Base connection class for network-style connections (#41839)

* Create base class for network-style connections

* clean up some differences

* Move NetworkConnectionBase

* Tweak netconf for tests

* Tweak when network_os is checked to avoid failing tests

* Pull back exec_command

lib/ansible/plugins/connection/__init__.py

@@ -17,7 +17,8 @@ from ansible.errors import AnsibleError
 from ansible.module_utils.six import string_types
 from ansible.module_utils._text import to_bytes, to_text
 from ansible.plugins import AnsiblePlugin
-from ansible.plugins.loader import shell_loader
+from ansible.plugins.loader import shell_loader, connection_loader
+from ansible.utils.path import unfrackpath
 
 try:
     from __main__ import display
@@ -280,3 +281,86 @@ class ConnectionBase(AnsiblePlugin):
 
     def reset(self):
         display.warning("Reset is not implemented for this connection")
+
+
+class NetworkConnectionBase(ConnectionBase):
+    """
+    A base class for network-style connections.
+    """
+
+    force_persistence = True
+    # Do not use _remote_is_local in other connections
+    _remote_is_local = True
+
+    def __init__(self, play_context, new_stdin, *args, **kwargs):
+        super(NetworkConnectionBase, self).__init__(play_context, new_stdin, *args, **kwargs)
+
+        self._network_os = self._play_context.network_os
+
+        self._local = connection_loader.get('local', play_context, '/dev/null')
+        self._local.set_options()
+
+        self._implementation_plugins = []
+
+        # reconstruct the socket_path and set instance values accordingly
+        self._ansible_playbook_pid = kwargs.get('ansible_playbook_pid')
+        self._update_connection_state()
+
+    def __getattr__(self, name):
+        try:
+            return self.__dict__[name]
+        except KeyError:
+            if not name.startswith('_'):
+                for plugin in self._implementation_plugins:
+                    method = getattr(plugin, name, None)
+                    if method is not None:
+                        return method
+            raise AttributeError("'%s' object has no attribute '%s'" % (self.__class__.__name__, name))
+
+    def exec_command(self, cmd, in_data=None, sudoable=True):
+        return self._local.exec_command(cmd, in_data, sudoable)
+
+    def put_file(self, in_path, out_path):
+        """Transfer a file from local to remote"""
+        return self._local.put_file(in_path, out_path)
+
+    def fetch_file(self, in_path, out_path):
+        """Fetch a file from remote to local"""
+        return self._local.fetch_file(in_path, out_path)
+
+    def reset(self):
+        '''
+        Reset the connection
+        '''
+        if self._socket_path:
+            display.vvvv('resetting persistent connection for socket_path %s' % self._socket_path, host=self._play_context.remote_addr)
+            self.close()
+        display.vvvv('reset call on connection instance', host=self._play_context.remote_addr)
+
+    def close(self):
+        if self._connected:
+            self._connected = False
+        self._implementation_plugins = []
+
+    def _update_connection_state(self):
+        '''
+        Reconstruct the connection socket_path and check if it exists
+
+        If the socket path exists then the connection is active and set
+        both the _socket_path value to the path and the _connected value
+        to True.  If the socket path doesn't exist, leave the socket path
+        value to None and the _connected value to False
+        '''
+        ssh = connection_loader.get('ssh', class_only=True)
+        control_path = ssh._create_control_path(
+            self._play_context.remote_addr, self._play_context.port,
+            self._play_context.remote_user, self._play_context.connection,
+            self._ansible_playbook_pid
+        )
+
+        tmp_path = unfrackpath(C.PERSISTENT_CONTROL_PATH_DIR)
+        socket_path = unfrackpath(control_path % dict(directory=tmp_path))
+
+        if os.path.exists(socket_path):
+            self._connected = True
+            self._socket_path = socket_path