davidmerrick / micronaut-slack-starter

Starter project for building Slack apps with Micronaut

Micronaut Slack Starter

Starter project for a Micronaut Slack app, written in Kotlin. This is forked from my quarantinebot project.

Includes:

• Dockerfile for building with GraalVM for blazing-fast cold start time on AWS Lambda.
• Terraform configs for deploying infrastructure.
• Netty server for running locally.
• Health check endpoint.

Creating a Slack bot

Create an app via https://api.slack.com/. Add it to your workspace.

Event subscriptions

Subscribe to bot events: app_mention, message.channels, and message.im.

Permissions

Add scopes for app_mentions:read, im:history, and chat:write.

Bots

Enable Always Show My Bot as Online.

Running tests locally

1. Do a ./gradlew build to generate kapt annotations
2. Run tests as usual in IntelliJ

Running application locally

Included in the build is Micronaut's Netty server. Invoke ./gradlew run to start it on port 8080. Make sure to set the SLACK_TOKEN environment variable to your Slack app's token.

Compilation and deployment with GraalVM

1. Run docker build . -t quarantinebot
2. After build, run the container, then exit. docker run -ti quarantinebot /bin/bash
3. Copy the function.zip out of the container. docker cp $(docker ps --last 1 --quiet):/home/application/function.zip ./
4. On AWS Lambda, set the runtime to "Custom runtime". Use ./bootstrap as the handler.
5. Enjoy your insanely fast lambda.

References

• Micronaut GraalVM tutorial
• Netty on GraalVM