Extract shared adapter validation helpers

dns_sync/adapter_support.py

@@ -0,0 +1,41 @@
+from .adapters import Endpoint, NormalizedObject, PlanAction
+
+
+def require_endpoint_plugin(
+    endpoint: Endpoint,
+    plugin_name: str,
+) -> None:
+    expected = plugin_name.strip().lower()
+
+    if not expected:
+        raise ValueError("Adapter plugin name cannot be empty")
+
+    if endpoint.plugin != expected:
+        raise RuntimeError(
+            f"Adapter {expected!r} cannot use endpoint "
+            f"{endpoint.identity!r}"
+        )
+
+
+def require_action_endpoint(
+    action: PlanAction,
+    endpoint: Endpoint,
+) -> None:
+    if action.endpoint_id != endpoint.identity:
+        raise RuntimeError(
+            f"Plan action for {action.endpoint_id!r} does not belong "
+            f"to adapter endpoint {endpoint.identity!r}"
+        )
+
+
+def require_desired(
+    action: PlanAction,
+    *,
+    context: str = "Adapter apply",
+) -> NormalizedObject:
+    if action.desired is None:
+        raise RuntimeError(
+            f"{context} requires desired state"
+        )
+
+    return action.desired

dns_sync/plugins/adapters/npm.py

@@ -13,6 +13,11 @@ from ...adapters import (
     PlanOperation,
     RetireRequest,
 )
+from ...adapter_support import (
+    require_action_endpoint,
+    require_desired,
+    require_endpoint_plugin,
+)
 from ...certificates.material import CertificateMaterial
 from ...npm_client import NpmClient
 from ...object_normalizer import normalize_discovered_object
@@ -67,6 +72,7 @@ class Plugin:
     )
 
     def __init__(self, config, endpoint):
+        require_endpoint_plugin(endpoint, self.name)
         self.config = config
         self.endpoint = endpoint
         self.client = NpmClient(config, endpoint)
@@ -593,16 +599,14 @@ class Plugin:
         self,
         action: PlanAction,
     ) -> ApplyResult | None:
-        desired = action.desired
-
-        if desired is None:
-            raise RuntimeError(
-                "NPM apply requires desired state"
+        desired = require_desired(
+            action,
+            context="NPM apply",
         )
 
-        if action.endpoint_id != self.endpoint.identity:
-            raise RuntimeError(
-                "NPM apply action endpoint does not match adapter"
+        require_action_endpoint(
+            action,
+            self.endpoint,
         )
 
         if (

external_plugins/verizon/__init__.py

@@ -8,6 +8,11 @@ from dns_sync.adapters import (
     PlanAction,
     PlanOperation,
 )
+from dns_sync.adapter_support import (
+    require_action_endpoint,
+    require_desired,
+    require_endpoint_plugin,
+)
 from dns_sync.models import DesiredRecord
 from .provider import Plugin as VerizonProvider
 
@@ -32,10 +37,7 @@ class Plugin:
     )
 
     def __init__(self, config, endpoint):
-        if endpoint.plugin != self.name:
-            raise RuntimeError(
-                "Verizon adapter requires a verizon endpoint"
-            )
+        require_endpoint_plugin(endpoint, self.name)
 
         self.config = config
         self.endpoint = endpoint
@@ -121,9 +123,9 @@ class Plugin:
         )
 
     def apply(self, action: PlanAction) -> ApplyResult | None:
-        if action.endpoint_id != self.endpoint.identity:
-            raise RuntimeError(
-                "Plan action belongs to a different endpoint"
+        require_action_endpoint(
+            action,
+            self.endpoint,
         )
 
         if action.operation in {
@@ -132,12 +134,12 @@ class Plugin:
         }:
             return None
 
-        if action.desired is None:
-            raise RuntimeError(
-                "Verizon apply action requires desired state"
+        desired = require_desired(
+            action,
+            context="Verizon apply action",
         )
 
-        record = self._desired_record(action.desired)
+        record = self._desired_record(desired)
 
         if action.operation == PlanOperation.CREATE:
             detail = self.provider.add_record(record)
@@ -168,11 +170,11 @@ class Plugin:
             )
 
         applied = NormalizedObject(
-            object_type=action.desired.object_type,
-            logical_key=action.desired.logical_key,
+            object_type=desired.object_type,
+            logical_key=desired.logical_key,
             local_key=str(slot),
-            payload=dict(action.desired.payload),
-            references=action.desired.references,
+            payload=dict(desired.payload),
+            references=desired.references,
         )
 
         return ApplyResult(

tests/test_adapter_support.py

@@ -0,0 +1,106 @@
+import unittest
+
+from dns_sync.adapter_support import (
+    require_action_endpoint,
+    require_desired,
+    require_endpoint_plugin,
+)
+from dns_sync.adapters import (
+    Endpoint,
+    NormalizedObject,
+    PlanAction,
+    PlanOperation,
+)
+
+
+class AdapterSupportTests(unittest.TestCase):
+    def test_endpoint_plugin_accepts_matching_plugin(self):
+        endpoint = Endpoint("npm", "node.example:81")
+
+        require_endpoint_plugin(endpoint, "npm")
+
+
+    def test_endpoint_plugin_rejects_wrong_plugin(self):
+        endpoint = Endpoint("npm", "node.example:81")
+
+        with self.assertRaisesRegex(
+            RuntimeError,
+            "cannot use endpoint",
+        ):
+            require_endpoint_plugin(
+                endpoint,
+                "verizon",
+            )
+
+
+    def test_endpoint_plugin_rejects_empty_expected_name(self):
+        endpoint = Endpoint("npm", "node.example:81")
+
+        with self.assertRaisesRegex(
+            ValueError,
+            "cannot be empty",
+        ):
+            require_endpoint_plugin(endpoint, " ")
+
+
+    def test_action_endpoint_accepts_matching_endpoint(self):
+        endpoint = Endpoint("npm", "node.example:81")
+        action = PlanAction(
+            endpoint_id=endpoint.identity,
+            operation=PlanOperation.CREATE,
+        )
+
+        require_action_endpoint(action, endpoint)
+
+
+    def test_action_endpoint_rejects_other_endpoint(self):
+        endpoint = Endpoint("npm", "node.example:81")
+        action = PlanAction(
+            endpoint_id="npm://other.example:81",
+            operation=PlanOperation.CREATE,
+        )
+
+        with self.assertRaisesRegex(
+            RuntimeError,
+            "does not belong",
+        ):
+            require_action_endpoint(action, endpoint)
+
+
+    def test_require_desired_returns_desired_object(self):
+        desired = NormalizedObject(
+            object_type="example",
+            logical_key="object",
+            payload={},
+        )
+
+        action = PlanAction(
+            endpoint_id="example://endpoint",
+            operation=PlanOperation.CREATE,
+            desired=desired,
+        )
+
+        self.assertIs(
+            require_desired(action),
+            desired,
+        )
+
+
+    def test_require_desired_fails_closed(self):
+        action = PlanAction(
+            endpoint_id="example://endpoint",
+            operation=PlanOperation.CREATE,
+        )
+
+        with self.assertRaisesRegex(
+            RuntimeError,
+            "Test mutation requires desired state",
+        ):
+            require_desired(
+                action,
+                context="Test mutation",
+            )
+
+
+if __name__ == "__main__":
+    unittest.main()

tests/test_npm_adapter.py

@@ -6,6 +6,7 @@ from dns_sync.adapters import (
     CERTIFICATES,
     PROXY_HOSTS,
     Capability,
+    Endpoint,
     CapabilityOperation,
     NormalizedObject,
     ObjectReference,
@@ -94,6 +95,29 @@ class NpmAdapterTests(unittest.TestCase):
         self.assertIs(adapters[0].client, first_client)
         self.assertIs(adapters[1].client, second_client)
 
+    def test_adapter_rejects_endpoint_for_other_plugin(self):
+        config = self.config()
+        endpoint = Endpoint(
+            "verizon",
+            "192.168.1.1:443",
+        )
+
+        with patch(
+            "dns_sync.plugins.adapters.npm.NpmClient"
+        ) as client_class:
+            with self.assertRaisesRegex(
+                RuntimeError,
+                "cannot use endpoint",
+            ):
+                load_adapter(
+                    "npm",
+                    config,
+                    endpoint,
+                )
+
+        client_class.assert_not_called()
+
+
     def test_capabilities_cover_discovery_apply_and_verify(self):
         adapter = self.adapter(Mock())
 

tests/test_verizon_adapter.py

@@ -5,6 +5,7 @@ from unittest.mock import Mock, patch
 from dns_sync.adapters import (
     DNS_RECORDS,
     Capability,
+    Endpoint,
     CapabilityOperation,
     NormalizedObject,
     PlanAction,
@@ -79,6 +80,32 @@ class VerizonAdapterTests(unittest.TestCase):
             },
         )
 
+    def test_adapter_rejects_endpoint_for_other_plugin(self):
+        config = self.config()
+        endpoint = Endpoint(
+            "npm",
+            "192.168.1.3:81",
+        )
+
+        with patch.dict(
+            os.environ,
+            {
+                "ENABLED_PLUGINS": "npm,verizon",
+                "DNS_SYNC_PLUGIN_PATH": "external_plugins",
+            },
+            clear=False,
+        ):
+            with self.assertRaisesRegex(
+                RuntimeError,
+                "cannot use endpoint",
+            ):
+                load_adapter(
+                    "verizon",
+                    config,
+                    endpoint,
+                )
+
+
     def test_capabilities_cover_dns_discovery_apply_and_verify(self):
         adapter = self.adapter(Mock())
 
@@ -259,7 +286,7 @@ class VerizonAdapterTests(unittest.TestCase):
         with self.assertRaisesRegex(RuntimeError, "cannot discover"):
             adapter.discover("certificates")
 
-        with self.assertRaisesRegex(RuntimeError, "different endpoint"):
+        with self.assertRaisesRegex(RuntimeError, "does not belong"):
             adapter.apply(
                 PlanAction(
                     endpoint_id="verizon://different:443",