Fixed linting warnings and added pylint

dot-env-example → .flaskenv

@@ -1,2 +1,2 @@
-PORT=8080
+FLASK_RUN_PORT=8080
 FLASK_APP=service:app

.gitattributes

@@ -0,0 +1,3 @@
+* text=auto eol=lf
+*.{cmd,[cC][mM][dD]} text eol=crlf
+*.{bat,[bB][aA][tT]} text eol=crlf

Makefile

@@ -1,34 +1,74 @@
-.PHONY: all help install venv test run
+# These can be overidden with env vars.
+REGISTRY ?= rofrano
+IMAGE_NAME ?= hitcounter
+IMAGE_TAG ?= 1.0
+IMAGE ?= $(REGISTRY)/$(IMAGE_NAME):$(IMAGE_TAG)
+PLATFORM ?= "linux/amd64,linux/arm64"
 
+.PHONY: help
 help: ## Display this help
 	@awk 'BEGIN {FS = ":.*##"; printf "\nUsage:\n  make \033[36m<target>\033[0m\n"} /^[a-zA-Z_0-9-\\.]+:.*?##/ { printf "  \033[36m%-15s\033[0m %s\n", $$1, $$2 } /^##@/ { printf "\n\033[1m%s\033[0m\n", substr($$0, 5) } ' $(MAKEFILE_LIST)
 
+.PHONY: all
 all: help
 
+.PHONY: clean
+clean:	## Removes all dangling build cache
+	$(info Removing all dangling build cache..)
+	-docker rmi $(IMAGE)
+	docker image prune -f
+	docker buildx prune -f
+
+.PHONY: venv
 venv: ## Create a Python virtual environment
 	$(info Creating Python 3 virtual environment...)
 	python3 -m venv .venv
 
+.PHONY: install
 install: ## Install dependencies
 	$(info Installing dependencies...)
 	sudo pip install -r requirements.txt
 
+.PHONY: lint
 lint: ## Run the linter
 	$(info Running linting...)
-	flake8 service --count --select=E9,F63,F7,F82 --show-source --statistics
-	flake8 service --count --max-complexity=10 --max-line-length=127 --statistics
+	flake8 . --count --select=E9,F63,F7,F82 --show-source --statistics
+	flake8 . --count --max-complexity=10 --max-line-length=127 --statistics
+	pylint service
 
+.PHONY: test
 test: ## Run the unit tests
 	$(info Running tests...)
 	nosetests --with-spec --spec-color
 
+.PHONY: run
 run: ## Run the service
 	$(info Starting service...)
 	honcho start
 
-depoy: ## Deploy the service on Kubernetes
-	$(info Deploying service...)
-	kubectl apply -f kube/redis.yaml
-	kubectl apply -f kube/secrets.yaml
-	kubectl apply -f kube/deployment.yaml
-	kubectl apply -f kube/service.yaml
+.PHONY: deploy
+depoy: ## Deploy the service on local Kubernetes
+	$(info Deploying service locally...)
+	kubectl apply -k kube/overlay/local
+
+############################################################
+# COMMANDS FOR BUILDING THE IMAGE
+############################################################
+
+.PHONY: init
+init: export DOCKER_BUILDKIT=1
+init:	## Creates the buildx instance
+	$(info Initializing Builder...)
+	docker buildx create --use --name=qemu
+	docker buildx inspect --bootstrap
+
+.PHONY: build
+build:	## Build all of the project Docker images
+	$(info Building $(IMAGE) for $(PLATFORM)...)
+	docker buildx build --file Dockerfile  --pull --platform=$(PLATFORM) --tag $(IMAGE) --push .
+
+.PHONY: remove
+remove:	## Stop and remove the buildx builder
+	$(info Stopping and removing the builder image...)
+	docker buildx stop
+	docker buildx rm

service/__init__.py

@@ -1,4 +1,4 @@
-# Copyright 2016, 2020 John J. Rofrano. All Rights Reserved.
+# Copyright 2016, 2022 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.
@@ -18,6 +18,7 @@
 import os
 import logging
 from flask import Flask
+from service.utils import log_handlers
 
 # NOTE: Do not change the order of this code
 # The Flask app must be created
@@ -28,16 +29,13 @@
 # Create the Flask aoo
 app = Flask(__name__)
 
-# Import the routes After the Flask app is created
-from service import routes, models, error_handlers
+# Dependencies require we import the routes AFTER the Flask app is created
+# pylint: disable=wrong-import-position, wrong-import-order, cyclic-import
+from service import routes
+from service.utils import error_handlers  # noqa: F401, E402
 
 # Set up logging for production
-app.logger.propagate = False
-if __name__ != "__main__":
-    gunicorn_logger = logging.getLogger("gunicorn.error")
-    if gunicorn_logger:
-        app.logger.handlers = gunicorn_logger.handlers
-        app.logger.setLevel(gunicorn_logger.level)
+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, "*"))

service/models.py

@@ -1,5 +1,5 @@
 ######################################################################
-# Copyright 2016, 2020 John Rofrano. All Rights Reserved.
+# Copyright 2016, 2022 John 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.
@@ -19,18 +19,18 @@
 import os
 import logging
 from redis import Redis
-from redis.exceptions import ConnectionError
+from redis.exceptions import ConnectionError as RedisConnectionError
 
 logger = logging.getLogger(__name__)
 
 DATABASE_URI = os.getenv("DATABASE_URI", "redis://localhost:6379")
 
 
-class DatabaseConnectionError(ConnectionError):
-    pass
+class DatabaseConnectionError(RedisConnectionError):
+    """Indicates that a database connection error has occurred"""
 
 
-class Counter(object):
+class Counter():
     """An integer counter that is persisted in Redis
 
     You can establish a connection to Redis using an environment
@@ -71,6 +71,7 @@ def increment(self):
         return Counter.redis.incr(self.name)
 
     def serialize(self):
+        """Creates a Python dictionary from the instance"""
         return dict(name=self.name, counter=int(Counter.redis.get(self.name)))
 
     ######################################################################
@@ -86,7 +87,7 @@ def all(cls):
                 for key in cls.redis.keys("*")
             ]
         except Exception as err:
-            raise DatabaseConnectionError(err)
+            raise DatabaseConnectionError(err) from err
         return counters
 
     @classmethod
@@ -98,15 +99,16 @@ def find(cls, name):
             if count:
                 counter = Counter(name, count)
         except Exception as err:
-            raise DatabaseConnectionError(err)
+            raise DatabaseConnectionError(err) from err
         return counter
 
     @classmethod
     def remove_all(cls):
+        """Deletes all of the counters"""
         try:
             cls.redis.flushall()
         except Exception as err:
-            raise DatabaseConnectionError(err)
+            raise DatabaseConnectionError(err) from err
 
     ######################################################################
     #  R E D I S   D A T A B A S E   C O N N E C T I O N   M E T H O D S
@@ -120,7 +122,7 @@ def test_connection(cls):
             cls.redis.ping()
             logger.info("Connection established")
             success = True
-        except ConnectionError:
+        except RedisConnectionError:
             logger.warning("Connection Error!")
         return success
 

service/routes.py

@@ -1,4 +1,4 @@
-# Copyright 2015, 2021 John J. Rofrano All Rights Reserved.
+# Copyright 2015, 2022 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.
@@ -14,14 +14,10 @@
 """
 Redis Counter Demo in Docker
 """
-import os
 from flask import jsonify, abort, url_for
-from . import app, status  # HTTP Status Codes
-from service import DATABASE_URI
-from .models import Counter, DatabaseConnectionError
-
-DEBUG = os.getenv("DEBUG", "False") == "True"
-PORT = os.getenv("PORT", "8080")
+from service import app, DATABASE_URI
+from service.utils import status  # HTTP Status Codes
+from service.models import Counter, DatabaseConnectionError
 
 
 ############################################################
@@ -47,6 +43,7 @@ def index():
 ############################################################
 @app.route("/counters", methods=["GET"])
 def list_counters():
+    """Lists all counters in the database"""
     app.logger.info("Request to list all counters...")
     try:
         counters = Counter.all()
@@ -61,17 +58,18 @@ def list_counters():
 ############################################################
 @app.route("/counters/<name>", methods=["GET"])
 def read_counters(name):
-    app.logger.info("Request to Read counter: {}...".format(name))
+    """Reads a counter from the database"""
+    app.logger.info("Request to Read counter: %s...", name)
 
     try:
         counter = Counter.find(name)
     except DatabaseConnectionError as err:
         abort(status.HTTP_503_SERVICE_UNAVAILABLE, err)
 
     if not counter:
-        abort(status.HTTP_404_NOT_FOUND, "Counter {} does not exist".format(name))
+        abort(status.HTTP_404_NOT_FOUND, f"Counter [{name}] does not exist")
 
-    app.logger.info("Returning: {}...".format(counter.value))
+    app.logger.info("Returning: %d...", counter.value)
     return jsonify(counter.serialize())
 
 
@@ -80,11 +78,12 @@ def read_counters(name):
 ############################################################
 @app.route("/counters/<name>", methods=["POST"])
 def create_counters(name):
+    """Creates a counter in the database"""
     app.logger.info("Request to Create counter...")
     try:
         counter = Counter.find(name)
         if counter is not None:
-            return jsonify(code=409, error="Counter already exists"), 409
+            return jsonify(code=409, error=f"Counter [{name}] already exists"), 409
 
         counter = Counter(name)
     except DatabaseConnectionError as err:
@@ -103,12 +102,13 @@ def create_counters(name):
 ############################################################
 @app.route("/counters/<name>", methods=["PUT"])
 def update_counters(name):
+    """Updates a counter in the database"""
     app.logger.info("Request to Update counter...")
     try:
         counter = Counter.find(name)
         if counter is None:
             return (
-                jsonify(code=404, error="Counter {} does not exist".format(name)),
+                jsonify(code=404, error=f"Counter [{name}] does not exist"),
                 404,
             )
 
@@ -124,6 +124,7 @@ def update_counters(name):
 ############################################################
 @app.route("/counters/<name>", methods=["DELETE"])
 def delete_counters(name):
+    """Removes te counter from teh database"""
     app.logger.info("Request to Delete counter...")
     try:
         counter = Counter.find(name)
@@ -142,6 +143,7 @@ def delete_counters(name):
 
 @app.before_first_request
 def init_db():
+    """Initialize the Redis database"""
     try:
         app.logger.info("Initializing the Redis database")
         Counter.connect(DATABASE_URI)

service/error_handlers.py → service/utils/error_handlers.py

@@ -1,9 +1,38 @@
+# Copyright 2016, 2022 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.
+"""
+Module: error_handlers
+"""
 from flask import jsonify
-from . import app, status
+from service import app
+from . 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)
@@ -32,6 +61,21 @@ def method_not_supported(error):
     )
 
 
+# @app.errorhandler(status.HTTP_415_UNSUPPORTED_MEDIA_TYPE)
+# def mediatype_not_supported(error):
+#     """Handles unsupported media requests with 415_UNSUPPORTED_MEDIA_TYPE"""
+#     message = str(error)
+#     app.logger.warning(message)
+#     return (
+#         jsonify(
+#             status=status.HTTP_415_UNSUPPORTED_MEDIA_TYPE,
+#             error="Unsupported media type",
+#             message=message,
+#         ),
+#         status.HTTP_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"""
@@ -49,7 +93,7 @@ def internal_server_error(error):
 
 @app.errorhandler(status.HTTP_503_SERVICE_UNAVAILABLE)
 def service_unavailable(error):
-    """Handles unexpected server error with 503_SERVICE_UNAVAILABLE"""
+    """ Handles unexpected server error with 503_SERVICE_UNAVAILABLE """
     message = str(error)
     app.logger.error(message)
     return (