Handle SIGTERM and SIGINT signal (#3)

Part of https://plan.wireit.in/deepstack/browse/VUL-294/

Co-authored-by: Pranav <jadhavpranav89@gmail.com>
Reviewed-on: #3

src/index.ts

@@ -19,9 +19,25 @@ async function startServer() {
 
   const PORT = process.env.PORT || 6000;
 
-  app.listen(PORT, () => {
+  const httpServer = app.listen(PORT, () => {
     console.log(`🚀 Server ready at http://localhost:${PORT}${server.graphqlPath}`);
   });
+
+  const shutdown = async (signal: string) => {
+    console.log(`${signal} received, shutting down gracefully...`);
+
+    httpServer.close(() => {
+      console.log('HTTP server closed');
+    });
+
+    await server.stop();
+    console.log('Apollo server stopped');
+
+    process.exit(0);
+  };
+
+  process.on('SIGTERM', () => shutdown('SIGTERM'));
+  process.on('SIGINT', () => shutdown('SIGINT'));
 }
 
 startServer().catch(error => {

stack/stack-orchestrator/compose/docker-compose-mock-lockdrop-watcher.yml

@@ -7,7 +7,7 @@ services:
       VERIFIED_PARTICIPANTS_PATH: /tmp/watcher-data/verified-participants.json
       GENERATED_WATCHER_EVENTS_OUTPUT_PATH: /tmp/watcher-data/generated
     working_dir: /app/
-    command: "node --enable-source-maps dist/index.js"
+    command: ["node", "--enable-source-maps", "dist/index.js"]
     volumes:
       - watcher-data:/tmp/watcher-data
     ports: