From 4873012914a7f89d198801f8a7966c1e825eb60c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Piotr=20Ma=C5=9Blanka?= <piotr.maslanka@henrietta.com.pl>
Date: Mon, 30 Dec 2019 20:37:51 +0100
Subject: [PATCH] daemon cleaned up
---
docs/exception_handling/index.rst | 13 +++++++++++
docs/index.rst | 1 +
satella/posix/__init__.py | 7 ++----
satella/posix/daemon.py | 7 ++++--
satella/posix/pidlock.py | 36 ++++++++++++++++++++-----------
satella/posix/signals.py | 10 ++++++---
6 files changed, 52 insertions(+), 22 deletions(-)
create mode 100644 docs/exception_handling/index.rst
diff --git a/docs/exception_handling/index.rst b/docs/exception_handling/index.rst
new file mode 100644
index 00000000..0ea44485
--- /dev/null
+++ b/docs/exception_handling/index.rst
@@ -0,0 +1,13 @@
+Exception handling
+==================
+
+Satella provides a rich functionality to register exception hooks.
+
+Writing your own exception handlers
+-----------------------------------
+
+To write your own exception handlers, subclass the following class:
+
+.. autoclass:: satella.exception_handling.BaseExceptionHandler
+ :members:
+
diff --git a/docs/index.rst b/docs/index.rst
index bea56862..30e19e9e 100644
--- a/docs/index.rst
+++ b/docs/index.rst
@@ -14,6 +14,7 @@ Welcome to satella's documentation!
coding/concurrent
instrumentation/traceback
instrumentation/metrics
+ exception_handling/index
json
posix
recipes
diff --git a/satella/posix/__init__.py b/satella/posix/__init__.py
index 183ac7e0..88c5ed05 100644
--- a/satella/posix/__init__.py
+++ b/satella/posix/__init__.py
@@ -1,17 +1,13 @@
-# coding=UTF-8
"""
-UNIX things
+POSIX things
"""
-from __future__ import print_function, absolute_import, division
-import logging
import os
from .daemon import daemonize
from .pidlock import AcquirePIDLock
from .signals import hang_until_sig
-logger = logging.getLogger(__name__)
__all__ = [
'daemonize',
@@ -27,6 +23,7 @@ def is_running_as_root():
Is this process running as root?
Checks whether EUID is 0
+
:return: bool
"""
return os.geteuid() == 0
diff --git a/satella/posix/daemon.py b/satella/posix/daemon.py
index 73615c42..69d81a02 100644
--- a/satella/posix/daemon.py
+++ b/satella/posix/daemon.py
@@ -20,6 +20,9 @@ logger = logging.getLogger(__name__)
DEVNULL = '/dev/null'
+__all__ = ['daemonize']
+
+
def daemonize(exit_via: tp.Callable = sys.exit,
redirect_std_to_devnull: bool = True,
uid: tp.Optional[int] = None,
@@ -58,10 +61,10 @@ def daemonize(exit_via: tp.Callable = sys.exit,
_parse_ug(gid, grp, 'gr_gid', os.setegid)
-def _parse_ug(no, module, fieldname, osfun):
+def _parse_ug(no, module, field_name, osfun):
if no is not None:
if isinstance(no, str):
- no = getattr(module.getpwnam(no), fieldname)
+ no = getattr(module.getpwnam(no), field_name)
osfun(no)
diff --git a/satella/posix/pidlock.py b/satella/posix/pidlock.py
index ef920b07..30ded11a 100644
--- a/satella/posix/pidlock.py
+++ b/satella/posix/pidlock.py
@@ -24,13 +24,17 @@ class AcquirePIDLock:
Usage:
- with AcquirePIDLock('myservice.pid'):
+ >>> with AcquirePIDLock('myservice.pid'):
+ >>> ... rest of code ..
- .. rest of code ..
+ Or alternatively
- Exiting the context manager deletes the file.
+ >>> pid_lock = AcquirePIDLock('myservice.pid')
+ >>> pid_lock.acquire()
+ >>> ...
+ >>> pid_lock.release()
- The constructor doesn't throw, __enter__ does, one of:
+ The constructor doesn't throw, __enter__ or acquire() does, one of:
* AcquirePIDLock.FailedToAcquire - base class for errors. Thrown if can't read the file
* AcquirePIDLock.LockIsHeld - lock is already held. This has two attributes - pid (int), the PID of holder,
@@ -55,8 +59,18 @@ class AcquirePIDLock:
self.fileno = None
- def _acquire(self):
- """The mechanical process of acquisition"""
+ def release(self):
+ if self.fileno is not None:
+ os.close(self.fileno)
+ os.unlink(self.path)
+
+ def acquire(self):
+ """
+ Acquire the PID lock
+
+ :raises LockIsHeld: if lock if held
+ :raises FailedToAcquire: if for example a directory exists in that place
+ """
try:
self.fileno = os.open(self.path, os.O_CREAT | os.O_EXCL)
except (IOError, OSError):
@@ -69,7 +83,7 @@ class AcquirePIDLock:
'PID file found but doesn''t have an int, skipping')
return
except IOError as e:
- raise FailedToAcquire()
+ raise FailedToAcquire(repr(e))
# Is this process alive?
try:
@@ -81,17 +95,15 @@ class AcquirePIDLock:
def __enter__(self):
try:
- self._acquire()
+ self.acquire()
except LockIsHeld as e:
if self.delete_on_dead and (not e.is_alive):
os.unlink(self.path)
- self._acquire()
+ self.acquire()
else:
raise
self.success = True
def __exit__(self, exc_type, exc_val, exc_tb):
- if self.fileno is not None:
- os.close(self.fileno)
- os.unlink(self.path)
+ self.release()
diff --git a/satella/posix/signals.py b/satella/posix/signals.py
index 9c3b1959..ad51aa5a 100644
--- a/satella/posix/signals.py
+++ b/satella/posix/signals.py
@@ -14,10 +14,14 @@ def __sighandler(a, b):
end = True
-def hang_until_sig(extra_signals: tp.Optional[tp.List] = None):
- """Will hang until this process receives SIGTERM or SIGINT.
+def hang_until_sig(extra_signals: tp.Optional[tp.List[int]] = None):
+ """
+ Will hang until this process receives SIGTERM or SIGINT.
If you pass extra signal IDs (signal.SIG*) with extra_signals,
- then also on those signals this call will release."""
+ then also on those signals this call will release.
+
+ :param extra_signals: a list of extra signals to listen to
+ """
extra_signals = extra_signals or []
global end
--
GitLab