more logging and exception handling in ansible-connection (#20619)

adds more logging to handle display being called from plugins.  Also
rearranges some of the exception handling to better catch exceptions and
log to local syslog

bin/ansible-connection

@@ -49,6 +49,8 @@ from ansible.module_utils.six.moves import cPickle, StringIO
 from ansible.playbook.play_context import PlayContext
 from ansible.plugins import connection_loader
 from ansible.utils.path import unfrackpath, makedirs_safe
+from ansible.errors import AnsibleConnectionFailure
+from ansible.utils.display import Display
 
 
 def do_fork():
@@ -101,9 +103,9 @@ def recv_data(s):
         data += d
     return data
 
-def log(msg, host=None):
+def log(msg, host=None, **kwargs):
     if host:
-        msg = '[%s] %s' % (host, msg)
+        msg = '<%s> %s' % (host, msg)
     facility = getattr(syslog, C.DEFAULT_SYSLOG_FACILITY, syslog.LOG_USER)
     syslog.openlog('ansible-connection', 0, facility)
     syslog.syslog(syslog.LOG_INFO, str(msg))
@@ -117,17 +119,14 @@ class Server():
 
         self._start_time = datetime.datetime.now()
 
-        try:
-            self.log('loading connection plugin %s' % str(play_context.connection))
         self.conn = connection_loader.get(play_context.connection, play_context, sys.stdin)
-            self.conn._connect()
+        rc, out, err = self.conn._connect()
+        if rc != 0:
+            raise AnsibleConnectionFailure(err)
 
         self.socket = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
         self.socket.bind(path)
         self.socket.listen(1)
-        except Exception as exc:
-            self.log(traceback.format_exc())
-            raise
 
         signal.signal(signal.SIGALRM, self.alarm_handler)
 
@@ -137,7 +136,7 @@ class Server():
             return meth(*args, **kwargs)
 
     def log(self, msg):
-        log(msg, self.play_context.remote_addr)
+        log(msg, host=self.play_context.remote_addr)
 
     def alarm_handler(self, signum, frame):
         '''
@@ -259,6 +258,8 @@ def main():
         print(traceback.format_exc())
         sys.exit(1)
 
+    display.verbosity = pc.verbosity
+
     # here we create a hash to use later when creating the socket file,
     # so we can hide the info about the target host/user/etc.
     m = hashlib.sha256()
@@ -280,7 +281,12 @@ def main():
     if not os.path.exists(sf_path):
         pid = do_fork()
         if pid == 0:
+            try:
                 server = Server(sf_path, pc)
+            except AnsibleConnectionFailure as exc:
+                log(str(exc), pc.remote_addr)
+            except Exception as exc:
+                log(traceback.format_exc(), pc.remote_addr)
             fcntl.lockf(lock_fd, fcntl.LOCK_UN)
             os.close(lock_fd)
             server.run()
@@ -334,4 +340,6 @@ def main():
     sys.exit(rc)
 
 if __name__ == '__main__':
+    display = Display()
+    display.display = log
     main()