Add external adapter plugin boundary

2026-09-20 14:44:51 -04:00
parent 572dd9eae4
commit d6ad917b57
7 changed files with 454 additions and 28 deletions
@@ -0,0 +1,225 @@
+import os
+import tempfile
+import textwrap
+import unittest
+from pathlib import Path
+from types import SimpleNamespace
+from unittest.mock import patch
+
+from dns_sync.adapters import Endpoint
+from dns_sync.registry import (
+    enabled_plugins,
+    load_adapter,
+)
+
+
+class PluginRegistryTests(unittest.TestCase):
+    def test_default_enabled_plugin_is_npm(self):
+        with patch.dict(os.environ, {}, clear=True):
+            self.assertEqual(
+                enabled_plugins(),
+                frozenset({"npm"}),
+            )
+
+    def test_enabled_plugins_are_explicit(self):
+        with patch.dict(
+            os.environ,
+            {
+                "ENABLED_PLUGINS": (
+                    "npm,verizon"
+                )
+            },
+            clear=True,
+        ):
+            self.assertEqual(
+                enabled_plugins(),
+                frozenset(
+                    {
+                        "npm",
+                        "verizon",
+                    }
+                ),
+            )
+
+    def test_duplicate_enabled_plugin_is_rejected(self):
+        with patch.dict(
+            os.environ,
+            {
+                "ENABLED_PLUGINS": "npm,npm",
+            },
+            clear=True,
+        ):
+            with self.assertRaisesRegex(
+                RuntimeError,
+                "duplicate plugin",
+            ):
+                enabled_plugins()
+
+    def test_disabled_adapter_is_not_loaded(self):
+        config = SimpleNamespace()
+        endpoint = Endpoint(
+            "verizon",
+            "192.168.1.1:443",
+        )
+
+        with patch.dict(
+            os.environ,
+            {
+                "ENABLED_PLUGINS": "npm",
+            },
+            clear=True,
+        ):
+            with self.assertRaisesRegex(
+                RuntimeError,
+                "is not enabled",
+            ):
+                load_adapter(
+                    "verizon",
+                    config,
+                    endpoint,
+                )
+
+    def test_external_adapter_is_loaded(self):
+        with tempfile.TemporaryDirectory() as directory:
+            root = Path(directory)
+            plugin = root / "example"
+            plugin.mkdir()
+
+            (plugin / "__init__.py").write_text(
+                textwrap.dedent(
+                    """
+                    class Plugin:
+                        name = "example"
+
+                        def __init__(
+                            self,
+                            config,
+                            endpoint,
+                        ):
+                            self.config = config
+                            self.endpoint = endpoint
+                    """
+                )
+            )
+
+            config = SimpleNamespace()
+            endpoint = Endpoint(
+                "example",
+                "example.test:443",
+            )
+
+            with patch.dict(
+                os.environ,
+                {
+                    "ENABLED_PLUGINS": (
+                        "example"
+                    ),
+                    "DNS_SYNC_PLUGIN_PATH": (
+                        directory
+                    ),
+                },
+                clear=True,
+            ):
+                adapter = load_adapter(
+                    "example",
+                    config,
+                    endpoint,
+                )
+
+            self.assertEqual(
+                adapter.name,
+                "example",
+            )
+            self.assertEqual(
+                adapter.endpoint,
+                endpoint,
+            )
+
+    def test_external_adapter_can_import_plugin_submodule(self):
+        with tempfile.TemporaryDirectory() as directory:
+            root = Path(directory)
+            plugin = root / "example_package"
+            plugin.mkdir()
+
+            (plugin / "helper.py").write_text(
+                "VALUE = 'loaded-from-submodule'\n"
+            )
+
+            (plugin / "__init__.py").write_text(
+                textwrap.dedent(
+                    """
+                    from .helper import VALUE
+
+                    class Plugin:
+                        name = "example_package"
+
+                        def __init__(
+                            self,
+                            config,
+                            endpoint,
+                        ):
+                            self.config = config
+                            self.endpoint = endpoint
+                            self.value = VALUE
+                    """
+                )
+            )
+
+            config = SimpleNamespace()
+            endpoint = Endpoint(
+                "example_package",
+                "example.test:443",
+            )
+
+            with patch.dict(
+                os.environ,
+                {
+                    "ENABLED_PLUGINS": (
+                        "example_package"
+                    ),
+                    "DNS_SYNC_PLUGIN_PATH": directory,
+                },
+                clear=True,
+            ):
+                adapter = load_adapter(
+                    "example_package",
+                    config,
+                    endpoint,
+                )
+
+            self.assertEqual(
+                adapter.value,
+                "loaded-from-submodule",
+            )
+
+    def test_missing_enabled_adapter_fails_closed(self):
+        with tempfile.TemporaryDirectory() as directory:
+            config = SimpleNamespace()
+            endpoint = Endpoint(
+                "missing",
+                "example.test:443",
+            )
+
+            with patch.dict(
+                os.environ,
+                {
+                    "ENABLED_PLUGINS": "missing",
+                    "DNS_SYNC_PLUGIN_PATH": (
+                        directory
+                    ),
+                },
+                clear=True,
+            ):
+                with self.assertRaisesRegex(
+                    RuntimeError,
+                    "Unknown adapter plugin",
+                ):
+                    load_adapter(
+                        "missing",
+                        config,
+                        endpoint,
+                    )
+
+
+if __name__ == "__main__":
+    unittest.main()