ROS Master on android is throwing error while closing connection

asked 2018-04-18 12:51:53 -0600

vvyogi
53 ●8 ●10 ●14

updated 2018-04-18 13:36:27 -0600

I am running a public ROS master on an android phone and I am able to subscribe and publish to nodes (running on Android) side from PC.

It appears that whenever I close the existing connection (by pressing Ctrl+C) from the PC side. The ROS master running on android throws the following error

04-18 23:23:05.318 23100-23150/? E/XmlRpcErrorLogger: No such handler: system.multicall
org.apache.xmlrpc.server.XmlRpcNoSuchHandlerException: No such handler: system.multicall
    at org.apache.xmlrpc.server.AbstractReflectiveHandlerMapping.getHandler(AbstractReflectiveHandlerMapping.java:214)
    at org.apache.xmlrpc.server.XmlRpcServerWorker.execute(XmlRpcServerWorker.java:45)
    at org.apache.xmlrpc.server.XmlRpcServer.execute(XmlRpcServer.java:86)
    at org.apache.xmlrpc.server.XmlRpcStreamServer.execute(XmlRpcStreamServer.java:200)
    at org.apache.xmlrpc.webserver.Connection.run(Connection.java:208)
    at org.apache.xmlrpc.util.ThreadPool$Poolable$1.run(ThreadPool.java:68)

Apart from this error, the master is also throwing `Connection refused' messages.

04-19 00:11:00.557 25453-25908/? I/HttpMethodDirector: I/O exception (java.net.ConnectException) caught when processing request: Connection refused
04-19 00:11:00.558 25453-25908/? I/HttpMethodDirector: Retrying request
04-19 00:11:00.567 25453-25908/? I/HttpMethodDirector: I/O exception (java.net.ConnectException) caught when processing request: Connection refused
    Retrying request
04-19 00:11:00.576 25453-25458/? I/art: Do partial code cache collection, code=28KB, data=30KB
04-19 00:11:00.576 25453-25908/? I/HttpMethodDirector: I/O exception (java.net.ConnectException) caught when processing request: Connection refused
04-19 00:11:00.577 25453-25908/? I/HttpMethodDirector: Retrying request
04-19 00:11:00.580 25453-25458/? I/art: After code cache collection, code=28KB, data=30KB
    Increasing code cache capacity to 128KB
04-19 00:11:00.588 25453-25906/? E/UpdatePublisherRunnable: java.lang.RuntimeException: java.net.ConnectException: Connection refused
04-19 00:11:00.599 25453-25534/? D/Echo node:  ACDEFGHIJKLMNOPQRSTUVWXYZ TEST TEST TEST
04-19 00:11:09.071 25453-25524/? E/XmlRpcErrorLogger: No such handler: system.multicall
    org.apache.xmlrpc.server.XmlRpcNoSuchHandlerException: No such handler: system.multicall
        at org.apache.xmlrpc.server.AbstractReflectiveHandlerMapping.getHandler(AbstractReflectiveHandlerMapping.java:214)
        at org.apache.xmlrpc.server.XmlRpcServerWorker.execute(XmlRpcServerWorker.java:45)
        at org.apache.xmlrpc.server.XmlRpcServer.execute(XmlRpcServer.java:86)
        at org.apache.xmlrpc.server.XmlRpcStreamServer.execute(XmlRpcStreamServer.java:200)
        at org.apache.xmlrpc.webserver.Connection.run(Connection.java:208)
        at org.apache.xmlrpc.util.ThreadPool$Poolable$1.run(ThreadPool.java:68)

Also, I have observed a pattern. When publishing first time with rostopic pub /topic_name, the message goes through without error. Then if I break (Ctrl+C) and resend, the pub request is met with the above error (second code snippet) and then the message gets through.

Has anyone else faced such an error?
It appears to be a bug (it is not pointing to any of files created be me). Is this a serious issue and is there a fix for this?

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answered 2018-04-18 13:45:27 -0600

gvdhoorn
86574 ●283 ●1432 ●1054 http://cor.tudelft.nl/

updated 2018-04-18 13:46:39 -0600

This is / was a known issue and should be fixed in the most recent binary packages / the next release.

See rosjava/android_core#236, fixed in rosjava/rosjava_core#273.

It would appear that at least #q205122 is a duplicate of this.

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If I may suggest: use Google for these things, especially if you have such an explicit error message. Just copy-paste the error message and press search. Good chance you'll get some informative results. It's not that we don't want to help, but searching yourself will be much faster.