def monitor_process(self, origin_pid: Pid, target, ref=None):
""" Locate the process referenced by the target and place the origin
pid into its ``monitors_`` collection. When something happens to the
``target``, a special message will be sent to the ``origin``.
Remote targets are supported.
:param ref: If not None, will be reused, else a new random ref will
be generated.
:type ref: None or term.reference.Reference
:type origin_pid: term.pid.Pid
:param origin_pid: The (possibly remote) process who will be monitoring
the target from now and wants to know when we exit.
:type target: term.pid.Pid or term.atom.Atom
:param target: Name or pid of a monitor target process.
:rtype: term.reference.Reference
:raises pyrlang.node.ProcessNotFoundError: if target does not exist.
"""
target_pid = self.where_is(target)
m_ref = ref if ref is not None \
else Reference.create(node_name=self.node_name_,
creation=self.dist_.creation_)
if not origin_pid.is_local_to(self):
# Origin is remote and wants to monitor local process
return self._monitor_local_process(origin_pid, target_pid, m_ref)
if target_pid.is_local_to(self):
# Target is local and we notify a local process
return self._monitor_local_process(origin_pid, target_pid, m_ref)
# Target is remote and a distribution message has to be sent
return self._monitor_remote_process(origin_pid, target_pid, m_ref)
def _monitor_remote_process(self, origin_pid: Pid, target_pid: Pid,
ref: Reference):
monitor_msg = ('monitor_p', origin_pid, target_pid, ref)
self._dist_command(receiver_node=target_pid.node_name_,
message=monitor_msg)
# if the origin is local, register monitor in it. Remote pids are
# handled by the remote
assert origin_pid.is_local_to(self)
origin_p = self.where_is_process(origin_pid)
origin_p.add_monitor(pid=target_pid, ref=ref)
def _demonitor_local_process(self, origin_pid: Pid, target_pid: Pid,
ref: Reference):
target_proc = self.processes_.get(target_pid, None)
if target_proc is not None:
target_proc.remove_monitored_by(ref=ref, pid=origin_pid)
else:
msg = "Demonitor target %s does not exist" % target_pid
LOG.error(msg)
raise ProcessNotFoundError(msg)
# if the origin is local, unregister monitor from it
# Remotely set monitors have remote origin
if origin_pid.is_local_to(self):
origin_p = self.where_is_process(origin_pid)
origin_p.remove_monitor(ref=ref, pid=target_pid)
def _monitor_local_process(self, origin_pid: Pid, target_pid: Pid,
ref: Reference):
""" Monitor a local target. """
target_proc = self.processes_.get(target_pid, None)
# LOG.info("Monitor: orig=%s targ=%s -> %s", origin, target, target_proc)
if target_proc is not None:
target_proc.add_monitored_by(pid=origin_pid, ref=ref)
else:
msg = "Monitor target %s does not exist" % target_pid
LOG.error(msg)
raise ProcessNotFoundError(msg)
# if the origin is local, register monitor in it.
# Remotely set monitors have remote origin
if origin_pid.is_local_to(self):
origin_p = self.where_is_process(origin_pid)
origin_p.add_monitor(pid=target_proc.pid_, ref=ref)