list targets

As correctly pointed out by dhoogfr , the proper way to list targets on an agent is to use list target


$ emctl config agent listtargets
Oracle Enterprise Manager Cloud Control 13c Release 2
Copyright (c) 1996, 2016 Oracle Corporation.  All rights reserved.
[srv01.example.com, host]
[srv01.example.com:3872, oracle_emd]
[agent13c2_2_srv01.example.com_3830, oracle_home]
[DB01.example.com, oracle_database]
[OraDB12Home1_14_srv01.example.com_743, oracle_home]
[DB01_srv01.example.com_CDBROOT, oracle_pdb]
[DB01_srv01.example.com_PDB01, oracle_pdb]
[LISTENER001_srv01.example.com, oracle_listener]

Not really easy to parse, and it does not contain all information. Let’s imagine I want to get the TARGET_NAME out of my SID? hard…

What is actually emctl doing ? It is parsing the targets.xml with perl. Oracle wrote a module, called ias::simpleXPath, that helps parsing the file.


$AGENT_HOME/perl/bin/perl -l -I$AGENT_HOME/sysman/admin/scripts -Mias::simpleXPath -e '
  foreach $t(
    simpleXPathQueryForNodes(
      "targets.xml","Targets/Target")){
    print 
      "[".($t->{"attributes"}->{"NAME"}).
      ", ".($t->{"attributes"}->{"TYPE"}).
      "]"}'

ias::simpleXPath is a wrapper for XML::Parser. XML::Parser is a supported perl that is included in the agent home. So no need to install your own perl modules for this purpose!

back to by example, if I want to get the target name for my SID DB01


$AGENT_HOME/perl/bin/perl -l -MXML::Parser -e '
  $xmlfile = "targets.xml";
  die "Cannot find file $xmlfile"
    unless -f $xmlfile;
  $parser = new XML::Parser;
  $parser->setHandlers(
    Start => \&startElement,
    End => \&endElement);
  $parser->parsefile($xmlfile);
  sub startElement {
    ( $parseinst, $element, %attrs ) = @_;
    if ($element eq "Target") {
      $tn=$attrs{"NAME"};
      $tt=$attrs{"TYPE"};
    }
    if ($element eq "Property" &&
        $attrs{"NAME"} eq "SID" ) {
      $sid=$attrs{"VALUE"};
    }
  }
  sub endElement {
    ( $parseinst, $element ) = @_;
    if ($element eq "Target"){
      if (
        lc $sid eq lc "DB01"
      ) {
        print $tn . ":" . $tt;
      }
      $sid="";
    }
  }
'
DB01.example.com:oracle_database

This could be useful, for instance if you want to start a blackout


emctl start blackout db01_black DB01.example.com:oracle_database

For listener, you could retrieve the LsnrName for your listener LISTENER001


$AGENT_HOME/perl/bin/perl -l -MXML::Parser -e '
  $xmlfile = "targets.xml";
  die "Cannot find file $xmlfile"
    unless -f $xmlfile;
  $parser = new XML::Parser;
  $parser->setHandlers(
    Start => \&startElement,
    End => \&endElement);
  $parser->parsefile($xmlfile);
  sub startElement {
    ( $parseinst, $element, %attrs ) = @_;
    if ($element eq "Target") {
      $tn=$attrs{"NAME"};
      $tt=$attrs{"TYPE"};
    }
    if ($element eq "Property" &&
        $attrs{"NAME"} eq "LsnrName" ) {
      $lsn=$attrs{"VALUE"};
    }
  }
  sub endElement {
    ( $parseinst, $element ) = @_;
    if ($element eq "Target"){
      if (
        lc $lsn eq lc "LISTENER001"
      ) {
        print $tn . ":" . $tt;
      }
      $lsn="";
    }
  }
'
LISTENER001_srv01.example.com:oracle_listener

Which you could also blackout before rebooting.

The parser is not limited to Entreprise Manager targets, you could use it for oraInventory/ContentsXML/inventory.xml or whatever files.

There are plenty of other mean to read xml, from the database, xmllint, powershell.

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