subname enhanced ROS dynamic reconfigure server

dynamic_reconfigure_server2.py

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"""
Python client API for dynamic_reconfigure (L{DynamicReconfigureClient}) as well as 
example server implementation (L{DynamicReconfigureServer}).
"""

# This is an enhanced version of
# driver_common/dynamic_reconfigure/src/dynamic_reconfigure/server.py
# to support the "subname" parameter.

from __future__ import with_statement

import roslib; roslib.load_manifest('dynamic_reconfigure')
import rospy
import rosservice                  
import threading
import time
from dynamic_reconfigure import DynamicReconfigureCallbackException
from dynamic_reconfigure.srv import Reconfigure as ReconfigureSrv
from dynamic_reconfigure.msg import Config as ConfigMsg
from dynamic_reconfigure.msg import ConfigDescription as ConfigDescrMsg
from dynamic_reconfigure.msg import IntParameter, BoolParameter, StrParameter, DoubleParameter, ParamDescription
from dynamic_reconfigure.encoding import *

class Server(object):
    def __init__(self, type, callback, subname = None):
        self.mutex = threading.Lock()
        self.type = type
        self.config = type.defaults.copy() # (see https://code.ros.org/trac/ros/ticket/3394 )

        self.subname = subname
        if subname is None:
            self._prefix = '~'
        else:
            self._prefix = subname + '/'

        self.description = encode_description(type)
        self._copy_from_parameter_server()
        self.callback = callback
        self._clamp(self.config) 

        self.descr_topic = rospy.Publisher(self._prefix+'parameter_descriptions', ConfigDescrMsg, latch=True)
        self.descr_topic.publish(self.description);
        
        self.update_topic = rospy.Publisher(self._prefix+'parameter_updates', ConfigMsg, latch=True)
        self._change_config(self.config, type.all_level)
        
        self.set_service = rospy.Service(self._prefix+'set_parameters', ReconfigureSrv, self._set_callback)

    def update_configuration(self, changes):
        with self.mutex:
            new_config = dict(self.config)
            new_config.update(changes)
            self._clamp(new_config)
            return self._change_config(new_config, self._calc_level(new_config, self.config))

    def _copy_from_parameter_server(self):
        for param in self.type.config_description:
            try:
                self.config[param['name']] = rospy.get_param(self._prefix + param['name'])
            except KeyError:
                pass

    def _copy_to_parameter_server(self):
        for param in self.type.config_description:
            rospy.set_param(self._prefix + param['name'], self.config[param['name']])

    def _change_config(self, config, level):
        if self.subname != '':
            # call the callback with the subname
            self.config = self.callback(config, level, subname=self.subname)
        else:
            # backwards-compatible call to callback
            self.config = self.callback(config, level)
        if self.config is None:
            msg = 'Reconfigure callback should return a possibly updated configuration.'
            rospy.logerr(msg)
            raise DynamicReconfigureCallbackException(msg)
        
        self._copy_to_parameter_server()
        
        self.update_topic.publish(encode_config(self.config))

        return self.config
   
    def _calc_level(self, config1, config2):
        level = 0
        for param in self.type.config_description:
            if config1[param['name']] != config2[param['name']]:
                level |= param['level']

        return level

    def _clamp(self, config):
        for param in self.type.config_description: 
            maxval = self.type.max[param['name']] 
            minval = self.type.min[param['name']] 
            val = config[param['name']]
            if val > maxval and maxval != "": 
                config[param['name']] = maxval 
            elif val < minval and minval != "": 
                config[param['name']] = minval 

    def _set_callback(self, req):
        return encode_config(self.update_configuration(decode_config(req.config)))

dynamic_server.patch

--- dynamic_reconfigure/src/dynamic_reconfigure/server.py	2012-08-17 09:30:37.331027429 +0200
+++ /tmp/dynamic_reconfigure_server2.py	2012-08-17 09:26:57.360940524 +0200
@@ -35,6 +35,10 @@
 example server implementation (L{DynamicReconfigureServer}).
 """
 
+# This is an enhanced version of
+# driver_common/dynamic_reconfigure/src/dynamic_reconfigure/server.py
+# to support the "subname" parameter.
+
 from __future__ import with_statement
 
 import roslib; roslib.load_manifest('dynamic_reconfigure')
@@ -50,22 +54,29 @@
 from dynamic_reconfigure.encoding import *
 
 class Server(object):
-    def __init__(self, type, callback):
+    def __init__(self, type, callback, subname = None):
         self.mutex = threading.Lock()
         self.type = type
-        self.config = type.defaults
+        self.config = type.defaults.copy() # (see https://code.ros.org/trac/ros/ticket/3394 )
+
+        self.subname = subname
+        if subname is None:
+            self._prefix = '~'
+        else:
+            self._prefix = subname + '/'
+
         self.description = encode_description(type)
         self._copy_from_parameter_server()
         self.callback = callback
         self._clamp(self.config) 
 
-        self.descr_topic = rospy.Publisher('~parameter_descriptions', ConfigDescrMsg, latch=True)
+        self.descr_topic = rospy.Publisher(self._prefix+'parameter_descriptions', ConfigDescrMsg, latch=True)
         self.descr_topic.publish(self.description);
         
-        self.update_topic = rospy.Publisher('~parameter_updates', ConfigMsg, latch=True)
+        self.update_topic = rospy.Publisher(self._prefix+'parameter_updates', ConfigMsg, latch=True)
         self._change_config(self.config, type.all_level)
         
-        self.set_service = rospy.Service('~set_parameters', ReconfigureSrv, self._set_callback)
+        self.set_service = rospy.Service(self._prefix+'set_parameters', ReconfigureSrv, self._set_callback)
 
     def update_configuration(self, changes):
         with self.mutex:
@@ -77,16 +88,21 @@
     def _copy_from_parameter_server(self):
         for param in self.type.config_description:
             try:
-                self.config[param['name']] = rospy.get_param("~" + param['name'])
+                self.config[param['name']] = rospy.get_param(self._prefix + param['name'])
             except KeyError:
                 pass
 
     def _copy_to_parameter_server(self):
         for param in self.type.config_description:
-            rospy.set_param('~' + param['name'], self.config[param['name']])
+            rospy.set_param(self._prefix + param['name'], self.config[param['name']])
 
     def _change_config(self, config, level):
-        self.config = self.callback(config, level)
+        if self.subname != '':
+            # call the callback with the subname
+            self.config = self.callback(config, level, subname=self.subname)
+        else:
+            # backwards-compatible call to callback
+            self.config = self.callback(config, level)
         if self.config is None:
             msg = 'Reconfigure callback should return a possibly updated configuration.'
             rospy.logerr(msg)

This allows one node to run multiple dynamic reconfigure Servers simultaneously. This is useful in the case where a single process (node) controls multiple pieces of hardware, each with their own config.

In the server code, make an instance of Server while setting the subname keyword argument in the constructor to a string:

srv1 = dynamic_reconfigure_server2.Server(DisplayConfig,
                                                   self.display_callback1,
                                                   subname='/displays/display1' )

Then (likely from another node), get a client by calling dynamic_reconfigure.client.Client('/displays/display1').

I should note that this is a fork of the ROS cturtle dynamic_reconfigure_server.py file.

Also, this code fixes a subtle bug in the original code.

For comparison with a recent question on answers.ros.org, I just updated this to include my code as a patch file against the original.