[DHCP] Improve the DHCP agent log

[Rodolfo Alonso]

All DHCP agent updates (RPC events and calls) are stored in ``DhcpAgent._queue``, that is a ``queue.ResourceProcessingQueue`` instance. In order to measure the load of the DHCP agent, it could be useful to log the number of remaining events when each one is processed. That will provide a rough number of the load of the DHCP agent.

The event method call are logged using the decorator ``@log_helpers.log_method_call``. However when a port is created, the port information is stored in a ``dhcp.DictModel`` instance, that is not correctly printed in the log messages.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.opendev.org/c/openstack/neutron/+/924392

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/c/openstack/neutron/+/924392
Committed: https://opendev.org/openstack/neutron/commit/88e83dc7f042533bc5b587307a2a2f6b0311b5da
Submitter: "Zuul (22348)"
Branch: master

commit 88e83dc7f042533bc5b587307a2a2f6b0311b5da
Author: Rodolfo Alonso Hernandez <email address hidden>
Date: Thu Jul 18 09:47:01 2024 +0000

    [DHCP] Inform about the number of pending events to be processed

    After the execution of an RPC event received, the DHCP agent will log
    the number of pending events stored in ``DhcpAgent._queue``, that is a
    ``ResourceProcessingQueue`` instance.

    This patch also improves the ``DictModel`` class. When an instance of
    this class is printed in a log message, the ``__repr__`` method will
    call the ``__str__`` method, that returns the key/values stored in the
    local dictionary.

    Closes-Bug: #2073490
    Change-Id: I69dc6235f7599b687e49428aaa02c4b70154f393

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/neutron 25.0.0.0rc1 release candidate.