[releases/1.2] Fix pywintypes error during the launch of the discovery service after a fresh install of MeasurementLink (#407)

Fix pywintypes error during the launch of the discovery service after a fresh install of MeasurementLink (#397)

* Fix launching of discovery service during fresh install

Author: samchris007

ni_measurementlink_service/_internal/discovery_client.py

@@ -20,12 +20,10 @@
 from ni_measurementlink_service.measurement.info import MeasurementInfo, ServiceInfo
 
 if sys.platform == "win32":
-    import errno
     import msvcrt
 
     import win32con
     import win32file
-    import winerror
 
 _logger = logging.getLogger(__name__)
 # Save Popen object to avoid "ResourceWarning: subprocess N is still running"
@@ -283,7 +281,7 @@ def _start_service(
         try:
             with _open_key_file(str(key_file_path)) as _:
                 return discovery_service_subprocess
-        except IOError:
+        except OSError:
             pass
         if time.time() >= timeout_time:
             raise TimeoutError("Timed out waiting for discovery service to start")
@@ -293,7 +291,7 @@ def _start_service(
 def _service_already_running(key_file_path: pathlib.Path) -> bool:
     try:
         _delete_existing_key_file(key_file_path)
-    except IOError:
+    except OSError:
         return True
     return False
 
@@ -344,14 +342,7 @@ def _open_key_file(path: str) -> typing.TextIO:
                 None,
             )
         except win32file.error as e:
-            if e.winerror == winerror.ERROR_FILE_NOT_FOUND:
-                raise FileNotFoundError(errno.ENOENT, e.strerror, path) from e
-            elif (
-                e.winerror == winerror.ERROR_ACCESS_DENIED
-                or e.winerror == winerror.ERROR_SHARING_VIOLATION
-            ):
-                raise PermissionError(errno.EACCES, e.strerror, path) from e
-            raise
+            raise OSError(None, e.strerror, path, e.winerror) from e
 
         # The CRT file descriptor takes ownership of the Win32 file handle.
         # os.O_TEXT is unnecessary because Python handles newline conversion.

tests/unit/test_discovery_client.py

@@ -12,6 +12,7 @@
 from ni_measurementlink_service._internal.discovery_client import (
     DiscoveryClient,
     _get_discovery_service_address,
+    _open_key_file,
     _start_service,
 )
 from ni_measurementlink_service._internal.stubs.ni.measurementlink.discovery.v1.discovery_service_pb2_grpc import (
@@ -20,6 +21,9 @@
 from ni_measurementlink_service.measurement.info import MeasurementInfo, ServiceInfo
 from tests.utilities.fake_discovery_service import FakeDiscoveryServiceStub
 
+if sys.platform == "win32":
+    import win32file
+
 _PROVIDED_MEASUREMENT_SERVICES = [
     "ni.measurementlink.measurement.v1.MeasurementService",
     "ni.measurementlink.measurement.v2.MeasurementService",
@@ -129,19 +133,37 @@ def test___get_discovery_service_address___key_file_not_exist___throws_timeouter
         "ni_measurementlink_service._internal.discovery_client._START_SERVICE_TIMEOUT", 5.0
     )
     mocker.patch(
-        "ni_measurementlink_service._internal.discovery_client._open_key_file", side_effect=IOError
+        "ni_measurementlink_service._internal.discovery_client._open_key_file", side_effect=OSError
     )
     mocker.patch(
         "ni_measurementlink_service._internal.discovery_client._get_registration_json_file_path",
         return_value=temp_registration_json_file_path,
     )
     mocker.patch("subprocess.Popen")
 
-    with pytest.raises(IOError) as exc_info:
+    with pytest.raises(OSError) as exc_info:
         _get_discovery_service_address()
     assert exc_info.type is TimeoutError
 
 
+@pytest.mark.parametrize(
+    "windows_error_code", [2, 3]
+)  # ERROR_FILE_NOT_FOUND = 2, ERROR_PATH_NOT_FOUND = 3
+def test___key_file_not_exist___open_key_file___raises_file_not_found_error(
+    mocker: MockerFixture, temp_discovery_key_file_path: pathlib.Path, windows_error_code: int
+) -> None:
+    if sys.platform != "win32":
+        pytest.skip("Windows-only test")
+    else:
+        mocker.patch(
+            "win32file.CreateFile",
+            side_effect=win32file.error(windows_error_code, None, None),
+        )
+
+        with pytest.raises(FileNotFoundError):
+            _open_key_file(str(temp_discovery_key_file_path))
+
+
 def test___start_discovery_service___key_file_exist_after_poll___service_start_success(
     mocker: MockerFixture,
     temp_directory: pathlib.Path,
@@ -152,7 +174,7 @@ def test___start_discovery_service___key_file_exist_after_poll___service_start_s
 
     mocker.patch(
         "ni_measurementlink_service._internal.discovery_client._open_key_file",
-        side_effect=[IOError, IOError, IOError, temp_discovery_key_file_path],
+        side_effect=[OSError, OSError, OSError, temp_discovery_key_file_path],
     )
     mock_popen = mocker.patch("subprocess.Popen")