Set different networks for db-backend and backend-proxy

Signed-off-by: Anca Iordache <anca.iordache@docker.com>

nginx-flask-mysql/backend/Dockerfile

@@ -1,5 +1,4 @@
 FROM python:3.8-alpine
-ENV PYTHONUNBUFFERED 1
 WORKDIR /code
 COPY requirements.txt /code/
 RUN pip install -r requirements.txt

nginx-flask-mysql/backend/hello.py

@@ -6,7 +6,8 @@ import mysql.connector
 passfile = open('/run/secrets/db-password', 'r')
 
 #give db some time to start
-time.sleep(3)
+time.sleep(5)
+        
 #connect to db
 conn = mysql.connector.connect(
     user='root', 
@@ -15,12 +16,19 @@ conn = mysql.connector.connect(
     database='example',
     auth_plugin='mysql_native_password'
 )
+
 passfile.close()
-
+# populate db
 cursor = conn.cursor()
+def prepare_db():
+    cursor.execute('DROP TABLE IF EXISTS blog')
+    cursor.execute('CREATE TABLE blog (id INT AUTO_INCREMENT PRIMARY KEY, title VARCHAR(255))')
+    cursor.executemany('INSERT INTO blog (id, title) VALUES (%s, %s);', [(i, 'Blog post #%d'% i) for i in range (1,5)])
+    conn.commit()
+prepare_db()
 
+# server
 app = Flask(__name__)
-
 @app.route('/')
 def listBlog():
     cursor.execute('SELECT title FROM blog')
@@ -29,13 +37,6 @@ def listBlog():
         response = response  + '<div>' + c[0] + '</div>'
     return response
 
-def prepare_db():
-    cursor.execute('DROP TABLE IF EXISTS blog')
-    cursor.execute('CREATE TABLE blog (id INT AUTO_INCREMENT PRIMARY KEY, title VARCHAR(255))')
-    cursor.executemany('INSERT INTO blog (id, title) VALUES (%s, %s);', [(i, 'Blog post #%d'% i) for i in range (1,5)])
-    conn.commit()
-
 
 if __name__ == '__main__':
-    prepare_db()
     app.run()