### How this function works The function will be triggered by a Pub/Sub event published with the specific topic SEND_MESSAGE_TO_SLACK_CHANNEL. The message should contain the channelId and the text. ### Prerequisites * You must have previous knowledge of **Slack APP**. * You must have previous knowledge of **Pub/Sub**. ### Function details First, you need to create a specific Slack app from which the message will be sent. This application must meet the following requirements: * You need to obtain the `Bot User OAuth Token` from `OAuth & Permissions` section on the App Management page. * Grant access to your app to write a message. In `OAuth & Permissions` section of the App Management page, make sure your app is scoped with this permission, for example, the `chat:write` scope. * You need to integrate your app to the channel to which you want to send a message. * You need to obtain the `Channel ID` from the `About` tab in `Channel Details` in Slack. Then, install this function passing as a parameter: - **SLACK_API_TOKEN**: The Slack `Bot User OAuth Token`. ### Call the function Here is an example of how to use the function when it is installed: ```js const dataBuffer = Buffer.from(JSON.stringify({ channelId: 'C12345678', text: 'Hello from my slack app.', })); await pubsub.topic('SEND_MESSAGE_TO_SLACK_CHANNEL').publish(dataBuffer); ``` So, the message will be sent according to the channel specify by the `channelId`. ### Resources For more information about creating a Slack App and meet the requirements, see: + [Sending Slack messages](https://api.slack.com/messaging/sending)