Improve script

Move code to functions.
Manage arguments.
debug and error dedicated messages.
Exit with error message if a command fails.

ceph/ceph.backup.deb.files.sh

@@ -9,58 +9,218 @@
 # }}}
 
 # Vars {{{
-DEBUG=1
+PROGNAME=$(basename "${0}"); readonly PROGNAME
+PROGDIR=$(readlink -m $(dirname "${0}")); readonly PROGDIR
+ARGS="${*}"; readonly ARGS
+readonly NBARGS="${#}"
+[ -z "${DEBUG}" ] && DEBUG=1
 
-CEPH_DEB_PKG_DIR=$(mktemp --directory --tmpdir="/tmp" -- ceph-deb-files-XXXXXX.tmp)
+# Default values for some vars
-CEPH_DEB_PKG_PATTERN="ceph|Ceph|rados|RADOS|rbd|rgw"
+CEPH_VERSION_DEFAULT=$(ceph version | cut -d" " -f3)
+BKP_DIR_DEFAULT="/srv/ceph"
 
-CEPH_VERSION=$(ceph version | cut -d" " -f3)
+## Colors
+readonly PURPLE='\033[1;35m'
+readonly RED='\033[0;31m'
+readonly RESET='\033[0m'
+readonly COLOR_DEBUG="${PURPLE}"
+# }}}
+usage() {                                                       # {{{
+
+	cat <<- EOF
+usage: $PROGNAME [-d]
+
+Try to download all deb files of all Ceph related packages installed
+on the system (eg. ceph, rbd, rados,…) and create one tar file.
+
+EXAMPLES :
+    - Backup Ceph related packages to default directory (${BKP_DIR_DEFAULT})
+        ${PROGNAME}
+
+    - Store tar files to a different location
+        ${PROGNAME} --dir /opt/backup/ceph
+
+OPTIONS :
+    -d,--dir,--directory
+        Path to store tar files
+        (default: ${BKP_DIR_DEFAULT})
+
+    --debug
+        Enable debug messages.
+
+    --help
+        Print this help message.
+EOF
+
+}
+# }}}
+debug_message() {                                               # {{{
+
+	local_message="${1}"
+
+	## Print message if DEBUG is enable (=0)
+	[ "${DEBUG}" -eq "0" ] && printf '\e[1;35m%-6b\e[m\n' "DEBUG − ${PROGNAME} : ${local_message}"
+
+	return 0
+}
+# }}}
+error_message() {                                               # {{{
+
+	local_error_message="${1}"
+	local_error_code="${2}"
+
+	## Print error message
+	printf '%b\n' "ERROR − ${PROGNAME} : ${RED}${local_error_message}${RESET}"
+
+	exit "${local_error_code:=66}"
+}
+# }}}
+define_vars() {                                                 # {{{
+
+	# If BKP_DIR wasn't defined (argument) {{{
+	if [ -z "${BKP_DIR}" ]; then
+		## Use default value
+		BKP_DIR="${BKP_DIR_DEFAULT}"
+	fi
+	# }}}
+	# If CEPH_VERSION wasn't defined (argument) {{{
+	if [ -z "${CEPH_VERSION}" ]; then
+		## Use default value
+		CEPH_VERSION="${CEPH_VERSION_DEFAULT}"
+	fi
+	# }}}
+	# If CEPH_VERSION remains empty {{{
+	if [ -z "${CEPH_VERSION}" ]; then
+		error_message "Can't get ceph version. \
+Ensure you have enought permissions to run \`ceph\` command." 01
+	fi
+	# }}}
 
-BKP_DIR="/srv/ceph"
 	BKP_TAR_PATH="${BKP_DIR}/ceph-deb_${CEPH_VERSION}-$(date +%Y%m%d).tar"
 
 	EXISTENT_BACKUP_TAR="$(find "${BKP_DIR}" -type f -iname "ceph-deb_${CEPH_VERSION}*")"
+	CEPH_DEB_PKG_PATTERN="ceph|Ceph|rados|RADOS|rbd|rgw"
+
+	## Temp file vars {{{
+	CEPH_DEB_PKG_DIR=$(mktemp --directory --tmpdir="/tmp" -- ceph-deb-files-XXXXXX.tmp)
+	## }}}
+
+}
 # }}}
 
-# If Ceph is installed on the system
+main() {                                                        # {{{
-if [ "$(command -v ceph)" ]; then
 
-	# and no backup of this version already exists
+	## If Ceph is not available on the system {{{
-	if [ ! "${EXISTENT_BACKUP_TAR}" ]; then
+	### AND Exit with error
-		## Ensure to create backup directory
+	! command -v ceph >/dev/null \
-		mkdir -p -- "${BKP_DIR}"
+		&& error_message "Ceph doesn't seems to be available on this host. Please take a look to \`ceph version\` command." 11
+	## }}}
 
-		## Create and go to a temp directory
+	## Define all vars
-		cd -- "${CEPH_DEB_PKG_DIR}" > /dev/null || exit 2
+	define_vars
+
+	## If a backup already exists {{{
+	### AND Print debug message
+	### AND Delete temp directory
+	### AND Exit
+	test -f "${EXISTENT_BACKUP_TAR}" \
+		&& debug_message "A backup of this version already exists : ${EXISTENT_BACKUP_TAR}" \
+		&& rmdir -- "${CEPH_DEB_PKG_DIR}" \
+		&& exit 0
+	## }}}
+
+	## Ensure backup directory exists
+	mkdir --parents -- "${BKP_DIR}"
+
+	## Go to temp directory
+	cd -- "${CEPH_DEB_PKG_DIR}" > /dev/null \
+		|| error_message "Can't cd to ${CEPH_DEB_PKG_DIR}" 12
 
 	## Download deb files of all ceph related packages installed on the system
-		## Use aptitude before Debian Stretch because apt doesn't yet know "download" action
+	debug_message "Download (with apt) deb files of all ceph related packages installed on the system."
-		if [ "$(cat /etc/debian_version | cut -d"." -f1)" -lt "9" ]; then
+	apt download -- $(dpkg -l | awk -v pattern="${CEPH_DEB_PKG_PATTERN}" '$0~pattern {print $2"="$3}') 2>/dev/null \
-			[ "${DEBUG}" -eq "0" ] && printf '%b\n' "Download (with aptitude) deb files of all ceph related packages installed on the system."
+		|| error_message "Can't download Ceph related packages (pattern: ${CEPH_DEB_PKG_PATTERN})." 13
-			aptitude download -- $(dpkg -l | awk -v pattern="${CEPH_DEB_PKG_PATTERN}" '$0~pattern {print $2"="$3}') || exit 3
-		else
-			[ "${DEBUG}" -eq "0" ] && printf '%b\n' "Download (with apt) deb files of all ceph related packages installed on the system."
-			apt download -- $(dpkg -l | awk -v pattern="${CEPH_DEB_PKG_PATTERN}" '$0~pattern {print $2"="$3}') || exit 3
-		fi
 
-		[ "${DEBUG}" -eq "0" ] && printf '%b\n' "Backup Ceph deb files in version : ${CEPH_VERSION}"
+	debug_message "Backup Ceph deb files in version : ${CEPH_VERSION}"
-		tar cf "${BKP_TAR_PATH}" ./*.deb > /dev/null 2>&1 || exit 4
+	tar cf "${BKP_TAR_PATH}" ./*.deb > /dev/null 2>&1 \
+		|| error_message "Error with creation of ${BKP_TAR_PATH} archive file." 14
 
 	## Remove deb files
-		rm -rf -- *.deb
+	rm --force -- *.deb \
+		|| error_message "Can't delete temp deb files." 15
 
-		cd - > /dev/null || exit 2
+	cd - > /dev/null \
+		|| error_message "Can't cd to previous directory (before ${CEPH_DEB_PKG_DIR})" 16
 
 	## Remove temp directory
-		rmdir -- "${CEPH_DEB_PKG_DIR}"
+	rmdir -- "${CEPH_DEB_PKG_DIR}" \
-	else
+		|| error_message "Can't delete temp directory (${CEPH_DEB_PKG_DIR})" 17
-		[ "${DEBUG}" -eq "0" ] && printf '%b\n' "A backup of this version already exists : ${EXISTENT_BACKUP_TAR}"
+
-		exit 0
+}
-	fi
+# }}}
+
+# Manage arguments                                                # {{{
+# This code can't be in a function due to argument management
+
+if [ ! "${NBARGS}" -eq "0" ]; then
+
+	manage_arg="0"
+
+	## If the first argument is not an option
+	if ! printf -- '%s' "${1}" | grep -q -E -- "^-+";
+	then
+		## Print help message and exit
+		printf '%b\n' "${RED}Invalid option: ${1}${RESET}"
+		printf '%b\n' "---"
+		usage
 
-else
-		[ "${DEBUG}" -eq "0" ] && printf '%b\n' "Ceph doesn't seems to be available. Please take a look on \`ceph version\` command"
 		exit 1
 	fi
 
+	# Parse all options (start with a "-") one by one
+	while printf -- '%s' "${1}" | grep -q -E -- "^-+"; do
+
+	case "${1}" in
+		-d|--dir|--directory|--backup-dir )   ## Define BKP_DIR
+			## Move to the next argument
+			shift
+			## Define var
+			readonly BKP_DIR="${1}"
+			;;
+		--debug )                             ## debug
+			DEBUG=0
+			;;
+		--help )                              ## help
+			usage
+			## Exit after help informations
+			exit 0
+			;;
+		* )                                   ## unknow option
+			printf '%b\n' "${RED}Invalid option: ${1}${RESET}"
+			printf '%b\n' "---"
+			usage
+			exit 1
+			;;
+	esac
+
+	debug_message "Arguments management − \
+${RED}${1}${COLOR_DEBUG} option managed."
+
+	## Move to the next argument
+	shift
+	manage_arg=$((manage_arg+1))
+
+	done
+
+	debug_message "Arguments management − \
+${RED}${manage_arg}${COLOR_DEBUG} argument(s) successfully managed."
+else
+	debug_message "Arguments management − \
+No arguments/options to manage."
+fi
+
+# }}}
+
+main
+
 exit 0