have client message broker back-off when receiving 5xx responses

[Simon Poirier]

Current client tries sending messages on schedule. When we get a massive backlog of messages (due to outage or bugs) we are basically getting DDOS-ed, getting 503 messages.

As an operator of landscape SaaS, I would like to have at least those 2 throttling mechanisms added to clients when 5xx status are received

- an exponential back-off timer of the broker (urgent or standard exchanges) are queued to avoid hammering the message-system with too many simultaneous clients.
- a reverse-exponential reduction of the broker max_messages to reduce server load and keep the broker "nice"

This might lengthen recovery from downtime, but should make the recovery smoother.

[Kevin Nasto (silverdrake11)]

The pull request is here https://github.com/CanonicalLtd/landscape-client/pull/107

[Launchpad Janitor (janitor)]

This bug was fixed in the package landscape-client - 23.02-0ubuntu1

---------------
landscape-client (23.02-0ubuntu1) lunar; urgency=medium

  * New upstream release 23.02:
    - Preventing the generation of large messages and logs that can overwhelm
      Landscape Server (LP: #1995775)
    - Improved MOTD slowdown on machines with many tap network interfaces
      (LP: #2006396)
    - No longer using deprecated apt-key when storing trusted GPG keys
      (LP: #1973202)
    - Fixed issue recognising Parallels VMs as Virtual Machine clients
      (LP: #1827909)
    - Fixes for incorrect logfile rotation config (LP: #1968189)
    - Client-side backoff handling to moderate traffic to Landscape Server
      during high load (LP: #1947399)
    - Avoid sending empty messages when catching up to expected next message
      (LP: #1917540)
    - --is-registered CLI option to quickly check if client is registered
      (LP: #1912516)
    - Can now report Ubuntu Pro attachment information if the version of
      Landscape Server it is registered to supports this (LP: #2006401)
    - Packages installed as dependencies as part of package profiles are now
      appropriately autoremovable (LP: #1878957)
    - Registration timeouts give an error instead of timing out (LP: #1889464)
    - RHEV hypervisor VMs are now recognized as virtual machines (LP: #1884116)
    - Doing a Landscape-driven release upgrade from a release running python 2
      to one running python 3 no longer hangs forever (LP: #1943291)

 -- Mitch Burton <email address hidden> Wed, 08 Feb 2023 10:23:31 -0800