Add redis as limiter storage instaed of memcache

Author: Aadesh-Baral

backend/__init__.py

@@ -38,7 +38,7 @@ def format_url(endpoint):
 mail = Mail()
 oauth = OAuth()
 limiter = Limiter(
-    storage_uri=EnvironmentConfig.MEMCACHED_URI,
+    storage_uri=EnvironmentConfig.REDIS_URI,
     key_func=get_remote_address,
     headers_enabled=True,
 )
@@ -134,9 +134,9 @@ def add_api_endpoints(app):
             "message": "You have exceeded the rate limit. Please try again later.",
             "status": 429,
         },
-        "MemcacheUnexpectedCloseError": {
-            "SubCode": "MemcacheUnexpectedCloseError",
-            "message": "Connection to Memcache server lost.",
+        "ConnectionError": {
+            "SubCode": "RedisConnectionError",
+            "message": "Connection to Redis server refused.",
             "status": 500,
         },
     }

backend/config.py

@@ -110,12 +110,12 @@ class EnvironmentConfig:
         "TM_API_RATE_LIMIT_THRESHOLD", "100 per hour"
     )
     # Memcache configuration
-    MEMCACHED_PORT = os.getenv("TM_MEMCACHE_PORT", None)
-    MEMCACHED_HOST = os.getenv("TM_MEMCACHE_HOST", None)
-    if MEMCACHED_PORT and MEMCACHED_HOST:
-        MEMCACHED_URI = f"memcached://{MEMCACHED_HOST}:{MEMCACHED_PORT}"
+    REDIS_PORT = os.getenv("TM_REDIS_PORT", None)
+    REDIS_HOST = os.getenv("TM_REDIS_HOST", None)
+    if REDIS_PORT and REDIS_HOST:
+        REDIS_URI = f"redis://{REDIS_HOST}:{REDIS_PORT}"
     else:
-        MEMCACHED_URI = None
+        REDIS_URI = None
 
     # Languages offered by the Tasking Manager
     # Please note that there must be exactly the same number of Codes as languages.

docker-compose.yml

@@ -17,6 +17,9 @@ services:
     <<: *backend
     container_name: backend
     restart: always
+    depends_on:
+      - postgresql
+      - redis
     labels:
       - traefik.http.routers.backend.rule=Host(`localhost`) && PathPrefix(`/api/`)
       - traefik.http.services.backend.loadbalancer.server.port=5000
@@ -43,7 +46,14 @@ services:
     env_file: ${ENV_FILE:-tasking-manager.env}
     networks:
       - tm-web
-
+  redis:
+    image: bitnami/redis:7.0.4
+    container_name: redis
+    environment:
+      - ALLOW_EMPTY_PASSWORD=yes
+    restart: always
+    networks:
+      - tm-web
   traefik:
     image: traefik:v2.3
     restart: always

example.env

@@ -149,7 +149,14 @@ POSTGRES_PASSWORD=tm
 
 # If disabled project update emails will not be sent. 
 # Set it disabled in case of testing instances
-TM_SEND_PROJECT_EMAIL_UPDATES = 1
+TM_SEND_PROJECT_EMAIL_UPDATES=1
+
+# Default threshold to rate limit api calls, seperated by comma
+TM_API_RATE_LIMIT_THRESHOLD=2/second, 100/hour
+
+# Redis configuration for rate limiter storage(optional, in memory storage is used by default if not provided.).
+TM_REDIS_HOST=localhost
+TM_REDIS_PORT=6379
 
 # TM_SERVICE_DESK
 # If the organisation has a service desk, configures the link

requirements.txt

@@ -36,7 +36,7 @@ Mako==1.1.3
 markdown==3.3.3
 MarkupSafe==1.1.1
 mccabe==0.6.1
-pymemcache==3.5.2
+redis==3.5.0
 newrelic==5.22.1.152
 nose==1.3.7
 oauthlib==2.0.2