From 418f021c2312756824c6ffd223f86adb9531272e Mon Sep 17 00:00:00 2001
From: michele <michele@frontdam.com>
Date: Thu, 20 Mar 2014 13:45:16 +0100
Subject: [PATCH] control ZFS pool with ZPOOL envvar; simplify code

---
 zfsbk.sh   | 34 +++++++++++++++---------------
 zfssnap.sh | 62 ++++++++++++++++++++++++------------------------------
 2 files changed, 44 insertions(+), 52 deletions(-)

diff --git a/zfsbk.sh b/zfsbk.sh
index b5ea4e5..43d3735 100755
--- a/zfsbk.sh
+++ b/zfsbk.sh
@@ -1,11 +1,13 @@
 #! /bin/sh
 
-# change this to the name of your ZFS pool.
-zpool="zroot"
+# change this to the name of your ZFS pool. Or set ZPOOL envvar at runtime
+zpool=${ZPOOL:-"zroot"}
 
+# name of backup to take
+bkname=${1:-"default"}
 # make a backup collection having 1 full and N-1 incremental backups.
 # set to 1 to avoid incrementals and always take full dumps.
-max_incremental=4
+max_incremental=${2:-"4"}
 
 usage () {
     echo "Usage:"
@@ -18,23 +20,21 @@ usage () {
     echo "UPLOAD_PATH   upload generated backup to this path. scp:// or rsync://"
 }
 
-# first argument: name of backup set
-if [ $# -lt 1 ]
-then
+failmsg () {
+    echo $*
+    echo
     usage
     exit 1
-fi
+}
 
-bkname=$1
-if ! echo $bkname | grep -qiE '^[a-z0-9-]+$'
-then
-    echo "Given bkname is invalid. Want alphanumeric and hyphens."
-    exit 1
-fi
-if echo "$2" | grep -qE '^[1-9][0-9]*$'
-then
-    max_incremental=$2
-fi
+verify_zpool () {
+    zpool status $zpool >/dev/null 2>&1 || failmsg "ZFS pool '$zpool' not found. Fix your \$ZPOOL envvar."
+}
+
+verify_zpool
+
+echo $bkname | grep -qiE '^[a-z0-9]+$' || failmsg "Given bkname is invalid. Want alphanumeric."
+echo "$max_incremental" | grep -qE '^[1-9][0-9]*$' || failmsg "Invalid number of backups sequence steps, want positive integer."
 
 export PATH=$PATH:/usr/local/bin
 
diff --git a/zfssnap.sh b/zfssnap.sh
index 1840707..8acb7aa 100755
--- a/zfssnap.sh
+++ b/zfssnap.sh
@@ -1,70 +1,62 @@
 #! /bin/sh
 
-# change this to the name of your ZFS pool.
-zpool="zroot"
+# change this to the name of your ZFS pool. Or set ZPOOL envvar at runtime
+zpool=${ZPOOL:-"zroot"}
 
 # names of the DATASETs to exclude (datasets, not mountpoints!)
 # can override this list at runtime with EXCLUDES envvar.
 # can extend this list at runtime with EXTRA_EXCLUDES envvar.
-excludes="/usr/ports /usr/src /backups"
+excludes=${EXCLUDES:-"/usr/ports /usr/src /backups"}
 
 
 # You do not want to edit anything below here
 
 tstamp=`date +%Y%m%d-%H%M%S`
 label_pfx="zbk-"
-usrlabel=$1
-maxnum=$2
+
+# expecting optional arguments: $1 -> usrlabel, $2 -> numsnaps
+usrlabel=${1:-"default"}
+maxnum=${2:-"10"}
 
 usage () {
     echo Usage:
     echo "zfssnap [label [maxnum]]"
-    echo "default label: 'default'"
-    echo "default maxnum: infinite"
-    echo "Takes a ZFS snapshot with given custom label."
-    echo "If maxnum specified, keeps the so-many newest snaps only."
+    echo "* label: tag name of snapshot (alphanumeric, default 'default')"
+    echo "* maxnum: prune old snapshots when more than this snaps exist"
     echo
     echo "Optional envvars:"
+    echo "ZPOOL     name of ZFS pool to manage (default 'zroot')"
     echo "EXCLUDES  list of dataset paths to exclude from snaps. Overrides default."
     echo "EXTRA_EXCLUDES  list of dataset paths to exclude from snaps. Extends default."
     echo "default excluded DATASET paths:"
     echo $excludes
 }
 
+failmsg () {
+    echo $*
+    echo
+    usage
+    exit 1
+}
+
+verify_zpool () {
+    zpool status $zpool >/dev/null 2>&1 || failmsg "ZFS pool '$zpool' not found. Fix your \$ZPOOL envvar."
+}
+
+verify_zpool
+
 # build list of dataset paths to exclude
-if [ "x$EXCLUDES" != x ]
-then
-    excludes=$EXCLUDES
-elif [ "x$EXTRA_EXCLUDES" != x ]
+if [ "x$EXTRA_EXCLUDES" != x ]
 then
     excludes="$excludes $EXTRA_EXCLUDES"
 fi
 
 # label
-if [ "x$usrlabel" != "x" ]
-then
-    if echo "$usrlabel" | grep -qiE '^([a-z0-9]{1,10})$'
-    then
-        label_pfx="$label_pfx$usrlabel"
-    else
-        echo "Invalid label '$usrlabel'! Quitting."
-        usage
-        exit 1
-    fi
-else
-    label_pfx="${label_pfx}default"
-fi
+echo "$usrlabel" | grep -qiE '^([a-z0-9]{1,10})$' || failmsg "Invalid label '$usrlabel'! Quitting."
+label_pfx="$label_pfx$usrlabel"
 
 # maxnum
-if [ "x$maxnum" != "x" ]
-then
-    if ! echo "$maxnum" | grep -qE '^[0-9]+$'
-    then
-        echo "Invalid maxnum '$maxnum'! Terminating."
-        usage
-        exit 1
-    fi
-fi
+echo "$maxnum" | grep -qE '^[0-9]+$' || failmsg "Invalid maxnum '$maxnum'! Terminating."
 
 
 # add timestamp to label