Log connection info on start

[andrewvc]

It'd be nice to log the info about which host we've connected to both before and after connect for auditability.

[merretbuurman]

Hi! I agree. In my logs, there is a line "Connected to RabbitMQ at", but then it is empty. The code to display this is clearly there, but not working properly.

logstash_1  | [2018-10-17T16:26:08,894][INFO ][org.logstash.beats.Server] Starting server on port: 5044
logstash_1  | [2018-10-17T16:26:11,967][INFO ][logstash.inputs.rabbitmq ] Connected to RabbitMQ at 
logstash_1  | [2018-10-17T16:26:13,090][INFO ][logstash.agent           ] Successfully started Logstash API endpoint {:port=>9600}

(I'm using Logstash 6.4.2 as a OSS docker image, btw... But I've seen this in my previous 6.x Logstash deployments too).

[yaauie]

It looks like it's attempting to extract the :host property when logging, but the hash contains a :hosts (plural) instead.

I'm flagging this as blocked by #12 since it modifies the mapping to use :addresses.

I'll follow up on this once we figure out the path forward for the multiple host support.