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On Wed, Sep 20, 2017 at 10:14 PM, Matt Riedemann <mriedemos at gmail.com> wrote:
> On 9/20/2017 12:48 AM, Chen CH Ji wrote:
>>
>> in analyzing other code, found seems we don't need PUT
>> /servers/{server_id}/metadata/{key} ?
>>
>> as the id is only used for check whether it's in the body and we will
>> honor the whole body (body['meta'] in the code)
>>
>> https://github.com/openstack/nova/blob/master/nova/api/openstack/compute/server_metadata.py#L80
>>
>> looks like it's identical to
>> PUT /servers/{server_id}/metadata
>>
>> why we need this API or it should be something like
>>
>> PUT /servers/{server_id}/metadata/{key}but we only accept a value to
>> modify the meta given by {key} in the API side?
>>
>> Best Regards!
>>
>> Kevin (Chen) Ji 纪 晨
>>
>> Engineer, zVM Development, CSTL
>> Notes: Chen CH Ji/China/IBM at IBMCN Internet: jichenjc at cn.ibm.com
>> Phone: +86-10-82451493
>> Address: 3/F Ring Building, ZhongGuanCun Software Park, Haidian District,
>> Beijing 100193, PRC
>>
>>
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>
> This API is a bit confusing, and the code is too since it all goes down to
> some common code, and I think you're missing the 'delete' flag:
>
> https://github.com/openstack/nova/blob/5bf1bb47c7e17c26592a699d07c2faa59d98bfb8/nova/compute/api.py#L3830
>
> If delete=False, as it is in this case, we only add/update the existing
> metadata with the new metadata from the request body. If delete=True, then
> we overwrite the instance metadata with whatever is in the request.
>
> Does that answer your question?
>
> This API is problematic and we have bugs against it since it's not atomic,
> i.e. two concurrent requests will overwrite one of them. We should really
> have a generation ID or etag on this data to be sure it's atomically
> updated.
>

I think confusion is for updating the single metadata item by key [1].
and whether it has bug to allow update more than 1 item. But It does
not as schema restrict request body to allow only 1 item in body.

Which means update metadata item by key only allow to update that key
value only.

Also we do have tests to verify that:
https://github.com/openstack/nova/blob/5bf1bb47c7e17c26592a699d07c2faa59d98bfb8/nova/tests/unit/api/openstack/compute/test_server_metadata.py#L529


..1 https://developer.openstack.org/api-ref/compute/#create-or-update-metadata-item

> --
>
> Thanks,
>
> Matt
>
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