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perlawkreadfilelogfile

how to read a particular string from the log file inside a perl script


sample log,

2016-03-29 10:57:28 UTC 642 [31871] INFO node information: {"datacenter": "TEST-DC", "infraType": "saas", "service": "fusion", "extraInfo": {"systemType": "secondary-ha1", "tenantType": "sales", "tenantName": "sale1"}

I want to read "tenantName": "sale1" and the final string I need is "sale1"

tried with awk and cut inside the Perl script but didn't work out Any suggestions and/or hints will be appreciable

I got the solution with the answer from @Sobrique

used the modules JSON & List::MoreUtils

find( \&Count, $logDir);

my @uniqtotal = uniq @totCount;
$totalcount = @uniqtotal;

sub Count {
    if( $File::Find::name =~m!$logDir/(.*?)/$pattern! and -f $File::Find::name ) {
    my $jsonLine = `grep 'tenantName' $File::Find::name`;
    if ($jsonLine ne "") {
      $jsonLine =~ m/(\{.*\})/ ; 
      my $json_text = $1;
      my $json = decode_json ( $json_text ); 
      push @totCount, $json -> {extraInfo} -> {tenantName};
    }
   }
}

Solution

  • Don't awk and sed inside a perl script anyway.

    This is JSON, so best parsed as JSON.

    #!/usr/bin/env perl
    
    use strict;
    use warnings;
    
    use JSON;
    
    while ( <> ) {
       my ( $json_text ) = m/(\{.*\})/; 
       my $json = decode_json ( $json_text ); 
       print $json -> {extraInfo} -> {tenantName};
    }
    

    Or simplifying down to one liners, because that's the hoopy thing to be doing:

    perl -MJSON -ne 'print decode_json (/(\{.*\})/ && $1)->{extraInfo}{tenantName}'