Add REDIS_HOST and POSTGRES_HOST Environment Variables to Example Voting App Configuration (Fixes #370)

.gitignore

@@ -4,3 +4,4 @@ bin/
 obj/
 .vs/
 node_modules/
+.aider*

result/server.js

@@ -18,7 +18,7 @@ io.on('connection', function (socket) {
 });
 
 var pool = new Pool({
-  connectionString: 'postgres://postgres:postgres@db/postgres'
+  connectionString: `postgres://postgres:postgres@${process.env.POSTGRES_HOST || 'db'}/postgres`
 });
 
 async.retry(

result/test_config.js

@@ -0,0 +1,31 @@
+const assert = require('assert');
+
+describe('Database Configuration', () => {
+  let originalEnv;
+
+  beforeEach(() => {
+    originalEnv = process.env.POSTGRES_HOST;
+  });
+
+  afterEach(() => {
+    process.env.POSTGRES_HOST = originalEnv;
+  });
+
+  it('should use POSTGRES_HOST environment variable when set', () => {
+    process.env.POSTGRES_HOST = 'custom-host';
+    const { Pool } = require('pg');
+    const pool = new Pool({
+      connectionString: `postgres://postgres:postgres@${process.env.POSTGRES_HOST || 'db'}/postgres`
+    });
+    assert.ok(pool.options.connectionString.includes('custom-host'));
+  });
+
+  it('should default to "db" when POSTGRES_HOST is not set', () => {
+    delete process.env.POSTGRES_HOST;
+    const { Pool } = require('pg');
+    const pool = new Pool({
+      connectionString: `postgres://postgres:postgres@${process.env.POSTGRES_HOST || 'db'}/postgres`
+    });
+    assert.ok(pool.options.connectionString.includes('@db/'));
+  });
+});

vote/app.py

@@ -18,7 +18,7 @@
 
 def get_redis():
     if not hasattr(g, 'redis'):
-        g.redis = Redis(host="redis", db=0, socket_timeout=5)
+        g.redis = Redis(host=os.getenv('REDIS_HOST', 'redis'), db=0, socket_timeout=5)
     return g.redis
 
 @app.route("/", methods=['POST','GET'])

vote/test_config.py

@@ -0,0 +1,25 @@
+import os
+import unittest
+from app import get_redis
+from flask import g
+
+class TestConfig(unittest.TestCase):
+    def test_redis_host_config(self):
+        # Clear any existing redis connection
+        if hasattr(g, 'redis'):
+            delattr(g, 'redis')
+
+        # Test default value
+        os.environ.pop('REDIS_HOST', None)
+        redis_conn = get_redis()
+        self.assertEqual(redis_conn.connection_pool.connection_kwargs['host'], 'redis')
+
+        # Test custom value
+        os.environ['REDIS_HOST'] = 'custom-redis'
+        if hasattr(g, 'redis'):
+            delattr(g, 'redis')
+        redis_conn = get_redis()
+        self.assertEqual(redis_conn.connection_pool.connection_kwargs['host'], 'custom-redis')
+
+if __name__ == '__main__':
+    unittest.main()