Auto Local System Clients

CHANGELOG.rst

@@ -5,6 +5,9 @@ Brewtils Changelog
 ------
 TBD
 
+- Added support to auto generate requests when calling functions locally that are annotated with command decorators. This only supports
+  plugin classes that extend `object` and does not support recursive command loops. This is disabled by default (#547)
+  Examples: Plugin(..., auto_self_client=True)
 - Added support for SystemClient to define choice_validation_enabled flag during initialization or command execution.
   Default behavior is to skip choice validation if a parent request is present. (#585)
   Examples: SystemClient(..., choice_validation_enabled=True) or SystemClient().call_command(..., _choice_validation_enabled=True)

brewtils/plugin.py

@@ -43,6 +43,7 @@
 )
 from brewtils.resolvers.manager import ResolutionManager
 from brewtils.rest.easy_client import EasyClient
+from brewtils.rest.system_client import SystemClient
 from brewtils.specification import _CONNECTION_SPEC
 from typing import Optional, Union
 
@@ -138,6 +139,7 @@ class Plugin(object):
         - ``require``
         - ``requires``
         - ``requires_timeout``
+        - ``auto_self_client`` (defaults to "false")
 
     Connection information tells the Plugin how to communicate with Beer-garden. The
     most important of these is the ``bg_host`` (to tell the plugin where to find the
@@ -250,6 +252,9 @@ class Plugin(object):
 
         prefix_topic (str): Prefix for Generated Command Topics
 
+        auto_self_client (bool): Whether to automatically invoke SystemClient for local
+            system commands via self
+
         logger (:py:class:`logging.Logger`): Logger that will be used by the Plugin.
             Passing a logger will prevent the Plugin from preforming any additional
             logging configuration.
@@ -283,6 +288,10 @@ def __init__(self, client=None, system=None, logger=None, **kwargs):
         self._custom_logger = False
         self._logger = self._setup_logging(logger=logger, **kwargs)
 
+        self._auto_self_client = kwargs.pop("auto_self_client", False)
+        if not isinstance(self._auto_self_client, bool):
+            self._auto_self_client = str(self._auto_self_client).lower() == "true"
+
         # Need to pop out shutdown functions because these are not processed
         # until shutdown
         self.shutdown_functions = []
@@ -480,6 +489,26 @@ def _set_client(self, new_client):
         client_clazz._requires = self._system.requires
         client_clazz._current_request = client_clazz.current_request
 
+        # Can only inject System Clients if the Client inherits from a class object
+        # TODO: Should we add a configuration to explicitly disable this?
+        if self._auto_self_client and issubclass(client_clazz, object):
+
+            def system_client_getattribute(self, name):
+                try:
+                    if not name.startswith("_"):
+                        request = get_current_request_read_only()
+                        # Does not support recursive calls
+                        if request and request.command != name:
+                            if self.__class__._bg_commands:
+                                for bg_command in self.__class__._bg_commands:
+                                    if bg_command.name == name:
+                                        return getattr(SystemClient(), name)
+                except Exception:
+                    pass
+                return object.__getattribute__(self, name)
+
+            new_client.__class__.__getattribute__ = system_client_getattribute
+
         self._client = new_client
         global CLIENT
         CLIENT = new_client

brewtils/rest/system_client.py

@@ -414,10 +414,33 @@ def send_bg_request(self, *args, **kwargs):
         # tried to pass a parameter without a key:
         # client.command_name(param)
         if args:
-            raise RequestProcessException(
-                "Using positional arguments when creating a request is not allowed. "
-                "Please use keyword arguments instead."
-            )
+            if self.target_self:
+                _command = self._commands[kwargs["_command"]]
+                if _command:
+                    arg_counter = 0
+                    for arg in args:
+                        if arg_counter < len(_command.parameters):
+                            if _command.parameters[arg_counter].key in kwargs:
+                                raise RequestProcessException(
+                                    (
+                                        "Keyword argument overlapped with provided positional "
+                                        "argument. Please use all keyword arguments instead."
+                                    )
+                                )
+                            kwargs[_command.parameters[arg_counter].key] = arg
+                            arg_counter = arg_counter + 1
+                        else:
+                            raise RequestProcessException(
+                                (
+                                    "More positional arguments provided that command parameters. "
+                                    "Please use all keyword arguments instead."
+                                )
+                            )
+            else:
+                raise RequestProcessException(
+                    "Using positional arguments when creating a request is not allowed. "
+                    "Please use keyword arguments instead."
+                )
 
         # Need to pop here, otherwise we'll try to send as a request parameter
         raise_on_error = kwargs.pop("_raise_on_error", self._raise_on_error)

brewtils/specification.py

@@ -215,6 +215,14 @@ def _is_json_dict(s):
 }
 
 _PLUGIN_SPEC = {
+    "auto_self_client": {
+        "type": "bool",
+        "description": (
+            "Whether to automatically invoke SystemClient for local"
+            "system commands via self"
+        ),
+        "default": False,
+    },
     "instance_name": {
         "type": "str",
         "description": "The instance name",

test/plugin_test.py

@@ -201,6 +201,7 @@ def test_env(self, client, bg_system):
         os.environ["BG_GROUP"] = "GroupA"
         os.environ["BG_PREFIX_TOPIC"] = "custom.topic"
         os.environ["BG_REQUIRE"] = "SystemA"
+        os.environ["BG_AUTO_SELF_CLIENT"] = "False"
 
         plugin = Plugin(client, system=bg_system, max_concurrent=1)
 
@@ -210,6 +211,7 @@ def test_env(self, client, bg_system):
         assert plugin._config.ssl_enabled is False
         assert plugin._config.ca_verify is False
         assert plugin._config.prefix_topic == "custom.topic"
+        assert plugin._config.auto_self_client is False
         assert "GroupA" == plugin._config.group
         assert "SystemA" in plugin._config.require