Add ability to set message headers

[viktorprogger]

AMQP protocol allows to set message headers. Let's discuss necessity of adding this ability to the package.
Plus: it's very handy to store some metadata like metrics.
Minus: it's AMQP-specific feature, not available in other queue adapters.

[viktorprogger]

What about sending Message metadata in headers instead of body?

[samdark]

How would you implement that in non-AMQP? By extending message body?

[xepozz]

Metadata may be converted to message body as an additional structure

{"body": [1, 2, 3], "headers":[...]}

for non-AMQP brokers
and

Message: {"body": [1, 2, 3]}
Headers: [...]

or just

Message: [1, 2, 3]
Headers: [...]

[samdark]

Won't that mean that you won't be able to process message the same way in these cases?

[xepozz]

It may be encapsulated into drivers. The queue api is clear and simple as it is at now. Headers will be added into the body only when drivers decides that it's broker doesn't support headers.
It works for any other metadata or features in general.

[samdark]

Yes, that could work.