add custom flags, opt expansion, command execution

1 files changed, 142 insertions, 32 deletions

diff --git a/backomp b/backomp
index bf91371..e45eff8 100755
--- a/backomp
+++ b/backomp
@@ -92,7 +92,7 @@ END {
 EOF
 
 err() {
-	echo "${0##*/}: error: $*" >&2
+	echo "${0##*/}: ${err_ctx}: error: $*" >&2
 }
 
 run() {
@@ -148,15 +148,14 @@ filter() {
 	mapfile -td $'\0' "${__dest_name}" < <(
 		printf '%s\0' "${__src[@]}" | awk -v 'RS=\0' -v 'ORS=\0' \
 			"${@}" -- "${__script}")
-	wait "$!"
-	if [[ "$?" -ne 0 ]]; then
+	if ! wait "$!"; then
 		err "${__label} failed"
 		return 1
 	fi
 
-	if [[ ${#__src[@]} -gt 0 ]]; then
+	if ((${#__src[@]})); then
 		exists "${__dest[0]}" && return 0
-		[[ "$?" -eq 1 ]] && \
+		[[ "$?" -eq 1 ]] &&
 			err "${__label} returned empty or invalid list"
 		return 1
 	fi
@@ -186,13 +185,14 @@ populate() {
 
 copy() {
 	local src="${1}" dest="${2}" link_dest="${3}"
-	local path res r_dest r_link_dest
+	local rsync_flags="${4}" rclone_flags="${5}"
+	local path res flags r_dest r_link_dest
 
 	for path in "${dest}" "${dest}.tmp"; do
 		exists "${path}"
 		res="$?"
 		if [[ "${res}" -ne 1 ]]; then
-			[[ "${res}" -eq 0 ]] && \
+			[[ "${res}" -eq 0 ]] &&
 				err "destination already exists: ${path}"
 			return 1
 		fi
@@ -206,14 +206,26 @@ copy() {
 			r_dest+="/${src##*/}"
 			r_link_dest+="${r_link_dest:+/${src##*/}}"
 		fi
-		run rclone copy --sftp-copy-is-hardlink \
+		mapfile -td $'\0' flags < <(
+			printf '%s' "${rclone_flags}" | xargs -r printf '%s\0')
+		if ! wait "$!"; then
+			err 'parsing rclone flags failed'
+			return 1
+		fi
+		run rclone copy "${flags[@]}" \
 			${r_link_dest:+"--copy-dest=${r_link_dest#rclone:}"} \
 			-- "${src}" "${r_dest#rclone:}" || return 1
 		run rclone move -- "${dest#rclone:}.tmp" "${dest#rclone:}"
 		return
 	fi
 
-	run rsync -ac --mkpath \
+	mapfile -td $'\0' flags < <(
+		printf '%s' "${rsync_flags}" | xargs -r printf '%s\0')
+	if ! wait "$!"; then
+		err 'parsing rsync flags failed'
+		return 1
+	fi
+	run rsync "${flags[@]}" --mkpath \
 		${link_dest:+"--link-dest=${link_dest}"} \
 		-- "${src}" "${dest}.tmp/" || return 1
 	run mv -T -- "${dest}.tmp" "${dest}" || return 1
@@ -239,6 +251,7 @@ prune() {
 backup() {
 	local src_path="${1}" dest_dir="${2}"
 	local retain="${3}" interval="${4}" week_start="${5}"
+	local rsync_flags="${6}" rclone_flags="${7}"
 	local dest_path snaps keep
 
 	if [[ ! -e "${src_path}" ]]; then
@@ -253,7 +266,8 @@ backup() {
 		&& return
 
 	dest_path="${dest_dir}/$(date -u '+%Y-%m-%d-%H%M%S')"
-	copy "${src_path}" "${dest_path}" "${snaps[0]}" || return 1
+	copy "${src_path}" "${dest_path}" "${snaps[0]}" \
+		"${rsync_flags}" "${rclone_flags}" || return 1
 
 	if [[ ! "${retain}" =~ ^( *([0-9]+|\*)\^?[hdwM] *)+$ ]]; then
 		err "invalid \$retain setting: ${retain}"
@@ -273,39 +287,135 @@ declare -A def_opts=(
 	['retain']='*h' # e.g. 24h7d4w12M or 24^h10d*M
 	['interval']='0'
 	['week_start']='mon'
+	['rsync_flags']='-ac'
+	['rclone_flags']='--checksum --sftp-copy-is-hardlink'
 )
-declare -A opts
+declare -A opts tainted_opts
+reset_opts() {
+	opts=()
+	tainted_opts=()
+	for k in "${!def_opts[@]}"; do
+		opts["${k}"]="${def_opts["${k}"]}"
+	done
+}
+reset_opts
+
+expand_opts() {
+	local str="${1}" default="${2}"
+	local res opt tainted=0
+
+	while [[ "${str}" =~ \\([\\$=!])|\$([A-Za-z0-9_]+)|\$\{([^}]*)\} ]]; do
+		res+="${str%%"${BASH_REMATCH[0]}"*}"
+		opt="${BASH_REMATCH[2]:-${BASH_REMATCH[3]}}"
+		if [[ -n "${BASH_REMATCH[1]}" ]]; then
+			res+="${BASH_REMATCH[1]}"
+		elif [[ "${opt}" == 'default' ]]; then
+			res+="${default}"
+		elif [[ -n "${opt}" ]]; then
+			res+="${opts["${opt}"]}"
+			if [[ ! -v opts["${opt}"] ]]; then
+				err "reference to undefined opt: ${opt}"
+				tainted=1
+			elif [[ -v tainted_opts["${opt}"] ]]; then
+				err "reference to tainted opt: ${opt}"
+				tainted=1
+			fi
+		fi
+		str="${str#*"${BASH_REMATCH[0]}"}"
+	done
+	printf '%s\n' "${res}${str}"
+	return "${tainted}"
+}
 
 declare -A seen
-while IFS='=' read -r f1 f2; do
-	[[ -z "${f1}" ]] || [[ "${f1}" == '#'* ]] && continue
+while IFS= read -r line; do
+	((++lnum))
+	[[ -z "${line}" || "${line}" == \#* ]] && continue
 
-	if [[ "${f1}" =~ ^\[(.*)]$ ]]; then
+	if [[ "${line}" =~ ^\[(.*)]$ ]]; then
 		base_path="${BASH_REMATCH[1]}"
-		declare -A opts="$(declare -p def_opts | sed '1s/[^=]*=//')"
-	elif [[ "${f1}" == '$'* ]]; then
-		opt="${f1:1}"
-		[[ "${f2}" == '-' ]] && opts["${opt}"]= ||
-			opts["${opt}"]="${f2:-"${def_opts["${opt}"]}"}"
-	else
-		dest="${base_path}/${f1}"
-		printf '[%d] [%s] %s => %s%s\n' "$((++dcount))" \
-			"${opts['retain']}" "${f2}" "${dest}"
+		reset_opts
+		continue
+	fi
+
+	err_ctx="line ${lnum}"
+	if [[ ! "${line}" =~ ^((\\[\\=]|[^=])+)=(.*)$ ]]; then
+		err "expected '='"
+		((++errors))
+		continue
+	fi
+	f1="${BASH_REMATCH[1]}"
+	f2="${BASH_REMATCH[3]}"
+	[[ "${f1}" == \$?* ]] && opt="${f1:1}" || opt=
+	err_ctx="${opt:+opt }${opt:-task $((++bcount))} (${err_ctx})"
 
-		dest_rp="$(realpath -m -- "${dest}")"
-		if [[ -v "seen["${dest_rp}"]" ]]; then
-			err "destination already seen: ${dest}"
+	tainted_src=0
+	tainted_dest=0
+	if [[ "${f2}" == \!?* ]]; then
+		cmd="${f2:1}"
+		f2="$(default="${opt:+${def_opts["${opt}"]}}" eval "${cmd}" \
+			2> >(while read -r x || [[ -n "${x}" ]]; do
+				[[ "${x}" =~ ^"${0}: line "[^:]+": "(.*) ]] &&
+					x="bash: ${BASH_REMATCH[1]}"
+				echo "${0##*/}: ${err_ctx}: stderr: ${x}"
+			done >&2))"
+		ret="$?"
+		[[ "${ret}" -ne 0 ]] && err "command failed (${ret}): ${cmd}"
+	else
+		f2="$(expand_opts "${f2}" "${opt:+${def_opts["${opt}"]}}")"
+		ret="$?"
+	fi
+	if [[ "${ret}" -ne 0 ]]; then
+		if [[ -n "${opt}" ]]; then
+			tainted_opts["${opt}"]=1
 			((++errors))
 			continue
 		fi
-		seen["${dest_rp}"]=
+		tainted_src=1
+	elif [[ -n "${opt}" ]]; then
+		opts["${opt}"]="${f2}"
+		unset tainted_opts["${opt}"]
+		continue
+	fi
 
-		backup "${f2}" "${dest}" \
-			"${opts['retain']}" \
-			"${opts['interval']}" \
-			"${opts['week_start']}" \
-			|| ((++errors))
+	src="${f2}"
+	dest="${base_path}${base_path:+/}$(expand_opts "${f1}")"
+	tainted_dest="$?"
+	printf '[%d] [%s] %s => %s\n' "${bcount}" "${opts['retain']}" \
+		"${src}" "${dest}"
+
+	skips=()
+	((tainted_src)) && skips+=('tainted source')
+	((tainted_dest)) && skips+=('tainted destination')
+	for k in "${!def_opts[@]}"; do
+		[[ -v tainted_opts["${k}"] ]] && skips+=("tainted opt: ${k}")
+	done
+	[[ -z "${src}" ]] && skips+=('source blank')
+	if ((!tainted_dest)); then
+		if [[ -z "${dest}" ]]; then
+			skips+=('destination blank')
+		else
+			dest_rp="$(realpath -m -- "${dest}")"
+			[[ -v seen["${dest_rp}"] ]] &&
+				skips+=("destination already seen: ${dest}")
+			seen["${dest_rp}"]=
+		fi
+	fi
+	if ((${#skips[@]})); then
+		for x in "${skips[@]}"; do
+			err "${x}"
+		done
+		((++errors))
+		continue
 	fi
+
+	backup "${src}" "${dest}" \
+		"${opts['retain']}" \
+		"${opts['interval']}" \
+		"${opts['week_start']}" \
+		"${opts['rsync_flags']}" \
+		"${opts['rclone_flags']}" \
+		|| ((++errors))
 done < "${1}"
 
 ((!errors))