Correct errors about freezer-api supporting for V1 and V2 api

At present, the codes as follows：
db/elastic/driver.py:
Def get_engine (self):
    If not self._engine:
        Self._engine = db_session.ElasticSearchEngineV2(self.backend)
    Return self._engine
There is that freezer-api can't support support v1.
Actually, there is enable_v1_api ,but it is not used correctly.
The documents will be modified in other patches.

For example:
1)freezer-api v1:
  /etc/freezer/freezer-api.conf:
      [DEFAULT]
          enable_v1_api = True
	  [storage]
          driver = elasticsearch
          backend = elasticsearch
	  [elasticsearch]
          hosts = http://172.16.1.200:9200
          number_of_replicas = 0
          index = freezer

  /etc/freezer/scheduler.conf:
      [DEFAULT]
          enable_v1_api = True

   command: freezer --os-backup-api-version 1  job-list

2)freezer-api v2:
  /etc/freezer/freezer-api.conf:
      [DEFAULT]
          enable_v1_api = False
		  or
		  # enable_v1_api = False
	  [storage]
          driver = elasticsearch
          backend = elasticsearch
	  [elasticsearch]
          hosts = http://172.16.1.200:9200
          number_of_replicas = 0
          index = freezer

  /etc/freezer/scheduler.conf:
      [DEFAULT]
         enable_v1_api = False
		 or
		 # enable_v1_api = False

   command: freezer job-list

Change-Id: Iccee3a7cde986d0ba2aaf018fafa6bca411c34bf

etc/freezer/freezer-api.conf.sample

@@ -12,36 +12,26 @@
 # Maximum value: 65535
 #bind_port = 9090
 
-# Deploy the v1 OpenStack Freezer API.
-# When this option is set to ``True``, Freezer-api service will respond to
-# requests on registered endpoints conforming to the v1 OpenStack Freezer API.
-# NOTES:
-#     * Multi-tenancy is not supported under this api version.
-#     * Everything is user based.
-#     * Freezer api v1 doesn't support Oslo.db.
-#     * Use elasticsearch db with v1 api version
+# Deploy the OpenStack Freezer API.
+# Default is the v2 Freezer API.
+# When this option is set
+# to ``True``, Freezer-api service will respond
+# to requests on registered endpoints conforming
+# to the v1 OpenStack Freezer api.
+# The v1 OpenStack Freezer API:
+#    * Multi-tenancy is not supported under this
+#     api version.
+#    * Everything is user based.
+#    * Freezer api v1 doesn't support Oslo.db.
+#    * Use elasticsearch db with v1 api version
+# The v2 OpenStack Freezer API:
+#    * Multi-tenancy is supported under this api version.
+#    * Freezer api v2 supports Oslo.db.
+#    * Recommended to use oslo.db with api v2
 # Possible values:
-#     * True
-#     * False
-# Related options:
-#     * enable_v2_api
-#                      (boolean value)
-#enable_v1_api = false
-
-# Deploy the v2 OpenStack Freezer API.
-# When this option is set to ``True``, Freezer-api service will respond to
-# requests on registered endpoints conforming to the v2 OpenStack Freezer api.
-#     NOTES:
-#         * Multi-tenancy is supported under this api version.
-#         * Freezer api v2 supports Oslo.db.
-#         * Recommended to use oslo.db with api v2
-#     Possible values:
-#         * True
-#         * False
-#     Related options:
-#         * enable_v1_api
-#                          (boolean value)
-#enable_v2_api = true
+#    * True
+#    * False
+#enable_v1_api = False
 
 #
 # From oslo.log

freezer_api/api/versions.py

@@ -51,7 +51,8 @@ def api_versions(conf=None):
 class Resource(object):
 
     def _build_versions(self, host_url):
-        allowed_versions = {'v1': CONF.enable_v1_api, 'v2': CONF.enable_v2_api}
+        allowed_versions = {'v1': CONF.enable_v1_api,
+                            'v2': False if CONF.enable_v1_api else True}
 
         updated_versions = {'versions': []}
         for version in VERSIONS['versions']:

freezer_api/common/config.py

@@ -61,35 +61,27 @@ def api_common_opts():
                     ),
         cfg.BoolOpt('enable_v1_api',
                     default=False,
-                    help="""Deploy the v1 OpenStack Freezer API.
-When this option is set to ``True``, Freezer-api service will respond to
-requests on registered endpoints conforming to the v1 OpenStack Freezer API.
-NOTES:
-    * Multi-tenancy is not supported under this api version.
-    * Everything is user based.
-    * Freezer api v1 doesn't support Oslo.db.
-    * Use elasticsearch db with v1 api version
-Possible values:
-    * True
-    * False
-Related options:
-    * enable_v2_api
-                    """),
-        cfg.BoolOpt('enable_v2_api',
-                    default=True,
-                    help="""Deploy the v2 OpenStack Freezer API.
-When this option is set to ``True``, Freezer-api service will respond to
-requests on registered endpoints conforming to the v2 OpenStack Freezer api.
-    NOTES:
-        * Multi-tenancy is supported under this api version.
-        * Freezer api v2 supports Oslo.db.
-        * Recommended to use oslo.db with api v2
-    Possible values:
-        * True
-        * False
-    Related options:
-        * enable_v1_api
-                        """)
+                    help="""Default False, That is the v2 Freezer API
+                    will be deployed. When this option is set
+                    to ``True``, Freezer-api service will respond
+                    to requests on registered endpoints conforming
+                    to the v1 OpenStack Freezer api.
+                    The v1 OpenStack Freezer API functions
+                    as follows:
+                        * Multi-tenancy is not supported under this
+                         api version.
+                        * Everything is user based.
+                        * Freezer api v1 doesn't support Oslo.db.
+                        * Use elasticsearch db with v1 api version
+                    The v2 OpenStack Freezer API functions
+                    as follows:
+                        * Multi-tenancy is supported under this api version.
+                        * Freezer api v2 supports Oslo.db.
+                        * Recommended to use oslo.db with api v2
+                    Possible values:
+                        * True
+                        * False
+                    """)
     ]
 
     return _COMMON

freezer_api/db/elasticsearch/driver.py

@@ -19,8 +19,8 @@ from oslo_log import log
 from freezer_api.common import db_mappings
 from freezer_api.db import base as db_base
 from freezer_api.db.elasticsearch import es_manager
-from freezer_api.storage import elasticv2 as db_session
-
+from freezer_api.storage import elastic as db_session_v1
+from freezer_api.storage import elasticv2 as db_session_v2
 
 CONF = cfg.CONF
 LOG = log.getLogger(__name__)
@@ -89,7 +89,12 @@ class ElasticSearchDB(db_base.DBDriver):
 
     def get_engine(self):
         if not self._engine:
-            self._engine = db_session.ElasticSearchEngineV2(self.backend)
+            if CONF.enable_v1_api:
+                self._engine = db_session_v1.\
+                    ElasticSearchEngine(self.backend)
+            else:
+                self._engine = db_session_v2.\
+                    ElasticSearchEngineV2(self.backend)
         return self._engine
 
     def get_api(self):

freezer_api/service.py

@@ -33,13 +33,16 @@ FALCON_MINVERSION_MIDDLEWARE = pkg_resources.parse_version('0.2.0b1')
 
 
 def root_app_factory(loader, global_conf, **local_conf):
-    """Allows freezer to launch multiple applications at a time.
-    It will allow freezer to manage multiple versions.
+    """Freezer can manage multiple versions, but
+    only launch one version at a time, Otherwise it is
+     easy to cause confusion. If there is a demand in the future
+    for a single freezer-api instance to support both v1 and v2 at a time,
+    you need to add a new patch to implement it.
     """
-    if not CONF.enable_v1_api and '/v1' in local_conf:
-        del local_conf['/v1']
-    if not CONF.enable_v2_api and '/v2' in local_conf:
+    if CONF.enable_v1_api and '/v1' in local_conf:
         del local_conf['/v2']
+    else:
+        del local_conf['/v1']
     return urlmap.urlmap_factory(loader, global_conf, **local_conf)