replaced flask in favor of django

.gitignore

@@ -116,3 +116,6 @@ logs
 .idea/*
 .idea/
 .vscode/
+
+# static files
+static/

README.md

@@ -66,7 +66,7 @@ pip install flake8 && cp devops/scripts/commit-checks.sh .git/hooks/pre-commit
 
 Run `docker-compose up` to fire up the notification service app & critical dependencies (database, rabbitmq)
 
-Hit this url http://localhost:80/ to access the app.
+Hit this url http://localhost:80/ to access the app. This will send a request to the nginx LB that in turn proxies it to the web server backends.
 
 - Run `docker ps -a` to see all docker containers running on your development machine:
 

app/__init__.py

@@ -1,21 +1 @@
-from flask import Flask
-from config import config_by_name
-from flask_bcrypt import Bcrypt
-from flask_restful import Api
 
-flask_bcrypt = Bcrypt()
-
-
-def create_app(environment):
-    app = Flask(__name__, instance_relative_config=True)
-    app.config.from_object(config_by_name[environment])
-    flask_bcrypt.init_app(app)
-
-    from app.api.model import db
-    db.init_app(app)
-
-    from app.api.views import SendMessageView
-    api = Api(app)
-    api.add_resource(SendMessageView, '/api/v1.0/sendMessage')
-
-    return app, db

app/api/serializers.py

@@ -1 +1,9 @@
-from flask_restless import DefaultSerializer
+from rest_framework import serializers
+
+
+class SendMessageRequestSerializer(serializers.Serializer):
+    """
+    Serialize class for a send message request
+    """
+    messageId = serializers.CharField(max_length=64)
+    messageType = serializers.CharField(max_length=16)

app/api/views.py

@@ -1,11 +1,84 @@
-from flask_restful import Resource, reqparse
+from rest_framework import status, views
+from rest_framework.response import Response
+from app.auth.authentication import APIKeyAuth
+from app.auth.permissions import APIPermission
+from app.api.serializers import SendMessageRequestSerializer
 
+DELETE, GET, HEAD, OPTIONS, PATCH, POST, PUT = \
+    'delete', 'get', 'head', 'options', 'patch', 'post', 'put'
+
+
+class BaseAPIView(views.APIView):
+    """
+    Base API View class
+    """
+    authentication_classes = (APIKeyAuth, )
+    permission_classes = (APIPermission,)
+    allowed_methods = (GET, HEAD, OPTIONS, PATCH, POST, PUT)
 
-class SendMessageView(Resource):
     def __init__(self):
-        self.parser = reqparse.RequestParser()
+        self.req_data = None
+
+    def handler(self, request, *args, **kwargs):
+        allowed, response = self.is_allowed(request=request)
+        valid, self.req_data = self.validate(request.data)
+        if allowed and not valid:
+            response = self.bad_request()
+        if allowed and valid:
+            response = self.handle(request, *args, **kwargs)
+        return response
+
+    def post(self, request):
+        return self.handler(request, self.post.__name__)
+
+    def get(self, request, *args, **kwargs):
+        return self.handler(request, *args, **kwargs)
+
+    def validate(self, data):
+        valid = True
+        if hasattr(self, 'serializer'):
+            serialized = self.serializer(data=data)
+            valid = serialized.is_valid()
+            if not valid:
+                data = serialized.errors
+            else:
+                data.update(serialized.validated_data)
+        return valid, data
+
+    def is_allowed(self, request):
+        res = True, None
+        if request.method.lower() not in self.allowed_methods:
+            res = False, Response(
+                status=status.HTTP_405_METHOD_NOT_ALLOWED,
+                data={
+                    'detail': 'Method "{}" not allowed.'.format(
+                        request.method)
+                },
+                content_type="application/json"
+            )
+        return res
+
+    def bad_request(self):
+        return Response(
+            status=status.HTTP_400_BAD_REQUEST,
+            data=self.req_data,
+            content_type="application/json"
+        )
+
+    def handle(self, request, *args, **kwargs):
+        raise NotImplementedError(
+            "`handle` method has not been implemented"
+        )
+
+
+class HealthCheckView(BaseAPIView):
+    """
+    View that monitoring services can use to check on the 'aliveness' of a
+    running messaging service.
+    """
+    allowed_methods = (GET,)
 
-    def post(self):
-        self.parser.add_argument('messageId', type=str)
-        args = self.parser.parse_args()
-        return args, 201
+    def handle(self, request, *args, **kwargs):
+        return Response(
+            status=status.HTTP_200_OK, content_type="application/json"
+        )

app/auth/authentication.py

@@ -0,0 +1,37 @@
+from django.conf import settings
+from rest_framework import HTTP_HEADER_ENCODING, authentication, exceptions
+
+
+class BaseCustomAPIkeyAuth(authentication.BaseAuthentication):
+    """
+    This creates a custom authentication class that grants access to clients
+    that have the right Authorization header value set.
+    """
+    api_key = ('',)
+
+    def authenticate(self, request):
+        """
+        Authenticate the request and returns a tuple of (None, auth) for
+        successful api_key authentication, otherwise return None.
+        """
+        try:
+            incoming_api_key = request.META['HTTP_AUTHORIZATION']
+        except (AttributeError, KeyError):
+            return None
+        else:
+            if incoming_api_key not in self.api_keys:
+                raise exceptions.AuthenticationFailed()
+            else:
+                return None, incoming_api_key
+
+    @staticmethod
+    def authenticate_header(request):
+        """
+        Returns value for the WWW-Authenticate header in 401 response.
+        Otherwise a 403 forbidden response would be generated
+        """
+        return 'api-key'
+
+
+class APIKeyAuth(BaseCustomAPIkeyAuth):
+    api_keys = (settings.API_KEY, )

app/auth/permissions.py

@@ -0,0 +1,24 @@
+from django.conf import settings
+from rest_framework import permissions
+
+
+class BaseAPIPermission(permissions.BasePermission):
+    """
+    Custom permission to only allow requests bearing appropriate api key.
+    """
+    api_keys = ('',)
+
+    def has_permission(self, request, view):
+        """
+        returns True if permission is granted, False otherwise.
+        """
+        permitted = False
+        if request.user and request.user.is_authenticated:
+            permitted = True
+        elif request.auth and request.auth in self.api_keys:
+            permitted = True
+        return permitted
+
+
+class APIPermission(BaseAPIPermission):
+    api_keys = (settings.API_KEY,)