Replace gitlab-eventlistener with a working example

I moved this to a separate folder so that it was easy to add the sample
payload as well as instructions for trying it out locally.

Signed-off-by: Dibyo Mukherjee <dibyo@google.com>

docs/eventlisteners.md

@@ -296,10 +296,7 @@ accept to the `eventTypes` field.
 The body/header of the incoming request will be preserved in this Interceptor's
 response.
 
-<!-- FILE: examples/eventlisteners/gitlab-eventlistener-interceptor.yaml -->
-
-```YAML
----
+```yaml
 apiVersion: tekton.dev/v1alpha1
 kind: EventListener
 metadata:

examples/gitlab/README.md

@@ -0,0 +1,49 @@
+## GitLab Push EventListener
+
+Creates an EventListener that listens for Gitlab webhook events.
+
+### Try it out locally:
+
+1. Create the service account:
+
+   ```shell script
+   kubectl apply -f examples/role-resources/triggerbinding-roles
+   kubectl apply -f examples/role-resources/
+   ```
+
+1. Create the Gitlab EventListener:
+
+   ```shell script
+   kubectl apply -f examples/gitlab/gitlab-push-listener.yaml
+   ```
+
+1. Port forward:
+
+   ```shell script
+   kubectl port-forward \
+    "$(kubectl get pod --selector=eventlistener=gitlab-listener -oname)" \
+     8080
+   ```
+
+   **Note**: Instead of port forwarding, you can set the
+   [`serviceType`](https://github.com/tektoncd/triggers/blob/master/docs/eventlisteners.md#serviceType)
+   to `LoadBalancer` to expose the EventListener with a public IP.
+
+1. Test by sending the sample payload.
+
+   ```shell script
+   curl -v \
+   -H 'X-GitLab-Token: abcde' \
+   -H 'X-Gitlab-Event: Push Hook' \
+   -H 'Content-Type: application/json' \
+   --data-binary "@examples/gitlab/gitlab-push-event.json" \
+   http://localhost:8080
+   ```
+
+   The response status code should be `201 Created`
+
+1. You should see a new TaskRun that got created:
+
+   ```shell script
+   kubectl get taskruns | grep gitlab-run-
+   ```

examples/gitlab/gitlab-push-event.json

@@ -0,0 +1,59 @@
+{
+  "object_kind": "push",
+  "event_name": "push",
+  "before": "1a1736ec3d7b03349b31218a2f2c572c7c7206d6",
+  "after": "1a1736ec3d7b03349b31218a2f2c572c7c7206d6",
+  "ref": "refs/heads/master",
+  "checkout_sha": "1a1736ec3d7b03349b31218a2f2c572c7c7206d6",
+  "message": null,
+  "user_id": 111448,
+  "user_name": "Dibyo Mukherjee",
+  "user_username": "dibyom",
+  "user_email": "",
+  "user_avatar": "https://secure.gravatar.com/avatar/1d56773f447d86b8ffa33efb7a5d0cb5?s=80&d=identicon",
+  "project_id": 16507326,
+  "project": {
+    "id": 16507326,
+    "name": "triggers",
+    "description": "",
+    "web_url": "https://gitlab.com/dibyom/triggers",
+    "avatar_url": null,
+    "git_ssh_url": "git@gitlab.com:dibyom/triggers.git",
+    "git_http_url": "https://gitlab.com/dibyom/triggers.git",
+    "namespace": "Dibyo Mukherjee",
+    "visibility_level": 20,
+    "path_with_namespace": "dibyom/triggers",
+    "default_branch": "master",
+    "ci_config_path": null,
+    "homepage": "https://gitlab.com/dibyom/triggers",
+    "url": "git@gitlab.com:dibyom/triggers.git",
+    "ssh_url": "git@gitlab.com:dibyom/triggers.git",
+    "http_url": "https://gitlab.com/dibyom/triggers.git"
+  },
+  "commits": [
+    {
+      "id": "1a1736ec3d7b03349b31218a2f2c572c7c7206d6",
+      "message": "Add new file",
+      "timestamp": "2020-01-24T17:05:48+00:00",
+      "url": "https://gitlab.com/dibyom/triggers/-/commit/1a1736ec3d7b03349b31218a2f2c572c7c7206d6",
+      "author": {
+        "name": "Dibyo Mukherjee",
+        "email": "foo@bar.com"
+      },
+      "added": ["Readme.md"],
+      "modified": [],
+      "removed": []
+    }
+  ],
+  "total_commits_count": 1,
+  "push_options": {},
+  "repository": {
+    "name": "triggers",
+    "url": "git@gitlab.com:dibyom/triggers.git",
+    "description": "",
+    "homepage": "https://gitlab.com/dibyom/triggers",
+    "git_http_url": "https://gitlab.com/dibyom/triggers.git",
+    "git_ssh_url": "git@gitlab.com:dibyom/triggers.git",
+    "visibility_level": 20
+  }
+}

examples/gitlab/gitlab-push-listener.yaml

@@ -0,0 +1,74 @@
+apiVersion: tekton.dev/v1alpha1
+kind: TriggerTemplate
+metadata:
+  name: gitlab-echo-template
+spec:
+  params:
+    - name: gitrevision
+    - name: gitrepositoryurl
+  resourcetemplates:
+    - apiVersion: tekton.dev/v1alpha1
+      kind: TaskRun
+      metadata:
+        generateName: gitlab-run-
+      spec:
+        taskSpec:
+          inputs:
+            resources:
+              - name: source
+                type: git
+          steps:
+            - image: ubuntu
+              script: |
+                #! /bin/bash
+                ls -al $(inputs.resources.source.path)
+        inputs:
+          resources:
+            - name: source
+              resourceSpec:
+                type: git
+                params:
+                  - name: revision
+                    value: $(params.gitrevision)
+                  - name: url
+                    value: $(params.gitrepositoryurl)
+---
+apiVersion: tekton.dev/v1alpha1
+kind: TriggerBinding
+metadata:
+  name: gitlab-push-binding
+spec:
+  params:
+    - name: gitrevision
+      value: $(body.checkout_sha)
+    - name: gitrepositoryurl
+      value: $(body.repository.git_http_url)
+---
+apiVersion: v1
+kind: Secret
+metadata:
+  name: gitlab-secret
+type: Opaque
+stringData:
+  gitlabToken: abcde
+---
+apiVersion: tekton.dev/v1alpha1
+kind: EventListener
+metadata:
+  name: gitlab-listener
+spec:
+  # from examples/role-resources/servicaccount.yaml
+  serviceAccountName: tekton-triggers-example-sa
+  triggers:
+    - name: gitlab-push-events-trigger
+      interceptors:
+        - gitlab:
+            secretRef:
+              secretName: gitlab-secret
+              secretKey: gitlabToken
+            eventTypes:
+              - Push Hook # Only push events
+      bindings:
+        - name: gitlab-push-binding
+      template:
+        name: gitlab-echo-template