refactor: standardize error handling with new context managers for CMAPI exceptions

We do it for the API to return error details.

cmapi/cmapi_server/controllers/endpoints.py

@@ -12,7 +12,7 @@ import cherrypy
 import pyotp
 import requests
 
-from cmapi_server.exceptions import CMAPIBasicError
+from cmapi_server.exceptions import CMAPIBasicError, cmapi_error_to_422
 from cmapi_server.constants import (
     DEFAULT_MCS_CONF_PATH, DEFAULT_SM_CONF_PATH, EM_PATH_SUFFIX,
     MCS_BRM_CURRENT_PATH, MCS_EM_PATH, S3_BRM_CURRENT_PATH, SECRET_KEY,
@@ -924,14 +924,12 @@ class ClusterController:
         if node is None:
             raise_422_error(module_logger, func_name, 'missing node argument')
 
-        try:
+        with cmapi_error_to_422(module_logger, func_name):
             if not in_transaction:
                 with TransactionManager(extra_nodes=[node]):
                     response = ClusterHandler.add_node(node, config)
             else:
                 response = ClusterHandler.add_node(node, config)
-        except CMAPIBasicError as err:
-            raise_422_error(module_logger, func_name, err.message)
 
         module_logger.debug(f'{func_name} returns {str(response)}')
         return response
@@ -953,14 +951,12 @@ class ClusterController:
         if node is None:
             raise_422_error(module_logger, func_name, 'missing node argument')
 
-        try:
+        with cmapi_error_to_422(module_logger, func_name):
             if not in_transaction:
                 with TransactionManager(remove_nodes=[node]):
                     response = ClusterHandler.remove_node(node, config)
             else:
                 response = ClusterHandler.remove_node(node, config)
-        except CMAPIBasicError as err:
-            raise_422_error(module_logger, func_name, err.message)
 
         module_logger.debug(f'{func_name} returns {str(response)}')
         return response
@@ -1079,10 +1075,8 @@ class ClusterController:
                 module_logger, func_name, 'Wrong verification key.'
             )
 
-        try:
+        with cmapi_error_to_422(module_logger, func_name):
             response = ClusterHandler.set_api_key(new_api_key, totp_key)
-        except CMAPIBasicError as err:
-            raise_422_error(module_logger, func_name, err.message)
 
         module_logger.debug(f'{func_name} returns {str(response)}')
         return response

cmapi/cmapi_server/exceptions.py

@@ -1,5 +1,11 @@
 """Module contains custom exceptions."""
 
+from collections.abc import Iterator
+from contextlib import contextmanager
+from typing import Optional
+
+from cmapi_server.controllers.error import APIError
+
 
 class CMAPIBasicError(Exception):
     """Basic exception raised for CMAPI related processes.
@@ -20,3 +26,35 @@ class CEJError(CMAPIBasicError):
     Attributes:
         message -- explanation of the error
     """
+
+
+@contextmanager
+def exc_to_cmapi_error(prefix: Optional[str] = None) -> Iterator[None]:
+    """Context manager to standardize error wrapping into CMAPIBasicError.
+
+    Re-raises existing CMAPIBasicError untouched (to preserve detailed
+    messages). Any other exception type is wrapped into CMAPIBasicError with an
+    optional prefix and the original exception string appended as details.
+
+    :param prefix: Optional message prefix for wrapped errors
+    :raises CMAPIBasicError: for any wrapped non-CMAPIBasicError exceptions
+    """
+    try:
+        yield
+    except CMAPIBasicError:
+        # Preserve detailed messages from deeper layers (e.g., validation)
+        raise
+    except Exception as err:
+        msg = f"{prefix}. Details: {err}" if prefix else str(err)
+        raise CMAPIBasicError(msg) from err
+
+
+@contextmanager
+def cmapi_error_to_422(logger, func_name: str) -> Iterator[None]:
+    """Convert CMAPIBasicError to HTTP 422 APIError."""
+    try:
+        yield
+    except CMAPIBasicError as err:
+        # mirror raise_422_error behavior locally to avoid circular imports
+        logger.error(f'{func_name} {err.message}', exc_info=False)
+        raise APIError(422, err.message) from err

cmapi/cmapi_server/handlers/cluster.py

@@ -6,12 +6,13 @@ from typing import Optional
 
 from mcs_node_control.models.misc import get_dbrm_master
 from mcs_node_control.models.node_config import NodeConfig
+from tracing.traced_session import get_traced_session
 
 from cmapi_server.constants import (
     CMAPI_CONF_PATH,
     DEFAULT_MCS_CONF_PATH,
 )
-from cmapi_server.exceptions import CMAPIBasicError
+from cmapi_server.exceptions import CMAPIBasicError, exc_to_cmapi_error
 from cmapi_server.helpers import (
     broadcast_new_config,
     get_active_nodes,
@@ -27,7 +28,6 @@ from cmapi_server.node_manipulation import (
     remove_node,
     switch_node_maintenance,
 )
-from tracing.traced_session import get_traced_session
 
 
 class ClusterAction(Enum):
@@ -171,7 +171,7 @@ class ClusterHandler:
 
         response = {'timestamp': str(datetime.now())}
 
-        try:
+        with exc_to_cmapi_error(prefix='Error while adding node'):
             add_node(
                 node, input_config_filename=config,
                 output_config_filename=config
@@ -181,8 +181,6 @@ class ClusterHandler:
                     host=node, input_config_filename=config,
                     output_config_filename=config
                 )
-        except Exception as err:
-            raise CMAPIBasicError('Error while adding node.') from err
 
         response['node_id'] = node
         update_revision_and_manager(
@@ -218,13 +216,11 @@ class ClusterHandler:
         )
         response = {'timestamp': str(datetime.now())}
 
-        try:
+        with exc_to_cmapi_error(prefix='Error while removing node'):
             remove_node(
                 node, input_config_filename=config,
                 output_config_filename=config
             )
-        except Exception as err:
-            raise CMAPIBasicError('Error while removing node.') from err
 
         response['node_id'] = node
         active_nodes = get_active_nodes(config)

cmapi/cmapi_server/node_manipulation.py

@@ -15,6 +15,7 @@ from typing import Optional
 import requests
 from lxml import etree
 from mcs_node_control.models.node_config import NodeConfig
+from tracing.traced_session import get_traced_session
 
 from cmapi_server import helpers
 from cmapi_server.constants import (
@@ -25,7 +26,6 @@ from cmapi_server.constants import (
     MCS_DATA_PATH,
 )
 from cmapi_server.managers.network import NetworkManager
-from tracing.traced_session import get_traced_session
 
 PMS_NODE_PORT = '8620'
 EXEMGR_NODE_PORT = '8601'
@@ -640,7 +640,7 @@ def _rebalance_dbroots(root, test_mode=False):
                         # timed out
                         # possible node is not ready, leave retry as-is
                         pass
-                    except Exception as e:
+                    except Exception:
                         retry = False
 
                 if not found_master: