Mistral Keystone.projects_get action failed with 404 due to incorrect url

[Evgeny Zhuravlev]

Upgarded from Yoga to Zed using kolla-ansible. After successful upgrade I've found error in mistral-extra action 'keystone.projects_get'.

openstack action execution run keystone.projects_get '{"project": "e2b8a106cfba484588b3141a76ebbb5f"}'

{"result": "The action raised an exception [action=<mistral_lib.actions.base.KeystoneAction object at 0x7f992a2363b0>, action_ex_id=None, msg='KeystoneAction.projects.get failed: Not Found (HTTP 404) (Request-ID: req-bb07ee44-7230-4994-aca0-7eeca006c112)']"}

In the keystone log for bad request we can see
"GET /projects/e2b8a106cfba484588b3141a76ebbb5f HTTP/1.1" 404 207 36194 "-" "python-keystoneclient"

For good request via openstack cli 'openstack project show e2b8a106cfba484588b3141a76ebbb5f'
"GET /v3/projects/e2b8a106cfba484588b3141a76ebbb5f HTTP/1.1" 200 524 30045 "-" "python-keystoneclient"

After a few hours of investigation we found difference in ansible role for mistral:

Zed
/usr/local/share/kolla-ansible/ansible/roles/mistral/templates/mistral.conf.j2
www_authenticate_uri = {{ keystone_internal_url }}

Yoga
www_authenticate_uri = {{ keystone_internal_url }}/v3

Changing back to {{ keystone_internal_url }}/v3 has fixed keystone 404 errors.
Mistral code base in this part was not changed since Jan 21, 2020 (https://github.com/openstack/mistral/blob/stable/zed/mistral/utils/openstack/keystone.py)

affected version of kolla-ansible which we used:
kolla-ansible 15.1.1.dev38

mistral python modules inside docker containers
keystoneauth1 5.0.0
keystonemiddleware 10.1.0
python-keystoneclient 5.0.1
mistral 14.0.0
python-mistralclient 4.5.0
mistral-extra 13.0.0
mistral-lib 2.7.0