Allow subclassing pipe based event handlers (refactor PipeIOEventHandler to base class and impl)

lib/tfw/components/__init__.py

@@ -10,4 +10,4 @@ from .terminal_commands import TerminalCommands
 from .log_monitoring_event_handler import LogMonitoringEventHandler
 from .fsm_managing_event_handler import FSMManagingEventHandler
 from .snapshot_provider import SnapshotProvider
-from .pipe_io_event_handler import PipeIOEventHandler
+from .pipe_io_event_handler import PipeIOEventHandlerBase, PipeIOEventHandler

lib/tfw/components/pipe_io_event_handler.py

@@ -1,3 +1,4 @@
+from abc import abstractmethod
 from json import loads, dumps, JSONDecodeError
 
 from tfw import EventHandlerBase
@@ -8,37 +9,45 @@ from .pipe_io_server import PipeIOServer
 LOG = logging.getLogger(__name__)
 
 
-class PipeIOEventHandler(EventHandlerBase):
+class PipeIOEventHandlerBase(EventHandlerBase):
     def __init__(self, key, in_pipe_path, out_pipe_path, permissions=0o600):
         super().__init__(key)
-        self._pipe_io_server = JSONProxyPipeIOServer(
+        self.pipe_io = CallbackPipeIOServer(
             in_pipe_path,
             out_pipe_path,
-            self.server_connector.send,
+            self.handle_pipe_event,
             permissions
         )
-        self._pipe_io_server.start()
+        self.pipe_io.start()
+
+    @abstractmethod
+    def handle_pipe_event(self, message):
+        raise NotImplementedError()
 
     def cleanup(self):
-        self._pipe_io_server.stop()
+        self.pipe_io.stop()
 
+
+class CallbackPipeIOServer(PipeIOServer):
+    def __init__(self, in_pipe_path, out_pipe_path, callback, permissions):
+        super().__init__(in_pipe_path, out_pipe_path, permissions)
+        self.callback = callback
+
+    def handle_message(self, message):
+        self.callback(message)
+
+
+class PipeIOEventHandler(PipeIOEventHandlerBase):
     def handle_event(self, message):
         try:
             json_bytes = dumps(message).encode()
-            self._pipe_io_server.send_message(json_bytes)
+            self.pipe_io.send_message(json_bytes)
         except TypeError:
             LOG.error("Message %s not JSON serializable! Ignoring...", message)
 
-
-
-class JSONProxyPipeIOServer(PipeIOServer):
-    def __init__(self, in_pipe_path, out_pipe_path, proxy_method, permissions):
-        super().__init__(in_pipe_path, out_pipe_path, permissions)
-        self.proxy = proxy_method
-
-    def handle_message(self, message):
+    def handle_pipe_event(self, message):
         try:
             json = loads(message)
-            self.proxy(json)
+            self.server_connector.send(json)
         except JSONDecodeError:
-            LOG.error("Invalid JSON received on %s! Ignoring...", self._in_pipe)
+            LOG.error("Invalid JSON received on %s! Ignoring...", self.pipe_io.in_pipe)