journald support of postfix_mail* plugins

plugins/node.d/postfix_mailstats

@@ -1,9 +1,10 @@
 #!/usr/bin/perl -w
+# -*- perl -*-
 
 =head1 NAME
 
 postfix_mailstats - Plugin to monitor the number of mails delivered and
-rejected by postfix
+rejected by postfix, with support for journald logs
 
 =head1 CONFIGURATION
 
@@ -13,15 +14,22 @@ if you need to override the defaults below:
  [postfix_mailstats]
   env.logdir  - Which logfile to use
   env.logfile - What file to read in logdir
+  env.use_journald - Set to 1 to use journald instead of a logfile
+  env.journalctlargs
 
 =head2 DEFAULT CONFIGURATION
 
  [postfix_mailstats]
   env.logdir  /var/log
   env.logfile mail.log
+  env.use_journald 0
+  env.journalctlargs [email protected]
 
 =head1 AUTHOR
 
+Original plugin contributed by Nicolai Langfeldt,
+extended for journald support by Stephan Kleber with some help by ChatGPT.
+
 Records show that the plugin was contributed by Nicolai Langfeldt in
 2003.  Nicolai can't find anything in his email about this and expects
 the plugin is based on the corresponding exim plugin - to which it now
@@ -46,77 +54,125 @@ munin-node.
 =cut
 
 use strict;
-
 use Munin::Plugin;
 
+my $statefile = $ENV{'MUNIN_PLUGSTATE'} . "/munin-plugin-postfix_mailstats.state";
 my $pos;
-my $delivered;
-my $LOGDIR  = (defined($ENV{'logdir'}) ? $ENV{'logdir'} : '/var/log');
-my $LOGFILE = (defined($ENV{'logdir'}) ? $ENV{'logfile'} : 'mail.log');
+my $delivered = 0;
+my %rejects = ();
+
+my $LOGDIR      = $ENV{'logdir'}  || '/var/log';
+my $LOGFILE     = $ENV{'logfile'} || 'mail.log';
+my $USE_JOURNALD = $ENV{'use_journald'} || 0;
+my $journalctlargs = $ENV{'journalctlargs'} // '[email protected]';
 
 my $logfile = "$LOGDIR/$LOGFILE";
 
-if ( defined($ARGV[0]) and $ARGV[0] eq "autoconf" )
+if ( $ARGV[0] and $ARGV[0] eq "autoconf" )
 {
-    if (-d $LOGDIR)
-    {
-        if (-f $logfile)
+    if ($USE_JOURNALD) {
+        # Check if journalctl command is available
+        if (system("which journalctl > /dev/null 2>&1") == 0) {
+            print "yes\n";
+            exit 0;
+        } else {
+            print "no (journalctl not found)\n";
+            exit 0;
+        }
+    } else {
+        # Logfile handling
+        if (-d $LOGDIR)
         {
-            if (-r $logfile)
+            if (-f $logfile)
             {
-                print "yes\n";
-                exit 0;
+                if (-r $logfile)
+                {
+                    print "yes\n";
+                    exit 0;
+                }
+                else
+                {
+                    print "no (logfile '$logfile' not readable)\n";
+                }
             }
             else
             {
-                print "no (logfile '$logfile' not readable)\n";
+                print "no (logfile '$logfile' not found)\n";
             }
         }
         else
         {
-            print "no (logfile '$logfile' not found)\n";
+            print "no (could not find logdir '$LOGDIR')\n";
         }
     }
-    else
-    {
-        print "no (could not find logdir '$LOGDIR')\n";
-    }
 
     exit 0;
 }
 
-my @state = restore_state();
-
-$pos = shift @state;
-$delivered = shift @state;
-
-$pos = 0 unless defined($pos);
-$delivered = 0 unless defined($delivered);
-
-my %rejects = @state;
+if ($USE_JOURNALD) {
+    if (!defined $pos)
+    {
+        # Initial run.
+        $pos = 0;
+    }
 
-if (! -f $logfile)
-{
-    print "delivered.value U\n";
-    foreach my $reason (sort keys %rejects)
+    # Parse logs from journald
+    parseJournald();
+} else {
+    # Load statefile if it exists
+    if ( -f $statefile)
     {
-        my $fieldname = clean_fieldname("r$reason");
-        print "$fieldname.value U\n";
+        open (IN, '<', $statefile) or die "Unable to open state-file: $!\n";
+        if (<IN> =~ /^(\d+):(\d+)/)
+        {
+            ($pos, $delivered) = ($1, $2);
+        }
+        while (<IN>)
+        {
+            if (/^([0-9a-z.\-]+):(\d+)$/)
+            {
+                $rejects{$1} = $2;
+            }
+        }
+        close IN;
+    }
+
+    # Logfile handling
+    if (! -f $logfile)
+    {
+        print "delivered.value U\n";
+        foreach my $reason (sort keys %rejects)
+        {
+            my $fieldname = clean_fieldname("r$reason");
+            print "$fieldname.value U\n";
+        }
+        exit 0;
     }
-    exit 0;
-}
 
+    my $startsize = (stat $logfile)[7];
 
-my $startsize = (stat $logfile)[7];
+    if (!defined $pos)
+    {
+        # Initial run.
+        $pos = $startsize;
+    }
 
-if (!defined $pos)
-{
-    # Initial run.
+    parseLogfile($logfile, $pos, $startsize);
     $pos = $startsize;
+
+    # Save statefile
+    if(-l $statefile) {
+        die("$statefile is a symbolic link, refusing to touch it.");
+    }
+    open (OUT, '>', $statefile) or die "Unable to open statefile: $!\n";
+    print OUT "$pos:$delivered\n";
+    foreach my $i (sort keys %rejects)
+    {
+        print OUT "$i:", $rejects{$i}, "\n";
+    }
+    close OUT;
 }
 
-$pos = parseLogfile($logfile, $pos, $startsize);
-
 if ( $ARGV[0] and $ARGV[0] eq "config" )
 {
     print "graph_title Postfix message throughput\n";
@@ -148,31 +204,60 @@ foreach my $reason (sort keys %rejects)
     print "$fieldname.value ", $rejects{$reason}, "\n";
 }
 
-save_state($pos, $delivered, %rejects);
-
+# Function to parse logs from a regular logfile
 sub parseLogfile
 {
     my ($fname, $start, $stop) = @_;
+    open (LOGFILE, $fname)
+        or die "Unable to open logfile $fname for reading: $!\n";
+    seek (LOGFILE, $start, 0)
+        or die "Unable to seek to $start in $fname: $!\n";
 
-	my ($logfd, $reset) = tail_open($fname, $start);
-
-    while (tell($logfd) < $stop)
+    while (tell (LOGFILE) < $stop)
     {
-	my $line = <$logfd>;
-	chomp ($line);
-
-	if ($line =~ / to=.*, status=sent /)
-	{
-	    $delivered++;
-	}
-	elsif ($line =~ /postfix\/smtpd.*proxy-reject: \S+ (\S+)/ ||
-	       $line =~ /postfix\/smtpd.*reject: \S+ \S+ \S+ (\S+)/ ||
-	       $line =~ /postfix\/postscreen.*reject: \S+ \S+ \S+ (\S+)/ ||
-	       $line =~ /postfix\/cleanup.* reject: (\S+)/ ||
-	       $line =~ /postfix\/cleanup.* milter-reject: \S+ \S+ \S+ (\S+)/)
-	{
-	    $rejects{$1}++;
-	}
+        my $line = <LOGFILE>;
+        chomp ($line);
+
+        if ($line =~ / to=.*, status=sent /)
+        {
+            $delivered++;
+        }
+        elsif ($line =~ /postfix\/smtpd.*proxy-reject: \S+ (\S+)/ ||
+               $line =~ /postfix\/smtpd.*reject: \S+ \S+ \S+ (\S+)/ ||
+               $line =~ /postfix\/cleanup.* reject: (\S+)/ ||
+               $line =~ /postfix\/cleanup.* milter-reject: \S+ \S+ \S+ (\S+)/)
+        {
+            $rejects{$1}++;
+        }
     }
-    return tail_close($logfd);
+    close(LOGFILE) or warn "Error closing $fname: $!\n";
 }
+
+# Function to parse logs from journald
+sub parseJournald
+{
+    my $cmd;
+    $cmd = "journalctl --no-pager --quiet --since=" . `date -dlast-sunday +%Y-%m-%d` . " $journalctlargs";
+    open(my $journal, '-|', $cmd) 
+        or die "Unable to read journald logs: $!\n";
+
+    while (my $line = <$journal>) {
+        chomp($line);
+
+        if ($line =~ / to=.*, status=sent /)
+        {
+            $delivered++;
+        }
+        elsif ($line =~ /postfix\/smtpd.*proxy-reject: \S+ (\S+)/ ||
+               $line =~ /postfix\/smtpd.*reject: \S+ \S+ \S+ (\S+)/ ||
+               $line =~ /postfix\/postscreen.*reject: \S+ \S+ \S+ (\S+)/ ||
+               $line =~ /postfix\/cleanup.* reject: (\S+)/ ||
+               $line =~ /postfix\/cleanup.* milter-reject: \S+ \S+ \S+ (\S+)/)
+        {
+            $rejects{$1}++;
+        }
+    }
+    close($journal) or warn "Error closing journald stream: $!\n";
+}
+
+# vim:syntax=perl