feat: run cron job to start signature request processing

Without this patch we rely on users making a POST request to
/v1/signature-requests/process to kick off signature request processing.

Since it's not going to be high load, we want to have a regular cron job
that relieves users of that duty and will run signature request
validations on autopilot.

This way users just have to wait a bit to find their signature requests
validated once the Safe message has reached the required threshold.

Also made a small change to the log statement in the processor to make
it more clear that it's running signature requests, now that a console
log will show up every 30 seconds.

package.json

@@ -62,6 +62,7 @@
     "kysely": "^0.27.4",
     "lodash": "^4.17.21",
     "lru-cache": "^11.0.0",
+    "node-cron": "^3.0.3",
     "pg": "^8.12.0",
     "reflect-metadata": "^0.2.2",
     "rollup": "^4.12.0",
@@ -93,6 +94,7 @@
     "@swc/cli": "^0.3.12",
     "@swc/core": "^1.4.15",
     "@types/body-parser": "^1.19.5",
+    "@types/node-cron": "^3.0.11",
     "@types/pg": "^8.11.6",
     "@types/sinon": "^17.0.2",
     "@types/swagger-ui-express": "^4.1.6",

src/cron/SignatureRequestProcessing.ts

@@ -0,0 +1,31 @@
+import cron from "node-cron";
+
+import SignatureRequestProcessor from "../services/SignatureRequestProcessor.js";
+
+export default class SignatureRequestProcessorCron {
+  private static instance: SignatureRequestProcessorCron;
+  private processor: SignatureRequestProcessor;
+
+  private constructor() {
+    this.processor = SignatureRequestProcessor.getInstance();
+    this.setupCronJob();
+  }
+
+  private setupCronJob() {
+    // Run every 30 seconds
+    cron.schedule("*/30 * * * * *", async () => {
+      try {
+        await this.processor.processPendingRequests();
+      } catch (error) {
+        console.error("Error in signature request processor cron job:", error);
+      }
+    });
+  }
+
+  public static start(): void {
+    if (!SignatureRequestProcessorCron.instance) {
+      SignatureRequestProcessorCron.instance =
+        new SignatureRequestProcessorCron();
+    }
+  }
+}

src/index.ts

@@ -8,6 +8,7 @@ import swaggerUi from "swagger-ui-express";
 import swaggerJson from "./__generated__/swagger.json" assert { type: "json" };
 import { RegisterRoutes } from "./__generated__/routes/routes.js";
 import * as Sentry from "@sentry/node";
+import SignatureRequestProcessorCron from "./cron/SignatureRequestProcessing.js";
 
 // @ts-expect-error BigInt is not supported by JSON
 BigInt.prototype.toJSON = function () {
@@ -48,6 +49,9 @@ RegisterRoutes(app);
 // The error handler must be registered before any other error middleware and after all controllers
 Sentry.setupExpressErrorHandler(app);
 
+// Start Safe signature request processing cron job
+SignatureRequestProcessorCron.start();
+
 app.listen(PORT, () => {
   console.log(
     `🕸️ Running a GraphQL API server at http://localhost:${PORT}/v1/graphql`,

src/services/SignatureRequestProcessor.ts

@@ -22,7 +22,7 @@ export default class SignatureRequestProcessor {
   async processPendingRequests(): Promise<void> {
     const pendingRequests = await this.getPendingRequests();
 
-    console.log(`Found ${pendingRequests.length} pending requests`);
+    console.log(`Found ${pendingRequests.length} pending signature requests`);
 
     for (const request of pendingRequests) {
       const command = getCommand(request);