fix: make test suite pass on Windows and Python 3.12+

- Fix event loop issues in ASGI tests under newer asgiref by wrapping communicator setup in an async coroutine run on the loop.
- Fix mmap file locking (PermissionError: [WinError 32]) on Windows in multiprocess tests by closing open database handles before unlinking/removing directories.
- Skip case-sensitive env var deprecation warning assertion on Windows where environment variables are case-insensitive.
- Conditionally define the parser benchmark test to avoid failure when pytest-benchmark is not installed.

Signed-off-by: MelvinjoseC <165891174+MelvinjoseC@users.noreply.github.com>

Author: MelvinjoseC

prometheus_client/values.py

@@ -5,6 +5,15 @@
 from .mmap_dict import mmap_key, MmapedDict
 
 
+_multi_process_cleanups = []
+
+
+def close_all_multiprocess_files():
+    for cleanup in _multi_process_cleanups:
+        cleanup()
+    _multi_process_cleanups.clear()
+
+
 class MutexValue:
     """A float protected by a mutex."""
 
@@ -52,6 +61,13 @@ def MultiProcessValue(process_identifier=os.getpid):
     # This avoids the need to also have mutexes in __MmapDict.
     lock = Lock()
 
+    def cleanup():
+        for f in files.values():
+            f.close()
+        files.clear()
+        values.clear()
+    _multi_process_cleanups.append(cleanup)
+
     class MmapedValue:
         """A float protected by a mutex backed by a per-process mmaped file."""
 
@@ -122,6 +138,14 @@ def get_exemplar(self):
             # TODO: Implement exemplars for multiprocess mode.
             return None
 
+        @classmethod
+        def close_all_files(cls):
+            with lock:
+                for f in files.values():
+                    f.close()
+                files.clear()
+                values.clear()
+
     return MmapedValue
 
 

tests/test_asgi.py

@@ -32,27 +32,32 @@ def setUp(self):
         # Setup ASGI scope
         self.scope = {}
         setup_testing_defaults(self.scope)
+        self.loop = asyncio.new_event_loop()
+        asyncio.set_event_loop(self.loop)
         self.communicator = None
 
     def tearDown(self):
         if self.communicator:
-            asyncio.new_event_loop().run_until_complete(
+            self.loop.run_until_complete(
                 self.communicator.wait()
             )
+        self.loop.close()
 
     def seed_app(self, app):
-        self.communicator = ApplicationCommunicator(app, self.scope)
+        async def _init():
+            self.communicator = ApplicationCommunicator(app, self.scope)
+        self.loop.run_until_complete(_init())
 
     def send_input(self, payload):
-        asyncio.new_event_loop().run_until_complete(
+        self.loop.run_until_complete(
             self.communicator.send_input(payload)
         )
 
     def send_default_request(self):
         self.send_input({"type": "http.request", "body": b""})
 
     def get_output(self):
-        output = asyncio.new_event_loop().run_until_complete(
+        output = self.loop.run_until_complete(
             self.communicator.receive_output(0)
         )
         return output
@@ -148,9 +153,9 @@ def test_gzip(self):
         increments = 2
         self.increment_metrics(metric_name, help_text, increments)
         app = make_asgi_app(self.registry)
-        self.seed_app(app)
         # Send input with gzip header.
         self.scope["headers"] = [(b"accept-encoding", b"gzip")]
+        self.seed_app(app)
         self.send_input({"type": "http.request", "body": b""})
         # Assert outputs are compressed.
         outputs = self.get_all_output()
@@ -164,9 +169,9 @@ def test_gzip_disabled(self):
         self.increment_metrics(metric_name, help_text, increments)
         # Disable compression explicitly.
         app = make_asgi_app(self.registry, disable_compression=True)
-        self.seed_app(app)
         # Send input with gzip header.
         self.scope["headers"] = [(b"accept-encoding", b"gzip")]
+        self.seed_app(app)
         self.send_input({"type": "http.request", "body": b""})
         # Assert outputs are not compressed.
         outputs = self.get_all_output()
@@ -175,8 +180,8 @@ def test_gzip_disabled(self):
     def test_openmetrics_encoding(self):
         """Response content type is application/openmetrics-text when appropriate Accept header is in request"""
         app = make_asgi_app(self.registry)
-        self.seed_app(app)
         self.scope["headers"] = [(b"Accept", b"application/openmetrics-text; version=1.0.0")]
+        self.seed_app(app)
         self.send_input({"type": "http.request", "body": b""})
 
         content_type = self.get_response_header_value('Content-Type').split(";")[0]
@@ -204,8 +209,8 @@ def test_qs_parsing(self):
             self.increment_metrics(*m)
 
         for i_1 in range(len(metrics)):
-            self.seed_app(app)
             self.scope['query_string'] = f"name[]={metrics[i_1][0]}_total".encode("utf-8")
+            self.seed_app(app)
             self.send_default_request()
 
             outputs = self.get_all_output()
@@ -220,7 +225,7 @@ def test_qs_parsing(self):
 
                 self.assert_not_metrics(output, *metrics[i_2])
 
-            asyncio.new_event_loop().run_until_complete(
+            self.loop.run_until_complete(
                 self.communicator.wait()
             )
 
@@ -237,8 +242,8 @@ def test_qs_parsing_multi(self):
         for m in metrics:
             self.increment_metrics(*m)
 
-        self.seed_app(app)
         self.scope['query_string'] = "&".join([f"name[]={m[0]}_total" for m in metrics[0:2]]).encode("utf-8")
+        self.seed_app(app)
         self.send_default_request()
 
         outputs = self.get_all_output()
@@ -249,6 +254,6 @@ def test_qs_parsing_multi(self):
         self.assert_metrics(output, *metrics[1])
         self.assert_not_metrics(output, *metrics[2])
 
-        asyncio.new_event_loop().run_until_complete(
+        self.loop.run_until_complete(
             self.communicator.wait()
         )

tests/test_multiprocess.py

@@ -24,21 +24,26 @@ def setUp(self):
     def tearDown(self):
         os.environ.pop('prometheus_multiproc_dir', None)
         os.environ.pop('PROMETHEUS_MULTIPROC_DIR', None)
+        values.close_all_multiprocess_files()
         values.ValueClass = MutexValue
         shutil.rmtree(self.tempdir)
 
     def test_deprecation_warning(self):
         os.environ['prometheus_multiproc_dir'] = self.tempdir
         with warnings.catch_warnings(record=True) as w:
+            warnings.simplefilter("always")
             values.ValueClass = get_value_class()
             registry = CollectorRegistry()
             collector = MultiProcessCollector(registry)
             Counter('c', 'help', registry=None)
 
             assert os.environ['PROMETHEUS_MULTIPROC_DIR'] == self.tempdir
-            assert len(w) == 1
-            assert issubclass(w[-1].category, DeprecationWarning)
-            assert "PROMETHEUS_MULTIPROC_DIR" in str(w[-1].message)
+            if os.name != 'nt':
+                assert len(w) == 1
+                assert issubclass(w[-1].category, DeprecationWarning)
+                assert "PROMETHEUS_MULTIPROC_DIR" in str(w[-1].message)
+            else:
+                assert len(w) == 0
 
     def test_mark_process_dead_respects_lowercase(self):
         os.environ['prometheus_multiproc_dir'] = self.tempdir
@@ -61,8 +66,9 @@ def _value_class(self):
 
     def tearDown(self):
         del os.environ['PROMETHEUS_MULTIPROC_DIR']
-        shutil.rmtree(self.tempdir)
+        values.close_all_multiprocess_files()
         values.ValueClass = MutexValue
+        shutil.rmtree(self.tempdir)
 
     def test_counter_adds(self):
         c1 = Counter('c', 'help', registry=None)
@@ -119,6 +125,7 @@ def test_gauge_liveall(self):
         g2.set(2)
         self.assertEqual(1, self.registry.get_sample_value('g', {'pid': '123'}))
         self.assertEqual(2, self.registry.get_sample_value('g', {'pid': '456'}))
+        values.close_all_multiprocess_files()
         mark_process_dead(123, os.environ['PROMETHEUS_MULTIPROC_DIR'])
         self.assertEqual(None, self.registry.get_sample_value('g', {'pid': '123'}))
         self.assertEqual(2, self.registry.get_sample_value('g', {'pid': '456'}))
@@ -140,6 +147,7 @@ def test_gauge_livemin(self):
         g1.set(1)
         g2.set(2)
         self.assertEqual(1, self.registry.get_sample_value('g'))
+        values.close_all_multiprocess_files()
         mark_process_dead(123, os.environ['PROMETHEUS_MULTIPROC_DIR'])
         self.assertEqual(2, self.registry.get_sample_value('g'))
 
@@ -160,6 +168,7 @@ def test_gauge_livemax(self):
         g1.set(2)
         g2.set(1)
         self.assertEqual(2, self.registry.get_sample_value('g'))
+        values.close_all_multiprocess_files()
         mark_process_dead(123, os.environ['PROMETHEUS_MULTIPROC_DIR'])
         self.assertEqual(1, self.registry.get_sample_value('g'))
 
@@ -171,6 +180,7 @@ def test_gauge_sum(self):
         g1.set(1)
         g2.set(2)
         self.assertEqual(3, self.registry.get_sample_value('g'))
+        values.close_all_multiprocess_files()
         mark_process_dead(123, os.environ['PROMETHEUS_MULTIPROC_DIR'])
         self.assertEqual(3, self.registry.get_sample_value('g'))
 
@@ -182,6 +192,7 @@ def test_gauge_livesum(self):
         g1.set(1)
         g2.set(2)
         self.assertEqual(3, self.registry.get_sample_value('g'))
+        values.close_all_multiprocess_files()
         mark_process_dead(123, os.environ['PROMETHEUS_MULTIPROC_DIR'])
         self.assertEqual(2, self.registry.get_sample_value('g'))
 
@@ -192,6 +203,7 @@ def test_gauge_mostrecent(self):
         g2.set(2)
         g1.set(1)
         self.assertEqual(1, self.registry.get_sample_value('g'))
+        values.close_all_multiprocess_files()
         mark_process_dead(123, os.environ['PROMETHEUS_MULTIPROC_DIR'])
         self.assertEqual(1, self.registry.get_sample_value('g'))
 
@@ -202,6 +214,7 @@ def test_gauge_livemostrecent(self):
         g2.set(2)
         g1.set(1)
         self.assertEqual(1, self.registry.get_sample_value('g'))
+        values.close_all_multiprocess_files()
         mark_process_dead(123, os.environ['PROMETHEUS_MULTIPROC_DIR'])
         self.assertEqual(2, self.registry.get_sample_value('g'))
 
@@ -626,6 +639,7 @@ def test_corruption_detected(self):
             list(self.d.read_all_values())
 
     def tearDown(self):
+        self.d.close()
         os.unlink(self.tempfile)
 
 

tests/test_parser.py

@@ -375,8 +375,15 @@ def collect(self):
         self.assertEqual(text.encode('utf-8'), generate_latest(registry, ALLOWUTF8))
 
 
-def test_benchmark_text_string_to_metric_families(benchmark):
-    text = """# HELP go_gc_duration_seconds A summary of the GC invocation durations.
+try:
+    import pytest_benchmark
+    HAS_BENCHMARK = True
+except ImportError:
+    HAS_BENCHMARK = False
+
+if HAS_BENCHMARK:
+    def test_benchmark_text_string_to_metric_families(benchmark):
+        text = """# HELP go_gc_duration_seconds A summary of the GC invocation durations.
 # TYPE go_gc_duration_seconds summary
 go_gc_duration_seconds{quantile="0"} 0.013300656000000001
 go_gc_duration_seconds{quantile="0.25"} 0.013638736
@@ -422,11 +429,11 @@ def test_benchmark_text_string_to_metric_families(benchmark):
 hist_sum 2
 """
 
-    @benchmark
-    def _():
-        # We need to convert the generator to a full list in order to
-        # accurately measure the time to yield everything.
-        return list(text_string_to_metric_families(text))
+        @benchmark
+        def _():
+            # We need to convert the generator to a full list in order to
+            # accurately measure the time to yield everything.
+            return list(text_string_to_metric_families(text))
 
 
 if __name__ == '__main__':