Simple Slack Bot - NASA

It uses APOD API from NASA.

Commands

Development

Bot was created by following Slack's tutorial for making bots with Ruby.

Running a bot locally

foreman start

Deploying bot to Heroku

• [ToDo] Configure Heroku toolbelt locally

• From the comfort of your terminal create new app on Heroku

  heroku create <app-name>

• Add environment variables to this app with commands similar to the following. We'd like to execute this for every variable listed in our .env file.

  heroku config:add ENV_VAR_NAME=<its-value>

• Deploy it by running the following command locally

  git push heroku master

https://nasa-apod-bot.herokuapp.com/

Set up an automatic deployment on Semaphore

If we set up Semaphore server for the master branch, our application will automatically be deployed to Heroku after every green build on master.

Wake up Dyno with an outgoing webhook in Slack

Every app deployd to Heroku gets few Heroku Dynos, lightweight containers. When app is using Heroku on a free tier it gets very tired Dyno, which goes to sleep after 30 mins of inactivity.

To entertain a Dyno, I've set up one Outgoing WebHook for Slack. Let's call it Houston. When mentioned, Houston pings my Heroku application. So, at the moment, Houston listens for triggers in Slack chat messages. When a trigger word (Houston) is noticed, Slack will send relevant data to external URL(s) in real-time.

Configure webhook

When creating the Outgoing WebHook, I've:

• filled the URL box with the URL of deployed application on Heroku https://nasa-apod-bot.herokuapp.com/houston
• specified trigger word houston

When nasa is inactive on Slack it will ignore every picture request. Then I just type houston :)

On a side note, this page lets us to customize some webhook's details (e.g. Name, Icon, select Slack channel(s))

Verify if request is known

Webhook page from above also shows the token which is included in every outgoing playload. This lets me to verify that a post request came from my Slack team. At the momment, logic for this lives in the web.rb file.

return if params[:token] != ENV["SLACK_WEBHOOK_TOKEN"]

Trivia

Houston, we've had a problem.

Sentence coined by NASA astronaut Jack Swigert, best known as the command module pilot aboard Apollo 13. Here is one awesome project if you'd like to read stories about the early space exploration.