@util.synchronized("watcher_set_opt")
    def set_opt(self, key, val):
        action = 0

        if key in self._options:
            self._options[key] = val
            action = -1    # XXX for now does not trigger a reload
        elif key == "numprocesses":
            val = int(val)
            if val < 0:
                val = 0
            if self.singleton and val > 1:
                raise ValueError('Singleton watcher has a single process')
            self.numprocesses = val
        elif key == "warmup_delay":
            self.warmup_delay = float(val)
        elif key == "working_dir":
            self.working_dir = val
            action = 1
        elif key == "uid":
            self.uid = util.to_uid(val)
            action = 1
        elif key == "gid":
            self.gid = util.to_gid(val)
            action = 1
        elif key == "send_hup":
            self.send_hup = val
        elif key == "stop_signal":
            self.stop_signal = util.to_signum(val)
        elif key == "stop_children":
            self.stop_children = util.to_bool(val)
        elif key == "shell":
            self.shell = val
            action = 1
        elif key == "env":
            if PY2 and IS_WINDOWS:
                # Windows on Python 2 does not accept Unicode values
                # in env dictionary
                self.env = dict((b(k), b(v)) for k, v in val.iteritems())
            else:
                self.env = val
            action = 1
        elif key == "cmd":
            self.cmd = val
            action = 1
        elif key == "args":
            self.args = val
            action = 1
        elif key == "graceful_timeout":
            self.graceful_timeout = float(val)
            action = -1
        elif key == "max_age":
            self.max_age = int(val)
            action = 1
        elif key == "max_age_variance":
            self.max_age_variance = int(val)
            action = 1
        elif (key.startswith('stdout_stream') or
              key.startswith('stderr_stream')):
            action = self._reload_stream(key, val)
        elif key.startswith('hooks'):
            val = val.split(',')
            if len(val) == 2:
                ignore_error = util.to_bool(val[1])
            else:
                ignore_error = False
            hook = val[0]
            self._reload_hook(key, hook, ignore_error)
            action = 0

        # send update event
        self.notify_event("updated", {"time": time.time()})
        return action
Set a watcher option.
dataset/ETHPy150Open circus-tent/circus/circus/watcher.py/Watcher.set_opt