There are many call's between httpd and heat-api.

[Kiran Totad]

When users are trying to get resource details of a specified stack , there are many call's between httpd and heat-api.
For stack Identification ,the following are requested:
1) Identify the stack based on stack id
2) Get the template details
3) Gets the details of specified stack
4) Gets the resource of specified stack
5) Get implementation details with nova api
To list out resource of a stack:
1) Get the stack
2) Gets the templates details
3) Gets the resource details of a specified stack
In each case Two request have been made to get the details
1st: get : HTTP <302> response
2nd: get: HTTP <201> response

As user knows HTTP <302> used for url redirection and <201> is for success, those two request should be merged into one request to get details in one request. By which the number of interaction between httpd and heat-api can be minimize. This will improve the performance of the use case.

[Zane Bitter (zaneb)]

It is indeed unfortunate that the API requires you to know *both* the name and the UUID of the stack before you can fetch details about it directly.

That said, I am yet to be convinced that this is a major problem. It only takes one API call to figure out the name & UUID if you don't know them both already. In the context of the 5+ you're apparently doing (though I have no idea why) that seems fairly minimal.

> This will improve the performance of the use case.

Do we have any evidence for this?

[huangsm (huangsm)]

I think , in the same environment, one direct request should be processed faster than that redirect.
I tests like that:

[root@localhost ~ 11:31 26]$ time curl http://192.168.133.104:8004/v1/706f6efb173f4454a89b15fd76abf1c9/stacks/hsm-hot1 -H "User-Agent: python-heatclient" -H "Accept: application/json" -H "X-Auth-Token:6af97cfa0eb34d59b9955335354f8dd4" -L
{"stack": {"disable_rollback": true, "description": "Simple template to deploy a single compute instance", "parent": null, "tags": null, "stack_name": "hsm-hot1", "stack_user_project_id": "0bc52e9bbca64507bf41cfb508f02f1e", "stack_status_reason": "'NoneType' object has no attribute '__getitem__'", "creation_time": "2017-12-15T06:19:13", "links": [{"href": "http://192.168.133.104:8004/v1/706f6efb173f4454a89b15fd76abf1c9/stacks/hsm-hot1/6d1226cc-a63f-4904-9546-7ec191de4fc3", "rel": "self"}], "capabilities": [], "notification_topics": [], "updated_time": "2017-12-15T06:23:49", "timeout_mins": null, "stack_status": "DELETE_FAILED", "stack_owner": null, "parameters": {"OS::project_id": "706f6efb173f4454a89b15fd76abf1c9", "OS::stack_id": "6d1226cc-a63f-4904-9546-7ec191de4fc3", "OS::stack_name": "hsm-hot1"}, "id": "6d1226cc-a63f-4904-9546-7ec191de4fc3", "template_description": "Simple template to deploy a single compute instance"}}
real 0m0.075s
user 0m0.004s
sys 0m0.002s
[root@localhost ~ 11:31 27]$ time curl http://192.168.133.104:8004/v1/706f6efb173f4454a89b15fd76abf1c9/stacks/hsm-hot1/6d1226cc-a63f-4904-9546-7ec191de4fc3 -H "User-Agent: python-heatclient" -H "Accept: application/json" -H "X-Auth-Token:6af97cfa0eb34d59b9955335354f8dd4"
{"stack": {"disable_rollback": true, "description": "Simple template to deploy a single compute instance", "parent": null, "tags": null, "stack_name": "hsm-hot1", "stack_user_project_id": "0bc52e9bbca64507bf41cfb508f02f1e", "stack_status_reason": "'NoneType' object has no attribute '__getitem__'", "creation_time": "2017-12-15T06:19:13", "links": [{"href": "http://192.168.133.104:8004/v1/706f6efb173f4454a89b15fd76abf1c9/stacks/hsm-hot1/6d1226cc-a63f-4904-9546-7ec191de4fc3", "rel": "self"}], "capabilities": [], "notification_topics": [], "updated_time": "2017-12-15T06:23:49", "timeout_mins": null, "stack_status": "DELETE_FAILED", "stack_owner": null, "parameters": {"OS::project_id": "706f6efb173f4454a89b15fd76abf1c9", "OS::stack_id": "6d1226cc-a63f-4904-9546-7ec191de4fc3", "OS::stack_name": "hsm-hot1"}, "id": "6d1226cc-a63f-4904-9546-7ec191de4fc3", "template_description": "Simple template to deploy a single compute instance"}}
real 0m0.045s
user 0m0.002s
sys 0m0.004s

[OpenStack Infra (hudson-openstack)]

Change abandoned by Zane Bitter (<email address hidden>) on branch: master
Review: https://review.opendev.org/527312