Bash script to merge NGINX logrotate files.

merge_nginx_logrotated.sh

#!/bin/bash
print_cron_rules() { echo "ClNFVCBDUk9OVEFCOgoKQGhvdXJseSAvdXNyL2Jpbi9tZXJnZV9uZ2lueF9sb2dyb3RhdGVkLnNoIC92YXIvbG9nL25naW54IGhvdXIKQGRhaWx5IC91c3IvYmluL21lcmdlX25naW54X2xvZ3JvdGF0ZWQuc2ggL3Zhci9sb2cvbmdpbnggZGF5CkB3ZWVrbHkgL3Vzci9iaW4vbWVyZ2VfbmdpbnhfbG9ncm90YXRlZC5zaCAvdmFyL2xvZy9uZ2lueCB3ZWVrCkBtb250aGx5IC91c3IvYmluL21lcmdlX25naW54X2xvZ3JvdGF0ZWQuc2ggL3Zhci9sb2cvbmdpbnggbW9udGgKCg==" | base64 -d; }
usage() { echo "Usage: ${BASH_SOURCE[0]} [DIR] [ hour | day | week | month ] <error>"; print_cron_rules; exit 1; } ; if [[ "$#" -lt 1 ]]; then usage; fi
DIR="$(realpath "${1}")"
TIME="${2:-hour}"
ERROR_LOG="${3:-false}"
ZSTD_LEVEL="19"
MERGE_ROTATED_LOCKFILE="/tmp/MERGE_ROTATED_IS_RUNNING.${TIME}.lock"
hour() { date +hour.%d-%m-%Y_%Hh%Mm%Ss.%A ; }
day() { date +day.%d-%m-%Y_%Hh%Mm.%A ; }
week() { date +week.%U.%d-%m-%Y_%Hh%Mm ; }
month() { date +month.%d-%m-%Y_%Hh%Mm.%B ; }
TIMESTAMP="$(${TIME})"; DATE_TIME="$(date -u "+%Y-%m-%d %H:%M:%S %Z")"; ME="$(basename "$0")"
# exit_with_failure() outputs a message before exiting the script.
exit_with_failure() { echo; echo "FAILURE: $1"; echo; del_lock; exit 1; }
# command_exists() tells if a given command exists. | check_command() check if command exists and exit if not exists
command_exists() { command -v "$1" >/dev/null 2>&1; }; check_command() { if ! command_exists "$1"; then exit_with_failure "Command '$1' not found"; fi; }
# set_lock() sets lock file
set_lock() { if ! echo "$DATE_TIME" > "$MERGE_ROTATED_LOCKFILE"; then exit_with_failure "Can not create lock file '$MERGE_ROTATED_LOCKFILE'"; fi; }
# del_lock() delets lock file
del_lock() { rm -f "$MERGE_ROTATED_LOCKFILE"; }
# check_lock() checks lock file and exit if the file exists
check_lock() { if [[ -f "$MERGE_ROTATED_LOCKFILE" ]]; then exit_with_failure "$ME is already running. Please wait... In case of problems simply delete the file: '$MERGE_ROTATED_LOCKFILE'"; fi; }


# MAIN
check_lock
set_lock
check_command zstd; check_command zcat

if [[ !  -d "${DIR}/merged" ]]; then
	exit_with_failure "'${DIR}/merged' directory not found, please create it"
fi

if [[ "${TIME}" == "hour" ]]; then
	mkdir -p "${DIR}/merged/hour"
	zcat $(ls -1rt ${DIR}/access.log.*.gz) | zstd -f -${ZSTD_LEVEL} -o "${DIR}/merged/hour/${TIMESTAMP}.zst"
	rm $(ls -1rt ${DIR}/access.log.*.gz)
	if [[ "${ERROR_LOG}" == "error" ]]; then
	        zcat $(ls -1rt ${DIR}/error.log.*.gz) | zstd -f -${ZSTD_LEVEL} -o "${DIR}/merged/hour/error.${TIMESTAMP}.zst"
		rm $(ls -1rt ${DIR}/error.log.*.gz)
	fi
fi

if [[ "${TIME}" == "day" ]]; then
	mkdir -p "${DIR}/merged/day"
	zstdcat $(ls -1rt ${DIR}/merged/hour/hour.*.zst) | zstd -f -${ZSTD_LEVEL} -o "${DIR}/merged/day/${TIMESTAMP}.zst"
	rm $(ls -1rt ${DIR}/merged/hour/hour.*.zst)
        if [[ "${ERROR_LOG}" == "error" ]]; then
		zstdcat $(ls -1rt ${DIR}/merged/hour/error.hour.*.zst) | zstd -f -${ZSTD_LEVEL} -o "${DIR}/merged/day/error.${TIMESTAMP}.zst"
		rm $(ls -1rt ${DIR}/merged/hour/error.hour.*.zst)
	fi
fi

if [[ "${TIME}" == "week" ]]; then
        mkdir -p "${DIR}/merged/week"
        zstdcat $(ls -1rt ${DIR}/merged/day/day.*.zst) | zstd -f -${ZSTD_LEVEL} -o "${DIR}/merged/week/${TIMESTAMP}.zst"
	rm $(ls -1rt ${DIR}/merged/day/day.*.zst)
        if [[ "${ERROR_LOG}" == "error" ]]; then
		zstdcat $(ls -1rt ${DIR}/merged/day/error.day.*.zst) | zstd -f -${ZSTD_LEVEL} -o "${DIR}/merged/week/error.${TIMESTAMP}.zst"
		rm $(ls -1rt ${DIR}/merged/day/error.day.*.zst)
	fi
fi

if [[ "${TIME}" == "month" ]]; then
        mkdir -p "${DIR}/merged/month"
        zstdcat $(ls -1rt ${DIR}/merged/week/week.*.zst) | zstd -f -${ZSTD_LEVEL} -o "${DIR}/merged/month/${TIMESTAMP}.zst"
	rm $(ls -1rt ${DIR}/merged/week/week.*.zst)
        if [[ "${ERROR_LOG}" == "error" ]]; then
		zstdcat $(ls -1rt ${DIR}/merged/week/error.week.*.zst) | zstd -f -${ZSTD_LEVEL} -o "${DIR}/merged/month/error.${TIMESTAMP}.zst"
		rm $(ls -1rt ${DIR}/merged/week/error.week.*.zst)
	fi
fi

del_lock