Comment 3 for bug 1768824

Reviewed: https://review.openstack.org/568372
Committed: https://git.openstack.org/cgit/openstack/designate/commit/?id=1924abff40341337bd00659ff01a14ea91701475
Submitter: Zuul
Branch: master

commit 1924abff40341337bd00659ff01a14ea91701475
Author: Erik Olof Gunnar Andersson <email address hidden>
Date: Mon May 14 13:50:03 2018 -0700

    Add unique constraint to service_statuses

    In the current implementation, if for any reason a duplicate
    service entry gets created, the call to update that service
    will fail endlessly, and instead cause the service to create
    new entries everytime update_service_status gets called. Causing
    it to fill the database with duplicate entries.

    This patch adds a unique constraint to the service_statuses
    table based on the service_name and hostname, to ensure that
    this cannot happen.

    In addition we add a new test to the storage driver and further
    expanded the central service test coverage.

    Change-Id: I307a8f7dd8b8a83effa447a846db3288efa32dba
    Closes-Bug: #1768824