17040 FIX agent_netapp_ontap: KeyError: 'used'

SUP-20332

Change-Id: I7215a9420c469ddc21a39162c0ce8e015932db90

.werks/17040.md

@@ -0,0 +1,24 @@
+[//]: # (werk v2)
+# agent_netapp_ontap: KeyError: 'used'
+
+key        | value
+---------- | ---
+date       | 2024-10-09T16:23:37+00:00
+version    | 2.3.0p20
+class      | fix
+edition    | cre
+component  | checks
+level      | 1
+compatible | yes
+
+This change affects users monitoring NetApp through the Ontap REST API. Previously
+the special agent might crash with the following error
+```
+ File "/omd/sites/IDT_Dessau/lib/python3/cmk/special_agents/agent_netapp_ontap.py", line 287, in fetch_luns
+    space_used=element_data["space"]["used"],
+KeyError: 'used
+```
+If this happens now, the state of the check will be 'UNKN' and the summary will contain a suggestion that the space used is not available.
+
+It is important to note that we have not been able to reproduce the problem where the lun volume does not provide information about how much space is used.
+Therefore, other errors may occur in this scenario that cannot be addressed by this werk. Please report such problems so that we can address them.

cmk/plugins/netapp/agent_based/netapp_ontap_luns.py

@@ -86,6 +86,10 @@ def _check_netapp_ontap_luns(
     yield Result(state=State.OK, summary=f"Volume: {lun.volume_name}")
     yield Result(state=State.OK, summary=f"SVM: {lun.svm_name}")
 
+    if lun.space_used is None:
+        yield Result(state=State.UNKNOWN, summary="Space used is unknown")
+        return
+
     yield from check_netapp_luns(
         item=item,
         online=lun.enabled,

cmk/plugins/netapp/models.py

@@ -200,7 +200,7 @@ class LunModel(BaseModel):
 
     name: str
     space_size: int
-    space_used: int
+    space_used: int | None = None
     enabled: bool
     read_only: bool
     svm_name: str
@@ -210,6 +210,8 @@ def size(self) -> float:
         return self.space_size / MEGA
 
     def free_space(self) -> float:
+        if self.space_used is None:
+            raise ValueError("space_used must be available to calculate free space")
         return (self.space_size - self.space_used) / MEGA
 
     def item_name(self) -> str:

cmk/special_agents/agent_netapp_ontap.py

@@ -290,7 +290,7 @@ def fetch_luns(connection: HostConnection) -> Iterable[models.LunModel]:
         yield models.LunModel(
             name=element_data["name"],
             space_size=element_data["space"]["size"],
-            space_used=element_data["space"]["used"],
+            space_used=element_data["space"].get("used"),
             enabled=element_data["enabled"],
             read_only=element_data["status"]["read_only"],
             svm_name=element_data["svm"]["name"],

tests/unit/cmk/plugins/netapp/test_netapp_ontap_luns.py

@@ -38,3 +38,33 @@ def test_check_netapp_luns() -> None:
         Result(state=State.OK, summary="Volume: test_volume_name"),
         Result(state=State.OK, summary="SVM: test_svm_name"),
     ]
+
+
+def test_check_netapp_luns_no_used_space() -> None:
+    lun_model = LunModelFactory.build(
+        name="/vol/test/lun1",
+        volume_name="test_volume_name",
+        svm_name="test_svm_name",
+        space_used=None,
+    )
+    section = {lun_model.item_name(): lun_model}
+
+    result = list(
+        _check_netapp_ontap_luns(
+            "lun1",
+            {  # not revelevant for this test - but needed
+                "levels": (80.0, 90.0),
+                "trend_range": 24,
+            },
+            section,
+            # not revelevant for this test - but needed:
+            {"lun1.delta": (0.0, 0.0)},
+            0.0,
+        )
+    )
+
+    assert result == [
+        Result(state=State.OK, summary="Volume: test_volume_name"),
+        Result(state=State.OK, summary="SVM: test_svm_name"),
+        Result(state=State.UNKNOWN, summary="Space used is unknown"),
+    ]