restructure repo, separate sample app from docker configs

05-example-web-application/api-node/.dockerignore

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+node_modules

05-example-web-application/api-node/Makefile

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+.PHONY: run-local
+run-local:
+	PGUSER=postgres \
+    PGHOST=localhost \
+    PGPASSWORD=foobarbaz \
+    PGDATABASE=postgres \
+    PGPORT=5432 \
+    node ./src/index.js
+
+.PHONY: build-naive
+build-naive:
+	docker build --file ./Dockerfile.naive .

05-example-web-application/api-node/README.md

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+```
+npm init
+npm install express pg
+```
+
+```
+node src/index.js
+```

05-example-web-application/api-node/package.json

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+{
+  "name": "api-node",
+  "version": "1.0.0",
+  "description": "simple api that connects to postgres",
+  "main": "src/index.js",
+  "scripts": {
+    "dev": "nodemon src/index.js",
+    "test": "echo \"Error: no test specified\" && exit 1"
+  },
+  "author": "",
+  "license": "ISC",
+  "dependencies": {
+    "express": "^4.18.2",
+    "morgan": "^1.10.0",
+    "pg": "^8.8.0"
+  },
+  "devDependencies": {
+    "nodemon": "^2.0.20"
+  }
+}

05-example-web-application/api-node/src/db.js

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+const { Pool } = require('pg');
+
+const pool = new Pool();
+
+// the pool will emit an error on behalf of any idle clients
+// it contains if a backend error or network partition happens
+pool.on('error', (err, client) => {
+  console.error('Unexpected error on idle client', err);
+  process.exit(-1);
+});
+
+// async/await - check out a client
+const getDateTime = async () => {
+  const client = await pool.connect();
+  try {
+    const res = await client.query('SELECT NOW() as now;');
+    return res.rows[0];
+  } catch (err) {
+    console.log(err.stack);
+  } finally {
+    client.release();
+  }
+};
+
+module.exports = { getDateTime };

05-example-web-application/api-node/src/index.js

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+const { getDateTime } = require('./db');
+
+const express = require('express');
+const morgan = require('morgan');
+
+const app = express();
+const port = 3000;
+
+// setup the logger
+app.use(morgan('tiny'));
+
+app.get('/', async (req, res) => {
+  const dateTime = await getDateTime();
+  const response = dateTime;
+  response.api = 'node';
+  res.send(response);
+});
+
+const server = app.listen(port, () => {
+  console.log(`Example app listening on port ${port}`);
+});
+
+process.on('SIGTERM', () => {
+  debug('SIGTERM signal received: closing HTTP server');
+  server.close(() => {
+    debug('HTTP server closed');
+  });
+});