Barbican-ipa-backend

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This is an initial design for the Barbican back-end work to allow it to integrate with IPA.

Background:

We want to be able to integrate Barbican and IPA in such a way that we can use either Barbican or IPA to retrieve secrets. At the very least, we want to be able to retrieve barbican secrets from IPA, which means that we need to be able to store the Barbican metadata in IPA.

One approach would be to generate an event each time a barbican secret/metadata is created. This event could then be consumed by IPA and the relevant data updated accordingly. This may actually be less invasive on the Barbican side.

Another approach is to generalize the database store in Barbican and have it call an adapter that talks to IPA instead. Lets see how this adapter approach would work.

Changes in Barbican:

Barbican has the following tables, which it accesses through the Repository object:

           self._set_repo('tenant_repo', TenantRepo, kwargs)
           self._set_repo('tenant_secret_repo', TenantSecretRepo, kwargs)
           self._set_repo('secret_repo', SecretRepo, kwargs)
           self._set_repo('datum_repo', EncryptedDatumRepo, kwargs)
           self._set_repo('kek_repo', KEKDatumRepo, kwargs)
           self._set_repo('secret_meta_repo', SecretStoreMetadatumRepo,
                          kwargs)
           self._set_repo('order_repo', OrderRepo, kwargs)
           self._set_repo('order_plugin_meta_repo', OrderPluginMetadatumRepo,
                          kwargs)
           self._set_repo('transport_key_repo', TransportKeyRepo, kwargs)
           self._set_repo('container_repo', ContainerRepo, kwargs)
           self._set_repo('container_secret_repo', ContainerSecretRepo,
                          kwargs)

Each repo inherits from BaseRepo, which contains the following methods:

   def get_session(self, session=None): 
   def get(self, entity_id, keystone_id=None,
           force_show_deleted=False,
           suppress_exception=False, session=None):
   def create_from(self, entity, session=None):
   def save(self, entity):
   def update(self, entity_id, values, purge_props=False):
   def delete_entity_by_id(self, entity_id, keystone_id):
   (plus a bunch of internal specific methods which could be overridden by the repos)
   def _do_entity_name(self):
   def _do_create_instance(self):
   def _do_build_get_query(self, entity_id, keystone_id, session):
   def _do_validate(self, values):
   (these are internal only - so far):
   def _update(self, entity_id, values, purge_props=False):
   def _update_values(self, entity_ref, values):
   def _do_convert_values(self, values):
        

In addition, the different repos have some dependencies and methods:

   TenantRepo:
   def find_by_keystone_id(self, keystone_id, suppress_exception=False,
                           session=None):
   
   SecretRepo:
   def get_by_create_date(self, keystone_id, offset_arg=None, limit_arg=None,
                          name=None, alg=None, mode=None, bits=0,
                          suppress_exception=False, session=None):
   EncryptedDatumRepo: (none)
   SecretStoreMetadatumRepo: (none)
   KekDatumRepo:
   def find_or_create_kek_datum(self, tenant,
                                plugin_name,
                                suppress_exception=False,
                                session=None):
   TenantSecretRepo: (none)
   OrderRepo:
   def get_by_create_date(self, keystone_id, offset_arg=None, limit_arg=None,
                          suppress_exception=False, session=None):
   ContainerRepo:
   def get_by_create_date(self, keystone_id, offset_arg=None, limit_arg=None,
                          suppress_exception=False, session=None):
   ContainerSecretRepo: (none)
   ContainerConsumerRepo:
   def get_by_container_id(self, container_id,
                           offset_arg=None, limit_arg=None,
                           suppress_exception=False, session=None):
   def get_by_values(self, container_id, name, URL, suppress_exception=False,
                     show_deleted=False, session=None):
   def create_from(self, new_consumer, container):
   TransportKeyRepo:
   def get_by_create_date(self, plugin_name=None,
                          offset_arg=None, limit_arg=None,
                          suppress_exception=False, session=None):
   def get_latest_transport_key(self, plugin_name, suppress_exception=False,
                                session=None)
   So the rough idea would be:
   SecretRepo <= GeneralRepo <-- (IPARepo or BasicRepo)
   SecretRepo etc. does a lot with sessions which are alchemy objects.
   They dont have to be though -- we can define a special "IPASession" object that has the same methods in it. (save, flush etc)

All of this is pretty heavyweight though -- do we really need it? We need to examine if there really is a use case for this. All this going back and forth - from barbican to IPA to KRA sounds pretty awful. And I'm not sure anyone would want to do it. Its easy to store/retrieve secrets from Barbican in IPA - we just need to make sure that the keystone_id is passed down when the secret is stored. Still have to consider how to deal with two step process (if we do).

We need to consider how to handle secret generation -- do that through IPA? What about containers? Lets look at the current and future use cases of Barbican and decide what kinds of secrets we want to store/retrieve.