rearrange zpool args, style

CHANGES.md

@@ -4,23 +4,30 @@ ZFS Prune Snapshots Changes
 Not Yet Released
 ----------------
 
-- Show snapshot size (used) and number of snapshots processed
+(nothing yet)
+
+`v1.4.0`
+--------
+
+- Show snapshot size (used) and number of snapshots processed (6e3891ddd1)
+- Add list only option (`-l`) to just list datasets that match (e4ba772f2c)
 
 `v1.3.0`
 --------
 
-- Add recursive deletion option (-R) (482420faba)
+- Add recursive deletion option (`-R`) (482420faba)
 
 `v1.2.0`
 --------
 
 - Add zfs binary check ([#8](https://github.com/bahamas10/zfs-prune-snapshots/pull/8))
-- Support inverting of prefix/suffix match ([#17](https://github.com/bahamas10/zfs-prune-snapshots/pull/17))
+- Support inverting of prefix/suffix match (`-i`)
+  ([#17](https://github.com/bahamas10/zfs-prune-snapshots/pull/17))
 
 `v1.1.0`
 --------
 
-- Support suffix matching (-s) (e7aa72160f8)
+- Support suffix matching (`-s`) (e7aa72160f8)
 
 `v1.0.1`
 --------

README.md

@@ -53,7 +53,7 @@ be considered for deletion - possible specifiers are
 Usage
 -----
 
-    usage: zfs-prune-snapshots [-hniqvV] [-p <prefix] <time> [[dataset1] ...]
+    usage: zfs-prune-snapshots [-hnliqRvV] [-p <prefix>] [-s <suffix>] <time> [[dataset1] ...]
 
     remove snapshots from one or more zpools that match given criteria
 
@@ -78,6 +78,10 @@ Usage
         remove snapshots older than two months on the tank pool that end
         with the string "_frequent"
 
+        # zfs-prune-snapshots -i -p 'autosnap_' 1M zones
+        remove snapshots older than a month on the zones pool that do not
+        start with the string "autosnap_"
+
     timespec
         the first argument denotes how old a snapshot must be for it to
         be considered for deletion - possible specifiers are
@@ -93,10 +97,13 @@ Usage
     options
         -h             print this message and exit
         -n             dry-run, don't actually delete snapshots
+        -l             list only mode, just list matching snapshots names
+                       without deleting (like dry-run mode with machine-parseable output)
         -p <prefix>    snapshot prefix string to match
         -s <suffix>    snapshot suffix string to match
-        -i			   invert matching of prefix and suffix
+        -i             invert matching of prefix and suffix
         -q             quiet, do not printout removed snapshots
+        -R             recursively delete, pass '-R' directly to 'zfs destroy'
         -v             increase verbosity
         -V             print the version number and exit
 

man/zfs-prune-snapshots.1

@@ -18,6 +18,10 @@ print this message and exit
 \fB\fC\-n\fR
 dry\-run, don't actually delete snapshots
 .TP
+\fB\fC\-l\fR
+list only mode, just list matching snapshots names without deleting (like
+dry\-run mode with machine\-parseable output)
+.TP
 \fB\fC\-p <prefix>\fR
 snapshot prefix string to match
 .TP

man/zfs-prune-snapshots.md

@@ -27,6 +27,10 @@ OPTIONS
 `-n`
   dry-run, don't actually delete snapshots
 
+`-l`
+  list only mode, just list matching snapshots names without deleting (like
+  dry-run mode with machine-parseable output)
+
 `-p <prefix>`
   snapshot prefix string to match
 

zfs-prune-snapshots

@@ -6,67 +6,111 @@
 # Date: November 20, 2015
 # License: MIT
 
-VERSION='v1.3.0'
+VERSION='v1.4.0'
 
 usage() {
 	local prog=${0##*/}
-	cat <<-EOF
-	usage: $prog [-hniqRvV] [-p <prefix>] [-s <suffix>] <time> [[dataset1] ...]
+	cat <<EOF
+usage: $prog [-hnliqRvV] [-p <prefix>] [-s <suffix>] <time> [[dataset1] ...]
 
-	remove snapshots from one or more zpools that match given criteria
+remove snapshots from one or more zpools that match given criteria
 
-	examples
-	    # $prog 1w
-	    remove snapshots older than a week across all zpools
+examples
+    # $prog 1w
+    remove snapshots older than a week across all zpools
 
-	    # $prog -vn 1w
-	    same as above, but with increased verbosity and without
-	    actually deleting any snapshots (dry-run)
+    # $prog -vn 1w
+    same as above, but with increased verbosity and without
+    actually deleting any snapshots (dry-run)
 
-	    # $prog 3w tank1 tank2/backup
-	    remove snapshots older than 3 weeks on tank1 and tank2/backup.
-	    note that this script will recurse through *all* of tank1 and
-	    *all* datasets below tank2/backup
+    # $prog 3w tank1 tank2/backup
+    remove snapshots older than 3 weeks on tank1 and tank2/backup.
+    note that this script will recurse through *all* of tank1 and
+    *all* datasets below tank2/backup
 
-	    # $prog -p 'autosnap_' 1M zones
-	    remove snapshots older than a month on the zones pool that start
-	    with the string "autosnap_"
+    # $prog -p 'autosnap_' 1M zones
+    remove snapshots older than a month on the zones pool that start
+    with the string "autosnap_"
 
-	    # $prog -s '_frequent' 2M tank
-	    remove snapshots older than two months on the tank pool that end
-	    with the string "_frequent"
+    # $prog -s '_frequent' 2M tank
+    remove snapshots older than two months on the tank pool that end
+    with the string "_frequent"
 
-	    # $prog -i -p 'autosnap_' 1M zones
-	    remove snapshots older than a month on the zones pool that do not
-	    start with the string "autosnap_"
+    # $prog -i -p 'autosnap_' 1M zones
+    remove snapshots older than a month on the zones pool that do not
+    start with the string "autosnap_"
 
-	timespec
-	    the first argument denotes how old a snapshot must be for it to
-	    be considered for deletion - possible specifiers are
+timespec
+    the first argument denotes how old a snapshot must be for it to
+    be considered for deletion - possible specifiers are
 
-	        s seconds
-	        m minutes
-	        h hours
-	        d days
-	        w weeks
-	        M months
-	        y years
+	s seconds
+	m minutes
+	h hours
+	d days
+	w weeks
+	M months
+	y years
 
-	options
-	    -h             print this message and exit
-	    -n             dry-run, don't actually delete snapshots
-	    -p <prefix>    snapshot prefix string to match
-	    -s <suffix>    snapshot suffix string to match
-	    -i             invert matching of prefix and suffix
-	    -q             quiet, do not printout removed snapshots
-	    -R             recursively delete, pass '-R' directly to 'zfs destroy'
-	    -v             increase verbosity
-	    -V             print the version number and exit
-	EOF
+options
+    -h             print this message and exit
+    -n             dry-run, don't actually delete snapshots
+    -l             list only mode, just list matching snapshots names
+		   without deleting (like dry-run mode with machine-parseable
+		   output)
+    -p <prefix>    snapshot prefix string to match
+    -s <suffix>    snapshot suffix string to match
+    -i             invert matching of prefix and suffix
+    -q             quiet, do not printout removed snapshots
+    -R             recursively delete, pass '-R' directly to 'zfs destroy'
+    -v             increase verbosity
+    -V             print the version number and exit
+EOF
 }
 
 debug() {
-	((verbosity >= 1)) && echo "$@"
+	((verbosity >= 1)) && echo "$@" >&2
+	return 0
+}
+
+# get epoch time
+get-epoch() {
+	local time=0
+
+	# try bash built-in, date(1), and finally perl
+	time=$(printf '%(%s)T\n' -1 2>/dev/null)
+	_validate-epoch "$time" 'printf' && return 0
+
+	time=$(date '+%s' 2>/dev/null)
+	_validate-epoch "$time" 'date'   && return 0
+
+	time=$(perl -le 'print time' 2>/dev/null)
+	_validate-epoch "$time" 'perl'   && return 0
+
+	return 1
+}
+
+# validate a given epoch time for sanity
+_validate-epoch() {
+	local time=$1
+	local method=$2
+	local num_re='^([0-9]+)$'
+
+	debug "checking time received from $method"
+
+	if [[ -z $time ]]; then
+		debug "time invalid - empty"
+		return 1
+	elif ! [[ $time =~ $num_re ]]; then
+		debug "time invalid - not a number :: '$time'"
+		return 1
+	elif ! (( time > 0 )); then
+		debug "time invalid - not greater than 0 :: '$time'"
+		return 1
+	fi
+
+	debug "successfully got epoch time :: $time"
+	echo "$time"
 	return 0
 }
 
@@ -101,6 +145,7 @@ human-time() {
 	echo '0 seconds'
 }
 
+# convert bytes to a human-readable string
 human-size() {
 	local bytes=$1
 
@@ -122,26 +167,22 @@ human-size() {
 	echo '0 B'
 }
 
-if ! type -P zfs &>/dev/null; then
-	echo "Error! zfs command not found. Are you on the right machine?"
-	exit 1
-fi
-
 recursive=false
 dryrun=false
+listonly=false
 verbosity=0
 prefix=
 suffix=
 invert=false
-quiet=false
-while getopts 'hniqRp:s:vV' option; do
+while getopts 'hniqlRp:s:vV' option; do
 	case "$option" in
 		h) usage; exit 0;;
 		n) dryrun=true;;
 		i) invert=true;;
+		l) listonly=true;;
 		p) prefix=$OPTARG;;
 		s) suffix=$OPTARG;;
-		q) quiet=true;;
+		q) exec 1>/dev/null;;
 		R) recursive=true;;
 		v) ((verbosity++));;
 		V) echo "$VERSION"; exit 0;;
@@ -179,73 +220,122 @@ else
 fi
 
 shift
-pools=("$@")
 
+pools=("$@")
 destroyargs=()
+code=0
+totalused=0
+numsnapshots=0
+humanpools=${pools[*]}
+humanpools=${humanpools:-<all>}
+
 if $recursive; then
 	destroyargs+=('-R')
 fi
-now=$(date +%s)
-code=0
-totalused=0
-count=0
-while read -r creation snapshot used _; do
+
+if ! now=$(get-epoch); then
+	echo 'failed to get epoch time' >&2
+	exit 1
+fi
+
+if ! command -v zfs &>/dev/null; then
+	echo "Error! zfs command not found. Are you on the right machine?" >&2
+	exit 1
+fi
+
+# first pass of the pools (to calculate totals and filter unwanted datasets
+lines=()
+while read -r line; do
+	read -r creation used snapshot _ <<< "$line"
+
 	# ensure optional prefix matches
 	snapname=${snapshot#*@}
-	if $invert; then
-		if [[ -n $prefix && $prefix == "${snapname:0:${#prefix}}" ]]; then
-			debug "skipping $snapshot: does match prefix $prefix"
+	if [[ -n $prefix ]]; then
+		match=false
+		if [[ $prefix == "${snapname:0:${#prefix}}" ]]; then
+			match=true
+		fi
+
+		if $invert && $match; then
+			debug "skipping $snapshot: does match prefix '$prefix'"
 			continue
 		fi
-	else
-		if [[ -n $prefix && $prefix != "${snapname:0:${#prefix}}" ]]; then
-			debug "skipping $snapshot: doesn't match prefix $prefix"
+
+		if ! $invert && ! $match; then
+			debug "skipping $snapshot: doesn't match prefix '$prefix'"
 			continue
 		fi
 	fi
 
 	# ensure optional suffix matches
-	if $invert; then
-		if [[ -n $suffix && $suffix == "${snapname: -${#suffix}}" ]]; then
-			debug "skipping $snapshot: does match suffix $suffix"
+	if [[ -n $suffix ]]; then
+		match=false
+		if [[ $suffix == "${snapname: -${#suffix}}" ]]; then
+			match=true
+		fi
+
+		if $invert && $match; then
+			debug "skipping $snapshot: does match suffix '$suffix'"
 			continue
 		fi
-	else
-		if [[ -n $suffix && $suffix != "${snapname: -${#suffix}}" ]]; then
-			debug "skipping $snapshot: doesn't match suffix $suffix"
+
+		if ! $invert && ! $match; then
+			debug "skipping $snapshot: doesn't match suffix '$suffix'"
 			continue
 		fi
 	fi
 
 	# ensure snapshot is older than the cutoff time
 	delta=$((now - creation))
-	human=$(human-time "$delta")
+	ht=$(human-time "$delta")
 	if ((delta <= seconds)); then
-		debug "skipping $snapshot: $human old"
+		debug "skipping $snapshot: $ht old"
 		continue
 	fi
 
-	# remove the snapshot
-	humanused=$(human-size "$used")
-
-	if ! $quiet || $dryrun; then
-		echo -n "removing $snapshot: $human old ($humanused)"
-	fi
-	if $dryrun; then
-		echo ' <dry-run: no action taken>'
-	else
-		if ! $quiet; then
-			echo
-		fi
-		zfs destroy "${destroyargs[@]}" "$snapshot" || code=1
+	# print the snapshot here if `-l`
+	if $listonly; then
+		echo "$snapshot"
 	fi
 
-	((total += used))
-	((count++))
-done < <(zfs list -Hpo creation,name,used -t snapshot -r "${pools[@]}")
+	# we care about this dataset
+	((totalused += used))
+	((numsnapshots++))
+	lines+=("$line")
+done < <(zfs list -Hpo creation,used,name -t snapshot -r "${pools[@]}")
 
-if ! $quiet; then
-	echo "processed $count snapshots ($(human-size "$total"))"
+# finish if running with `-l`
+if $listonly; then
+	debug "running in '-l' mode - exiting here"
+	exit 0
 fi
 
+humantotal=$(human-size "$totalused")
+
+echo "found $numsnapshots snapshots ($humantotal) on pools: $humanpools"
+
+# process snapshots found
+i=0
+for line in "${lines[@]}"; do
+	read -r creation used snapshot _ <<< "$line"
+
+	((i++))
+
+	delta=$((now - creation))
+	ht=$(human-time "$delta")
+	hu=$(human-size "$used")
+
+	if $dryrun; then
+		echo -n '[dry-run] '
+	fi
+
+	echo "[$i/$numsnapshots] removing $snapshot: $ht old ($hu)"
+
+	if ! $dryrun; then
+		zfs destroy "${destroyargs[@]}" "$snapshot" || code=1
+	fi
+done
+
+echo "removed $numsnapshots snapshots ($humantotal)"
+
 exit "$code"