Perl language example

The environment and shared library classes provide information about the environment and libraries associated with an AE. This example takes one argument, an integer. If the integer equals 0, the AE outputs the environment it sees. If the integer equals 1, the AE looks the environment up as a library.

package Libenv;
use nzae::Ae;
use strict;
use autodie;
our @ISA = qw(nzae::Ae);
my $ae = Libenv->new();
$ae->run();
sub _run()
{
my $self = shift;
$self->iter();
}
sub iter()
{
#use while loop over library function getNext()
my $self = shift;
while ($self->getNext())
{
my @row = $self->getInputRow();
my $size = scalar(@row);
my $env;
if ($size > 0)
{
if ( $row[0] == 0 )
{
$env = $self->getEnvironment();
}
else
{
$env = $self->yieldSharedLibraries();
}
unless(defined $env)
{
$self->userError("Error fetching information");
}
my $limit = defined $row[1]? $row[1] : undef;
try
{
for my $key ( keys %$env )
{
$self->output($key, $env->{$key});
if ( defined $limit && $limit)
{
$limit--;
if ($limit == 0)
{
last;
}
}
}
}
catch
{
croak(nzae::Exceptions::AeInternalError->new(longmess("Error writing
output")));
};
}
else
{
$self->userError("Error fetching row");
}
}
}
1;

Deploy the script:

$NZ_EXPORT_DIR/ae/utilities/bin/compile_ae --language perl --version 3 \
--template deploy Libenv.pm

Register the example:

$NZ_EXPORT_DIR/ae/utilities/bin/register_ae --language perl --version 3 \
--template udtf --exe Libenv.pm --sig "lib_env(int4, int4)" \
--return "table(name varchar(1000), value varchar(1000))"

Given a positive integer value, the second argument acts as a limit to the number of results returned. This is used in place of keyword LIMIT to exit the AE cleanly when the number of results returned must be limited.

Note that the output from this example is specific to the environment. Therefore, your actual output will resemble, but not match, the following text.

SELECT * FROM TABLE WITH FINAL(lib_env(1, 3));
NAME | VALUE
-----------------+---------------------------------------------------
LIBNZAEPARENT | /nz/data.1.0/base/317943/library/319587/host/libnzaeparent.so
LIBNZAEADAPTERS |
/nz/data.1.0/base/317943/library/319331/host/libnzaeadapters.so
LIBNZAECHILD | /nz/data.1.0/base/317943/library/319332/host/libnzaechild.so
(3 rows)
SELECT * FROM TABLE WITH FINAL (lib_env(0, 5));
NAME VALUE
------------------------------------+---------------
NZAE_RUNTIME_USER_QUERY | 1
NPS_PLATFORM | xs
NZAE_OUTPUT_COLUMNS | 1,1
NZAE_DEBUG_LEVEL | 0
NZAE_REMOTE_NAME_DATA_SLICE | 0
(5 rows)