This sample shows how to build a serverless Slack app using Slack Events API to receive events, with IBM Cloud Functions to process these events.
A previous version of this sample was using API Connect to expose the actions as HTTP endpoints. With the introduction of web actions in Cloud Functions this was no longer needed. You can browse this tag to view the code using API Connect.
Built using IBM Cloud, the app uses:
- Cloud Functions - to implement the app bot and commands
- Cloudant - to keep track of app installations
- and Slack Events API.
When a user installs the app in a Slack team, or interacts with a bot user, or uses a custom command, Slack calls the app implementation. Slack will talk directly with IBM Cloud Functions.
From the perspective of the developer of the Slack app, there is no server involved, only actions in a serverless environment. Furthermore the code is not running if no user interacts with the app and if the app gets popular, it will benefit from IBM Cloud Functions scalability.
architecture_diagram digraph G { node [fontname = "helvetica"] rankdir=LR user -> slack slack -> openwhisk openwhisk -> cloudant slack [shape=square style=filled color="%23e9a820" fontcolor=white label="%23 Slack"] openwhisk [shape=circle style=filled color="%23325c80" fontcolor=white label="Cloud Functions"] cloudant [shape=circle style=filled color="%2372c7e7" fontcolor=white label="Cloudant"] } architecture_diagram )
In this sample, we will:
- create the Slack app in Slack,
- prepare the Cloud Functions environment, creating the actions implementing our Slack app,
- complete the integration by updating the endpoints in the Slack app,
- add our Slack app to a Slack team,
- test our Slack app.
To deploy this app, you need:
- IBM Cloud account. Sign up for IBM Cloud, or use an existing account.
- Slack account
- The IBM Cloud CLI and the Cloud Functions plugin
Your own Slack team is recommended if you want to play with the integration without impacting others.
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Proceed to the new app creation in Slack
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Type a name for your app, select your Slack team.
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Click Create
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View the App Credentials
We will need the Client ID, Client Secret and Verification Token in the next steps.
At this stage, we will put the configuration of the Slack app on hold. For the next app configuration steps to work we need to have our actions up and running.
-
Clone the app to your local environment from your terminal using the following command:
git clone https://github.com/IBM-Cloud/openwhisk-slackapp.git -
or Download and extract the source code from this archive
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Open the IBM Cloud console
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Create a Cloudant instance named cloudant-for-slackapp.
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Open the Cloudant service dashboard and create a new database named registrations
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Select the database
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Create a new document.
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Replace the default JSON with the content of the file cloudant-designs.json
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Copy the file named template.local.env into local.env
cp template.local.env local.env -
Get the service credentials for the Cloudant service created above and set CLOUDANT_url, CLOUDANT_apikey in
local.envto the corresponding value (url and apikey). -
Set the values for SLACK_CLIENT_ID, SLACK_CLIENT_SECRET, SLACK_VERIFICATION_TOKEN - these are the App Credentials we've seen in the previous steps.
-
Ensure your
ibmcloud fncommand line interface is property configured with:ibmcloud fn listThis shows the packages, actions, triggers and rules currently deployed in your namespace.
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Create the actions:
./deploy.sh --installIf all goes well it outputs:
Creating slackapp package ok: created package slackapp Adding app registration command ok: created action slackapp/slackapp-register Adding app event processing ok: created action slackapp/slackapp-event Adding app command processing ok: created action slackapp/slackapp-command OAuth URL: https://us-south.functions.cloud.ibm.com/api/v1/web/<your-namespace-id>/slackapp/slackapp-register Command URL: https://us-south.functions.cloud.ibm.com/api/v1/web/<your-namespace-id>/slackapp/slackapp-command Event Subscription Request URL: https://us-south.functions.cloud.ibm.com/api/v1/web/<your-namespace-id>/slackapp/slackapp-eventNote: the script can also be used to --uninstall the Cloud Functions artifacts to --update the artifacts if you change the action code, or simply with --env to show the environment variables set in local.env.
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Copy the file named template.local.cmd into local.cmd
copy template.local.cmd local.cmd -
Get the service credentials for the Cloudant service created above and set CLOUDANT_url in
local.cmdto the corresponding value (url). Make sure you take the full url including the username and password https://username:[email protected]. -
Set the values for SLACK_CLIENT_ID, SLACK_CLIENT_SECRET, SLACK_VERIFICATION_TOKEN - these are the App Credentials we've seen in the previous steps.
-
Ensure your
ibmcloud fncommand line interface is property configured with:ibmcloud fn listThis shows the packages, actions, triggers and rules currently deployed in your namespace.
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Create the actions:
deploy.cmd --installIf all goes well it outputs:
Creating slackapp package ok: created package slackapp Adding app registration command ok: created action slackapp/slackapp-register Adding app event processing ok: created action slackapp/slackapp-event Adding app command processing ok: created action slackapp/slackapp-commandNote: the script can also be used to --uninstall the Cloud Functions artifacts to --update the artifacts if you change the action code, or simply with --env to show the environment variables set in local.cmd.
Our actions are ready. Back to the Slack app configuration.
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Go to the Event Subscriptions section of your app
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Enable Events
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Set the Request URL to the URL of the
slack-eventweb action. The URL should look likehttps://us-south.functions.cloud.ibm.com/api/v1/web/your-namespace-id/slackapp/slackapp-event
Slack will contact this URL immediately. It should turn to Verified if the Cloud Functions configuration steps worked.
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Add a new Bot User Event for message.im
This allows us to react to direct messages sent to a bot. We could select more event type but for our simple app will only deal with this one today.
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Save the changes
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Under OAuth and Permissions, add a new Redirect URL. This URL will be called when a user installs your application in a team. It should point to the
slackapp-registerweb action. The URL should look likehttps://us-south.functions.cloud.ibm.com/api/v1/web/your-namespace-id/slackapp/slackapp-register
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Click Save URLs
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Under Slash Commands, Create New Command
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Set the values
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Command: /myserverlessapp
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Request URL: URL of the
slackapp-commandweb action. The URL should look likehttps://us-south.functions.cloud.ibm.com/api/v1/web/your-namespace-id/slackapp/slackapp-command -
Short Description: A test command
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Usage Hint: [param1] [param2]
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Save. This automatically creates a bot for the app.
- Go to OAuth & Permissions.
- Under Scopes / Bot Token Scopes, add the two OAuth Scopes: chat:write and users:read
Our app is finally ready to be installed!
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To see what's happening behind the scene as Slack calls our actions, open a new command prompt and run
ibmcloud fn activation pollLeave it running. Actions triggered by Slack will show up there
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Go to Manage Distribution
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Click the Add the Slack button
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Authorize the app
After a few seconds, the app is installed. You should see logs appearing in the activation polling as Slack will be sending the registration info we will use later to interact with Slack channels and users.
In your web browser, you should see
Registration was successful. You can try the command in Slack or send a direct message to the bot.Ideally you would redirect to another page once the registration is completed.
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Go into your team in Slack
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Send a direct message to our new bot friend
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The bot replies
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Go to the #general channel (although this could work from any place in Slack) and type
/myyou should see the custom command
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Try the command
/myserverless two paramsas example
| File | Description |
|---|---|
| deploy.cmd deploy.sh |
Helper script to install, uninstall, update the actions. |
| File | Description |
|---|---|
| slackapp-register.js | Handles the installation of the app in a team. It stores the authorization token in Cloudant for future use by the bot and commands. |
| slackapp-event.js | Handles events triggered by the Events API. In this sample, it handles messages sent to the bot user and simply echoes the message sent by the user. |
| slackapp-command.js | Handles custom commands. In this sample, it echoes the command parameters. |
Please create a pull request with your desired changes.
Polling activations is good start to debug the action execution. Run
ibmcloud fn activation poll
and send a message to the bot or use a custom command.
See License.txt for license information.
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