[Minor] Add rate limiting for bench

bench/config/nginx.py

@@ -23,6 +23,7 @@ def make_nginx_conf(bench_path, yes=False):
 		"socketio_port": config.get('socketio_port'),
 		"bench_name": bench_name,
 		"bench_name_hash": bench_name_hash,
+		"limit_conn_shared_memory": get_limit_conn_shared_memory(),
 		"error_pages": get_error_pages(),
 
 		# for nginx map variable
@@ -160,3 +161,10 @@ def get_error_pages():
 	return {
 		502: os.path.join(templates, '502.html')
 	}
+
+def get_limit_conn_shared_memory():
+	"""Allocate 2 percent of total virtual memory as shared memory for nginx limit_conn_zone"""
+	import psutil
+	total_vm = (psutil.virtual_memory().total) / (1024 * 1024) # in MB
+
+	return int(0.02 * total_vm)

bench/config/production_setup.py

@@ -127,5 +127,9 @@ def reload_supervisor():
 		pass
 
 def reload_nginx():
-	subprocess.check_output(['sudo', find_executable('nginx'), '-t'])
+	try:
+		subprocess.check_output(['sudo', find_executable('nginx'), '-t'])
+	except:
+		raise
+
 	service('nginx', 'reload')

bench/config/templates/nginx.conf

@@ -21,6 +21,8 @@ server {
 
 	root {{ sites_path }};
 
+	limit_conn per_host_{{ bench_name_hash }} 8;
+
 	{% if ssl_certificate and ssl_certificate_key %}
 	ssl on;
 	ssl_certificate      {{ ssl_certificate }};
@@ -139,7 +141,7 @@ upstream {{ bench_name}}-socketio-server {
     server 127.0.0.1:{{ socketio_port or 3000 }} fail_timeout=0;
 }
 
-limit_conn_zone $host zone=per_host_{{ bench_name_hash }}:3000m;
+limit_conn_zone $host zone=per_host_{{ bench_name_hash }}:{{ limit_conn_shared_memory }}m;
 
 # setup maps
 {%- set site_name_variable="$host" %}

requirements.txt

@@ -3,6 +3,7 @@ jinja2
 virtualenv
 requests
 honcho
+psutil
 python-crontab
 semantic_version
 GitPython==0.3.2.rc1