nounify

The unified notification service for all HTTP requests.

nounify can receives any notification from any services via HTTP. For example, you can send a notification from GitHub Webhooks, Google Pub/Sub, and so on. When receiving a notification via HTTP request, nounify validates and modifies the notification message based on Rego policies. Rego can not only permit or deny the request but also creating a new message from notification data. So you can customize the notification message for each channel.

For example, here is a rule that converts a GitHub Webhook message to a Slack message. The rule is triggered when a new issue is opened, and the message is sent to the #github-notify channel with the octopus emoji.

package schema.github_webhook

msg[{
  "channel": "github-notify",
  "color": "#2EB67D",
  "emoji": ":octopus:",
  "title": "New issue opened",
  "body": input.body.issue.body,
  "fields": [
    {
      "name": "Author",
      "value": input.body.issue.user.login,
      "link": input.body.issue.user.html_url,
    },
    {
      "name": "Issue",
      "value": sprintf("#%d: %s", [input.body.issue.number, input.body.issue.title]),
      "link": input.body.issue.html_url,
    },
  ],
}] {
  input.header["X-Github-Event"] == "issues"
  input.body.action == "opened"
}

When creating a new issue such as this, the following message will be emitted.

Usage

Prerequisites

Create a Slack App and get OAuth token.
- The app should have chat:write, chat:write.customize and chat:write.public scope.
- Install the app to your workspace.
If you need to receive messages from GitHub App, create a GitHub App.
- Enable permissions for your interest and subscribe them. See Using webhooks with GitHub Apps for more information.
- Install the app to your repository.
- Set random secret key for webhook, and keep it secret.

Deploy

Set following environment variables to deploy nounify.

Basic settings
- NOUNIFY_ADDR (required): The address to listen to. e.g. 0.0.0.0:8080
- NOUNIFY_RULE (required): The path to the Rego policy file. e.g. policies.rego
- NOUNIFY_SLACK_OAUTH_TOKEN (required): The OAuth token of Slack App. It's recommended to set the token as a secret.
Authentication settings
- NOUNIFY_GITHUB_SECRET (optional): The secret key for GitHub webhook. If you don't need to receive messages from GitHub, you can skip this.
- NOUNIFY_GITHUB_ACTION_TOKEN (optional): If set, nounify validates the token in Authorization header as Bearer from GitHub Actions OIDC.
- NOUNIFY_GOOGLE_ID_TOKEN (optional): If set, nounify validates the token in Authorization header as Bearer from Google ID Token.