Merge pull request #1512 from edx/feanil/nginx_rate_limiting

Feanil/nginx rate limiting

playbooks/roles/edxapp/defaults/main.yml

@@ -147,6 +147,11 @@ EDXAPP_LMS_PREVIEW_NGINX_PORT: 18020
 EDXAPP_CMS_NGINX_PORT: 18010
 EDXAPP_CMS_SSL_NGINX_PORT: 48010
 
+# NGINX Rate limiting related vars
+EDXAPP_ENABLE_RATE_LIMITING: false
+EDXAPP_COURSE_REQUEST_RATE: '5r/s'
+EDXAPP_COURSE_REQUEST_BURST_RATE: 10
+
 EDXAPP_LANG: 'en_US.UTF-8'
 EDXAPP_LANGUAGE_CODE : 'en'
 EDXAPP_TIME_ZONE: 'America/New_York'

playbooks/roles/nginx/templates/edx/app/nginx/sites-available/lms.j2

@@ -10,6 +10,11 @@ upstream lms-backend {
     {% endfor %}
 }
 
+{%- if EDXAPP_ENABLE_RATE_LIMITING -%}
+# Make Zone
+limit_req_zone $cookie_{{ EDXAPP_SESSION_COOKIE_NAME }} zone=cookies:10m rate={{ EDXAPP_COURSES_REQUEST_RATE }};
+{%- endif -%}
+
 server {
   # LMS configuration file for nginx, templated by ansible
 
@@ -68,6 +73,16 @@ server {
     try_files $uri @proxy_to_lms_app;
   }
 
+  location /courses {
+    {%- if EDXAPP_ENABLE_RATE_LIMITING -%}
+    # Set Limit  
+    limit_req zone=cookies burst={{ EDXAPP_COURSE_REQUEST_BURST_RATE }};
+    {%- endif -%}
+
+    {%- include "basic-auth.j2" %}
+    try_files $uri @proxy_to_lms_app;
+  }
+
   {% include "robots.j2" %}
   {% include "static-files.j2" %}