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diff --git a/external_libs/python/python-daemon-2.0.5/doc/FAQ b/external_libs/python/python-daemon-2.0.5/doc/FAQ deleted file mode 100644 index 1fcc4658..00000000 --- a/external_libs/python/python-daemon-2.0.5/doc/FAQ +++ /dev/null @@ -1,156 +0,0 @@ -‘python-daemon’ Frequently Asked Questions -########################################## - -:Author: Ben Finney <ben+python@benfinney.id.au> -:Updated: 2015-01-10 - -.. contents:: -.. - 1 General - 1.1 What is the purpose of the ‘python-daemon’ library? - 1.2 How can I run a service communicating with a separate daemon process? - 2 Security - 2.1 Why is the umask set to 0 by default? - 3 File descriptors - 3.1 Why does the output stop after opening the daemon context? - 3.2 How can I preserve a ‘logging’ handler's file descriptor? - -General -======= - -What is the purpose of the ‘python-daemon’ library? ---------------------------------------------------- - -The ‘python-daemon’ library has a deliberately narrow focus: that of -being a reference implementation for `PEP 3143`_, “Standard daemon -process library”. - -.. _`PEP 3143`: http://www.python.org/dev/peps/pep-3143 - -How can I run a service communicating with a separate daemon process? ---------------------------------------------------------------------- - -As specified in `PEP 3143`_, the ‘python-daemon’ library is -specifically focussed on the goal of having the *current running -program* become a well-behaved Unix daemon process. This leaves open -the question of how this program is started, or about multiple -programs interacting. As detailed in PEP 3143: - - A daemon is not a service - - There is a related concept in many systems, called a “service”. A - service differs from the model in this PEP, in that rather than - having the *current* program continue to run as a daemon process, - a service starts an *additional* process to run in the background, - and the current process communicates with that additional process - via some defined channels. - - The Unix-style daemon model in this PEP can be used, among other - things, to implement the background-process part of a service; but - this PEP does not address the other aspects of setting up and - managing a service. - -A possible starting point for such a “service” model of execution is -in a `message from 2009-01-30`_ to the ``python-ideas`` forum. - -.. _`message from 2009-01-30`: http://mail.python.org/pipermail/python-ideas/2009-January/002606.html - - -Security -======== - -Why is the umask set to 0 by default? -------------------------------------- - -A daemon should not rely on the parent process's umask value, which is -beyond its control and may prevent creating a file with the required -access mode. So when the daemon context opens, the umask is set to an -explicit known value. - -If the conventional value of 0 is too open, consider setting a value -such as 0o022, 0o027, 0o077, or another specific value. Otherwise, -ensure the daemon creates every file with an explicit access mode for -the purpose. - - -File descriptors -================ - -Why does the output stop after opening the daemon context? ----------------------------------------------------------- - -The specified behaviour in `PEP 3143`_ includes the requirement to -detach the process from the controlling terminal (to allow the process -to continue to run as a daemon), and to close all file descriptors not -known to be safe once detached (to ensure any files that continue to -be used are under the control of the daemon process). - -If you want the process to generate output via the system streams -‘sys.stdout’ and ‘sys.stderr’, set the ‘DaemonContext’'s ‘stdout’ -and/or ‘stderr’ options to a file-like object (e.g. the ‘stream’ -attribute of a ‘logging.Handler’ instance). If these objects have file -descriptors, they will be preserved when the daemon context opens. - -How can I preserve a ‘logging’ handler's file descriptor? ---------------------------------------------------------- - -The ‘DaemonContext.open’ method conforms to `PEP 3143`_ by closing all -open file descriptors, but excluding those files specified in the -‘files_preserve’ option. This option is a list of files or file -descriptors. - -The Python standard library ‘logging’ module provides log handlers -that write to streams, including to files via the ‘StreamHandler’ -class and its sub-classes. The documentation (both the online `logging -module documentation`_ and the docstrings for the code) makes no -mention of a way to get at the stream associated with a handler -object. - -However, looking at the source code for ‘StreamHandler’, in Python 2.5 -as ``/usr/lib/python2.5/logging/__init__.py``, shows a ‘stream’ -attribute that is bound to the stream object. The attribute is not -marked private (i.e. it is not named with a leading underscore), so we -can presume it is part of the public API. - -That attribute can then be used to specify that a logging handler's -file descriptor should, when the ‘DaemonContext’ opens, be excluded -from closure:: - - import logging - import daemon - - # any subclass of StreamHandler should provide the ‘stream’ attribute. - lh = logging.handlers.TimedRotatingFileHandler( - "/var/log/foo.log", - # … - ) - - # … do some logging and other activity … - - daemon_context = daemon.DaemonContext() - daemon_context.files_preserve = [lh.stream] - - daemon_context.open() - - # … continue as a daemon process … - -.. _`logging module documentation`: http://docs.python.org/library/logging - - -.. - This is free software: you may copy, modify, and/or distribute this work - under the terms of the Apache License version 2.0 as published by the - Apache Software Foundation. - No warranty expressed or implied. See the file ‘LICENSE.ASF-2’ for details. - -.. - Local variables: - coding: utf-8 - mode: text - mode: rst - time-stamp-format: "%:y-%02m-%02d" - time-stamp-start: "^:Updated:[ ]+" - time-stamp-end: "$" - time-stamp-line-limit: 20 - End: - vim: fileencoding=utf-8 filetype=rst : |