patched gunicorn (master) to adapt to evnetlet change with 0.31 and up.

Dockerfile

@@ -1,4 +1,4 @@
-FROM python:3.7-slim
+FROM python:3.11-slim
 
 RUN apt-get update && \
     apt-get install -y libxmlsec1-dev build-essential libxmlsec1 libxmlsec1-openssl pkg-config && \
@@ -12,6 +12,9 @@ COPY requirements.txt .
 
 RUN pip install -U -r requirements.txt
 
+# patch for gunicorn and eventlet
+COPY new_geventlet.py /usr/local/lib/python3.11/site-packages/gunicorn/workers/geventlet.py
+
 WORKDIR /app
 COPY . /app
 ENV FLASK_APP=app.py

new_geventlet.py

@@ -0,0 +1,188 @@
+# -*- coding: utf-8 -
+#
+# This file is part of gunicorn released under the MIT license.
+# See the NOTICE for more information.
+
+from functools import partial
+import sys
+
+try:
+    import eventlet
+except ImportError:
+    raise RuntimeError("eventlet worker requires eventlet 0.24.1 or higher")
+else:
+    from pkg_resources import parse_version
+    if parse_version(eventlet.__version__) < parse_version('0.24.1'):
+        raise RuntimeError("eventlet worker requires eventlet 0.24.1 or higher")
+
+from eventlet import hubs, greenthread
+from eventlet.greenio import GreenSocket
+import eventlet.wsgi
+import greenlet
+
+from gunicorn.workers.base_async import AsyncWorker
+
+# ALREADY_HANDLED is removed in 0.30.3+ now it's `WSGI_LOCAL.already_handled: bool`
+# https://github.com/eventlet/eventlet/pull/544
+EVENTLET_WSGI_LOCAL = getattr(eventlet.wsgi, "WSGI_LOCAL", None)
+EVENTLET_ALREADY_HANDLED = getattr(eventlet.wsgi, "ALREADY_HANDLED", None)
+
+
+def _eventlet_socket_sendfile(self, file, offset=0, count=None):
+    # Based on the implementation in gevent which in turn is slightly
+    # modified from the standard library implementation.
+    if self.gettimeout() == 0:
+        raise ValueError("non-blocking sockets are not supported")
+    if offset:
+        file.seek(offset)
+    blocksize = min(count, 8192) if count else 8192
+    total_sent = 0
+    # localize variable access to minimize overhead
+    file_read = file.read
+    sock_send = self.send
+    try:
+        while True:
+            if count:
+                blocksize = min(count - total_sent, blocksize)
+                if blocksize <= 0:
+                    break
+            data = memoryview(file_read(blocksize))
+            if not data:
+                break  # EOF
+            while True:
+                try:
+                    sent = sock_send(data)
+                except BlockingIOError:
+                    continue
+                else:
+                    total_sent += sent
+                    if sent < len(data):
+                        data = data[sent:]
+                    else:
+                        break
+        return total_sent
+    finally:
+        if total_sent > 0 and hasattr(file, 'seek'):
+            file.seek(offset + total_sent)
+
+
+
+def _eventlet_serve(sock, handle, concurrency):
+    """
+    Serve requests forever.
+
+    This code is nearly identical to ``eventlet.convenience.serve`` except
+    that it attempts to join the pool at the end, which allows for gunicorn
+    graceful shutdowns.
+    """
+    pool = eventlet.greenpool.GreenPool(concurrency)
+    server_gt = eventlet.greenthread.getcurrent()
+
+    while True:
+        try:
+            conn, addr = sock.accept()
+            gt = pool.spawn(handle, conn, addr)
+            gt.link(_eventlet_stop, server_gt, conn)
+            conn, addr, gt = None, None, None
+        except eventlet.StopServe:
+            sock.close()
+            pool.waitall()
+            return
+
+
+def _eventlet_stop(client, server, conn):
+    """
+    Stop a greenlet handling a request and close its connection.
+
+    This code is lifted from eventlet so as not to depend on undocumented
+    functions in the library.
+    """
+    try:
+        try:
+            client.wait()
+        finally:
+            conn.close()
+    except greenlet.GreenletExit:
+        pass
+    except Exception:
+        greenthread.kill(server, *sys.exc_info())
+
+
+def patch_sendfile():
+    # As of eventlet 0.25.1, GreenSocket.sendfile doesn't exist,
+    # meaning the native implementations of socket.sendfile will be used.
+    # If os.sendfile exists, it will attempt to use that, failing explicitly
+    # if the socket is in non-blocking mode, which the underlying
+    # socket object /is/. Even the regular _sendfile_use_send will
+    # fail in that way; plus, it would use the underlying socket.send which isn't
+    # properly cooperative. So we have to monkey-patch a working socket.sendfile()
+    # into GreenSocket; in this method, `self.send` will be the GreenSocket's
+    # send method which is properly cooperative.
+    if not hasattr(GreenSocket, 'sendfile'):
+        GreenSocket.sendfile = _eventlet_socket_sendfile
+
+
+class EventletWorker(AsyncWorker):
+
+    def patch(self):
+        hubs.use_hub()
+        eventlet.monkey_patch()
+        patch_sendfile()
+
+    def is_already_handled(self, respiter):
+        # eventlet >= 0.30.3
+        if getattr(EVENTLET_WSGI_LOCAL, "already_handled", None):
+            raise StopIteration()
+        # eventlet < 0.30.3
+        if respiter == EVENTLET_ALREADY_HANDLED:
+            raise StopIteration()
+        return super().is_already_handled(respiter)
+
+    def init_process(self):
+        self.patch()
+        super().init_process()
+
+    def handle_quit(self, sig, frame):
+        eventlet.spawn(super().handle_quit, sig, frame)
+
+    def handle_usr1(self, sig, frame):
+        eventlet.spawn(super().handle_usr1, sig, frame)
+
+    def timeout_ctx(self):
+        return eventlet.Timeout(self.cfg.keepalive or None, False)
+
+    def handle(self, listener, client, addr):
+        if self.cfg.is_ssl:
+            client = eventlet.wrap_ssl(client, server_side=True,
+                                       **self.cfg.ssl_options)
+
+        super().handle(listener, client, addr)
+
+    def run(self):
+        acceptors = []
+        for sock in self.sockets:
+            gsock = GreenSocket(sock)
+            gsock.setblocking(1)
+            hfun = partial(self.handle, gsock)
+            acceptor = eventlet.spawn(_eventlet_serve, gsock, hfun,
+                                      self.worker_connections)
+
+            acceptors.append(acceptor)
+            eventlet.sleep(0.0)
+
+        while self.alive:
+            self.notify()
+            eventlet.sleep(1.0)
+
+        self.notify()
+        try:
+            with eventlet.Timeout(self.cfg.graceful_timeout) as t:
+                for a in acceptors:
+                    a.kill(eventlet.StopServe())
+                for a in acceptors:
+                    a.wait()
+        except eventlet.Timeout as te:
+            if te != t:
+                raise
+            for a in acceptors:
+                a.kill()