Overview

Lazy to constantly check for the latest update in the team's project repository? Webhooks can be used to push notifications into your chat tool from your CI/CD platform.

Prerequisites

Tech Stack

• I used the [official Rocket.Chat docker image](hub.docker.com/_/rocket-chat) as my testing environment. You can refer to the steps here in the its Docker page.

• I will be using Gitlab for the CI/CD platform.

Additional steps for Rocket.Chat

Create personal access token

• The personal access token will be used when calling Rocket.Chat REST API endpoints.

• A User-Id and Token will be provided upon creation.

Create a new role for specific permissions

When setting up, the user you will be using would be with Admin role.

The minimum [permissions](docs.rocket.chat/use-rocket.chat/rocket.cha..) required are:

1. bot role

2. Manage Own Incoming Integrations and Manage Own Outgoing Integrations

As users are granted permissions via roles, it would be recommended to create a new role for granular control of permissions.

In this case, I created a role named integrations-role with permissions Manage Own Incoming Integrations and Manage Own Outgoing Integrations tied to it.

---

Configure Integrations

1) Create incoming integration in Rocket.Chat

The incoming integration in Rocket.Chat will generate the webhook URL that will be used in Gitlab to trigger notifications to the target channel.

Enabling script in incoming integrations

It's quite interesting and puzzling that the script option is disabled by default. This is because if no script is enabled, the incoming integration will return empty messages when the webhook is triggered.

I have customized the [sample incoming webhook script](https://docs.rocket.chat/use-rocket.chat/rocket.chat-workspace-administration/integrations#script-details) on the content to be sent to the webhook when triggered by Gitlab events.

class Script {

    process_incoming_request({ request }) {

      content = request.content

      dataToPrint = {
        "event_name": content.event_name,
        "branch": content.ref,
        "project_repo": content.repository.name,
        "changes": content.commits
      }

      return {
        content:{
          text: JSON.stringify(dataToPrint, undefined, 4)
         }
      };

    }
}

In the REST API call, I have minified the script into 1 line for the Create Integration curl command below.

• Replace the placeholders (in angle brackets <>) with appropriate values

curl --location --request POST 'http://localhost/api/v1/integrations.create' \
--header 'X-Auth-Token: <REPLACE_WITH_X_AUTH_TOKEN>' \
--header 'X-User-Id: <REPLACE_WITH_USER_ID>' \
--header 'Content-type: application/json' \
--data-raw '{
    "name": "incoming-restapi-integration",
    "type": "webhook-incoming",
    "username": "<USERNAME>",
    "alias": "Incoming-from-Gitlab",
    "channel": "#<CHANNEL_NAME>",
    "scriptEnabled": true,
    "enabled": true,
    "script": "class Script{process_incoming_request({request}){content=request.content;dataToPrint={event_name:content.event_name,branch:content.ref,project_repo:content.repository.name,changes:content.commits};return{content:{text:JSON.stringify(dataToPrint,undefined,4)}}}}"
}'

If you want to update the incoming integrations subsequently, you can use the following Update Integration curl command

• Note the difference is the inclusion of the required key integrationId

curl --location --request PUT 'http://localhost/api/v1/integrations.update' \
--header 'X-Auth-Token: <REPLACE_WITH_X_AUTH_TOKEN>' \
--header 'X-User-Id: <REPLACE_WITH_USER_ID>' \
--header 'Content-type: application/json' \
--data-raw '{
    "name": "incoming-restapi-integration",
    "type": "webhook-incoming",
    "username": "<USERNAME>",
    "alias": "Incoming-from-Gitlab",
    "channel": "#<CHANNEL_NAME>",
    "scriptEnabled": true,
    "enabled": true,
    "script": "class Script{process_incoming_request({request}){content=request.content;dataToPrint={event_name:content.event_name,branch:content.ref,project_repo:content.repository.name,changes:content.commits};return{content:{text:JSON.stringify(dataToPrint,undefined,4)}}}}",
    "integrationId": "<INTEGRATION_ID>"
}'

Caveats

1. There seems to be a known bug where the token and webhook URL created via GUI console will result in Service Unavailable error, even on the latest version i.e. v5.4.0 at the time of writing.

2. Hence, the incoming integration must be managed using the [Integrations endpoints](https://developer.rocket.chat/reference/api/rest-api/endpoints/core-endpoints/integration-endpoints).

   • This means creating and updating the endpoints should be done via the REST API

   • If you try to make changes via the GUI, the integrations will not be updated regardless.

2) Configure webhook in Gitlab

Next, configure the type of events that will trigger a notification to Rocket.Chat.

You can retrieve the webhook URL via the Administration Workspace dashboard.

1. From the menu button, click on Workspace

2. Click on Integrations to reveal the existing integrations. Select the one you created

3. You should be able to find the webhook URL for your selected integration

To make the local environment accessible, I used ngrok http 80

• Use ngrok for testing purpose only!

• It can potentially expose your devices to threat actors if you leave the connection persistently online. Read this article from Huntress to better understand the security context

For simplicity, I will be selecting push events for all branches.

Steps

1. Navigate to Settings > Webhooks

2. Provide the webhook URL generated in Rocket.Chat incoming integration

3. Select the Triggers that will invoke the webhook

4. Use Gitlab Test feature to verify the connectivity

---

Verification

Upon clicking on the Test dropdown, you can select the event type to test. In our case, we will be clicking on the Push events.

Upon triggering the push event, a notification is triggered to send the push event information into the specified channel.

In this screenshot, the notification from Gitlab provides us with the following details

1. The type of event i.e. push events

2. The file(s) that have been added, modified and deleted

You can see that there are 3 commits for this push event.

---

Final Thoughts

My initial motivations spark when I didn't stay up-to-date with the latest changes in the team's centralized repository🤦🏻‍♀️ As notifications are done manually through message broadcast, there is inevitably the human error of forgetting to push such manual notifications 😣

Hopefully, this will allow me to be more diligent in following the latest changes in the selected project repositories 🌚

Cheers!