Source Code for Module rosh.impl.service

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 33  # Revision $Id: service.py 13210 2011-02-14 01:05:08Z kwc $ 
 34   
 35  from __future__ import with_statement 
 36   
 37  import sys 
 38   
 39  import roslib.message 
 40   
 41  import rosgraph.masterapi 
 42  import rosmsg 
 43  import rosservice 
 44  import rospy 
 45   
 46  from rosh.impl.exceptions import ROSHException 
 47  from rosh.impl.namespace import Namespace, Concept 
 48   
 49 -def Service(service_name, service_type, handler): 
 50      if type(service_name) == Namespace: 
 51          return rospy.Service(service_name._name, service_type, handler) 
 52      else: 
 53          return rospy.Service(service_name, service_type, handler) 
 54   
 55 -def get_service_class_by_service_name(service_name): 
 56      #TODO: this is technically a bug because it doesn't use the ctx's 
 57      #master handle 
 58      type_name = rosservice.get_service_type(service_name) 
 59      if type_name: 
 60          val = roslib.message.get_service_class(type_name, reload_on_error=True) 
 61          if not val: 
 62              pkg, base_type = roslib.names.package_resource_name(type_name) 
 63              print >> sys.stderr, """Cannot retrieve type [%s]. 
 64  Please type 'rosmake %s' 
 65  """%(type_name, pkg) 
 66          else: 
 67              return val 
 68   
 69 -class ServiceInfo(object): 
 70 -    def __init__(self, name, node, uri): 
 71          self.name, self.node, self.uri = name, node, uri 
 72 -    def __repr__(self): 
 73          return self.__str__() 
 74 -    def __str__(self): 
 75          return "Name: %s\nNode: %s\nURI: %s"%(self.name, self.node, self.uri) 
 76           
 77   
 78 -def service_info(config, name): 
 79      master = config.ctx.master 
 80      try: 
 81          uri = master.lookupService(name) 
 82      except rosgraph.masterapi.Error: 
 83          return None 
 84   
 85      #TODO: convert rosservice to take in master handle 
 86      #can't use rosservice because it doesn't let us pass in master 
 87      #handle 
 88      _, _, srvs = master.getSystemState() 
 89      l = [nodelist for s, nodelist in srvs if s == name][0] 
 90      node_name = l[0] 
 91      node = config.ctx.nodes[node_name] 
 92      return ServiceInfo(name, node, uri) 
 93   
 94 -class ServiceNS(Namespace): 
 95   
 96 -    def __init__(self, name, config): 
 97          """ 
 98          ctor. 
 99          @param config: Namespace configuration instance. Safe to set 
100          to None if self._config is initialize proper to calling any 
101          methods. 
102          @type  config: L{NamespaceConfig} 
103          """ 
104          super(ServiceNS, self).__init__(name, config) 
105          self._type = self._service_info = None 
106          self._init_type() 
107          self._is_wait_for_service = True # per API review 
108   
109 -    def _info(self): 
110          """ 
111          info() API 
112          """ 
113          if self._service_info is None: 
114              self._service_info = service_info(self._config, self._name) 
115          return self._service_info 
116       
117 -    def _list(self): 
118          """ 
119          Override Namespace._list() 
120          """ 
121          # hide rosh services 
122          return [s for s in rosservice.get_service_list(namespace=self._ns) if not s.startswith('/rosh_')] 
123   
124 -    def _get_type(self): 
125          "rostype() API" 
126          return self._type 
127           
128 -    def _set_type(self, type_): 
129          "rostype() API" 
130          self._init_type(type_) 
131       
132 -    def _init_type(self, t=None): 
133          if self._type is not None and t is None: 
134              # already initialized 
135              return 
136           
137          if t is None: 
138              try: 
139                  self._type = get_service_class_by_service_name(self._name) 
140                  self._type_name = self._type._type 
141              except: 
142                  # right now the contract of init_type is to 
143                  # soft-fail and require callers to check _type 
144                  # state 
145                  self._type = self._type_name = None 
146          else: 
147              if type(t) == str: 
148                  t = roslib.message.get_service_class(t) 
149                  if t is None: 
150                      raise ValueError("cannot load service type: %s"%(t)) 
151              else: 
152                  if not type(t) == type: 
153                      raise ValueError("invalid service type: %s"%(type(t))) 
154                  if not issubclass(t, roslib.message.ServiceDefinition): 
155                      raise ValueError("invalid service type: %s"%(t.__class__.__name__)) 
156              self._type = t 
157              self._type_name = t._type 
158           
159 -    def __repr__(self): 
160          return self.__str__() 
161   
162 -    def __str__(self): 
163          if self._type is None: 
164              self._init_type() 
165          if self._type is None: 
166              return self._ns 
167          else: 
168              return rosmsg.get_srv_text(self._type._type) 
169   
170 -    def _props(self): 
171          return ['wait_for_service'] 
172   
173 -    def _set_wait_for_service(self, val): 
174          self._is_wait_for_service = val 
175           
176 -    def __call__(self, *args, **kwds): 
177          """ 
178          Call service 
179          """ 
180          # lazy-init 
181          if self._type is None: 
182              self._init_type() 
183          if self._type is None: 
184              raise ROSHException("cannot call service [%s]: unknown type"%(self._ns)) 
185          # TODO: cache ServiceProxy objects for faster creation 
186          # TODO: optimize wait_for_service to use ctx.master for faster calling 
187          if self._is_wait_for_service: 
188              rospy.wait_for_service(self._ns) 
189          request = self._type._request_class(*args, **kwds) 
190          return rospy.ServiceProxy(self._ns, self._type)(request) 
191       
192 -class Services(Concept): 
193   
194 -    def __init__(self, ctx, lock): 
195          super(Services, self).__init__(ctx, lock, ServiceNS) 
196