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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