#!/bin/bash
#
# A simple wrapper script to rotate the service's logs. Creates a little bit
# crafted logrotate configuration (if it doesn't exist yet) and calls the
# standard logrotate.
#
# Uses the copytruncate utility which must be available on path.
# Doesn't rotate logs for stopped services.
#
# Author: Kovács Zoltán <kovacs.zoltan@smartfront.hu>
#         Kovács Zoltán <kovacsz@marcusconsulting.hu>
# License: GNU/GPL v3+ (https://www.gnu.org/licenses/gpl-3.0.en.html)
# 2025-03-17 v1.2
# mod: rotates non-empty logs even if the service isn't running.
# 2024-08-24 v1.1
# new: docker-compose v2 compatibility - tested with Ubuntu 24.04 LTS.
# 2023-06-18 v1.0
# new: forked from the "Smartfront's DOCKER_skeleton" repository.
# 2021-09-14 v0.2
# add: Rotates the web logs (if any) as well.
# 2021-09-02 v0.1 Initial release

# Accepted environment variables and their defaults.
PAR_BASEDIR=${PAR_BASEDIR:-""}                  # Service's base folder
PAR_CONFDIR=${PAR_CONFDIR:-""}              	# Folder containing configs
PAR_LOGDIR=${PAR_LOGDIR:-""}              	# Folder containing logs

# Other initialisations.
CONFDIR="configs"				# Folder containing configs
LOGDIR="logs"					# Folder containing logs
YMLFILE="docker-compose.yml"

# Messages.
MSG_MISSINGDEP="Fatal: missing dependency"

# Basic environment settings.
LANG=C
LC_ALL=C
# We need also the sbin directories.
if ! [[ "$PATH" =~ '/sbin:' ]]; then
PATH="$PATH:/usr/local/sbin:/usr/sbin:/sbin"; fi

# Checks the dependencies.
TR=$(which tr 2>/dev/null)
if [ -z "$TR" ]; then echo "$MSG_MISSINGDEP tr."; exit 1 ; fi
for item in basename date dirname docker logrotate readlink
do
    if [ -n "$(which $item)" ]
    then export $(echo $item | "$TR" '[:lower:]' '[:upper:]' | "$TR" '-' '_')=$(which $item)
    else echo "$MSG_MISSINGDEP $item." >&2; exit 1; fi
done
# All dependencies are available via "$THECOMMAND" (upper case) call.
#
# Let's find which version of docker-compose is installed.
if [ $($DOCKER compose version 2>&1 >/dev/null; echo $?) -eq 0 ]; then
    # We'll use v2 if it is available.
    DOCKER_COMPOSE="$DOCKER"
    commandstring="compose"
else
    # Otherwise falling back to v1.
    DOCKER_COMPOSE="$(which docker-compose)"
    commandstring=""
fi
# One of the two is mandatory.
if [ -z "$DOCKER_COMPOSE" ];then echo "$MSG_MISSINGDEP docker-compose" >&2; exit 1; fi
# Below docker-compose should be called as "$DOCKER_COMPOSE" $commandstring sequence.

# Where I'm?
# https://gist.github.com/TheMengzor/968e5ea87e99d9c41782
SOURCE="${BASH_SOURCE[0]}"
while [ -h "$SOURCE" ]; do
    # resolve $SOURCE until the file is no longer a symlink
    SCRPATH="$( cd -P "$( "$DIRNAME" "$SOURCE" )" && pwd )" #"
    SOURCE="$("$READLINK" "$SOURCE")"
    # if $SOURCE was a relative symlink, we need to resolve it
    # relative to the path where the symlink file was located
    [[ $SOURCE != /* ]] && SOURCE="$SCRPATH/$SOURCE"
done; SCRPATH="$( cd -P "$( "$DIRNAME" "$SOURCE" )" && pwd )" #"
SCRFILE="$("$BASENAME" "$(test -L "$0" && "$READLINK" "$0" || echo "$0")")" #"

# Searches the base folder, containing a docker-compose.yml file.
# Called from the base folder (./)?
BASE_DIR="$PAR_BASEDIR"
TEST_DIR="$SCRPATH"
[[ -z "$BASE_DIR" ]] && [[ -r "$TEST_DIR/$YMLFILE" ]] && BASE_DIR="$TEST_DIR"
# Called from ./tools?
TEST_DIR="$("$DIRNAME" "$TEST_DIR")"
[[ -z "$BASE_DIR" ]] && [[ -r "$TEST_DIR/$YMLFILE" ]] && BASE_DIR="$TEST_DIR"
# Called from ./tools/*.d?
TEST_DIR="$("$DIRNAME" "$TEST_DIR")"
[[ -z "$BASE_DIR" ]] && [[ -r "$TEST_DIR/$YMLFILE" ]] && BASE_DIR="$TEST_DIR"
# On failure gives it up here.
if [ -z "$BASE_DIR" -o ! -r "$BASE_DIR/$YMLFILE" ]; then
    echo "$MSG_MISSINGYML" >&2; exit 1
fi

# Sets the absolute paths.
CONFDIR="${PAR_CONFDIR:-$BASE_DIR/$CONFDIR}"
CONFFILE="$CONFDIR/.${SCRFILE%.*}.conf"
STATEFILE="$CONFDIR/.${SCRFILE%.*}.state"
LOGDIR="${PAR_LOGDIR:-$BASE_DIR/$LOGDIR}"

# Locates the worker script.
WORKERSCRIPT="$SCRPATH/copytruncate"
[[ ! -x "$WORKERSCRIPT" ]] && WORKERSCRIPT="$(which copytruncate)"
[[ ! -x "$WORKERSCRIPT" ]] \
&& echo -e "$MSG_MISSINGDEP $WORKERSCRIPT." >&2 \
&& exit 1

# Creates the configuration if it doesn't exist yet.
if [ ! -e "$CONFFILE" ]; then
    cat > "$CONFFILE" << EOF
$LOGDIR/*.log {
  missingok
  daily
  rotate 30
  notifempty
# Must be consistent with prerotate script's settings!
  dateext
  dateyesterday
  dateformat %Y-%m-%d.
  extension log
  compress
# We'll use our own copytruncate script, because:
# * we haven't permission to change ownership, so the built-in copytruncate
#   method would fail (this is a bug in logrotate, I think);
# * we haven't permission to reload the service, so the create new log method
#   doesn't work - the service would still write to the already rotated file.
# The custom script:
# * copytruncates files having (by default) .log extesion and compresses the copy
#   (and returns with 1 exit code, thus, the logrotate will skip this file).
# * does nothing with files having any other extensions - e.g .1, .2 and so on
#   (and returns with 0 exit code, thus, the logrotate can process this file);
  prerotate
    $WORKERSCRIPT \$1
  endscript
# Only if the prerotate script didn't process it yet.
  copytruncate
}

$LOGDIR/web/*.log {
  missingok
  daily
  rotate 60
  notifempty
# Must be consistent with prerotate script's settings!
  dateext
  dateyesterday
  dateformat %Y-%m-%d.
  extension log
  compress
# We'll use our own copytruncate script, because:
# * we haven't permission to change ownership, so the built-in copytruncate
#   method would fail (this is a bug in logrotate, I think);
# * we haven't permission to reload the service, so the create new log method
#   doesn't work - the service would still write to the already rotated file.
# The custom script:
# * copytruncates files having (by default) .log extesion and compresses the copy
#   (and returns with 1 exit code, thus, the logrotate will skip this file).
# * does nothing with files having any other extensions - e.g .1, .2 and so on
#   (and returns with 0 exit code, thus, the logrotate can process this file);
  prerotate
    $WORKERSCRIPT \$1
  endscript
# Only if the prerotate script didn't process it yet.
  copytruncate
}
EOF
fi

# Rotates the logs.
"$LOGROTATE" -s "$STATEFILE" "$CONFFILE"

# That's all, Folks! :)