[PROTON-1952] Add possibility to set link-credit in proton receiver API

• Type: Improvement
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: proton-c-0.22.0
• Component/s: cpp-binding
• Labels: reproducer
• Assignee: Unassigned
• Reporter: Jeremy
• Created: 11/Oct/18 12:34
• Updated: 23/Apr/20 00:51

Description

In the amqp standard, link-credit is defined as: "the current maximum legal amount that the delivery-count can be increased by". Only the receiver can set its value.

In the current proton API, we can only add to the link-credit. We cannot set it (our need is to set it to a value less than the actual link-credit).

As to why we need this, we are trying to implement an asynchronous get with timeout (by returning a std::future).

I understand that in the amqp standard, there are 2 supported modes of delivery, and async get with timeout is not mentioned:

• Synchronous get (with/without timeout) 
• Asynchronous notifications

Therefore, we're implementing it for its convenience to us (the client receives the response/exception in his thread).

Problem arises when we start having timeouts. Briefly (I can give you more details here if you want), having the ability to set the link-credit to a lower value would facilitate our lives.