Method collect_children

Lib/socketserver.py:563–596

Internal routine to wait for children that have exited.

(self, *, blocking=False)

        block_on_close = True

        def collect_children(self, *, blocking=False):
            """Internal routine to wait for children that have exited."""
            if self.active_children is None:
                return

            # If we're above the max number of children, wait and reap them until
            # we go back below threshold. Note that we use waitpid(-1) below to be
            # able to collect children in size(<defunct children>) syscalls instead
            # of size(<children>): the downside is that this might reap children
            # which we didn't spawn, which is why we only resort to this when we're
            # above max_children.
            while len(self.active_children) >= self.max_children:
                try:
                    pid, _ = os.waitpid(-1, 0)
                    self.active_children.discard(pid)
                except ChildProcessError:
                    # we don't have any children, we're done
                    self.active_children.clear()
                except OSError:
                    break

            # Now reap all defunct children.
            for pid in self.active_children.copy():
                try:
                    flags = 0 if blocking else os.WNOHANG
                    pid, _ = os.waitpid(pid, flags)
                    # if the child hasn't exited yet, pid will be 0 and ignored by
                    # discard() below
                    self.active_children.discard(pid)
                except ChildProcessError:
                    # someone else reaped it
                    self.active_children.discard(pid)
                except OSError:
                    pass

        def handle_timeout(self):
            """Wait for zombies after self.timeout seconds of inactivity.