Connecting App Signal with Incident.io using Cloudflare Workers

We started using Incident.io on Tuist for incident management. The tool is great, but we were missing a way to connect it with our monitoring system, AppSignal. When you look at the integrations available, App Signal isn’t there.

Luckily AppSignal supports sending webhooks when anomalies are detected, but the schema of the payload and the headers didn’t match what Incident.io expected. For example, Incident.io expects the requests to come with an Authorization: Bearer xxx header.

To make the integration work, we decided to use Cloudflare Workers. We created a worker that transforms the payload sent by AppSignal into the one that Incident.io expects, and adds the Authorization header. The worker is deployed to Cloudflare, and we configured AppSignal to send the webhooks to the worker’s URL. Below is the code of the worker:

const token = "...."
export default {
  async fetch(request, env, ctx) {
    const alert = await request.json()
    const { alert_id, metric_name, human_comparison_value, trigger_description } = alert;
    // https://docs.appsignal.com/application/integrations/webhooks.html#exception-incidents

    await fetch("https://api.incident.io/v2/alert_events/http/....", { headers: {
      "Authorization": `Bearer ${token}`,
      "Content-Type": "application/json"
    }, method: "POST", body: JSON.stringify({
      "title": `${metric_name} peaked above ${human_comparison_value}`,
      "description": trigger_description,
      "deduplication_key": `${alert_id}`,
      "status": "firing",
      "metadata": {
        ...alert
      }
    })})
    return new Response(JSON.stringify({status: "success"}), {status: 200, headers: {"Content-Type": "application/json"}});
  },
};

Hopefully, Incident.io will provide an integration with AppSignal in the future, but until then, this solution works well for us.