Move CommandHandler to a separate file

tfw/components/pipe_io/__init__.py

@@ -1,2 +1,3 @@
-from .pipe_io_handler import PipeIOHandler, PipeIOHandlerBase, CommandHandler
+from .pipe_io_handler import PipeIOHandler, PipeIOHandlerBase
+from .command_handler import CommandHandler
 from .pipe_connector import ProxyPipeConnectorHandler

tfw/components/pipe_io/command_handler.py

@@ -0,0 +1,58 @@
+from subprocess import PIPE, Popen
+from functools import partial
+from os import getpgid, killpg
+from os.path import join
+from signal import SIGTERM
+from secrets import token_urlsafe
+from threading import Thread
+from contextlib import suppress
+
+from pipe_io_server import terminate_process_on_failure
+
+from .pipe_io_handler import PipeIOHandler, DEFAULT_PERMISSIONS
+
+
+class CommandHandler(PipeIOHandler):
+    def __init__(self, command, permissions=DEFAULT_PERMISSIONS):
+        super().__init__(
+            self._generate_tempfilename(),
+            self._generate_tempfilename(),
+            permissions
+        )
+
+        self._proc_stdin = open(self.pipe_io.out_pipe, 'rb')
+        self._proc_stdout = open(self.pipe_io.in_pipe, 'wb')
+        self._proc = Popen(
+            command, shell=True, executable='/bin/bash',
+            stdin=self._proc_stdin, stdout=self._proc_stdout, stderr=PIPE,
+            start_new_session=True
+        )
+        self._monitor_proc_thread = self._start_monitor_proc()
+
+    def _generate_tempfilename(self):
+        # pylint: disable=no-self-use
+        random_filename = partial(token_urlsafe, 10)
+        return join('/tmp', f'{type(self).__name__}.{random_filename()}')
+
+    def _start_monitor_proc(self):
+        thread = Thread(target=self._monitor_proc, daemon=True)
+        thread.start()
+        return thread
+
+    @terminate_process_on_failure
+    def _monitor_proc(self):
+        return_code = self._proc.wait()
+        if return_code == -int(SIGTERM):
+            # supervisord asked the program to terminate, this is fine
+            return
+        if return_code != 0:
+            _, stderr = self._proc.communicate()
+            raise RuntimeError(f'Subprocess failed ({return_code})! Stderr:\n{stderr.decode()}')
+
+    def cleanup(self):
+        with suppress(ProcessLookupError):
+            process_group_id = getpgid(self._proc.pid)
+            killpg(process_group_id, SIGTERM)
+            self._proc_stdin.close()
+            self._proc_stdout.close()
+        super().cleanup()

tfw/components/pipe_io/pipe_io_handler.py

@@ -1,16 +1,8 @@
 import logging
 from abc import abstractmethod
 from json import loads, dumps
-from subprocess import PIPE, Popen
-from functools import partial
-from os import getpgid, killpg
-from os.path import join
-from signal import SIGTERM
-from secrets import token_urlsafe
-from threading import Thread
-from contextlib import suppress
 
-from pipe_io_server import PipeIOServer, terminate_process_on_failure
+from pipe_io_server import PipeIOServer
 
 LOG = logging.getLogger(__name__)
 DEFAULT_PERMISSIONS = 0o600
@@ -53,49 +45,3 @@ class PipeIOHandler(PipeIOHandlerBase):
     def handle_pipe_event(self, message_bytes):
         json = loads(message_bytes)
         self.connector.send_message(json)
-
-
-class CommandHandler(PipeIOHandler):
-    def __init__(self, command, permissions=DEFAULT_PERMISSIONS):
-        super().__init__(
-            self._generate_tempfilename(),
-            self._generate_tempfilename(),
-            permissions
-        )
-
-        self._proc_stdin = open(self.pipe_io.out_pipe, 'rb')
-        self._proc_stdout = open(self.pipe_io.in_pipe, 'wb')
-        self._proc = Popen(
-            command, shell=True, executable='/bin/bash',
-            stdin=self._proc_stdin, stdout=self._proc_stdout, stderr=PIPE,
-            start_new_session=True
-        )
-        self._monitor_proc_thread = self._start_monitor_proc()
-
-    def _generate_tempfilename(self):
-        # pylint: disable=no-self-use
-        random_filename = partial(token_urlsafe, 10)
-        return join('/tmp', f'{type(self).__name__}.{random_filename()}')
-
-    def _start_monitor_proc(self):
-        thread = Thread(target=self._monitor_proc, daemon=True)
-        thread.start()
-        return thread
-
-    @terminate_process_on_failure
-    def _monitor_proc(self):
-        return_code = self._proc.wait()
-        if return_code == -int(SIGTERM):
-            # supervisord asked the program to terminate, this is fine
-            return
-        if return_code != 0:
-            _, stderr = self._proc.communicate()
-            raise RuntimeError(f'Subprocess failed ({return_code})! Stderr:\n{stderr.decode()}')
-
-    def cleanup(self):
-        with suppress(ProcessLookupError):
-            process_group_id = getpgid(self._proc.pid)
-            killpg(process_group_id, SIGTERM)
-            self._proc_stdin.close()
-            self._proc_stdout.close()
-        super().cleanup()