Allow configuring read and send timeout in Nginx (#305)

* allow configuring read and write timeout in nginx

* tweaking the comment

Author: slim-bean

prometheus-ksonnet/lib/config.libsonnet

@@ -86,5 +86,10 @@
 
     // oauth2-proxy
     oauth_enabled: false,
+
+    // Nginx proxy_read_timeout (in seconds) 60s is the nginx default
+    nginx_proxy_read_timeout: '60',
+    // Nginx proxy_send_timeout (in seconds) 60s is the nginx default
+    nginx_proxy_send_timeout: '60',
   },
 }

prometheus-ksonnet/lib/nginx.libsonnet

@@ -9,7 +9,9 @@
       proxy_set_header    X-Forwarded-For $proxy_add_x_forwarded_for;
       proxy_set_header    X-Forwarded-Proto $scheme;
       proxy_set_header    X-Forwarded-Host $http_host;
-    ||| % service + if allowWebsockets then |||
+      proxy_read_timeout  %(nginx_proxy_read_timeout)s;
+      proxy_send_timeout  %(nginx_proxy_send_timeout)s;
+    ||| % (service + $._config) + if allowWebsockets then |||
       # Allow websocket connections https://www.nginx.com/blog/websocket-nginx/
       proxy_set_header    Upgrade $http_upgrade;
       proxy_set_header    Connection "Upgrade";