Add syslog_facility parameter handling with systemd.journal (#41078)

* Add syslog_facility parameter handling with systemd.journal

- Fixed issue #41072

Signed-off-by: Hideki Saito <saito@fgrep.org>

changelogs/fragments/syslog_facility-for-journald.yml

@@ -0,0 +1,5 @@
+---
+bugfixes:
+- Fixed runtime module to be able to handle syslog_facility properly
+  when python systemd module installed in a target system.
+  (https://github.com/ansible/ansible/pull/41078)

docs/docsite/rst/porting_guides/porting_guide_2.7.rst

@@ -54,6 +54,14 @@ Modules
 
 Major changes in popular modules are detailed here
 
+* The :ref:`DEFAULT_SYSLOG_FACILITY` configuration option tells Ansible modules to use a specific
+  `syslog facility <https://en.wikipedia.org/wiki/Syslog#Facility>`_ when logging information on all
+  managed machines. Due to a bug with older Ansible versions, this setting did not affect machines
+  using journald with the systemd Python bindings installed. On those machines, Ansible log
+  messages were sent to ``/var/log/messages``, even if you set :ref:`DEFAULT_SYSLOG_FACILITY`.
+  Ansible 2.7 fixes this bug, routing all Ansible log messages according to the value set for
+  :ref:`DEFAULT_SYSLOG_FACILITY`. If you have :ref:`DEFAULT_SYSLOG_FACILITY` configured, the
+  location of remote logs on systems which use journald may change.
 
 
 Modules removed

lib/ansible/module_utils/basic.py

@@ -2185,7 +2185,19 @@ class AnsibleModule(object):
                 for arg in log_args:
                     journal_args.append((arg.upper(), str(log_args[arg])))
                 try:
-                    journal.send(u"%s %s" % (module, journal_msg), **dict(journal_args))
+                    if HAS_SYSLOG:
+                        # If syslog_facility specified, it needs to convert
+                        #  from the facility name to the facility code, and
+                        #  set it as SYSLOG_FACILITY argument of journal.send()
+                        facility = getattr(syslog,
+                                           self._syslog_facility,
+                                           syslog.LOG_USER) >> 3
+                        journal.send(MESSAGE=u"%s %s" % (module, journal_msg),
+                                     SYSLOG_FACILITY=facility,
+                                     **dict(journal_args))
+                    else:
+                        journal.send(MESSAGE=u"%s %s" % (module, journal_msg),
+                                     **dict(journal_args))
                 except IOError:
                     # fall back to syslog since logging to journal failed
                     self._log_to_syslog(syslog_msg)