A Dart library to run Slack bots on Heroku

Initial setup

1. Create a Slack app.

• Note the client id, client secret, and verification token assigned to your app.

2. Follow the steps at https://github.com/igrigorik/heroku-buildpack-dart to configure a new Heroku instance for a Dart app.

• Instead of copying the example you will want to create a new Git project and build a skeletal server.
• Add the Slack client id, client secret, and verification token to the instance's configuration.

3. Deploy a first version of the server to Heroku.
4. Configure the Slack app.

• Add the desired slash commands and bot;
• Install the app for your team (this is the step that requires a working server).

5. Add the OAuth tokens Slack generated for your app to your Heroku instance's configuration.

Development workflow

1. Make a change, get it tested and reviewed, and make sure your master branch is up-to-date.
2. git push heroku master

Building the bot

Base server

The Server class and its configuration companion ServerConfig are used to start a server supporting authentication and slash commands. See examples/bin/server.dart for an example.

Background tasks

BackgroundTask supports, well, background tasks. It can be used to support periodic and long-running tasks. See examples/bin/background.dart for an example.

Note that for a task to be run by Heroku you need to define it in your Procfile:

my_task: ./dart-sdk/bin/dart bin/background.dart

and after re-deploying the bot you can then run the task manually with:

$ heroku run my_task

or use the Heroku scheduler to run it periodically.

Running the bot

Environment

A bot needs a few environment variables to function:

• USE_DELAYED_RESPONSES: should only be used in production where it allows slash commands to take more than 3 seconds to produce a result;
• SLACK_CLIENT_ID: the client id assigned to your Slack app;
• SLACK_CLIENT_SECRET: the client secret assigned to your Slack app;
• SLACK_VERIFICATION_TOKEN: the verification token assigned to your Slack app;
• SLACK_OAUTH_TOKEN: the oauth token assigned to your Slack app after it is installed for your team;
• (optional) SLACK_BOT_OAUTH_TOKEN: the oauth token assigned to your Slack app's bot user after the app is installed for your team.

Local testing

The following works for both servers and background tasks:

export FOO=foo BAR=bar dart bin/something.dart

where FOO, BAR, etc... are the environment variables the bot needs.