clapeters has asked for the wisdom of the Perl Monks concerning the following question:

I have a network that I monitor for performance. Each of the many nodes creates a performance monitoring XML file every 15 minutes. I would like to be able to extract specific data from the XML files, perform calculations on those bits of data, then create a gnuplot from that. I have what I need for the chart (gnuplot), but I cannot figure out how to get the data programmatically from the XML files.

You'll notice that the XML is in a format similar to this:

counter1
counter2
counter3
counter4
  value1
  value2
  value3
  value4

[download]

I am (obviously) new to this and was hoping for some pointers to get me going. I've read XML files with PERL in the past and have had a lot of luck with XML::Simple, but I can't get this working with my current files.

Specifically, I'd like to be able to extract Counter1/Value1 & Counter3/Value3, etc.

Thanks in advance!

Sample XML below. Let's say I'm looking for <mt>pmLicUlPrbCapDistr</mt> which can be found in <r>90083,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0</r> below.

<?xml version="1.0"?>
<?xml-stylesheet type="text/xsl" href="MeasDataCollection.xsl"?>
<!DOCTYPE mdc SYSTEM "MeasDataCollection.dtd">
<mdc xmlns:HTML="http://www.w3.org/TR/REC-xml">
    <mfh>
        <ffv>32.401 V6.2</ffv>
        <sn>SubNetwork=ONRM_ROOT_MO_R,SubNetwork=SAMPLE,MeContext=LTE0
+001_SITE</sn>
        <st></st>
        <vn></vn>
        <cbt>20140401204500Z</cbt>
    </mfh>
    <md>
        <neid>
            <neun>LTE0001_SITE</neun>
            <nedn>SubNetwork=ONRM_ROOT_MO_R,SubNetwork=SAMPLE,MeContex
+t=LTE0001_SITE</nedn>
            <nesw>CXP102051/18_R21BN</nesw>
        </neid>
        <mi>
            <mts>20140401210000Z</mts>
            <gp>900</gp>
            <mt>pmPdcpPktDiscDlEth</mt>
            <mv>
                <moid>ManagedElement=1,ENodeBFunction=1</moid>
                <r>0</r>
            </mv>
        </mi>
    </md>
    <md>
        <neid>
            <neun>LTE0001_SITE</neun>
            <nedn>SubNetwork=ONRM_ROOT_MO_R,SubNetwork=SAMPLE,MeContex
+t=LTE0001_SITE</nedn>
            <nesw>CXP102051/18_R21BN</nesw>
        </neid>
        <mi>
            <mts>20140401210000Z</mts>
            <gp>900</gp>
            <mt>pmLicDlCapActual</mt>
            <mt>pmLicUlCapActual</mt>
            <mt>pmLicDlPrbCapActual</mt>
            <mt>pmLicUlPrbCapActual</mt>
            <mt>pmPdcpPktDiscDlEth</mt>
            <mt>pmPdcpPktDiscUlEthPacing</mt>
            <mt>pmLicDlCapDistr</mt>
            <mt>pmLicUlCapDistr</mt>
            <mt>pmLicDlPrbCapDistr</mt>
            <mt>pmLicUlPrbCapDistr</mt>
            <mv>
                <moid>ManagedElement=1,Equipment=1,Subrack=1,Slot=1,Pl
+ugInUnit=1,DeviceGroup=dul,BbProcessingResource=1</moid>
                <r>0</r>
                <r>0</r>
                <r>0</r>
                <r>0</r>
                <r>0</r>
                <r>0</r>
                <r>81893,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0</r>
                <r>90083,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0</r>
                <r>81893,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0</r>
                <r>90083,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0</r>
            </mv>
        </mi>
    </md>
    <mff><ts>20140401210000Z</ts></mff>
</mdc>

[download]

Replies are listed 'Best First'.
Re: Extract Data from XML (unique xml format?)
by tangent (Parson) on Jun 16, 2015 at 20:49 UTC
    I'm not sure if I understand your requirement exactly, but here is a way to extract the values using XML::LibXML and Xpaths: 
    use XML::LibXML;

my $doc = XML::LibXML->load_xml(string => $xml);
my @mds = $doc->findnodes('//md');
for my $md ( @mds ) {
    my @mts = $md->findnodes('mi/mt');
    next unless @mts;
    my @rs = $md->findnodes('mi/mv/r');
    for my $i ( 0 .. $#mts ) {
        my ( $mt, $r ) = ( $mts[$i], $rs[$i] );
        print "mt: ", $mt->textContent, "\n";
        print "r: ", $r->textContent, "\n\n";
    }
}

    [download]
    Output using your example XML: 
    mt: pmPdcpPktDiscDlEth
r: 0

mt: pmLicDlCapActual
r: 0

mt: pmLicUlCapActual
r: 0

mt: pmLicDlPrbCapActual
r: 0

mt: pmLicUlPrbCapActual
r: 0

mt: pmPdcpPktDiscDlEth
r: 0

mt: pmPdcpPktDiscUlEthPacing
r: 0

mt: pmLicDlCapDistr
r: 81893,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0

mt: pmLicUlCapDistr
r: 90083,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0

mt: pmLicDlPrbCapDistr
r: 81893,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0

mt: pmLicUlPrbCapDistr
r: 90083,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0

    [download]
[reply]
[d/l]
[select]
      use XML::LibXML;

my $string = q|
<Root>
  <Parent>
    <child1>Child 1</child1>
    <child2>Child 2</child2>
    <child3>Child 3</child3>
  </Parent>
</Root>|;

my $doc = XML::LibXML->load_xml(string => $string);
my @nodes = $doc->findnodes('//Parent');
for my $node (@nodes) {
    my @childnodes = $node->childNodes or next;
    for my $cnode (@childnodes) {
        if ($cnode->nodeName =~ m/^child/) {
            print 'name: '. $cnode->nodeName . ', ';
            print 'content: '. $cnode->textContent ."\n";
        }
    }
}

# Output:
# name: child1, content: Child 1
# name: child2, content: Child 2
# name: child3, content: Child 3

      [download]
      ESDS - Microsoft Dynamics Hosting (Microsoft Dynamics ERP Partner)
[reply]
[d/l]

        This works as well AjitKhodke. Again, I so appreciate your help and responses from all.

[reply]

      Thanks so much tangent. This appears to be exactly what I'm looking for.

      I apologize for not being more clear. It made sense in my head, but not sure that's the best indicator of clarity.

[reply]

      “++,” and, without question, this is how I would recommend doing it.

      The overwhelming-advantage of XPath is that it lets you describe, in nothing more than a simple text-string, what you want.   It’s up to the XPath engine to figure out how to do it.   The example shown performs many searches and there’s not a drop of “how” code in it.   You want such an approach, that lets you be very “what if...?” in what you search-for and subsequently plot without writing code.

        simple text string? funny

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Re: Extract Data from XML (unique xml format?)
by GotToBTru (Prior) on Jun 16, 2015 at 20:11 UTC

    As the docs for XML::Simple indicate, you probably want to use one of the more recent modules. It suggests XML::LibXML. XML::Twig is popular here on PM. My own very limited experience with XML suggests that you first need to be good with xpaths.

    Dum Spiro Spero
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Re: Extract Data from XML (unique xml format?)
by Discipulus (Canon) on Jun 16, 2015 at 20:31 UTC
    Let's say I'm looking for <mt>pmLicUlPrbCapDistr</mt> which can be found in <r>90083,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0</r> below.

    I cannot understand what are you trying to extract.
    Anyway give a try to XML::Twig as suggested

    L*
    There are no rules, there are no thumbs..
    Reinvent the wheel, then learn The Wheel; may be one day you reinvent one of THE WHEELS.
[reply]
[d/l]

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