Add app factory

Author: rofrano

Procfile

@@ -1 +1 @@
-web: gunicorn --bind 0.0.0.0:$PORT --log-level=info service:app
+web: gunicorn --bind 0.0.0.0:$PORT --log-level=info wsgi:app

poetry.lock

@@ -10,6 +10,7 @@ readme = "README.md"
 python = "^3.11"
 Flask = "^3.0.2"
 redis = "^4.5.3"
+flask-redis = "^0.4.0"
 python-dotenv = "^1.0.0"
 gunicorn = "^21.2.0"
 honcho = "^1.1.0"

pyproject.toml

@@ -1,38 +1,62 @@
+# Copyright 2016, 2023 John J. Rofrano. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
 """
-Package: service
 Package for the application models and service routes
-This module creates and configures the Flask app and sets up the logging
-and SQL database
 """
-import sys
 from flask import Flask
+from flask_redis import FlaskRedis
 from service import config
-from .common import log_handlers
-
-# Create Flask application
-app = Flask(__name__)
-app.config.from_object(config)
-
-# Dependencies require we import the routes AFTER the Flask app is created
-# pylint: disable=wrong-import-position, wrong-import-order
-from service import routes
-# flake8: noqa: F401
-# pylint: disable=wrong-import-position
-from .common import error_handlers
-from .models import Counter
-
-# Set up logging for production
-log_handlers.init_logging(app, "gunicorn.error")
-
-app.logger.info(70 * "*")
-app.logger.info("  S E R V I C E   R U N N I N G  ".center(70, "*"))
-app.logger.info(70 * "*")
-
-try:
-    Counter.init_db(app)  # Initialize Redis
-except Exception as error:  # pylint: disable=broad-except
-    app.logger.critical("%s: Cannot continue", error)
-    # gunicorn requires exit code 4 to stop spawning workers when they die
-    sys.exit(4)
-
-app.logger.info("Service initialized!")
+from service.common import log_handlers
+
+# Globally accessible libraries
+# redis = FlaskRedis()
+
+
+############################################################
+# Initialize the Flask instance
+############################################################
+def init_app():
+    """Initialize the core application."""
+    app = Flask(__name__)
+    app.config.from_object(config)
+
+    # Initialize Plugins
+    # redis.init_app(app)
+
+    with app.app_context():
+        # Include our Routes
+
+        # pylint: disable=import-outside-toplevel, unused-import
+        from service import routes, models
+        from service.common import error_handlers
+
+        # Set up logging for production
+        log_handlers.init_logging(app, "gunicorn.error")
+
+        app.logger.info(70 * "*")
+        app.logger.info("  H I T   C O U N T E R   S E R V I C E  ".center(70, "*"))
+        app.logger.info(70 * "*")
+
+        app.logger.info("Service initialized!")
+
+        # Initialize the database
+        try:
+            app.logger.info("Initializing the Redis database")
+            models.Counter.connect(app.config['DATABASE_URI'])
+            app.logger.info("Connected!")
+        except models.DatabaseConnectionError as err:
+            app.logger.error(str(err))
+
+        return app

service/__init__.py

@@ -15,27 +15,17 @@
 ######################################################################
 
 """
-Module: error_handlers
+Error Handlers
+
+This module contains error handlers functions to send back errors as json
 """
 from flask import jsonify
-from service import app
-from . import status
-
+from flask import current_app as app
+from service.common import status
 
 ######################################################################
 # Error Handlers
 ######################################################################
-@app.errorhandler(status.HTTP_400_BAD_REQUEST)
-def bad_request(error):
-    """Handles bad requests with 400_BAD_REQUEST"""
-    message = str(error)
-    app.logger.warning(message)
-    return (
-        jsonify(
-            status=status.HTTP_400_BAD_REQUEST, error="Bad Request", message=message
-        ),
-        status.HTTP_400_BAD_REQUEST,
-    )
 
 
 @app.errorhandler(status.HTTP_404_NOT_FOUND)
@@ -64,46 +54,31 @@ def method_not_supported(error):
     )
 
 
-@app.errorhandler(status.HTTP_409_CONFLICT)
-def resource_conflict(error):
-    """Handles resource conflicts with HTTP_409_CONFLICT"""
-    message = str(error)
-    app.logger.warning(message)
-    return (
-        jsonify(
-            status=status.HTTP_409_CONFLICT,
-            error="Conflict",
-            message=message,
-        ),
-        status.HTTP_409_CONFLICT,
-    )
-
-
-@app.errorhandler(status.HTTP_415_UNSUPPORTED_MEDIA_TYPE)
-def mediatype_not_supported(error):
-    """Handles unsupported media requests with 415_UNSUPPORTED_MEDIA_TYPE"""
+@app.errorhandler(status.HTTP_500_INTERNAL_SERVER_ERROR)
+def internal_server_error(error):
+    """Handles unexpected server error with 500_SERVER_ERROR"""
     message = str(error)
-    app.logger.warning(message)
+    app.logger.error(message)
     return (
         jsonify(
-            status=status.HTTP_415_UNSUPPORTED_MEDIA_TYPE,
-            error="Unsupported media type",
+            status=status.HTTP_500_INTERNAL_SERVER_ERROR,
+            error="Internal Server Error",
             message=message,
         ),
-        status.HTTP_415_UNSUPPORTED_MEDIA_TYPE,
+        status.HTTP_500_INTERNAL_SERVER_ERROR,
     )
 
 
-@app.errorhandler(status.HTTP_500_INTERNAL_SERVER_ERROR)
-def internal_server_error(error):
-    """Handles unexpected server error with 500_SERVER_ERROR"""
+@app.errorhandler(status.HTTP_503_SERVICE_UNAVAILABLE)
+def service_unavailable(error):
+    """Handles unexpected server error with 503_SERVICE_UNAVAILABLE"""
     message = str(error)
     app.logger.error(message)
     return (
         jsonify(
-            status=status.HTTP_500_INTERNAL_SERVER_ERROR,
-            error="Internal Server Error",
+            status=status.HTTP_503_SERVICE_UNAVAILABLE,
+            error="Service is unavailable",
             message=message,
         ),
-        status.HTTP_500_INTERNAL_SERVER_ERROR,
+        status.HTTP_503_SERVICE_UNAVAILABLE,
     )

service/common/error_handlers.py

@@ -1,3 +1,4 @@
+# coding: utf8
 """
 Descriptive HTTP status codes, for code readability.
 See RFC 2616 and RFC 6585.

service/common/status.py

@@ -2,9 +2,8 @@
 Global Configuration for Application
 """
 import os
+import logging
 
-# Get the database from the environment (12 factor)
-DATABASE_URI = os.getenv("DATABASE_URI", "redis://localhost:6379")
-
-# Secret for session management
-SECRET_KEY = os.getenv("SECRET_KEY", "s3cr3t-key-shhhh")
+# Get configuration from environment
+DATABASE_URI = os.getenv("DATABASE_URI", "redis://:@localhost:6379/0")
+LOGGING_LEVEL = logging.INFO