chore(examples): add an example app to test google pubsub

examples/google-pubsub/index.js

@@ -0,0 +1,53 @@
+process.env.PUBSUB_EMULATOR_HOST = 'localhost:8085'
+process.env.PUBSUB_PROJECT_ID = 'test'
+
+const express = require('express')
+const timers = require('timers/promises');
+const app = express()
+const port = 3000;
+const Pubsub = require('@algoan/pubsub');
+const topicName = 'my_topic';
+
+const pubsubClient = Pubsub.PubSubFactory.create({
+  options: {
+    projectId: 'test',
+  }
+});
+const secondPubsubClient = Pubsub.PubSubFactory.create({
+  options: {
+    projectId: 'test',
+  }
+});
+
+let pubsubCall = 0;
+
+app.get('/', (req, res) => {
+  res.send(`PubSub calls: ${pubsubCall}`);
+});
+
+app.get('/emit', async (req, res) => {
+  secondPubsubClient.emit(topicName, {});
+  await timers.setTimeout(1000)
+  res.redirect('/');
+});
+
+app.get('/close', async (req, res) => {
+  await pubsubClient.client.close();
+  await timers.setTimeout(1000)
+  res.redirect('/');
+});
+
+app.listen(port, async () => {
+  await pubsubClient.listen(topicName, {
+    options: {
+      subscriptionOptions: {
+        name: topicName,
+      }
+    },
+    onMessage: () => {
+      console.log('Received message!')
+      pubsubCall++;
+    }
+  });
+  console.log(`Example app listening on port ${port}`)
+});