openstack endpoint list command take 10 seconds to produce output when is executed against keystone with HTTPS endpoint and large number of endpoints and/or regions.

Example:

    $ env | grep OS_AUTH_URL
    OS_AUTH_URL=https:/ /keystone. openstack. local:5000/ v3
    $ openstack endpoint list -f csv | wc -l
    55
    $ time openstack endpoint list > /dev/null

    real 0m13.357s
    user 0m2.070s
    sys 0m0.238s

Looking at the code, it seems that ListEndpoint. take_action unconditionally loop over all endpoints and issue GET request to /v3/services/ <endpoint. service_ id> API for EACH endpoint, sometimes several times for same service ID (at least 3 times, once for public, once for internal and once for admin).

We need to fix that.