`--inactive-conn-cleanup-timeout` (#1504)

* `--inactive-conn-cleanup-timeout`

* Specify default in docs

* Update README

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* Clarify usecase is comments

* Lint

---------

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

README.md

@@ -2619,6 +2619,7 @@ usage: -m [-h] [--tunnel-hostname TUNNEL_HOSTNAME] [--tunnel-port TUNNEL_PORT]
           [--tunnel-ssh-key-passphrase TUNNEL_SSH_KEY_PASSPHRASE]
           [--tunnel-remote-port TUNNEL_REMOTE_PORT] [--threadless]
           [--threaded] [--num-workers NUM_WORKERS] [--enable-events]
+          [--inactive-conn-cleanup-timeout INACTIVE_CONN_CLEANUP_TIMEOUT]
           [--enable-proxy-protocol] [--enable-conn-pool] [--key-file KEY_FILE]
           [--cert-file CERT_FILE] [--client-recvbuf-size CLIENT_RECVBUF_SIZE]
           [--server-recvbuf-size SERVER_RECVBUF_SIZE]
@@ -2682,6 +2683,16 @@ options:
   --enable-events       Default: False. Enables core to dispatch lifecycle
                         events. Plugins can be used to subscribe for core
                         events.
+  --inactive-conn-cleanup-timeout INACTIVE_CONN_CLEANUP_TIMEOUT
+                        Time after which inactive works must be cleaned up.
+                        Increase this value if your backend services are slow
+                        to response or when proxy.py is handling a high
+                        volume. When running proxy.py on Google Cloud (GCP)
+                        you may see 'backend_connection_closed_before_data_sen
+                        t_to_client', with curl clients you may see 'Empty
+                        reply from server' error when '--inactive-conn-
+                        cleanup-timeout' value is low for your use-case.
+                        Default 1 seconds
   --enable-proxy-protocol
                         Default: False. If used, will enable proxy protocol.
                         Only version 1 is currently supported.

proxy/core/work/threadless.py

@@ -20,6 +20,7 @@ from typing import (
     cast,
 )
 
+from ...common.flag import flags as proxy_flags
 from ...common.types import Readables, Writables, SelectableEvents
 from ...common.logger import Logger
 from ...common.constants import (
@@ -37,6 +38,20 @@ T = TypeVar('T')
 logger = logging.getLogger(__name__)
 
 
+proxy_flags.add_argument(
+    '--inactive-conn-cleanup-timeout',
+    default=DEFAULT_INACTIVE_CONN_CLEANUP_TIMEOUT,
+    help='Time after which inactive works must be cleaned up. '
+    + 'Increase this value if your backend services are slow to response '
+    + 'or when proxy.py is handling a high volume. When running proxy.py on Google Cloud (GCP) '
+    + "you may see 'backend_connection_closed_before_data_sent_to_client', with curl clients "
+    + "you may see 'Empty reply from server' error when '--inactive-conn-cleanup-timeout' "
+    + 'value is low for your use-case. Default {0} seconds'.format(
+        DEFAULT_INACTIVE_CONN_CLEANUP_TIMEOUT,
+    ),
+)
+
+
 class Threadless(ABC, Generic[T]):
     """Work executor base class.
 
@@ -87,7 +102,7 @@ class Threadless(ABC, Generic[T]):
             SelectableEvents,
         ] = {}
         self.wait_timeout: float = DEFAULT_WAIT_FOR_TASKS_TIMEOUT
-        self.cleanup_inactive_timeout: float = DEFAULT_INACTIVE_CONN_CLEANUP_TIMEOUT
+        self.cleanup_inactive_timeout: float = self.flags.inactive_conn_cleanup_timeout
         self._total: int = 0
         # When put at the top, causes circular import error
         # since integrated ssh tunnel was introduced.