Appendix L. Appendix - Troubleshooting, hints and tips for client users

L.1. How do I get a resource properties document?
L.2. When using a client I get an error concerning an unknown resource
L.3. When using a client I get an error concerning an unknown activity
L.4. When using a client my request completes with an error
L.5. When using a client I get an error concerning a server error
L.6. When using a client I get an error concerning an unknown resource but I know the resource is available and correctly configured
L.7. What happens if the client times out during a synchronous request?

L.1. How do I get a resource properties document?

Resource properties documents aren't currently supported for OGSA-DAI OMII-UK.

L.2. When using a client I get an error concerning an unknown resource

If a resource has been configured incorrectly then clients may be informed by the OGSA-DAI server that the resource is unknown. The OGSA-DAI server logs will provide information about why the configuration is incorrect.

Alternatively errors in resource configuration may only be realised when a request is submitted that contains activities that use the resource. e.g.

A problem has occured...
[1185804665299:2] uk.org.ogsadai.client.toolkit.REQUEST_COMPLETED_WITH_ERROR : ogsadai-114177657b5

The actual request execution status will contain more information in the entry for the activity that tried to use the resource.

L.3. When using a client I get an error concerning an unknown activity

Problems with activity configurations are manifested at the client-side as follows. For example:

[1185805382056:3] uk.org.ogsadai.client.toolkit.REQUEST_ERROR : ogsadai-11417822efa
[1185805382057:4] uk.org.ogsadai.GENERAL_REQUEST_USER_EXCEPTION
[1185805382057:5] uk.org.ogsadai.GENERAL_ACTIVITY_USER_EXCEPTION
[1185805382057:6] uk.org.ogsadai.UNSUPPORTED_ACTIVITY : uk.org.ogsadai.ListDirectoryX, FileResource

Either the client has specified an activity unknown to the resource or the activity is not known to the server.

L.4. When using a client my request completes with an error

These are caused when one or more activities in the request encounter or raise an error. These are manifested client-side as follows:

[1195650926263:4] uk.org.ogsadai.client.toolkit.REQUEST_COMPLETED_WITH_ERROR :
 ogsadai-116616aa6d9
...

Such problems can be caused by:

  • The client. For example:
    • The client provides an argument or value to an activity that is incorrect e.g. a syntactically incorrect query statement or a query that cites an unknown table or XML document.
    • An activity provides an argument or value to another activity that does not match the type expected by the activity.
  • The server. For example:
    • An activity provides an argument or value to another activity that is incorrect.
    • A resource or other component used by an activity has been badly configured or runs into some problem that is not the client's fault.

L.5. When using a client I get an error concerning a server error

This may be manifested client-side as follows:

[1185805813092:1] uk.org.ogsadai.client.toolkit.REQUEST_ERROR : ogsadai-1141788c349
[1185805813092:2] uk.org.ogsadai.SERVER_ERROR_WITH_HOST : 1185805812851:2, coal.epcc.ed.ac.uk

This means there is a problem on the OGSA-DAI server and you (or the OGSA-DAI server administrator) should check the OGSA-DAI server logs for the error with the given ID.

L.6. When using a client I get an error concerning an unknown resource but I know the resource is available and correctly configured

This might be evidenced as follows when when invoking operations on OGSA-DAI OMII-UK services:

 
{http://ogsadai.org.uk/namespaces/2007/04/service/execution}resourceUnknownFault:
<ns2:id xmlns:ns2="http://ogsadai.org.uk/namespaces/2007/04/service/faults">
  uk.org.ogsadai.RESOURCE_UNKNOWN_ERROR
</ns2:id>
<ns3:msg xmlns:ns3="http://ogsadai.org.uk/namespaces/2007/04/service/faults">
  [1179491427865:0] uk.org.ogsadai.RESOURCE_UNKNOWN_ERROR : null
</ns3:msg>
<ns4:parameter xmlns:ns4="http://ogsadai.org.uk/namespaces/2007/04/service/faults">
null
</ns4:parameter>

The most common cause of this is not having the file client-config.wsdd in a directory that is in your client's CLASSPATH

L.7.  What happens if the client times out during a synchronous request?

If a synchronous request takes a long time then the client connection to the OGSA-DAI server (via the data request execution service) may time out. In such circumstances, the OGSA-DAI server will continue to execute the workflow submitted by the client. There is however no way for the client to access their data since there is no means of getting the ID of the request (as known to the server) back to the client. This is a further argument in favour of the use of asynchronous requests for workflows that may have long execution times.