I'm not positive, but one issue I've seen is with multiple types, like you have here:
"fields": { "type": "json" }
But you are then sending it to 5002, which you have as:
type => "logs"
It shouldn't matter for anything but filter activation, etc. but I would try to only put one "type" on the entry. Also, is it possible you are sending the output to another index that you aren't looking at in kibana?