Add fix to read correct socket path recieved from ansible-connection (#27560)

Currently socket path is send from `ansible-connection` (running as background
process) over stdout. This can conflict with debug logs that are also send on
stdout resulting in incorrect socket path received by the main process.

To avoid this add a socket path delimiter string which is recevied by
main process and socket path is retrieved based on delimiter string.

This implementation will change in future when ansible-connection
framework is made more robust.

bin/ansible-connection

@@ -249,7 +249,7 @@ class Server():
                 break
             time.sleep(1)
             timeout -= 1
-        return (0, self.socket_path, '')
+        return 0, b'\n#SOCKET_PATH#: %s\n' % self.socket_path, ''
 
 
 def communicate(sock, data):

lib/ansible/plugins/connection/persistent.py

@@ -66,11 +66,12 @@ class Connection(ConnectionBase):
         (stdout, stderr) = p.communicate()
         stdin.close()
 
-        return (p.returncode, stdout, stderr)
+        return (p, stdout, stderr)
 
     def exec_command(self, cmd, in_data=None, sudoable=True):
         super(Connection, self).exec_command(cmd, in_data=in_data, sudoable=sudoable)
-        return self._do_it('EXEC: ' + cmd)
+        p, out, err = self._do_it('EXEC: ' + cmd)
+        return p.returncode, out, err
 
     def put_file(self, in_path, out_path):
         super(Connection, self).put_file(in_path, out_path)
@@ -90,5 +91,16 @@ class Connection(ConnectionBase):
         socket path exists. If the path exists (or the timeout has expired),
         returns the socket path.
         """
-        rc, out, err = self._do_it('RUN:')
-        return to_text(out, errors='surrogate_or_strict')
+        p, out, err = self._do_it('RUN:')
+        while True:
+            out = out.strip()
+            if out == b'':
+                # EOF file found
+                return None
+            elif out.startswith(b'#SOCKET_PATH#'):
+                break
+            else:
+                out = p.stdout.readline()
+
+        socket_path = out.split(b'#SOCKET_PATH#: ', 1)[1]
+        return to_text(socket_path, errors='surrogate_or_strict')