Merge "Pull config from CBS"

1 files changed, 78 insertions, 0 deletions

diff --git a/components/pm-subscription-handler/pmsh_service/mod/config_handler.py b/components/pm-subscription-handler/pmsh_service/mod/config_handler.py
new file mode 100755
index 00000000..e9edbca4
--- /dev/null
+++ b/components/pm-subscription-handler/pmsh_service/mod/config_handler.py
@@ -0,0 +1,78 @@
+# ============LICENSE_START===================================================
+#  Copyright (C) 2019-2020 Nordix Foundation.
+# ============================================================================
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may 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.
+#
+# SPDX-License-Identifier: Apache-2.0
+# ============LICENSE_END=====================================================
+
+import json
+from os import environ
+
+import requests
+from tenacity import retry, wait_fixed, stop_after_attempt
+
+from pmsh_service.mod import pmsh_logging as logger
+
+
+class ConfigHandler:
+    """ Handles retrieval of PMSH's configuration from Configbinding service."""
+
+    def __init__(self):
+        self.cbs_url = f'http://{self.cbs_hostname}:{str(self.cbs_port)}/' \
+            f'service_component_all/{self.hostname}'
+        self._config = None
+
+    @property
+    def cbs_hostname(self):
+        return _get_environment_variable('CONFIG_BINDING_SERVICE_SERVICE_HOST')
+
+    @property
+    def cbs_port(self):
+        return _get_environment_variable('CONFIG_BINDING_SERVICE_SERVICE_PORT')
+
+    @property
+    def hostname(self):
+        return _get_environment_variable('HOSTNAME')
+
+    @retry(wait=wait_fixed(2), stop=stop_after_attempt(5))
+    def get_config(self):
+        """ Retrieves PMSH's configuration from Configbinding service. If a non-2xx response
+        is received, it retries after 2 seconds for 5 times before raising an exception.
+
+        Returns:
+            dict: Dictionary representation of the the service configuration
+
+        Raises:
+            Exception: If any error occurred pulling configuration from Configbinding service.
+        """
+        if self._config is None:
+            logger.debug('No configuration found, pulling from Configbinding Service.')
+            try:
+                response = requests.get(self.cbs_url)
+                response.raise_for_status()
+                self._config = response.json()
+                logger.debug(f'PMSH Configuration from Configbinding Service: {self._config}')
+                return json.loads(self._config)
+            except Exception as err:
+                raise Exception(f'Error retrieving configuration from CBS: {err}')
+        else:
+            return self._config
+
+
+def _get_environment_variable(env_var_key):
+    try:
+        env_var = environ[env_var_key]
+    except KeyError as error:
+        raise KeyError(f'Environment variable {env_var_key} must be set. {error}')
+    return env_var