PYTHON-4755 - Stop supporting and testing against Eventlet (#2557)

Author: NoahStapp

.evergreen/generated_configs/variants.yml

@@ -319,14 +319,6 @@ buildvariants:
     tags: []
 
   # Green framework tests
-  - name: green-eventlet-rhel8
-    tasks:
-      - name: .test-standard .python-3.9 .sync
-    display_name: Green Eventlet RHEL8
-    run_on:
-      - rhel87-small
-    expansions:
-      GREEN_FRAMEWORK: eventlet
   - name: green-gevent-rhel8
     tasks:
       - name: .test-standard .sync

.evergreen/scripts/generate_config.py

@@ -300,12 +300,8 @@ def create_stable_api_variants():
 def create_green_framework_variants():
     variants = []
     host = DEFAULT_HOST
-    for framework in ["eventlet", "gevent"]:
+    for framework in ["gevent"]:
         tasks = [".test-standard .sync"]
-        if framework == "eventlet":
-            # Eventlet has issues with dnspython > 2.0 and newer versions of CPython
-            # https://jira.mongodb.org/browse/PYTHON-5284
-            tasks = [".test-standard .python-3.9 .sync"]
         expansions = dict(GREEN_FRAMEWORK=framework)
         display_name = get_variant_name(f"Green {framework.capitalize()}", host)
         variant = create_variant(tasks, display_name, host=host, expansions=expansions)

.evergreen/scripts/run_tests.py

@@ -67,13 +67,7 @@ def handle_perf(start_time: datetime):
 
 
 def handle_green_framework() -> None:
-    if GREEN_FRAMEWORK == "eventlet":
-        import eventlet
-
-        # https://github.com/eventlet/eventlet/issues/401
-        eventlet.sleep()
-        eventlet.monkey_patch()
-    elif GREEN_FRAMEWORK == "gevent":
+    if GREEN_FRAMEWORK == "gevent":
         from gevent import monkey
 
         monkey.patch_all()

.evergreen/scripts/utils.py

@@ -104,7 +104,7 @@ def get_test_options(
         parser.add_argument(
             "--green-framework",
             nargs=1,
-            choices=["eventlet", "gevent"],
+            choices=["gevent"],
             help="Optional green framework to test against.",
         )
         parser.add_argument(

doc/changelog.rst

@@ -9,6 +9,8 @@ PyMongo 4.16 brings a number of changes including:
 - Removed invalid documents from :class:`bson.errors.InvalidDocument` error messages as
   doing so may leak sensitive user data.
   Instead, invalid documents are stored in :attr:`bson.errors.InvalidDocument.document`.
+- Removed support for Eventlet.
+  Eventlet is actively being sunset by its maintainers and has compatibility issues with PyMongo's dnspython dependency.
 
 Changes in Version 4.15.1 (2025/09/16)
 --------------------------------------

pymongo/asynchronous/pool.py

@@ -628,7 +628,7 @@ async def _raise_connection_failure(self, error: BaseException) -> NoReturn:
         # signals and throws KeyboardInterrupt into the current frame on the
         # main thread.
         #
-        # But in Gevent and Eventlet, the polling mechanism (epoll, kqueue,
+        # But in Gevent, the polling mechanism (epoll, kqueue,
         # ..) is called in Python code, which experiences the signal as a
         # KeyboardInterrupt from the start, rather than as an initial
         # socket.error, so we catch that, close the socket, and reraise it.

pymongo/pool_shared.py

@@ -138,13 +138,11 @@ def _raise_connection_failure(
         msg = msg_prefix + msg
     if "configured timeouts" not in msg:
         msg += format_timeout_details(timeout_details)
-    if isinstance(error, socket.timeout):
-        raise NetworkTimeout(msg) from error
-    elif isinstance(error, SSLErrors) and "timed out" in str(error):
-        # Eventlet does not distinguish TLS network timeouts from other
-        # SSLErrors (https://github.com/eventlet/eventlet/issues/692).
-        # Luckily, we can work around this limitation because the phrase
-        # 'timed out' appears in all the timeout related SSLErrors raised.
+    if (
+        isinstance(error, socket.timeout)
+        or isinstance(error, SSLErrors)
+        and "timed out" in str(error)
+    ):
         raise NetworkTimeout(msg) from error
     else:
         raise AutoReconnect(msg) from error

pymongo/synchronous/pool.py

@@ -626,7 +626,7 @@ def _raise_connection_failure(self, error: BaseException) -> NoReturn:
         # signals and throws KeyboardInterrupt into the current frame on the
         # main thread.
         #
-        # But in Gevent and Eventlet, the polling mechanism (epoll, kqueue,
+        # But in Gevent, the polling mechanism (epoll, kqueue,
         # ..) is called in Python code, which experiences the signal as a
         # KeyboardInterrupt from the start, rather than as an initial
         # socket.error, so we catch that, close the socket, and reraise it.

pyproject.toml

@@ -52,7 +52,6 @@ dev = [
 pip = ["pip"]
 # TODO: PYTHON-5464
 gevent = ["gevent", "cffi>=2.0.0b1;python_version=='3.14'"]
-eventlet = ["eventlet"]
 coverage = [
     "pytest-cov",
     "coverage>=5,<=7.10.6"
@@ -113,15 +112,12 @@ filterwarnings = [
     "module:.*WindowsSelectorEventLoopPolicy:DeprecationWarning",
     "module:.*et_event_loop_policy:DeprecationWarning",
     # TODO: Remove as part of PYTHON-3923.
-    "module:unclosed <eventlet.green.ssl.GreenSSLSocket:ResourceWarning",
     "module:unclosed <socket.socket:ResourceWarning",
     "module:unclosed <ssl.SSLSocket:ResourceWarning",
     "module:unclosed <socket object:ResourceWarning",
     "module:unclosed transport:ResourceWarning",
     # pytest-asyncio known issue: https://github.com/pytest-dev/pytest-asyncio/issues/724
     "module:unclosed event loop:ResourceWarning",
-    # https://github.com/eventlet/eventlet/issues/818
-    "module:please use dns.resolver.Resolver.resolve:DeprecationWarning",
     # https://github.com/dateutil/dateutil/issues/1314
     "module:datetime.datetime.utc:DeprecationWarning",
 ]

test/asynchronous/test_encryption.py

@@ -399,7 +399,7 @@ async def test_use_after_close(self):
     )
     @unittest.skipIf(
         is_greenthread_patched(),
-        "gevent and eventlet do not support POSIX-style forking.",
+        "gevent does not support POSIX-style forking.",
     )
     @async_client_context.require_sync
     async def test_fork(self):