Add Task to Trigger Jenkins Pipeline using Tekton

The following task can be used to trigger an existing Jenkins pipeline from Tekton using the CURL request by providing the required parameters.

Signed-off-by: vinamra28 <[email protected]>

trigger-jenkins-pipeline/README.md

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+# Trigger Jenkins
+
+The following task can be used to trigger a Jenkins pipeline using CURL request from a Tekton Task.
+
+More details on Remote Access API can be found [here](https://www.jenkins.io/doc/book/using/remote-access-api/)
+
+## Install the Task
+
+```bash
+kubectl apply -f https://raw.githubusercontent.com/tektoncd/catalog/master/trigger-jenkins-pipeline/trigger-jenkins-pipeline.yaml
+```
+
+## Parameters
+
+- **JENKINS_HOST_URL**: The URL on which Jenkins is running (**Required**)
+- **JOB_NAME**: The Job name which needs to be triggered (**Required**)
+- **JENKINS_SECRETS**: The name of the secret containing the username and API token for authenticating the Jenkins (_Default_: jenkins-credentials) (**Required**)
+- **ARGS**: Extra parameters which needs to be appended in the `CURL` request. (_Default_: ""). `ARGS` is of type `array` so multiple arguments can be appended. `ARGS` can be provided as follows:-
+
+  ```yaml
+  params:
+    - name: ARGS
+      value: |
+        - "--form file0=@PATH_TO_FILE"
+        - "-form json='{"parameter": [{"name":"FILE_LOCATION_AS_SET_IN_JENKINS", "file":"file0"}]}'"
+  ```
+
+## Workspaces
+
+- **source**: In case any file needs to be provided to the Jenkins Job. (_Default_: `emptyDir: {}`)
+
+## Secrets
+
+This is a secret containing username and API token that is used in the task for making the CURL request.
+
+```yaml
+apiVersion: v1
+kind: Secret
+metadata:
+  name: jenkins-credentials
+type: Opaque
+stringData:
+  username: username
+  apitoken: api-token
+```
+
+## Usage
+
+1. Without `ARGS` parameters
+
+   ```yaml
+   apiVersion: tekton.dev/v1beta1
+   kind: TaskRun
+   metadata:
+     name: trigger-jenkins
+   spec:
+     taskRef:
+       name: trigger-jenkins-pipeline
+     params:
+       - name: JENKINS_HOST_URL
+         value: "http://localhost:8080"
+       - name: JOB_NAME
+         value: tekton
+     workspaces:
+       - name: source
+         emptyDir: {}
+   ```
+
+1. With `ARGS` parameters
+
+   ```yaml
+   apiVersion: tekton.dev/v1beta1
+   kind: TaskRun
+   metadata:
+     name: trigger-jenkins
+   spec:
+     taskRef:
+       name: trigger-jenkins-pipeline
+     params:
+       - name: JENKINS_HOST_URL
+         value: "http://localhost:8080"
+       - name: JOB_NAME
+         value: tekton
+       - name: ARGS
+         value: |
+           - "--data-urlencode json='{"parameter": [{"name":"id", "value":"123"}, {"name":"verbosity", "value":"high"}]}'"
+     workspaces:
+       - name: source
+         emptyDir: {}
+   ```

trigger-jenkins-pipeline/examples/run.yaml

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+apiVersion: tekton.dev/v1beta1
+kind: TaskRun
+metadata:
+  name: trigger-jenkins
+spec:
+  taskRef:
+    name: trigger-jenkins-pipeline
+  params:
+    - name: JENKINS_HOST_URL
+      value: http://localhost:8080
+    - name: JOB_NAME
+      value: tekton
+    - name: JENKINS_SECRETS
+      value: jenkins-credentials
+  workspaces:
+    - name: source
+      emptyDir: {}

trigger-jenkins-pipeline/examples/secrets.yaml

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+apiVersion: v1
+kind: Secret
+metadata:
+  name: jenkins-credentials
+type: Opaque
+stringData:
+  username: username
+  apitoken: api-token

trigger-jenkins-pipeline/trigger-jenkins-pipeline.yaml

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+apiVersion: tekton.dev/v1beta1
+kind: Task
+metadata:
+  name: trigger-jenkins-pipeline
+spec:
+  workspaces:
+    - name: source
+  params:
+    - name: JENKINS_HOST_URL
+      type: string
+      description: Server URL on which Jenkins is running
+    - name: JOB_NAME
+      type: string
+      description: Jenkins Job which needs to be triggered
+    - name: JENKINS_SECRETS
+      type: string
+      description: Jenkins secret containing credentials
+      default: jenkins-credentials
+    - name: ARGS
+      type: array
+      description: Extra arguments to append as a part of CURL request
+      default: [""]
+  steps:
+    - name: trigger-pipeline
+      image: registry.access.redhat.com/ubi8/ubi:latest
+      workingDir: $(workspaces.source.path)
+      args:
+        - $(params.ARGS)
+      script: |
+        #!/usr/bin/env bash
+
+        curl -X POST "$(params.JENKINS_HOST_URL)"/job/"$(params.JOB_NAME)"/build \
+        --user $USERNAME:$API_TOKEN $@
+      env:
+        - name: USERNAME
+          valueFrom:
+            secretKeyRef:
+              name: $(params.JENKINS_SECRETS)
+              key: username
+        - name: API_TOKEN
+          valueFrom:
+            secretKeyRef:
+              name: $(params.JENKINS_SECRETS)
+              key: apitoken