace/output/resource_name.

• If resource has output "action" like upload to blob storage, then container step is added for this action.

• If there is PVC volume present(taskrun holds owner reference to pipelinerun) then copy step is added as well.

  • If resource is declared only in output but not in input for task then copy step includes resource being copied to PVC to path /pvc/task_name/resource_name from /workspace/output/resource_name like the following example.

  kind: Task
  metadata:
  name: get-gcs-task
  namespace: default
  spec:
  outputs:
    resources:
      - name: gcs-workspace
    type: storage

  • If resource is declared both in input and output for task then copy step includes resource being copied to PVC to path /pvc/task_name/resource_name from /workspace/random-space/ if input resource has custom target directory(random-space) declared like the following example.

  kind: Task
  metadata:
  name: get-gcs-task
  namespace: default
  spec:
  inputs:
    resources:
      - name: gcs-workspace
    type: storage
    targetPath: random-space
  outputs:
    resources:
      - name: gcs-workspace
    type: storage

  • If resource is declared both in input and output for task without custom target directory then copy step includes resource being copied to PVC to path /pvc/task_name/resource_name from /workspace/random-space/ like the following example.

  kind: Task
  metadata:
  name: get-gcs-task
  namespace: default
  spec:
  inputs:
    resources:
      - name: gcs-workspace
    type: storage
    name: storage
  outputs:
    resources:
      - name: gcs-workspace
    type: storage