feat: log anonymizer

scripts/utils/logs/anonymize_logs.pl

@@ -0,0 +1,77 @@
+#!/usr/bin/perl -w
+
+=head1 LOG ANONYMIZER
+
+This script takes a log file and anonymizes it
+by replacing the IP addresses by a random IP address.
+
+This is to be compliant to GDPR while keeping logs for eventual statistics.
+
+Typically at some point in time, you would use this command on /var/log/nginx/mysite.log.*,
+move anonimized logs to a backup directory,
+and remove the original files.
+
+=cut
+
+use strict;
+use warnings;
+
+use Date::Parse qw(str2time);
+use POSIX qw(strftime);
+
+my $usage = "Usage: $0 < log file > [< log file > ...]\n";
+
+die($usage) unless (scalar @ARGV);
+
+sub int_to_ip($) {
+    my $number = shift;
+    # thank you cody
+    my ($a, $b, $c, $d) = ($number >> 24, ($number >> 16) & 0xFF, ($number >> 8) & 0xFF, $number & 0xFF);
+    return sprintf("%d.%d.%d.%d", $a, $b, $c, $d);
+}
+
+my %ip_to_anon = ();
+my $ip_next = 2**24;
+
+foreach my $fname (@ARGV) {
+    my ($start, $end); # start and end dates in the log file
+    print "Processing $fname\n";
+    my $target = "$fname.anonymized.gz";
+    my $modifier = "";
+    my $pipe = "<";
+    if ($fname =~ /\.gz$/) {
+        $modifier = "gunzip -c ";
+        $pipe = "-|";
+    }
+    open(my $IN, $pipe, "$modifier$fname") or die("Could not open $fname: $!");
+    open(my $OUT, "|-", "gzip > $target") or die("Could not create $target: $!");
+    while (my $line = <$IN>) {
+        if ($line =~ /(^\S+) /) {
+            if (not defined $ip_to_anon{$1}) {
+                # create an anonymous ip
+                $ip_to_anon{$1} = int_to_ip($ip_next++);
+            }
+            # substitute
+            $line =~ s/(^\S+) /$ip_to_anon{$1} /;
+        }
+        if ($line =~ m<\[(\d+/\w+/\d+:\d{2}:\d{2}:\d{2} \+\d+)\]>) {
+            my $line_epoch = str2time($1);
+            $start = $line_epoch if !defined $start || $line_epoch < $start;
+            $end = $line_epoch if !defined $end || $line_epoch > $end;
+        }
+        print $OUT $line;
+	}
+    close($IN);
+    close($OUT);
+    # rename target to reflect dates
+    if ($start && $end) {
+        my $start_str = strftime("%Y-%m-%d", gmtime($start));
+        my $end_str = strftime("%Y-%m-%d", gmtime($end));;
+        # put date after .log
+        my $new_target = $target;
+        # add time range but keep timestamp for the case of several rotation in a single day
+        $new_target =~ s/^(.+)\.log(\..*)?$/$1.$start_str--$end_str.$start.anonymized.log.gz/;
+        rename($target, $new_target) or print STDERR "Could not rename $target to $fname: $!";
+    }
+}
+