Add fully flexible script to yq task

* Add backwards compatibility for previous version
* Update default image
* Ensure the task will now fail when a command exited with a
non-zero exit code. This was a bug in previous yq versions, see:
mikefarah/yq#1062
* Add optional result
* Add default value for SCRIPT for backwards compatibility
* Handle empty SCRIPT param

task/yq/0.4/README.md

@@ -0,0 +1,28 @@
+# YQ Task
+
+The following task is used to interface with the yq tool on any file in your workspace.
+
+## Installing the Task
+
+```bash
+kubectl apply -f https://raw.githubusercontent.com/tektoncd/catalog/main/task/yq/0.4/yq.yaml
+```
+
+## Parameters
+
+- **SCRIPT**: The yq script to execute. Can be multiple lines for complex tasks.
+- **image**: The `yq` image to use. (_default:_ docker.io/mikefarah/yq:4.16.2@sha256:0d4f6e27bdcac7316f635acd524ab0eecc4ad50834b54d10322268650c7712cb)
+- **files**: (deprecated, use SCRIPT instead) A list of files to execute the expression on. Needs to be relative to the source workspace. (_default:_ [])
+- **expression**: (deprecated, use SCRIPT instead) The yq expression to apply. Can be used to replace yaml fields. (_default:_ "")
+
+## Workspaces
+
+- **source** : The workspace containing files on which we want to run yq commands.
+
+## Platforms
+
+The Task can be run on `linux/amd64` platform.
+
+## Usage
+
+For a real usage example checkout the [tests directory](https://github.com/tektoncd/catalog/tree/main/task/yq/0.4/tests) of this task for an example on how this task can be used on a Github repository. This can be used together with other git actions to commit such changes towards a GitOps repository for example which is automatically reconciled towards your infrastructure.

task/yq/0.4/tests/pre-apply-task-hook.sh

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+#!/bin/bash
+
+# Add git-clone
+add_task git-clone 0.7

task/yq/0.4/tests/resources.yaml

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+---
+apiVersion: v1
+kind: PersistentVolumeClaim
+metadata:
+  name: yq-pvc
+spec:
+  accessModes:
+    - ReadWriteOnce
+  resources:
+    requests:
+      storage: 100Mi

task/yq/0.4/tests/run.yaml

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+---
+apiVersion: tekton.dev/v1beta1
+kind: Pipeline
+metadata:
+  name: yq-pipeline
+spec:
+  params:
+    - name: new-image-sha
+      description: example of a value to use
+      default: "123"
+  workspaces:
+    - name: source
+  tasks:
+    - name: fetch-repository
+      taskRef:
+        name: git-clone
+      workspaces:
+        - name: output
+          workspace: source
+      params:
+        - name: url
+          value: https://github.com/GijsvanDulmen/yq-task-test
+        - name: revision
+          value: "main"
+        - name: subdirectory
+          value: ""
+        - name: deleteExisting
+          value: "true"
+    - name: yq-replace
+      taskRef:
+        name: yq
+      runAfter:
+        - fetch-repository
+      workspaces:
+        - name: source
+          workspace: source
+      params:
+        - name: SCRIPT
+          value: |
+            for var in "./helm/values.yaml" "./helm/values-development.yaml"
+              do
+                  /usr/bin/yq eval -i '.image="012345my-new-image-sha"' "$var"
+              done
+  finally:
+    - name: display-results
+      workspaces:
+        - name: source
+          workspace: source
+      taskSpec:
+        workspaces:
+          - name: source
+        steps:
+          - name: print
+            image: docker.io/library/bash:5.1.4@sha256:b208215a4655538be652b2769d82e576bc4d0a2bb132144c060efc5be8c3f5d6
+            script: |
+              #!/usr/bin/env bash
+              set -e
+              cat $(workspaces.source.path)/helm/values.yaml
+              cat $(workspaces.source.path)/helm/values-development.yaml
+---
+apiVersion: tekton.dev/v1beta1
+kind: PipelineRun
+metadata:
+  name: yq-pipeline-run
+spec:
+  pipelineRef:
+    name: yq-pipeline
+  workspaces:
+    - name: source
+      persistentvolumeclaim:
+        claimName: yq-pvc
+  taskRunSpecs:
+    - pipelineTaskName: yq-replace
+      taskPodTemplate:
+        securityContext:
+          runAsUser: 0

task/yq/0.4/yq.yaml

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+apiVersion: tekton.dev/v1beta1
+kind: Task
+metadata:
+  name: yq
+  labels:
+    app.kubernetes.io/version: "0.4"
+  annotations:
+    tekton.dev/pipelines.minVersion: "0.12.1"
+    tekton.dev/categories: Developer Tools
+    tekton.dev/tags: yq
+    tekton.dev/displayName: "YQ"
+    tekton.dev/platforms: "linux/amd64"
+spec:
+  description: >-
+    This task can be used to replace fields in YAML files. For example for altering helm charts on GitOps repos.
+  workspaces:
+    - name: source
+      description: A workspace that contains the file which needs to be altered.
+  params:
+    - name: SCRIPT
+      type: string
+      description: The yq script to execute. Can be multiple lines for complex tasks.
+      default: ""
+    - name: image
+      type: string
+      description: The yq image to use.
+      default: docker.io/mikefarah/yq:4.27.5@sha256:2be3626ed633fbe1fc33ee9343a1256a6be53334412b2251b9a859f8c145bb53
+    - name: files
+      type: array
+      description: (deprecated, use SCRIPT instead) A list of files to execute the expression on. Needs to be relative to the source workspace.
+      default: []
+    - name: expression
+      type: string
+      description: (deprecated, use SCRIPT instead) The yq expression to apply. Can be used to replace yaml fields.
+      default: ""
+  results:
+    - name: yq
+      description: The result from your yq command. You can write to it using `$(results.yq.path)`
+  steps:
+    - name: yq-script
+      image: $(params.image)
+      workingDir: $(workspaces.source.path)
+      args: ["$(params.files[*])"]
+      script: |
+        /usr/bin/env sh
+        set -e
+
+        # For backwards compatibility with previous versions
+        if [ "$(params.SCRIPT)" = "" ]; then
+          for var in "$@"
+          do
+              /usr/bin/yq eval -i "$(params.expression)" "$var"
+          done
+          exit $?
+        fi
+
+        $(params.SCRIPT)