Creating a Slack chat bot

In this tutorial, you will learn how to use serverless technologies to create a Slack bot that will run commands in a chat and respond to user messages.

To create a bot:

1. Prepare the environment.
2. Create an application and connect it to Yandex Cloud.
3. Get a token and a secret for the app.
4. Create functions.
5. Edit the API gateway.
6. Add commands to Slack.
7. Test the Slack bot.

Getting startedGetting started

Sign up for Yandex Cloud and create a billing account:

1. Go to the management console and log in to Yandex Cloud or create an account if you do not have one yet.
2. On the Yandex Cloud Billing page, make sure you have a billing account linked and it has the ACTIVE or TRIAL_ACTIVE status. If you do not have a billing account, create one.

If you have an active billing account, you can go to the cloud page to create or select a folder for your infrastructure to operate in.

Learn more about clouds and folders.

Required paid resourcesRequired paid resources

The cost of bot support includes:

• Fee for using the API gateway (see Yandex API Gateway pricing).
• Fee for using functions (see Yandex Cloud Functions pricing).

Prepare the environmentPrepare the environment

1. Download the archive with the files required to create a bot.
2. If you do not have a folder yet, create one.
3. Create a service account named sa-slack and assign it the editor role for your folder.

Create an app and connect it to Yandex CloudCreate an app and connect it to Yandex Cloud

Register the Slack appRegister the Slack app

1. Log in to Slack. To create a bot, make sure you have workspace management permissions.

2. Create an app:

   1. Click Create an App.
   2. Select From scratch.
   3. In the App Name field, enter the name for the app: ServerlessBotApp.
   4. Select the available workspace and click Create App.

3. Grant permissions to the ServerlessBotApp app:

   1. In the app control menu, select Features → OAuth & Permissions.
   2. Under Scopes → Bot Token Scopes, click Add an OAuth Scope and add the following permissions: chat:write, commands, and im:history.

4. Install the application: in the app control menu, select Settings → Install App and click Install to Workspace → Allow.

Set up a link between Slack and Yandex CloudSet up a link between Slack and Yandex Cloud

1. Create a function named for-slack-bot-challenge. Make sure it is private.

2. Create a function version:

   1. Specify the following parameters:

      • Runtime environment: python312.
      • Entry point: index.handler.
      • Timeout, sec: 5.
      • Service account: sa-slack service account you created earlier.

   2. Create a file named index.py and paste the contents of the 0_for-slack-bot-challenge.py file from the archive into it.

3. Create an API gateway:

   1. Specify the name: for-slack-bot.

   2. Under Specification, add the POST method configuration to the paths parameter:

      paths:
        /:
          get:
            x-yc-apigateway-integration:
              type: dummy
              content:
                '*': Hello, World!
              http_code: 200
              http_headers:
                Content-Type: text/plain
          post:
            x-yc-apigateway-integration:
              type: cloud_functions
              function_id: <function_ID>
              service_account_id: <service_account_ID>
              operationId: slack-challenge
      

      Where:

      • function_id: ID of the for-slack-bot-challenge function.
      • service_account_id: ID of the sa-slack service account.

Test the link between Slack and Yandex CloudTest the link between Slack and Yandex Cloud

1. Copy the service domain of the for-slack-bot API gateway.
2. Select the ServerlessBotApp app.
3. In the app control menu, select Features → Event Subscriptions.
4. Enable the Enable Events option.
5. In the Request URL field, insert the API gateway's address and wait for the Verified entry to appear.
6. In the Subscribe to bot events section, click Add Bot User Event and select the message.im event.
7. Click Save Changes.

Get a token and a secret for the appGet a token and a secret for the app

Select the ServerlessBotApp app:

1. In the app control menu, select Settings → Basic Information.
2. Copy the Signing Secret value from the App Credentials section: it will be used for the SLACK_SIGNING_SECRET environment variable.
3. In the app control menu, select Features → OAuth & Permissions.
4. In the OAuth Tokens for Your Workspace section, copy the Bot User OAuth Token value: it will be used for the SLACK_BOT_TOKEN environment variable.

Create functionsCreate functions

Using functions, you can configure the bot's reactions to user actions in the chat. In this tutorial, you will create the following functions:

• For messaging between the bot and the user.
• For getting the bot's response to a simple command.

Function for messagingFunction for messaging

1. Create a function named for-slack-bot-small-talk. Make sure it is private.

2. Create a function version:

   1. Specify the following parameters:

      • Runtime environment: python312.
      • Entry point: index.handler.
      • Timeout, sec: 5.
      • Service account: sa-slack service account you created earlier.

   2. Create a file named requirements.txt and specify the following libraries in it:

      slack_sdk
      slack_bolt
      boto3
      

   3. Create a file named index.py and paste the contents of the 1_for-slack-bot-small-talk.py file from the archive into it.

   4. Add environment variables:

      • SLACK_BOT_TOKEN
      • SLACK_SIGNING_SECRET

Function for responding to commandsFunction for responding to commands

1. Create a function named for-slack-bot-hello-from-serverless. Make sure it is private.

2. Create a function version:

   1. Specify the following parameters:

      • Runtime environment: python312.
      • Entry point: index.handler.
      • Timeout, sec: 5.
      • Service account: sa-slack service account you created earlier.

   2. Create a file named requirements.txt and specify the following libraries in it:

      slack_sdk
      slack_bolt
      boto3
      

   3. Create a file named index.py and paste the contents of the 2_for-slack-bot-hello-from-serverless.py file from the archive into it.

   4. Add environment variables:

      • SLACK_BOT_TOKEN
      • SLACK_SIGNING_SECRET

Edit the API gatewayEdit the API gateway

To make sure the bot starts responding to user messages, link the created functions to the app. To do this, edit the specification of the for-slack-bot API gateway and add the POST method configurations to the paths parameter:

  /:
    post:
      x-yc-apigateway-integration:
        type: cloud_functions
        function_id: <function_1_ID>
        service_account_id: <service_account_ID>
        operationId: small-talk
  /hello-from-serverless:
    post:
      x-yc-apigateway-integration:
        type: cloud_functions
        function_id: <function_2_ID>
        service_account_id: <service_account_ID>
        operationId: hello-from-serverless

Where:

• service_account_id: ID of the sa-slack service account.
• <ID_of_function_1>: ID of the for-slack-bot-small-talk function.
• <ID_of_function_2>: ID of the for-slack-bot-hello-from-serverless function.

Add a command to SlackAdd a command to Slack

Using commands, you can set up the bot's actions in the chat. Commands start with a / character and their list is always visible to the user.

1. Select the ServerlessBotApp app.

2. In the app control menu, select Features → Slash Commands and click Create New Command.

3. Add a command for the for-slack-bot-hello-from-serverless function:

   • In the Command field, enter /hello-from-serverless.
   • In the Request URL field, paste the url from the for-slack-bot API gateway specification, adding the /hello-from-serverless command's URL to it.
   • In the Short descriptions field, enter any short description of the command.
   • Click Save.

4. Re-install the application: in the app control menu, select Settings → Install App and click Reinstall to Workspace → Allow.

5. Enable users to send messages: in the app control menu, select Features → App Home and enable Allow users to send Slash commands and messages from the messages tab in the Show Tabs section.

Test the Slack botTest the Slack bot

Open the Slack client and choose a chat with the ServerlessBotApp bot under Apps.

1. To test the for-slack-bot-small-talk function:
   • Send a message saying :wave: in the chat. The bot should respond with Hi there, @<username>!.
   • Send a message saying knock knock in the chat. The bot should respond with Who's there?.
2. To test the for-slack-bot-hello-from-serverless function, send the /hello-from-serverless command in the chat. The bot should respond with Thanks!.

How to delete the resources you createdHow to delete the resources you created

To stop paying for the resources you created:

• Delete the API gateway.
• Delete the functions.