mk_sap: Add exclude_paths option to skip monitoring objects

agents/sap/sap.cfg

@@ -49,3 +49,22 @@ monitor_paths += [
     #'SAP CCMS Monitor Templates/Operating System/OperatingSystem/CPU/CPU_Utilization',
     #'*',
 ]
+
+# A list of strings using the same unix shell pattern syntax as
+# monitor_paths (see above). All monitoring objects whose path matches at
+# least one of these patterns are excluded from monitoring, even if the
+# path is matched by one of the monitor_paths patterns. This can be used
+# to skip single objects below a monitor_paths wildcard, e.g. the alert
+# container of a client which only holds purely technical number range
+# objects rolling over by design.
+# Anchoring the pattern to the affected subtree is recommended to avoid
+# accidentally excluding objects in other monitors.
+# Note: The path segments are built from the SAP field MTNAMESHRT, which
+# is limited to 40 characters. Long node names are therefore truncated
+# (e.g. "Client 000 Alert Messages for Number Ran") and patterns have to
+# match the truncated name. To verify the exact paths, temporarily enable
+# the debug output line in the plugin (search for 'node["PATH"]').
+exclude_paths += [
+    #'SAP CCMS Technical Expert Monitors/All Monitoring Contexts/Critical Number Ranges/Critical Number Ranges All Clients/Client 000 Alert Messages for Number Ran*',
+    #'SAP CCMS Technical Expert Monitors/All Monitoring Contexts/Critical Number Ranges/*/Client 066*',
+]

cmk/plugins/sap/agents/mk_sap.py

@@ -136,6 +136,13 @@
     "SAP CCMS Monitor Templates/Dialog Overview/*",
 ]
 monitor_types = []  # type: list[str]
+
+# A list of strings using the same unix shell pattern syntax as
+# monitor_paths (see above). All monitoring objects whose path matches at
+# least one of these patterns are excluded from monitoring, even if the
+# path is matched by one of the monitor_paths patterns. This can be used
+# to skip single objects below a monitor_paths wildcard.
+exclude_paths = []  # type: list[str]
 config_file = MK_CONFDIR + "/sap.cfg"
 
 cfg = {}  # type: list[dict[Any, Any]] | dict[Any, Any]
@@ -208,6 +215,15 @@ class SapError(Exception):
 
 
 def to_be_monitored(path, toplevel_match=False):
+    # Exclude rules are always matched against the full path. They are
+    # intentionally not shortened during toplevel matching: Shortening a
+    # rule which targets a single subtree node would exclude the whole
+    # monitor instead. A rule matching the toplevel path itself still
+    # skips the whole monitor and saves the RFC calls for its tree.
+    for rule in exclude_paths:
+        if fnmatch.fnmatch(path, rule):
+            return False
+
     for rule in monitor_paths:
         if toplevel_match and rule.count("/") > 1:
             rule = "/".join(rule.split("/")[:2])

tests/unit/cmk/plugins/sap/agents/test_mk_sap.py

@@ -112,6 +112,59 @@ def test_recursion(monkeypatch):
 }
 
 
+@pytest.mark.parametrize(
+    "monitor, exclude, path, toplevel_match, expected",
+    [
+        # default behaviour without exclude_paths stays untouched
+        (["SAP CCMS Monitor Templates/Dialog Overview/*"], [], "SAP CCMS Monitor Templates/Dialog Overview/ResponseTime", False, True),
+        (["SAP CCMS Monitor Templates/Dialog Overview/*"], [], "SAP CCMS Monitor Templates/Other Monitor/Foo", False, False),
+        # toplevel matching shortens monitor rules to the first two segments
+        (["SAP CCMS Monitor Templates/Dialog Overview/ResponseTime"], [], "SAP CCMS Monitor Templates/Dialog Overview", True, True),
+        # a matching exclude rule wins over a matching monitor rule.
+        # Note the truncated last path segment: segments come from the
+        # 40 character SAP field MTNAMESHRT, patterns must match the
+        # truncated name (pattern anchored to the subtree as recommended
+        # in sap.cfg)
+        (
+            ["SAP CCMS Technical Expert Monitors/All Monitoring Contexts/Critical Number Ranges/*"],
+            ["SAP CCMS Technical Expert Monitors/All Monitoring Contexts/Critical Number Ranges/Critical Number Ranges All Clients/Client 000 Alert Messages for Number Ran*"],
+            "SAP CCMS Technical Expert Monitors/All Monitoring Contexts/Critical Number Ranges/Critical Number Ranges All Clients/Client 000 Alert Messages for Number Ran",
+            False,
+            False,
+        ),
+        # sibling nodes not matching the exclude rule are still monitored
+        (
+            ["SAP CCMS Technical Expert Monitors/All Monitoring Contexts/Critical Number Ranges/*"],
+            ["SAP CCMS Technical Expert Monitors/All Monitoring Contexts/Critical Number Ranges/Critical Number Ranges All Clients/Client 000 Alert Messages for Number Ran*"],
+            "SAP CCMS Technical Expert Monitors/All Monitoring Contexts/Critical Number Ranges/Critical Number Ranges All Clients/Client 100 Alert Messages for Number Ran",
+            False,
+            True,
+        ),
+        # an exclude rule targeting a subtree node must not skip the whole
+        # monitor during toplevel matching (exclude rules are not shortened)
+        (
+            ["SAP CCMS Technical Expert Monitors/All Monitoring Contexts/Critical Number Ranges/*"],
+            ["SAP CCMS Technical Expert Monitors/All Monitoring Contexts/Critical Number Ranges/Critical Number Ranges All Clients/Client 000 Alert Messages for Number Ran*"],
+            "SAP CCMS Technical Expert Monitors/All Monitoring Contexts",
+            True,
+            True,
+        ),
+        # an exclude rule matching the toplevel path skips the whole monitor
+        (
+            ["*"],
+            ["SAP CCMS Monitor Templates/Dialog Overview*"],
+            "SAP CCMS Monitor Templates/Dialog Overview",
+            True,
+            False,
+        ),
+    ],
+)
+def test_to_be_monitored(monkeypatch, monitor, exclude, path, toplevel_match, expected):
+    monkeypatch.setattr(mk_sap, "monitor_paths", monitor)
+    monkeypatch.setattr(mk_sap, "exclude_paths", exclude)
+    assert mk_sap.to_be_monitored(path, toplevel_match) is expected
+
+
 def test_state_file_round_trip(monkeypatch, tmp_path):
     state_file = tmp_path / "sap.state"
     state_file.write_text(mk_sap.serialize_states(STATES))