OpenID Connect plugins should support OpenID Connect Discovery

[Alvaro Lopez]

Currently, the OpenID Connect plugins require the user to specify the access token endpoint for OpenID Connect. These plugins should allow users to specify the well-known location of an OpenID Connect Discovery Document, so that the access token endpoint and other OpenID related stuff can be obtained from it.

See

    https://openid.net/specs/openid-connect-discovery-1_0.html#ProviderMetadata

and

    https://developers.google.com/identity/protocols/OpenIDConnect#discovery

[Steve Martinelli (stevemar)]

that would be an excellent feature to have

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/330464

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/330464
Committed: https://git.openstack.org/cgit/openstack/keystoneauth/commit/?id=00746ea636f8cece848644100b5a340d062b61f4
Submitter: Jenkins
Branch: master

commit 00746ea636f8cece848644100b5a340d062b61f4
Author: Alvaro Lopez Garcia <email address hidden>
Date: Thu Jun 16 10:33:52 2016 +0200

    oidc: add discovery document support

    The OpenID Connect specifies that all providers must return a JSON
    discovery document [1] in a well-known location. We can let the user
    pass this document instead of the individual endpoints (i.e. token and
    authorization endpoint). Moreover, we can also check if the requested
    grant_type (implicit to the used plugin, and one of client_credentials,
    password, authorization_code) is supported by the provider before
    starting the auth flow.

    [1] https://openid.net/specs/openid-connect-discovery-1_0.html#ProviderMetadata

    Fixes-bug: #1583682
    Change-Id: I24b7960b25ddcff45552c0ab5541d92122d1d560