ROS 机器人源码分析之 self._launch_core_nodes() rosout/rosout

<pre class="python" name="code">    def _launch_core_nodes(self):
        """
        launch any core services that are not already running. master must
        be already running
        @raise RLException: if core launches fail
        """
        config = self.config
        master = config.master.get()
        tolaunch = []
        for node in config.nodes_core:
            node_name = rosgraph.names.ns_join(node.namespace, node.name)
            code, msg, _ = master.lookupNode(_ID, node_name)
            if code == -1:
                tolaunch.append(node)
            elif code == 1:
                print("core service [%s] found" % node_name)
            else:
                print("WARN: master is not behaving well (unexpected return value when looking up node)", file=sys.stderr)
                self.logger.error("ERROR: master return [%s][%s] on lookupNode call"%(code,msg))
                
        for node in tolaunch:
            node_name = rosgraph.names.ns_join(node.namespace, node.name)
            name, success = self.launch_node(node, core=True)
            if success:
                print("started core service [%s]" % node_name)
            else:
                raise RLException("failed to start core service [%s]"%node_name)

 

 ../../roslaunch/nodeprocess.py(290)start()
self.popen = subprocess.Popen(self.args, cwd=cwd, stdout=logfileout, stderr=logfileerr, env=full_env, close_fds=True, preexec_fn=os.setsid)

self.args:

[u'/../../rosout/rosout', u'__name:=rosout', u'__log:=/../../.ros/log/845a5a02-69dc-11e6-8965-000c290414d4/rosout-1.log']