client retrieval of freezer api endpoint

The api client queries keystone to obtain the freezer api endpoint,
provided that the freezer api service and endpoint have been registered in
keystone.

An optional parameter to specify the api endpoint is supported

Change-Id: I6626a60d1fd5d18a59376165e94c789832865ae0
Implements: blueprint freezer-apiclient-endpoint

backups.py

@@ -29,10 +29,13 @@ class BackupsManager(object):
 
     def __init__(self, client):
         self.client = client
-        self.endpoint = self.client.endpoint + 'backups/'
-        self.headers = {'X-Auth-Token': client.token}
+        self.endpoint = self.client.api_endpoint + '/v1/backups/'
 
-    def create(self, backup_metadata, username=None, tenant_name=None):
+    @property
+    def headers(self):
+        return {'X-Auth-Token': self.client.auth_token}
+
+    def create(self, backup_metadata):
         r = requests.post(self.endpoint,
                           data=json.dumps(backup_metadata),
                           headers=self.headers)
@@ -42,14 +45,14 @@ class BackupsManager(object):
         backup_id = r.json()['backup_id']
         return backup_id
 
-    def delete(self, backup_id, username=None, tenant_name=None):
+    def delete(self, backup_id):
         endpoint = self.endpoint + backup_id
         r = requests.delete(endpoint, headers=self.headers)
         if r.status_code != 204:
             raise exceptions.MetadataDeleteFailure(
                 "[*] Error {0}".format(r.status_code))
 
-    def list(self,  username=None, tenant_name=None):
+    def list(self):
         r = requests.get(self.endpoint, headers=self.headers)
         if r.status_code != 200:
             raise exceptions.MetadataGetFailure(
@@ -57,7 +60,7 @@ class BackupsManager(object):
 
         return r.json()['backups']
 
-    def get(self, backup_id, username=None, tenant_name=None):
+    def get(self, backup_id):
         endpoint = self.endpoint + backup_id
         r = requests.get(endpoint, headers=self.headers)
         if r.status_code == 200:

client.py

@@ -22,14 +22,15 @@ Hudson (tjh@cryptsoft.com).
 import os
 import sys
 
+from openstackclient.identity import client as os_client
+
 possible_topdir = os.path.normpath(os.path.join(os.path.abspath(sys.argv[0]),
                                    os.pardir, os.pardir, os.pardir))
 if os.path.exists(os.path.join(possible_topdir, 'freezer', '__init__.py')):
     sys.path.insert(0, possible_topdir)
 
-import keystoneclient
-
 from freezer.apiclient.backups import BackupsManager
+import exceptions
 
 
 class Client(object):
@@ -40,26 +41,66 @@ class Client(object):
                  password=None,
                  tenant_name=None,
                  auth_url=None,
-                 endpoint=None,
-                 session=None):
-        if endpoint is None:
-                raise Exception('Missing endpoint information')
-        self.endpoint = endpoint
-
-        if token is not None:
-            # validate the token ?
-            self.token = token
-        elif session is not None:
-            pass
-            # TODO: handle session auth
-            # assert isinstance(session, keystoneclient.session.Session)
-        else:
-            self.username = username
-            self.tenant_name = tenant_name
-            kc = keystoneclient.v2_0.client.Client(
-                username=username,
-                password=password,
-                tenant_name=tenant_name,
-                auth_url=auth_url)
-            self.token = kc.auth_token
+                 session=None,
+                 api_endpoint=None):
+        self.version = version
+        self.token = token
+        self.username = username
+        self.tenant_name = tenant_name
+        self.password = password
+        self.auth_url = auth_url
+        self._api_endpoint = api_endpoint
+        self.session = session
+        self._auth = None
         self.backups = BackupsManager(self)
+
+    def _update_api_endpoint(self):
+        services = self.auth.services.list()
+        try:
+            freezer_service = next(x for x in services if x.name == 'freezer')
+        except:
+            raise exceptions.AuthFailure(
+                'freezer service not found in services list')
+        endpoints = self.auth.endpoints.list()
+        try:
+            freezer_endpoint =\
+                next(x for x in endpoints
+                     if x.service_id == freezer_service.id)
+        except:
+            raise exceptions.AuthFailure(
+                'freezer endpoint not found in endpoint list')
+        self._api_endpoint = freezer_endpoint.publicurl
+
+    @property
+    def auth(self):
+        if self._auth is None:
+            if self.username and self.password:
+                self._auth = os_client.IdentityClientv2(
+                    auth_url=self.auth_url,
+                    username=self.username,
+                    password=self.password,
+                    tenant_name=self.tenant_name)
+            elif self.token:
+                self._auth = os_client.IdentityClientv2(
+                    endpoint=self.auth_url,
+                    token=self.token)
+            else:
+                raise exceptions.AuthFailure("Missing auth credentials")
+        return self._auth
+
+    @property
+    def auth_token(self):
+        return self.auth.auth_token
+
+    @property
+    def api_endpoint(self):
+        if self._api_endpoint is None:
+            self._update_api_endpoint()
+        return self._api_endpoint
+
+    def api_exists(self):
+        try:
+            if self.api_endpoint is not None:
+                return True
+        except:
+            return False

exceptions.py

@@ -20,27 +20,17 @@ Hudson (tjh@cryptsoft.com).
 """
 
 
-class FreezerClientException(Exception):
-    """
-    Base Freezer API Exception
-    """
-    message = ("Unknown exception occurred")
-
-    def __init__(self, message=None, *args, **kwargs):
-        if not message:
-            message = self.message
-        message = message % kwargs
-
-        Exception.__init__(self, message)
-
-
-class MetadataCreationFailure(FreezerClientException):
+class MetadataCreationFailure(Exception):
     message = "Metadata creation failed: %reason"
 
 
-class MetadataGetFailure(FreezerClientException):
+class MetadataGetFailure(Exception):
     message = "Metadata read failed: %reason"
 
 
-class MetadataDeleteFailure(FreezerClientException):
+class MetadataDeleteFailure(Exception):
     message = "Metadata deletion failed: %reason"
+
+
+class AuthFailure(Exception):
+    message = "Authentication Error: %reason"