Enhance queue functionality

[GwendolenLynch]

• Add QueueProcessorInterface and limited transaction count decorator
• Add message expiry & queue flushing QueueInterface decorators
• Test coverage

Use cases

• Per-transaction limit: High volume processing
• Age limit: Optional garbage collection strategy for non-critical deliveries

[frederikbosch]

Isn’t this a case where we would want to create an interface for processing the queue? And have two impementations? The one there is now and a LimitQueueProcessor.

Regarding the expiry. I think that belongs in a decorator of the queue storage. The processor should not have to check for the validity of a message.

[GwendolenLynch]

OK, all of the above taken on board and changes applied.

Notables:

• Also added a "flush" decorator, as that was also on my TODO to cover
• Abstracted some commonality in the queue tests for more DRY
• Tiny tweak in coverage on the Redis queue (now only one line untouched)

[frederikbosch]

Looks good, added some minor remarks. What is the usage of the FlushableQueue?

[GwendolenLynch]

Finals added.

What is the usage of the FlushableQueue?

Ah, forgot to update uses-cases, my bad. Literally, so the queues can just be dumped. We see it a lot in cases such as site development where developers will generate dozens, even thousands (let us not talk about the unnamed person who left a generator running on a Friday afternoon and came back on Monday to a dead server) of emails to test a service.

Not fussed if you don't want it in the core library, I can just add it to the bundle. :smile:

[frederikbosch]

Not fussed if you don't want it in the core library, I can just add it to the bundle.

Let's do that.

[GwendolenLynch]

:sparkles: like it never happened :wink:

[frederikbosch]

Added two minor minor remarks. Good to merge afterwards.

[frederikbosch]

Wonderful! Good to see you adding these nice features!