[Metricbeat] Add ability to collect client-provided name for rabbitmq connections

[kaiyan-sheng]

This PR is to add collection for Client-provided names in rabbitmq connections.

RabbitMQ 3.6.5 added the facility for the connecting client to report a friendly name string value to identify a connection for management purposes. This is strictly an identifier and, as it is client-reported, it cannot be relied upon for anything other than weak identification of connections.

closes #12851

How to test it:

Bring up rabbitmq by running: rabbitmq-server
How to send and receive messgaes: https://www.rabbitmq.com/tutorials/tutorial-one-go.html
How to start a connection with client-provided name:

cfg := amqp.Config{
		Properties: amqp.Table{
			"connection_name": "ThisIsMyName",
		},
	}
conn, err := amqp.DialConfig("amqp://guest:guest@localhost:5672/", cfg)
failOnError1(err, "Failed to connect to RabbitMQ")
defer conn.Close()

ch, err := conn.Channel()

[sayden]

Left a single comment. Tell me WDYT :)

[sayden]

I suggest to call this client_provided.name or event something like client.name. The reason is that probably we can enrich this with more fields in a near future (or maybe not) an, if so, we probably won't like to have
client_provided_name
client_provided_tag
client_provided_label

[jsoriano]

Take into account that this is a name for the connection, so +1 to something like client_provided.name, but don't use client.name, it would look like the name of the client.
We may also keep the original client_properties naming, so if there are more properties in the future we store them as:

rabbitmq.connection.client_properties.name
rabbitmq.connection.client_properties.tag
...

[kaiyan-sheng]

Yeah good point! Thanks @jsoriano and @sayden! I think I'm leaning towards using rabbitmq.connection.client_provided.name just to make it more consistent with the rabbitmq UI 😬

[odacremolbap]

tested, ok on my side.

for anyone testing integrations:

    cfg := amqp.Config{Properties: amqp.Table{"connection_name": "mb-rabbitmq-test"}}
    conn, err := amqp.DialConfig("amqp://guest:guest@localhost:5672/", cfg)

[kaiyan-sheng]

@odacremolbap Thanks for pointing that out. I need to update the PR description with how to test it.