perfSONAR User Q&A and Other Discussion

[Andrew Lake <>]

Hi Weiping,

Send an XQuery like the following to one of the global Lookup Services (gLS):

my $xquery = "declare namespace nmwg=\"http://ggf.org/ns/nmwg/base/2.0/\";\n";;
$xquery .= 
"/nmwg:store[\@type=\"LSStore\"]/nmwg:data/nmwg:metadata/summary:parameters/nmwg:parameter[\@name=\"keyword\"]";

The "value" attribute in the returned elements will contain the keywords. 
You'll have to sort out the unique ones. A list of global lookup services 
where you can send the above query are listed here: 
http://www.perfsonar.net/gls.root.hints. You only need to send the request to 
one since they should all be synced. A few on the list occasionally have 
problems so you may just want to stick to the es.net and internet2.edu 
services. 

Also the checks are case sensitive. This is a feature of xquery. There are 
some ways to make XQuery do a case insensitive search but none of them are 
that straight-forward.

Let me know if you need any clarification on the info above.

Thanks!
Andy

On Apr 30, 2010, at 2:01 PM, Weiping Mandrawa wrote:

> Andy,
> 
> Thank you for clarification and quick response.
> 
> I tested the code and it is working well.
> 
> 
> I have another question, 
> 
> let say I want to filter my lookup search based on Project name (e.g ESnet) 
> and 
> in the example code (ls-ex3-bwctl.pl)
> 
> \$keyword=\"project:ESnet\" . Is this case sensitive ? 
> and how do I get list of keyword "project"
> e.g LBNL, Internet2 etc to be used with lookup service
> 
> 
> Thank you
> 
> Kind Regards
> 
> Weiping
> 
> 
> 
> 
> 
> 
> 
>>>> Andrew Lake 
>>>> <>
>>>>  04/30/10 1:28 PM >>>
> Hi Weiping,
> 
> The html on the page was causing those lines to be displayed incorrectly. 
> The </ in the regular expression was the source of the problem. I have now 
> corrected the page. The correct code block looks like the following:
> 
> if( $hLSResult->{response} && $hLSResult->{response} =~ /^<./ ){
>            # Print list of matching bwctl server addresses
>            my $resParser = XML::LibXML->new();
>            my $hLSDoc = $resParser->parse_string($hLSResult->{response});
> 
> Also, if it helps you may download the code examples on this page here: 
> http://psps.perfsonar.net/ps-client-examples-v1.1.tar.gz. There is also a 
> link to this file on the bottom of the page.
> 
> Thanks!
> Andy
> 
> 
> On Apr 30, 2010, at 1:09 PM, Jason Zurawski wrote:
> 
>> Hello,  I am trying to understand lookup service based on the address
>> 
>> http://psps.perfsonar.net/client-doc.html
>> 
>> In the paragraph
>> 
>> The instance in the above example is the URL of an LS service to contact. 
>> Examples
>> 1. Find all SNMP Measurement Archives
>> 
>> 
>> There are examples how to crate XQuery to be sent to home lookup services
>> 
>> In the example code (XQuery to be sent up to home lookup based on Find all 
>> SNMP Measurement Archieves)
>> 
>> 
>> (Line1) if($hLSResult->{response} && $hLSResult->{response} =~ /^new();
>> (Line2)            my $hLSDoc = 
>> $resParser->parse_string($hLSResult->{response});
>> 
>> 
>> 
>> For some reason, perl can't understand (Line1) to (Line2)
>> 
>> for example
>> 
>> in Line2 , it is using $resParser but $resParser is not declared anywhere 
>> in the code
>> and when I run the code, it complains about it
>> 
>> 
>> 
>> if I change $resParser to $parser, it complains that
>> 
>> Thread 65 terminated abnormally: Can't call method "parse_string" on 
>> unblessed reference
>> 
>> 
>> Thank you
>> 
> 
>