CON-303 Cache CN 200-status /health_check responses for 1sec in nginx (…

…#3624)

creator-node/nginx_conf/nginx.conf

@@ -1,3 +1,8 @@
+# nginx Configuration file
+#
+# Notes:
+#   - any value below prefixed with $arg indicates a request query param, e.g. $arg_bypasscache will match query param `bypasscache=<value>`
+
 worker_processes 1;
 
 events {
@@ -19,7 +24,7 @@ http {
     # If inactive period passes, content WILL BE DELETED from the cache by the cache
     # manager, regardless whether or not it has expired.
     # https://www.nginx.com/blog/nginx-caching-guide#How-to-Set-Up-and-Configure-Basic-Caching
-    proxy_cache_path /usr/local/openresty/cache levels=1:2 keys_zone=cidcache:1000m
+    proxy_cache_path /usr/local/openresty/cache levels=1:2 keys_zone=cache:1000m
 					max_size=4g inactive=12h use_temp_path=off;
     proxy_read_timeout 3600; # 1 hour in seconds
 
@@ -30,10 +35,10 @@ http {
         # If present in cache, serve. Else, hit upstream server + update cache + serve.
         # http://nginx.org/en/docs/http/ngx_http_core_module.html#location
         location ~ (/ipfs/|/content/) {
-            proxy_cache cidcache;
+            proxy_cache cache;
             proxy_pass http://127.0.0.1:3000;
 
-            # Set client IP
+            # Set client IP as `X-Forwarded-For` response header
             proxy_set_header X-Forwarded-For $remote_addr;
 
             # proxy_cache_use_stale + proxy_cache_background_update -> deliver stale content when client requests
@@ -63,10 +68,30 @@ http {
             add_header X-Cache-Status $upstream_cache_status always;
         }
 
+        location = /health_check {
+            proxy_cache cache;
+
+            proxy_pass http://127.0.0.1:3000;
+
+            # Set client IP as `X-Forwarded-For` response header
+            proxy_set_header X-Forwarded-For $remote_addr;
+
+            # Never serve a stale response
+
+            # Cache responses with 200 status, for 1 second
+            proxy_cache_valid 200 1s;
+
+            # Bypass cache with bypasscache=true query string and save new response to proxy cache
+            proxy_cache_bypass $arg_bypasscache;
+
+            # Add response header to indicate the status of the cache with this request
+            add_header X-Cache-Status $upstream_cache_status always;
+        }
+
         # Pass all other requests to upstream server
         location / {
             proxy_pass http://127.0.0.1:3000;
             proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
         }
     }
-}
+}