Notifying Mentioned Users via Slack DM for Git Pull Request and Issue Comments with Hubot

Overview

I kept hearing complaints like “I missed a mention in a Git Pull Request or Issue comment because the email notification slipped by!”
So I built a mechanism that sends a Slack DM to the mentioned user.

System Overview

This time I built it on AWS.

• Git is GHE on EC2.
  • In the case of github.com, there is the problem of IPs not being fixed, so it seems we would need a mechanism that dynamically obtains and releases IPs.
• Hubot runs on a minimal t2.nano.
  • Initially I tried building it on IBM Bluemix, but support told me that IP restrictions were not yet available, so I went with AWS.
• The entry point for Hubot from GHE is an ELB that only allows the EIP.
  • I set up the ELB with the intention of creating various entry points going forward.
  • Originally the sole purpose was to send JIRA mentions to Slack DMs, so it was placed in the same Private Subnet.

Script

• getSlackUsernameByGitUsername
  • Basically the git name and slack name followed a unified naming convention, so I resolve them by converting with a regular expression.
  • If the git name is kenzo-tanaka, it is converted to the slack name kenzo.tanaka.
  • Users that do not conform to the naming convention are left to the conversion in the users list below.
    • kimika.himura is assumed to be someone who does not want to receive DMs.
• Dependent libraries
  • “hubot-slack”: “^4.4.0”
  • “hubot-slack-attachement”: “^1.0.1”

users = {
    "kenzo-tanaka": "kenzo0107",
    "kimika.himura": "no_send"
}

The full source is below.

Git Configuration

Set the URL to Hubot under the Organization or Owner you want to configure, via Settings > Hooks. ((Applying a Hook to all repositories across Organizations at once seems difficult unless you write a separate script. Since GitHub also recommends having a single Organization, this is what I went with this time!))

Other settings

• Content type: application/json
• Let me select individual events:
  • Issues
  • Issue comment
  • Pull request
  • Pull request review
  • Pull request review comment

• To make it more secure, please set a Secret.

The notification arrived!

I immediately tried mentioning someone in a Pull Request, and the notification arrived!
The emoji came through perfectly too!
And the URL was automatically linked!

That’s all. I hope this is helpful to you!