Add server support for customizing the backend storage file

This change updates the server, adding in support for customizing
the backend storage file used to store all server data. The server
currently uses a simple SQLite database for storage. Prior versions
of the server kept this database file in /tmp, to emphasize the
testing focus of the server. This change loosens that restriction,
now allowing users to customize where the database file lives. A
new configuration option, 'database_path', has been added that will
override the default /tmp location for the database file. This
value can also be passed in if invoking the server via script using
the '-d' flag.

kmip/tests/unit/services/server/test_config.py

@@ -68,6 +68,7 @@ class TestKmipServerConfig(testtools.TestCase):
         c._set_enable_tls_client_auth = mock.MagicMock()
         c._set_tls_cipher_suites = mock.MagicMock()
         c._set_logging_level = mock.MagicMock()
+        c._set_database_path = mock.MagicMock()
 
         # Test the right error is generated when setting an unsupported
         # setting.
@@ -115,6 +116,9 @@ class TestKmipServerConfig(testtools.TestCase):
         c.set_setting('logging_level', 'WARNING')
         c._set_logging_level.assert_called_once_with('WARNING')
 
+        c.set_setting('database_path', '/var/pykmip/pykmip.db')
+        c._set_database_path.assert_called_once_with('/var/pykmip/pykmip.db')
+
     def test_load_settings(self):
         """
         Test that the right calls are made and the right errors generated when
@@ -232,6 +236,7 @@ class TestKmipServerConfig(testtools.TestCase):
         c._set_enable_tls_client_auth = mock.MagicMock()
         c._set_tls_cipher_suites = mock.MagicMock()
         c._set_logging_level = mock.MagicMock()
+        c._set_database_path = mock.MagicMock()
 
         # Test that the right calls are made when correctly parsing settings.
         parser = configparser.SafeConfigParser()
@@ -250,6 +255,7 @@ class TestKmipServerConfig(testtools.TestCase):
             "\n    TLS_RSA_WITH_AES_256_CBC_SHA256"
         )
         parser.set('server', 'logging_level', 'ERROR')
+        parser.set('server', 'database_path', '/var/pykmip/pykmip.db')
 
         c._parse_settings(parser)
 
@@ -267,6 +273,7 @@ class TestKmipServerConfig(testtools.TestCase):
             "\n    TLS_RSA_WITH_AES_256_CBC_SHA256"
         )
         c._set_logging_level.assert_called_once_with('ERROR')
+        c._set_database_path.assert_called_once_with('/var/pykmip/pykmip.db')
 
         # Test that a ConfigurationError is generated when the expected
         # section is missing.
@@ -819,3 +826,55 @@ class TestKmipServerConfig(testtools.TestCase):
             c._set_logging_level,
             *args
         )
+
+    def test_set_database_path(self):
+        """
+        Test that the database_path configuration property can be set
+        correctly.
+        """
+        c = config.KmipServerConfig()
+        c._logger = mock.MagicMock()
+
+        self.assertNotIn('database_path', c.settings.keys())
+
+        with mock.patch('os.path.exists') as os_mock:
+            os_mock.return_value = True
+            c._set_database_path('/test/path/database.db')
+
+        self.assertIn('database_path', c.settings.keys())
+        self.assertEqual(
+            '/test/path/database.db',
+            c.settings.get('database_path')
+        )
+
+    def test_set_database_path_default(self):
+        """
+        Test that the database_path configuration property can be set correctly
+        without specifying a value.
+        """
+        c = config.KmipServerConfig()
+        c._logger = mock.MagicMock()
+
+        self.assertNotIn('database_path', c.settings.keys())
+
+        c._set_database_path(None)
+        self.assertIn('database_path', c.settings.keys())
+        self.assertEqual(None, c.settings.get('database_path'))
+
+    def test_set_database_path_invalid_value(self):
+        """
+        Test that the right error is raised when an invalid value is used to
+        set the database_path configuration property.
+        """
+        c = config.KmipServerConfig()
+        c._logger = mock.MagicMock()
+
+        self.assertNotIn('database_path', c.settings.keys())
+
+        args = (1, )
+        self.assertRaises(
+            exceptions.ConfigurationError,
+            c._set_database_path,
+            *args
+        )
+        self.assertNotEqual(1, c.settings.get('database_path'))