History container

[kbrock]

This history stores notification that have been sent.

This does not know much about the objects stored.

But it does know:

• old records are of no interest
• after records are searched, throw everything away
• in the scan, the match, and all of the ones closer to the head of the stack are of interest
• scan for records from the head (like a stack not a queue)

As we work through this, knowledge of the response code and notification may make things better

[kbrock]

Thanks @stevenharman for pointing out https://github.com/vanstee/grocer/blob/2fd146d4816795ad79f4e2c5beb5a101d00dc72e/lib/grocer/history.rb

• All of the ring buffer implementations that I see out there have a concept of full / out of space.
• They also assume a queue instead of a stack.
• As a nitpick, they also seem to want array size == capacity. Introducing the case where if the front == the back, you need to decide is it full or empty. allowing the array size to be capacity + 1 allows simpler code.

@vanstee 's implementation (link above) is so clean.
I worry about the base case. adding an alert to a full list. Wanted to avoid allocating a bunch of space for that use case. So this implementation looks more like C than ruby. Haven't profiled it, so it could be worse for all I know.

[kbrock]

Not knowing about error responses and notifications really simplifies the tests and keeps it simple.
But there are a few things that would be nice if it knew about other objects in the system.

Thinking about introducing:

1. know about notifications and auto assign an identifier - probably keep it from 1..(@SiZe*10)
2. ability to scan from the back for notifications that were sent a while ago (notification could get sent_at field)
3. know about error responses. find_culpret could assign the notification into the error response, maybe even assign the notifications that were resent as a result.

[kbrock]

I created a history with knowledge of the framework at https://github.com/kbrock/grocer/blob/knowledgeable_history/lib/grocer/history.rb

I think it makes for a nice pusher api, but not sure if so much knowledge should be embedded in a collection class.