Allow to run multiple io.process.Process objects simultaneously

Currently, Process incorrectly handles stdout/stderr channels which rely on global state: - static methods used to handle read/close events are instantiated on module import. Thus, they are being mocked by addHandler() which sets .channel to them. Starting a new process causes resetting that field on the global method objects, thus all processes will receive output from the last started process. To mitigate this, static methods are replaced with closure-like lambdas. - Process incorrectly raises stopped() event to close stdout/stderr. This event, however, is used to signal Manager's death. Thus, when process is completed, all sockets/pipes in the entire program are closed. This is why stopped() event has to be replaced with process-specific terminated() event and we need explicitly send close() to all process pipes.
circuits · Apr 2, 2016 · 884b071 · 884b071
1 parent 056e15f
commit 884b071
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Showing 2 changed files with 56 additions and 28 deletions.
diff --git a/circuits/io/process.py b/circuits/io/process.py
@@ -7,10 +7,23 @@
 from subprocess import Popen, PIPE
 
 from circuits.core.manager import TIMEOUT
-from circuits import handler, BaseComponent
+from circuits import handler, BaseComponent, Event
 
 from .file import File
-from .events import started, stopped, write
+from .events import started, write, close
+
+
+class terminated(Event):
+    """terminated Event
+
+    This Event is sent when a process is completed
+
+    :param args:  (process)
+    :type  tuple: tuple
+    """
+
+    def __init__(self, *args):
+        super(terminated, self).__init__(*args)
 
 
 class Process(BaseComponent):
@@ -73,39 +86,31 @@ def start(self):
         ).register(self)
 
         self._stderr_read_handler = self.addHandler(
-            handler("read", channel="{0:d}.stderr".format(self.p.pid))(
-                self.__class__._on_stderr_read
+            handler("read", channel=self._stderr.channel)(
+                lambda self, data: self.stderr.write(data)
             )
         )
 
         self._stdout_read_handler = self.addHandler(
-            handler("read", channel="{0:d}.stdout".format(self.p.pid))(
-                self.__class__._on_stdout_read
+            handler("read", channel=self._stdout.channel)(
+                lambda self, data: self.stdout.write(data)
             )
         )
 
         self._stderr_closed_handler = self.addHandler(
-            handler("closed", channel="{0:d}.stderr".format(self.p.pid))(
-                self.__class__._on_stderr_closed
+            handler("closed", channel=self._stderr.channel)(
+                lambda self: setattr(self, '_stderr_closed', True)
             )
         )
 
         self._stdout_closed_handler = self.addHandler(
-            handler("closed", channel="{0:d}.stdout".format(self.p.pid))(
-                self.__class__._on_stdout_closed
+            handler("closed", channel=self._stdout.channel)(
+                lambda self: setattr(self, '_stdout_closed', True)
             )
         )
 
         self.fire(started(self))
 
-    @staticmethod
-    def _on_stdout_closed(self):
-        self._stdout_closed = True
-
-    @staticmethod
-    def _on_stderr_closed(self):
-        self._stderr_closed = True
-
     def stop(self):
         if self.p is not None:
             self.p.terminate()
@@ -127,14 +132,6 @@ def status(self):
         if getattr(self, "p", None) is not None:
             return self.p.poll()
 
-    @staticmethod
-    def _on_stderr_read(self, data):
-        self.stderr.write(data)
-
-    @staticmethod
-    def _on_stdout_read(self, data):
-        self.stdout.write(data)
-
     @handler("generate_events")
     def _on_generate_events(self, event):
         if self.p is not None and self._status is None:
@@ -147,7 +144,12 @@ def _on_generate_events(self, event):
             self.removeHandler(self._stdout_read_handler)
             self.removeHandler(self._stderr_closed_handler)
             self.removeHandler(self._stdout_closed_handler)
-            self.fire(stopped(self))
+
+            self.fire(terminated(self))
+            self.fire(close(), self._stdin.channel,
+                               self._stdout.channel,
+                               self._stderr.channel)
+
             event.reduce_time_left(0)
             event.stop()
         else:

diff --git a/tests/io/test_process.py b/tests/io/test_process.py
@@ -14,7 +14,7 @@ def test(manager, watcher):
     p.start()
     assert watcher.wait("started", p.channel)
 
-    assert watcher.wait("stopped", p.channel)
+    assert watcher.wait("terminated", p.channel)
 
     s = p.stdout.getvalue()
     assert s == b"Hello World!\n"
@@ -39,3 +39,29 @@ def test2(manager, watcher, tmpdir):
 
     with foo.open("r") as f:
         assert f.read() == "Hello World!"
+
+def test_two_procs(manager, watcher):
+    p1 = Process(["echo", "1"]).register(manager)
+    p2 = Process("echo 2 ; sleep 1", shell = True).register(manager)
+
+    p1.start()
+    p2.start()
+
+    assert watcher.wait("terminated", p1.channel)
+    assert p1._terminated
+    assert not p2._terminated
+    assert not p2._stdout_closed
+    assert not p2._stderr_closed
+
+    watcher.clear()     # Get rid of first terminated()
+
+    s1 = p1.stdout.getvalue()
+    assert s1 == b"1\n"
+
+    assert watcher.wait("terminated", p2.channel)
+    assert p2._terminated
+    assert p2._stdout_closed
+    assert p2._stderr_closed
+
+    s2 = p2.stdout.getvalue()
+    assert s2 == b"2\n"