some varnish sanity checks

lib/cartodb/varnish.js

@@ -8,6 +8,7 @@ var net = require('net')
 
 function VarnishClient(host, port, ready_callback) {
 
+    var self = this;
     var ready = false;
     var cmd_callback = null;
     var client = null;
@@ -39,6 +40,14 @@ function VarnishClient(host, port, ready_callback) {
 
     });
 
+    client.on('error', function(err) {
+        console.log("[ERROR] some problem in varnish connection");
+    });
+
+    client.on('close', function() {
+        self.close();
+    });
+
     // sends the command to the server
     function _send(cmd, callback) {
       cmd_callback = callback;
@@ -98,6 +107,7 @@ function VarnishPool(opts, ready) {
 
 function VarnishQueue(host, port) {
 
+    var MAX_QUEUE = 2000;
     var queue = [];
     var ready = false;
 
@@ -122,6 +132,10 @@ function VarnishQueue(host, port) {
 
     this.run_cmd = function(cmd) {
         queue.push(cmd);
+        if(queue.length > MAX_QUEUE) {
+            console.log("varnish commando queu too long, removing commands");
+            queue.pop();
+        }
         if(ready) {
             _send_pending();
         }