issue #147: expose channel lock timeout parameter

Signed-off-by: Matteo Cafasso <[email protected]>

pebble/common/types.py

@@ -179,6 +179,9 @@ class Consts:
     term_timeout: float = 3
     """On UNIX once a SIGTERM signal is issued to a process,
     the amount of seconds to wait before issuing a SIGKILL signal."""
+    channel_lock_timeout: float = 60
+    """The process pool relies on a pipe protected by a lock.
+    The timeout when attempting to acquire the lock."""
 
 
 try:

pebble/pool/channel.py

@@ -19,8 +19,10 @@
 import select
 import multiprocessing
 
+from typing import Any, Callable
 from contextlib import contextmanager
-from typing import Any, Callable, Tuple
+
+from pebble.common import CONSTS
 
 
 class ChannelError(OSError):
@@ -150,11 +152,15 @@ def __exit__(self, *_):
 
     def _make_acquire_method(self) -> Callable:
         def unix_acquire() -> bool:
-            return (self.reader_mutex.acquire(timeout=LOCK_TIMEOUT) and
-                    self.writer_mutex.acquire(timeout=LOCK_TIMEOUT))
+            return (
+                self.reader_mutex.acquire(timeout=CONSTS.channel_lock_timeout)
+                and
+                self.writer_mutex.acquire(timeout=CONSTS.channel_lock_timeout)
+            )
 
         def windows_acquire() -> bool:
-            return self.reader_mutex.acquire(timeout=LOCK_TIMEOUT)
+            return self.reader_mutex.acquire(
+                timeout=CONSTS.channel_lock_timeout)
 
         return unix_acquire if os.name != 'nt' else windows_acquire
 
@@ -171,7 +177,7 @@ def windows_release():
     @property
     @contextmanager
     def reader(self):
-        if self.reader_mutex.acquire(timeout=LOCK_TIMEOUT):
+        if self.reader_mutex.acquire(timeout=CONSTS.channel_lock_timeout):
             try:
                 yield self
             finally:
@@ -182,7 +188,7 @@ def reader(self):
     @property
     @contextmanager
     def writer(self):
-        if self.writer_mutex.acquire(timeout=LOCK_TIMEOUT):
+        if self.writer_mutex.acquire(timeout=CONSTS.channel_lock_timeout):
             try:
                 yield self
             finally:
@@ -192,4 +198,3 @@ def writer(self):
 
 
 MILLISECONDS = 1000
-LOCK_TIMEOUT = 60