Building notes, projects, and occasional rants

RSS your yum updates

If you like RSS and use Fedora Core 3, then you can have the nightly yum update reports delivered to you via RSS.

The following setup requires: * using fedora core 3, or having the command rss-generate in yum (check man yum); * your mail is delivered via qmail; * you can install .qmail files.

You probably could workaround the last two. I might do that someday. For now, consider this as a quick (took me less than 20 minutes after I noticed rss-generate in yum manpage :) ) hack.

The setup is simple: each night, a cron runs on each server, and generates the RSS file. The file is then sent to a special mailbox, and there we filter the message and place it in a public HTTP site. You then configure your favorite RSS reader with that URL.

First I created a email address with .qmail file in my homedir:

cat > ~/.qmail-yum <<EOF'
& [email protected]

The second line should be a good email address. If something goes wrong with the script, it will fallback to the email address. At least you’ll know that something has gone bad.

Then you place the perl script in the correct place. You can download the convert\_yum\_rss\_mails\_to\ script, or paste it:

#!/usr/bin/perl -w

# Where to place RSS files? Should be available via Web
my $dir_for_rss_files = "/var/httpd/htdocs/yum_rss";
my $server;

while (<>) {
  $server = $1 if /^Subject: Yum changes for (.+)/;
  last if /^$/;

fallback('no_server') unless $server;

my $filename = "$dir_for_rss_files/$server.xml";

fallback("could not create file '$'") unless open(RSS, ">$");
print RSS <>;

sucess() if rename("$", $filename);

fallback("could not rename file '$'");

# qmail exit codes, see qmail-command man page
sub sucess   { exit(99) }
sub fallback { my $m = shift; print STDERR "Err: $m\\n"; exit(0)  }

That’s it. If something goes wrong, check your qmail-send logs. A message is written there.

Now you only need to generate the mails on each server. To do that download the script yum-rss-report.cron. It looks like this:


/usr/bin/yum --rss-filename=/dev/fd/1 -R 120 -d 0 -e 0 generate-rss |  \\
/bin/mail -s "Yum changes for `hostname`" [email protected]

This command will generate the RSS (the -R 120 will make sure that each server will wait a random number of seconds), and mail it to your address that you set up before. Make sure you change the address in this script, and make sure you can receive mail at that address.

Then, copy the edited script to all the servers that you want to report to you. On each one, copy the script to /etc/cron.daily and make sure you make it executable:

cp yum-rss-report.cron /etc/cron.daily
chmod 555 /etc/cron.daily/yum-rss-report.cron

That’s it! Just subscribe each server in you favorite RSS reader and each morning you’ll know which servers got upgraded and to which versions.

I have some improvements to make to these scripts, but they are good enough for now.