Demonstration of compressing and purging old logs

purge_remote_logs.sh

#!/bin/bash
# Compress and purge old logs
# by Stefan Midjich

# Compress logs older than X months
compressAge=2
# Purge logs older than X months
purgeAge=3

# Where are logs?
logBase=/var/log/remote

# Make no edits below this line if you want to live.
compressTime=$(date -d "$compressAge months ago" +%s)
purgeTime=$(date -d "$purgeAge months ago" +%s)
compressMonth=$(date -d @"$compressTime" +%m)
purgeMonth=$(date -d @"$purgeTime" +%m)

# Recursively compress all *.log files in $dir
compress () {
  dir=$1
  shift

  if [ ! -d "$dir" ]; then
    return 1
  fi

  for file in $dir/*; do
    if [ -f "$file" ]; then
      xz -z "$file"
    fi
    if [ -d "$file" ]; then
      compress "$file"
    fi
  done
}

# Reset year to same year as compressMonth
year=$(date -d @"$compressTime" +%Y)

# Check input
if [ -z "$logBase" -o -z "$year" -o -z "$purgeMonth" -o -z "$compressMonth" ]; then
  logger -p local0.error -t purge_remote_logs "Must configure script, see comments, exiting..."
  exit 1
fi

# Compress old logs
for dir in $logBase/$year/??; do
  if [ "$(basename $dir)" -eq $compressMonth ]; then
    logger -p local0.debug -t purge_remote_logs "Reached $dir, bailing on compress"
    break
  fi

  logger -p local0.info -t purge_remote_logs "Compressing logs in $dir" && compress "$dir" &>/dev/null

  # Reset permissions
  find "$dir" -type f -exec chmod 0640 {} \;
done

# Reset year before purging old logs
year=$(date -d @"$purgeTime" +%Y)

# Purge old logs
if [ -d "$logBase/$year/$purgeMonth" ]; then
  logger -p local0.info -t purge_remote_logs "Removing $logBase/$year/$purgeMonth" && rm -rf "$logBase/$year/$purgeMonth"
fi