#!perl

use 5.012; # strict, //
use warnings;
use JSON;


# create the JSON object from a string (you could get it from a file, or whatever)
my $json = JSON->new->allow_nonref();
my $string = <<EOT;
{
  "infra": {
    "config": {
      "rack": [
        {
          "componentId": "xxx-001",
          "model": "xxx",
          "server": [
            {
              "componentId": "server-001",
              "type": "xxxx",
              "model": "xxxx",
              "role": "Management",
              "specificAttributes": ""
            }
          ]
        }]
    },
    "platform": {
      "config": {
        "mgmtser": [{
          "componentId": "sr-001",
          "domainName": "xxxxx",
          "thinDiskMode": true,
          "deployment": "small"
            }
         ]}
     }
  }
}
EOT
my $href = $json->decode($string);

#recurse through the top level
my @retvals = h_recurse($href);
use Data::Dumper; print Dumper @retvals;
exit;

# define two subroutines, for recursing a hashref or an arrayref

sub h_recurse {
    my $r = shift;
    my @ret = ();
    die "'$r' not a hashref" unless UNIVERSAL::isa($r,'HASH');

    # go through each pair
    while(my ($key,$val) = each %$r ) {
        # if it's a hash or array ref, recurse into it; add the returns from the recursion to your active return list
        push @ret, h_recurse($val) if UNIVERSAL::isa($val,'HASH');
        push @ret, a_recurse($val) if UNIVERSAL::isa($val,'ARRAY');

        # if a literal key/value pair matches your requirements, add it to your return list
        push @ret, $r if $key eq 'componentId'; # change the logic here if you want only componentId whose value matches something specific
    }
    # once done, 
    return @ret;
}

sub a_recurse {
    my $r = shift;
    my @ret = ();
    die "'$r' not an arrayref" unless UNIVERSAL::isa($r,'ARRAY');
    for my $val (@$r) {
        push @ret, h_recurse($val) if UNIVERSAL::isa($val,'HASH');
        push @ret, a_recurse($val) if UNIVERSAL::isa($val,'ARRAY');
    }
    return @ret;
}