expose keep-alive timeout on command-line

bin/configurable-http-proxy

@@ -103,6 +103,11 @@ cli
   .option(
     "--storage-backend <storage-class>",
     "Define an external storage class. Defaults to in-MemoryStore."
+  )
+  .option(
+    "--keep-alive-timeout <timeout>",
+    "Set timeout (in milliseconds) for Keep-Alive connections",
+    5000
   );
 
 // collects multiple flags to an object
@@ -269,6 +274,8 @@ options.redirectTo = args.redirectTo;
 options.headers = args.customHeader;
 options.timeout = args.timeout;
 options.proxyTimeout = args.proxyTimeout;
+// cast to milliseconds, which is what
+options.keepAliveTimeout = args.keepAliveTimeout;
 
 // metrics options
 options.enableMetrics = !!args.metricsPort;

lib/configproxy.js

@@ -220,7 +220,11 @@ class ConfigurableProxy extends EventEmitter {
       this.metricsServer = http.createServer(metricsCallback);
     }
 
-    var httpOptions = { keepAlive: true, agent: this.agent };
+    var httpOptions = {
+      keepAlive: true,
+      agent: this.agent,
+      keepAliveTimeout: this.options.keepAliveTimeout || 5000,
+    };
 
     // proxy requests separately
     var proxyCallback = logErrors(this.handleProxyWeb);