Changeset 488a04c in trunk for src/allmydata/scripts

Timestamp:

2022-09-01T23:42:06Z (3 years ago)

Author:

meejah <meejah@…>

Branches:

master

Children:

1e6381c

Parents:

7c25e15

Message:

exit when stdin closes

File:

• src/allmydata/scripts/tahoe_run.py (modified) (5 diffs)

src/allmydata/scripts/tahoe_run.py ¶

@@ -21 +21 @@
 from twisted.python import usage
 from twisted.python.reflect import namedAny
-from twisted.internet.defer import maybeDeferred
+from twisted.internet.defer import maybeDeferred, Deferred
+from twisted.internet.protocol import Protocol
+from twisted.internet.stdio import StandardIO
 from twisted.application.service import Service
 
@@ -148 +150 @@
 
     def startService(self):
+
+        from twisted.internet import reactor
 
         def start():
@@ -188 +192 @@
             def created(srv):
                 srv.setServiceParent(self.parent)
+                # exiting on stdin-closed facilitates cleanup when run
+                # as a subprocess
+                on_stdin_close(reactor, reactor.stop)
             d.addCallback(created)
             d.addErrback(handle_config_error)
@@ -193 +200 @@
             return d
 
-        from twisted.internet import reactor
         reactor.callWhenRunning(start)
 
@@ -205 +211 @@
     def makeService(self, so):
         return DaemonizeTheRealService(self.nodetype, self.basedir, so)
+
+
+def on_stdin_close(reactor, fn):
+    """
+    Arrange for the function `fn` to run when our stdin closes
+    """
+    when_closed_d = Deferred()
+
+    class WhenClosed(Protocol):
+        """
+        Notify a Deferred when our connection is lost .. as this is passed
+        to twisted's StandardIO class, it is used to detect our parent
+        going away.
+        """
+
+        def connectionLost(self, reason):
+            when_closed_d.callback(None)
+
+    def on_close(arg):
+        try:
+            fn()
+        except Exception:
+            # for our "exit" use-case, this will _mostly_ just be
+            # ReactorNotRunning (because we're already shutting down
+            # when our stdin closes) but no matter what "bad thing"
+            # happens we just want to ignore it.
+            pass
+        return arg
+
+    when_closed_d.addBoth(on_close)
+    # we don't need to do anything with this instance because it gets
+    # hooked into the reactor and thus remembered
+    StandardIO(
+        proto=WhenClosed(),
+        reactor=reactor,
+    )
+    return None