CASMCMS-8952: Improve handling of no-op situations

CHANGELOG.md

@@ -6,6 +6,16 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 ## [Unreleased]
+### Added
+- Add code to the beginning of some CFS functions to check if they have been called without
+  necessary arguments, and if so, to log a warning and return immediately.
+- Added similar code to some PCS functions.
+- Created `PowerControlComponentsEmptyException`; raise it when some PCS functions receive
+  empty component list arguments.
+
+### Changed
+- If the status operator `_run` method finds no enabled components, stop immediately, as there is
+  nothing to do.
 
 ## [2.17.1] - 2024-03-21
 ### Changed

src/bos/operators/status.py

@@ -2,7 +2,7 @@
 #
 # MIT License
 #
-# (C) Copyright 2022-2023 Hewlett Packard Enterprise Development LP
+# (C) Copyright 2022-2024 Hewlett Packard Enterprise Development LP
 #
 # Permission is hereby granted, free of charge, to any person obtaining a
 # copy of this software and associated documentation files (the "Software"),
@@ -69,14 +69,16 @@ def _act(self, components):
     def _run(self) -> None:
         """ A single pass of detecting and acting on components  """
         components = self.bos_client.components.get_components(enabled=True)
+        if not components:
+            LOGGER.debug('No enabled components found')
+            return
         component_ids = [component['id'] for component in components]
         power_states = node_to_powerstate(component_ids)
         cfs_states = self._get_cfs_components()
         updated_components = []
-        if components:
-            # Recreate these filters to pull in the latest options values
-            self.boot_wait_time_elapsed = TimeSinceLastAction(seconds=options.max_boot_wait_time)._match
-            self.power_on_wait_time_elapsed = TimeSinceLastAction(seconds=options.max_power_on_wait_time)._match
+        # Recreate these filters to pull in the latest options values
+        self.boot_wait_time_elapsed = TimeSinceLastAction(seconds=options.max_boot_wait_time)._match
+        self.power_on_wait_time_elapsed = TimeSinceLastAction(seconds=options.max_power_on_wait_time)._match
         for component in components:
             updated_component = self._check_status(
                 component, power_states.get(component['id']), cfs_states.get(component['id']))

src/bos/operators/utils/clients/cfs.py

@@ -55,6 +55,9 @@ def get_components(session=None, **kwargs):
 
 
 def patch_components(data, session=None):
+    if not data:
+        LOGGER.warning("patch_components called without data; returning without action.")
+        return
     if not session:
         session = requests_retry_session()
     LOGGER.debug("PATCH %s with body=%s", COMPONENTS_ENDPOINT, data)
@@ -69,6 +72,9 @@ def patch_components(data, session=None):
 
 
 def get_components_from_id_list(id_list):
+    if not id_list:
+        LOGGER.warning("get_components_from_id_list called without IDs; returning without action.")
+        return []
     LOGGER.debug("get_components_from_id_list called with %d IDs", len(id_list))
     session = requests_retry_session()
     component_list = []
@@ -83,6 +89,9 @@ def get_components_from_id_list(id_list):
 
 
 def patch_desired_config(node_ids, desired_config, enabled=False, tags=None, clear_state=False):
+    if not node_ids:
+        LOGGER.warning("patch_desired_config called without IDs; returning without action.")
+        return
     LOGGER.debug("patch_desired_config called on %d IDs with desired_config=%s enabled=%s tags=%s"
                  " clear_state=%s", len(node_ids), desired_config, enabled, tags, clear_state)
     session = requests_retry_session()
@@ -107,6 +116,9 @@ def patch_desired_config(node_ids, desired_config, enabled=False, tags=None, cle
 
 
 def set_cfs(components, enabled, clear_state=False):
+    if not components:
+        LOGGER.warning("set_cfs called without components; returning without action.")
+        return
     LOGGER.debug("set_cfs called on %d components with enabled=%s clear_state=%s", len(components),
                  enabled, clear_state)
     configurations = defaultdict(list)

src/bos/operators/utils/clients/pcs.py

@@ -1,7 +1,7 @@
 #
 # MIT License
 #
-# (C) Copyright 2023 Hewlett Packard Enterprise Development LP
+# (C) Copyright 2023-2024 Hewlett Packard Enterprise Development LP
 #
 # Permission is hereby granted, free of charge, to any person obtaining a
 # copy of this software and associated documentation files (the "Software"),
@@ -58,6 +58,20 @@ class PowerControlTimeoutException(PowerControlException):
     """
 
 
+class PowerControlComponentsEmptyException(Exception):
+    """
+    Raised when one of the PCS utility functions that requires a non-empty
+    list of components is passed an empty component list. This will only
+    happen in the case of a programming bug.
+    
+    This exception is not raised for functions that require a node list
+    but that are able to return a sensible object to the caller that
+    indicates nothing has been done. For example, the status function.
+    This exception is instead used for functions that will fail if they run
+    with an empty node list, but which cannot return an appropriate
+    "no-op" value to the caller.
+    """
+
 def _power_status(xname=None, power_state_filter=None, management_state_filter=None,
                   session=None):
     """
@@ -118,11 +132,14 @@ def status(nodes, session=None, **kwargs):
       PowerControlException: Any non-nominal response from PCS.
       JSONDecodeError: Error decoding the PCS response
     """
+    status_bucket = defaultdict(set)
+    if not nodes:
+        LOGGER.warning("status called without nodes; returning without action.")
+        return status_bucket
     session = session or requests_retry_session()
     power_status_all = _power_status(xname=list(nodes), session=session, **kwargs)
-    status_bucket = defaultdict(set)
     for power_status_entry in power_status_all['status']:
-        # IF the returned xname has an error, it itself is the status regardless of
+        # If the returned xname has an error, it itself is the status regardless of
         # what the powerState field suggests. This is a major departure from how CAPMC handled errors.
         xname = power_status_entry.get('xname', '')
         if power_status_entry['error']:
@@ -139,12 +156,16 @@ def node_to_powerstate(nodes, session=None, **kwargs):
     For an iterable of nodes <nodes>; return a dictionary that maps to the current power state for the node in question.
     """
     power_states = {}
+    if not nodes:
+        LOGGER.warning("node_to_powerstate called without nodes; returning without action.")
+        return power_states
     session = session or requests_retry_session()
     status_bucket = status(nodes, session, **kwargs)
     for pstatus, nodeset in status_bucket.items():
         for node in nodeset:
             power_states[node] = pstatus
     return power_states
+
 def _transition_create(xnames, operation, task_deadline_minutes=None, deputy_key=None, session=None):
     """
     Interact with PCS to create a request to transition one or more xnames. The transition
@@ -170,7 +191,11 @@ def _transition_create(xnames, operation, task_deadline_minutes=None, deputy_key
     Raises:
         PowerControlException: Any non-nominal response from PCS, typically as a result of an unexpected payload
           response, or a failure to create a transition record.
+        PowerControlComponentsEmptyException: No xnames specified
     """
+    if not xnames:
+        raise PowerControlComponentsEmptyException(
+                "_transition_create called with no xnames! (operation=%s)" % operation)
     session = session or requests_retry_session()
     try:
         assert operation in set(['On', 'Off', 'Soft-Off', 'Soft-Restart', 'Hard-Restart', 'Init', 'Force-Off'])
@@ -202,6 +227,8 @@ def power_on(nodes, session=None, task_deadline_minutes=1, **kwargs):
     Sends a request to PCS for transitioning nodes in question to a powered on state.
     Returns: A JSON parsed object response from PCS, which includes the created request ID.
     """
+    if not nodes:
+        raise PowerControlComponentsEmptyException("power_on called with no nodes!")
     session = session or requests_retry_session()
     return _transition_create(xnames=nodes, operation='On', task_deadline_minutes=task_deadline_minutes,
                               session=session, **kwargs)
@@ -210,6 +237,8 @@ def power_off(nodes, session=None, task_deadline_minutes=1, **kwargs):
     Sends a request to PCS for transitioning nodes in question to a powered off state (graceful).
     Returns: A JSON parsed object response from PCS, which includes the created request ID.
     """
+    if not nodes:
+        raise PowerControlComponentsEmptyException("power_off called with no nodes!")
     session = session or requests_retry_session()
     return _transition_create(xnames=nodes, operation='Off', task_deadline_minutes=task_deadline_minutes,
                               session=session, **kwargs)
@@ -218,6 +247,8 @@ def soft_off(nodes, session=None, task_deadline_minutes=1, **kwargs):
     Sends a request to PCS for transitioning nodes in question to a powered off state (graceful).
     Returns: A JSON parsed object response from PCS, which includes the created request ID.
     """
+    if not nodes:
+        raise PowerControlComponentsEmptyException("soft_off called with no nodes!")
     session = session or requests_retry_session()
     return _transition_create(xnames=nodes, operation='Soft-Off', task_deadline_minutes=task_deadline_minutes,
                               session=session, **kwargs)
@@ -226,6 +257,8 @@ def force_off(nodes, session=None, task_deadline_minutes=1, **kwargs):
     Sends a request to PCS for transitioning nodes in question to a powered off state (forceful).
     Returns: A JSON parsed object response from PCS, which includes the created request ID.
     """
+    if not nodes:
+        raise PowerControlComponentsEmptyException("force_off called with no nodes!")
     session = session or requests_retry_session()
     return _transition_create(xnames=nodes, operation='Force-Off', task_deadline_minutes=task_deadline_minutes,
                               session=session, **kwargs)