Fix execute db_manager init failed

Previously, `db_manager init` command failed because pbr generated
script will not pass sys.argv as argument to main function. So fix
it.

And improve etcd_db.init_etcd_db to make it check whether each
directory already exists in etcd at first. If it exist and it's not
directory, delete and re-create it.

Change-Id: I7d9980e0a1b38d988fe8144d0cbd618ac12f5498
Closes-Bug: #1654638

README.rst

@@ -55,7 +55,12 @@ Valence installation
 
  6. Initialize etcd database
 
-    ``$ sudo db_manager init``
+    ``$ db_manager init``
+
+    Note: The TypeError exception "TypeError: NoneType object is not callable"
+    is caused by known python-etcd bug, which will not impact this db init
+    functionality.
+    https://github.com/jplana/python-etcd/issues/190
 
  7. Start valence service
 

valence/cmd/db_manager.py

@@ -16,24 +16,24 @@
 import logging
 import sys
 
-from valence.db.etcd_db import init_etcd_db
+from valence.db import etcd_db
 
 LOG = logging.getLogger(__name__)
 
 
 def init():
-    init_etcd_db()
+    etcd_db.init_etcd_db()
 
 
 def migrate():
     pass
 
 
-def main(argv):
+def main():
-    if argv[1] == 'init':
+    if sys.argv[1] == 'init':
         LOG.info("initialize database")
         init()
 
 
 if __name__ == '__main__':
-    main(sys.argv)
+    sys.exit(main())

valence/db/etcd_db.py

@@ -12,7 +12,6 @@
 # License for the specific language governing permissions and limitations
 # under the License.
 
-
 import etcd
 
 from valence import config
@@ -29,4 +28,16 @@ etcd_client = etcd.Client(config.etcd_host, config.etcd_port)
 def init_etcd_db():
     """initialize etcd database"""
     for directory in etcd_directories:
+        try:
+            if not etcd_client.read(directory).dir:
+                # This directory name already exists, but is regular file, not
+                # directory, so delete it.
+                etcd_client.delete(directory)
+            else:
+                # This directory already exists, so skip
+                continue
+        except etcd.EtcdKeyNotFound:
+            # This directory name don't exist
+            pass
+
         etcd_client.write(directory, None, dir=True, append=True)

valence/tests/unit/db/test_etcd_db.py

@@ -0,0 +1,78 @@
+# copyright (c) 2016 Intel, Inc.
+#
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+
+import mock
+import unittest
+
+import etcd
+
+from valence.db import etcd_db
+
+
+class TestDBInit(unittest.TestCase):
+
+    def setUp(self):
+        self.backup_directories = etcd_db.etcd_directories
+        etcd_db.etcd_directories = ['/test']
+
+    def tearDown(self):
+        etcd_db.etcd_directories = self.backup_directories
+
+    @mock.patch('etcd.Client.delete')
+    @mock.patch('etcd.Client.write')
+    @mock.patch('etcd.Client.read')
+    def test_init_db(self, mock_etcd_read, mock_etcd_write, mock_etcd_delete):
+        """Test init DB when no corresponding dir exists"""
+
+        # Directory don't exist in etcd db
+        mock_etcd_read.side_effect = etcd.EtcdKeyNotFound
+
+        etcd_db.init_etcd_db()
+
+        mock_etcd_read.assert_called_with('/test')
+        mock_etcd_write.assert_called_with(
+            '/test', None, dir=True, append=True)
+        mock_etcd_delete.assert_not_called()
+
+    @mock.patch('etcd.Client.delete')
+    @mock.patch('etcd.Client.write')
+    @mock.patch('etcd.Client.read')
+    def test_init_db_with_existing_key(self, mock_etcd_read, mock_etcd_write,
+                                       mock_etcd_delete):
+        """Test init DB when a regular key with same name already exists"""
+
+        # A regular key with same name already exists
+        mock_etcd_read.return_value = mock.Mock(dir=False)
+
+        etcd_db.init_etcd_db()
+
+        mock_etcd_read.assert_called_with('/test')
+        mock_etcd_write.assert_called_with(
+            '/test', None, dir=True, append=True)
+        mock_etcd_delete.assert_called_with('/test')
+
+    @mock.patch('etcd.Client.delete')
+    @mock.patch('etcd.Client.write')
+    @mock.patch('etcd.Client.read')
+    def test_init_db_with_existing_dir(self, mock_etcd_read, mock_etcd_write,
+                                       mock_etcd_delete):
+        """Test init DB when a dir with same name already exists"""
+
+        # A dir with same name already exists
+        mock_etcd_read.return_value = mock.Mock(dir=True)
+
+        etcd_db.init_etcd_db()
+
+        mock_etcd_read.assert_called_with('/test')
+        mock_etcd_write.assert_not_called()
+        mock_etcd_delete.assert_not_called()