New message is returned when redis is overloaded. Fix #214

[aitormagan]

A 503 status code is returned when redis is overloaded.

[XavierVal]

Do i need to configure something more to check this, i set the max memory to the actual one and after adding a couple ti returned me a error 500:

xx@linux-6b5c:~/git/Rush/bin> curl -X GET localhost:5001 -H "x-relayer-host:www.google.es" -H "x-relayer-persistence:BODY" -v* About to connect() to localhost port 5001 (#0)

• Trying ::1...
• Conexión rehusada
• Trying 127.0.0.1...
• connected
• Connected to localhost (127.0.0.1) port 5001 (#0)

  GET / HTTP/1.1
  User-Agent: curl/7.28.1
  Host: localhost:5001
  Accept: /
  x-relayer-host:www.google.es
  x-relayer-persistence:BODY

  < HTTP/1.1 201 Created
  < X-Powered-By: Express
  < Location: /response/c919cfe0-4e02-11e3-8d9c-69e0d0c454f5
  < Content-Type: application/json; charset=utf-8
  < Content-Length: 50
  < Date: Fri, 15 Nov 2013 14:32:42 GMT
  < Connection: keep-alive
  <
  {
  "id": "c919cfe0-4e02-11e3-8d9c-69e0d0c454f5"
• Connection #0 to host localhost left intact
  }* Closing connection #0

xxx@linux-6b5c:~/git/Rush/bin> curl -X GET localhost:5001 -H "x-relayer-host:www.google.es" -H "x-relayer-persistence:BODY" -v* About to connect() to localhost port 5001 (#0)

• Trying ::1...
• Conexión rehusada
• Trying 127.0.0.1...
• connected
• Connected to localhost (127.0.0.1) port 5001 (#0)

  GET / HTTP/1.1
  User-Agent: curl/7.28.1
  Host: localhost:5001
  Accept: /
  x-relayer-host:www.google.es
  x-relayer-persistence:BODY

  < HTTP/1.1 500 Internal Server Error
  < X-Powered-By: Express
  < Content-Type: application/json; charset=utf-8
  < Content-Length: 140
  < Date: Fri, 15 Nov 2013 14:32:43 GMT
  < Connection: keep-alive
  <
  {
  "exceptionId": "SVR1000",
  "exceptionText": "Generic Server Error: Error: Max queue size reached: infomem: 1216344 max_mem: 1215816"
• Connection #0 to host localhost left intact
  }* Closing connection #0

xxx@linux-6b5c:~/git/Rush/bin> git status

On branch redis_overload

[aitormagan]

Status 503 is only returned when Redis is full but I didn't considered the case of a full queue. I don't know which cases should be considered (maybe both). You have set the maximum size of a queue, but I think the message Julio got was caused because Redis was full (not the queue).

[XavierVal]

< HTTP/1.1 503 Service Unavailable
< X-Powered-By: Express
< Content-Type: application/json; charset=utf-8
< Content-Length: 103
< Date: Tue, 19 Nov 2013 09:02:18 GMT
< Connection: keep-alive
<
{
"exceptionId": "SVR1006",
"exceptionText": "Service temporarily unavailable: system overloaded"