Implement inotify based pipe connector

tfw/components/pipe_connector/__init__.py

@@ -0,0 +1 @@
+from .proxy_pipe_connector_handler import ProxyPipeConnectorHandler

tfw/components/pipe_connector/pipe_connector.py

@@ -0,0 +1,69 @@
+from stat import S_ISFIFO
+from os import access, mkdir, stat, R_OK
+from os.path import exists
+
+from pipe_io_server import PipeReaderServer, PipeWriterServer
+
+from tfw.internals.inotify import InotifyObserver, InotifyFileCreatedEvent, InotifyFileDeletedEvent
+
+
+class PipeConnector:
+    def __init__(self, path):
+        self.recv_pipes, self.send_pipes = {}, {}
+        self.observer = self.build_observer(path)
+        self.observer.on_any_event = self._on_any_event
+        self.observer.start()
+
+    def build_observer(self, path): # pylint: disable=no-self-use
+        if not exists(path):
+            mkdir(path)
+        if not access(path, R_OK):
+            raise ValueError('Path does not exist or is not accessible.')
+        observer = InotifyObserver(path, patterns=['*send*', '*recv*'])
+        return observer
+
+    def _on_any_event(self, event):
+        path = event.src_path
+        if isinstance(event, InotifyFileCreatedEvent) and self._is_pipe(path):
+            self._create_pipe(path)
+        elif isinstance(event, InotifyFileDeletedEvent):
+            self._delete_pipe(path)
+
+    @staticmethod
+    def _is_pipe(path):
+        return exists(path) and S_ISFIFO(stat(path).st_mode)
+
+    def _create_pipe(self, path):
+        if self._find_pipe(path):
+            return
+        server = None
+        if 'recv' in path:
+            pipes, server = self.recv_pipes, self.build_writer(path)
+        elif 'send' in path:
+            pipes, server = self.send_pipes, self.build_reader(path)
+        if server:
+            server.start()
+            pipes[path] = server
+
+    def _find_pipe(self, path):
+        if path in self.recv_pipes.keys():
+            return self.recv_pipes
+        if path in self.send_pipes.keys():
+            return self.send_pipes
+        return None
+
+    def build_reader(self, path): # pylint: disable=no-self-use
+        return PipeReaderServer(path, manager_pipes=False)
+
+    def build_writer(self, path): # pylint: disable=no-self-use
+        return PipeWriterServer(path, manage_pipes=False)
+
+    def _delete_pipe(self, path):
+        pipes = self._find_pipe(path)
+        if pipes:
+            pipes[path].stop()
+            del pipes[path]
+
+    def broadcast(self, message):
+        for _, server in self.recv_pipes.items():
+            server.send_message(message)

tfw/components/pipe_connector/proxy_pipe_connector_handler.py

@@ -0,0 +1,43 @@
+import logging
+from threading import Lock
+from json import dumps, loads, JSONDecodeError
+
+from pipe_io_server import PipeReaderServer
+
+from .pipe_connector import PipeConnector
+
+LOG = logging.getLogger(__name__)
+
+
+class ProxyPipeConnectorHandler:
+    keys = ['']
+
+    def __init__(self, path):
+        self.connector, self.pipes = None, None
+        self.path = path
+
+    def start(self):
+        self.pipes = ProxyPipeConnector(self.path, self.connector)
+
+    def handle_event(self, message, _):
+        self.pipes.broadcast(dumps(message).encode())
+
+
+class ProxyPipeConnector(PipeConnector):
+    def __init__(self, path, connector):
+        self.connector = connector
+        self.mutex = Lock()
+        super().__init__(path)
+
+    def build_reader(self, path):
+        reader = PipeReaderServer(path, manage_pipes=False)
+        reader.handle_message = self._handle_message
+        return reader
+
+    def _handle_message(self, message):
+        try:
+            json_object = loads(message)
+            with self.mutex:
+                self.connector.send_message(json_object)
+        except JSONDecodeError:
+            LOG.error('Received invalid JSON message: %s', message)

tfw/components/pipe_connector/test_pipe_connector.py

@@ -0,0 +1,144 @@
+# pylint: disable=redefined-outer-name
+from enum import Enum
+from dataclasses import dataclass
+from json import dumps
+from secrets import token_urlsafe
+from os import urandom, mkfifo, mkdir, mknod
+from os.path import join
+from tempfile import TemporaryDirectory
+
+from tfw.internals.inotify import InotifyFileCreatedEvent, InotifyFileDeletedEvent
+
+import pytest
+
+from .proxy_pipe_connector_handler import ProxyPipeConnector
+
+
+class Action(Enum):
+    SEND = 'send'
+    RECV = 'recv'
+
+
+@dataclass
+class PipeContext:
+    workdir: str
+    pipes: ProxyPipeConnector
+
+    def emit_pipe_creation_event(self, action, inode_creator):
+        filename = self.join(f'{self.generate_name()}_{action.value}')
+        inode_creator(filename)
+        self.pipes.observer.on_any_event(InotifyFileCreatedEvent(filename))
+        return filename
+
+    def join(self, path):
+        return join(self.workdir, path)
+
+    @staticmethod
+    def generate_name():
+        return urandom(4).hex()
+
+
+class MockPipeConnector(ProxyPipeConnector):
+    def __init__(self, path, connector):
+        self.reader_events, self.writer_events = [], []
+        super().__init__(path, connector)
+
+    def build_observer(self, path):
+        return MockObserver()
+
+    def build_reader(self, path):
+        self.reader_events.append(path)
+        reader = MockPipeServer()
+        reader.handle_message = self._handle_message
+        return reader
+
+    def build_writer(self, path):
+        self.writer_events.append(path)
+        return MockPipeServer()
+
+
+class MockObserver:
+    def start(self):
+        pass
+
+    def on_any_event(self, event):
+        pass
+
+
+class MockPipeServer:
+    def __init__(self):
+        self.messages = []
+
+    def handle_message(self, message):
+        pass
+
+    def send_message(self, message):
+        self.messages.append(message)
+
+    def start(self):
+        pass
+
+    def stop(self):
+        pass
+
+
+class MockConnector: # pylint: disable=too-few-public-methods
+    def __init__(self):
+        self.messages = []
+
+    def send_message(self, message):
+        self.messages.append(message)
+
+
+@pytest.fixture
+def context():
+    with TemporaryDirectory() as workdir:
+        yield PipeContext(workdir, MockPipeConnector(workdir, MockConnector()))
+
+
+def test_pipe_creation_deletion(context):
+    cases = [
+        (Action.RECV, context.pipes.recv_pipes, context.pipes.writer_events),
+        (Action.SEND, context.pipes.send_pipes, context.pipes.reader_events)
+    ]
+
+    for action, pipes, events in cases:
+        path = context.emit_pipe_creation_event(action, mkfifo)
+        assert events[-1] == path
+        assert path in pipes.keys()
+        context.pipes.observer.on_any_event(InotifyFileDeletedEvent(path))
+        assert path not in pipes.keys()
+
+
+def test_handle_message(context):
+    path = context.emit_pipe_creation_event(Action.SEND, mkfifo)
+    payload = {'key': token_urlsafe(16)}
+    context.pipes.send_pipes[path].handle_message(dumps(payload))
+    assert context.pipes.connector.messages[-1] == payload
+    context.pipes.send_pipes[path].handle_message(token_urlsafe(32))
+    assert len(context.pipes.connector.messages) == 1
+
+
+def test_broadcast(context):
+    paths = [
+        context.emit_pipe_creation_event(Action.RECV, mkfifo)
+        for _ in range(32)
+    ]
+    payload = {'key': token_urlsafe(16)}
+
+    context.pipes.broadcast(payload)
+    for path in paths:
+        assert context.pipes.recv_pipes[path].messages[-1] == payload
+
+
+def test_inode_types(context):
+    cases = [
+        (Action.RECV, context.pipes.recv_pipes, mkdir),
+        (Action.SEND, context.pipes.send_pipes, mkdir),
+        (Action.RECV, context.pipes.recv_pipes, mknod),
+        (Action.SEND, context.pipes.send_pipes, mknod)
+    ]
+
+    for action, pipes, creator in cases:
+        path = context.emit_pipe_creation_event(action, creator)
+        assert path not in pipes.keys()

tfw/components/process_management/log_inotify_observer.py

@@ -8,7 +8,6 @@ from .supervisor import ProcessLogManager
 
 class LogInotifyObserver(InotifyObserver, ProcessLogManager):
     def __init__(self, connector, process_name, supervisor_uri, log_tail=0):
-        self._prevent_log_recursion()
         self._connector = connector
         self._process_name = process_name
         self.log_tail = log_tail
@@ -16,11 +15,6 @@ class LogInotifyObserver(InotifyObserver, ProcessLogManager):
         ProcessLogManager.__init__(self, supervisor_uri)
         InotifyObserver.__init__(self, self._get_logfiles())
 
-    @staticmethod
-    def _prevent_log_recursion():
-        # This is done to prevent inotify event logs triggering themselves (infinite log recursion)
-        logging.getLogger('watchdog.observers.inotify_buffer').propagate = False
-
     def _get_logfiles(self):
         self._procinfo = self.supervisor.getProcessInfo(self._process_name)
         return self._procinfo['stdout_logfile'], self._procinfo['stderr_logfile']

tfw/internals/inotify/inotify.py

@@ -1,5 +1,5 @@
 # pylint: disable=too-few-public-methods
-
+import logging
 from typing import Iterable
 from time import time
 from os.path import abspath, dirname, isdir
@@ -11,6 +11,8 @@ from watchdog.events import (
     DirCreatedEvent, DirModifiedEvent, DirMovedEvent, DirDeletedEvent
 )
 
+logging.getLogger('watchdog.observers.inotify_buffer').propagate = False
+
 
 class InotifyEvent:
     def __init__(self, src_path):