Implemented the rate limiting from Redis

- Uses Redis cache to check for current count
- If not present then sets the value based on the database state
- Any Redis errors are swallowed. Cache failures should NOT fail  the request.

app/clients/redis/__init__.py

@@ -0,0 +1,5 @@
+from datetime import datetime
+
+
+def cache_key(service_id):
+    return "{}-{}-{}".format(str(service_id), datetime.utcnow().strftime("%Y-%m-%d"), "count")

app/clients/redis/redis_client.py

@@ -1,9 +1,10 @@
 from flask.ext.redis import FlaskRedis
+from flask import current_app
 
 
 class RedisClient:
-    active = False
     redis_store = FlaskRedis()
+    active = False
 
     def init_app(self, app):
         self.active = app.config.get('REDIS_ENABLED')
@@ -11,10 +12,30 @@ class RedisClient:
         if self.active:
             self.redis_store.init_app(app)
 
-    def set(self, key, value):
+    def set(self, key, value, ex=None, px=None, nx=False, xx=False, raise_exception=False):
         if self.active:
-            self.redis_store.set(key, value)
+            try:
+                self.redis_store.set(key, value, ex, px, nx, xx)
+            except Exception as e:
+                current_app.logger.exception(e)
+                if raise_exception:
+                    raise e
 
-    def get(self, key):
+    def inc(self, key, raise_exception=False):
         if self.active:
-            self.redis_store.get(key)
+            try:
+                return self.redis_store.inc(key)
+            except Exception as e:
+                current_app.logger.exception(e)
+                if raise_exception:
+                    raise e
+
+    def get(self, key, raise_exception=False):
+        if self.active:
+            try:
+                return self.redis_store.get(key)
+            except Exception as e:
+                current_app.logger.exception(e)
+                if raise_exception:
+                    raise e
+        return None