Savelogs

The savelogs program rotates logs, optionally saving the old ones elsewhere and signalling the programs that created the logfiles.

Description

/etc/savelogs.conf tells savelogs which logs to rotate, when to rotate them, whether to back them up, and what to do after a log is rotated.
The format of the configuration file is a filename, followed by a list of commands, with punctuation and case ignored:

• every {day|week|year}
  Rotate the log at this time. If you tell it WEEK (YEAR), the rotation will happen on a sunday (the last sunday of the year).

• save n in directory
  Save n old logs in the named directory as o.logfile. Any existing o. file will be renamed to oo.file to accomodate the new file (so the old o.log becomes oo.log, and so on), up to the number of files you want to save.

• touch mode
  After rotating the old log, create a new (empty) log with the given mode.

• size size
  Rotate the log if it gets larger than this size. If you suffix the size with K, the size is in kilobytes, and a M suffix means megabytes.

• signal action After rotating a log and touching it, run this command. savelogs attempts to batch signal, so that if multiple logs are rotated the actions will only be executed once.

For example, the following configuration file

/var/adm/syslog EVERY WEEK
            SAVE 2 IN /var/adm/OLD
            TOUCH 644
            SIGNAL "killall -HUP syslogd"

Rotates /var/adm/syslog every sunday, creating a new empty file with mode 644, saving two of the old logs in /var/adm/OLD, and sending a HUP signal to syslogd after it’s finished.

Source Code

=Version 1.5= Many many many feature changes

 1. Allow, globally and on a file by file basis, saving
    backups to numbered (_NN.file_) instead of
    dotted (_ooo.file_) names.
 2. Allow, globally and on a file by file basis, backup file
    compression.
 3. Set, globally and on a file by file basis, the format
    of the backup file from _ooo.file_ to _file.ooo_.

In addition, the code has been ported to more systems,
from recent versions of [freebsd][] ([macos][], to be
precise) to modern commercial [linux][]es.

=Version 1.4= Discard the old handbuilt parser and switch over to using lex and yacc. I wanted to do some tweaking of the features for savelogs and decided that it was enough of a pain so that this was the time to discard my hand-built parser for a generated one.

=Version 1.3= This version allows multiple SIGNALs per file, so I can do something like rotate many syslogs, hup syslogd, then hup a cwatch process if and only if /var/log/messages was one of those syslogs. I also made the code more portable by fitting it out with my autoconfiguration scripts. Savelogs now properly builds on pell, which is an SLS Linux system, egypt, which is my primary Mastodon build box, and downbelow, which runs an elderly version of FreeBSD.

=Version 1.1= The first version under version control.