chore: Refactoring event processors and service architecture (#2495)

server/services/worker.js

@@ -0,0 +1,86 @@
+// @flow
+import http from "http";
+import debug from "debug";
+import Koa from "koa";
+import {
+  globalEventQueue,
+  processorEventQueue,
+  websocketsQueue,
+  emailsQueue,
+} from "../queues";
+import Backlinks from "../queues/processors/backlinks";
+import Debouncer from "../queues/processors/debouncer";
+import Emails from "../queues/processors/emails";
+import Imports from "../queues/processors/imports";
+import Notifications from "../queues/processors/notifications";
+import Revisions from "../queues/processors/revisions";
+import Slack from "../queues/processors/slack";
+import Sentry from "../sentry";
+
+const log = debug("queue");
+
+const EmailsProcessor = new Emails();
+
+const eventProcessors = {
+  backlinks: new Backlinks(),
+  debouncer: new Debouncer(),
+  imports: new Imports(),
+  notifications: new Notifications(),
+  revisions: new Revisions(),
+  slack: new Slack(),
+};
+
+export default function init(app: Koa, server?: http.Server) {
+  // this queue processes global events and hands them off to services
+  globalEventQueue.process(function (job) {
+    Object.keys(eventProcessors).forEach((name) => {
+      processorEventQueue.add(
+        { ...job.data, service: name },
+        { removeOnComplete: true }
+      );
+    });
+
+    websocketsQueue.add(job.data, { removeOnComplete: true });
+  });
+
+  processorEventQueue.process(function (job) {
+    const event = job.data;
+    const processor = eventProcessors[event.service];
+    if (!processor) {
+      console.warn(
+        `Received event for processor that isn't registered (${event.service})`
+      );
+      return;
+    }
+
+    if (processor.on) {
+      log(`${event.service} processing ${event.name}`);
+
+      processor.on(event).catch((error) => {
+        if (process.env.SENTRY_DSN) {
+          Sentry.withScope(function (scope) {
+            scope.setExtra("event", event);
+            Sentry.captureException(error);
+          });
+        } else {
+          throw error;
+        }
+      });
+    }
+  });
+
+  emailsQueue.process(function (job) {
+    const event = job.data;
+
+    EmailsProcessor.on(event).catch((error) => {
+      if (process.env.SENTRY_DSN) {
+        Sentry.withScope(function (scope) {
+          scope.setExtra("event", event);
+          Sentry.captureException(error);
+        });
+      } else {
+        throw error;
+      }
+    });
+  });
+}