Oddly enough, I need exactly the same thing as mozowski. I require this format
[{"message":"some informational content"}]
When sending to a RabbitMQ exchange, but I can't get it right either to RabbitMQ or even to a plain stdout or file output. I can wrap one value in [] but not the whole thing which is what I need to do.
I have tried a wide variety of mutate and etc. but I must be missing something. (I am a logstash newbie.)