--- /dev/null
+#!/bin/sh
+
+# LOGLEVEL 1: Crash condition
+# LOGLEVEL 2: Unexpected condition
+# LOGLEVEL 3: Failed action (i.e. due to config error)
+# LOGLEVEL 4: Debug
+
+[ -n "$include_logging" ] && return 0
+include_logging="$0"
+
+LOGLEVEL="${LOGLEVEL:-3}"
+LOGFILE="${LOGFILE:-/dev/stderr}"
+
+logmsg(){
+ local ll="${1:-3}"
+ shift 1
+ if [ "$ll" -le "$LOGLEVEL" -a "$#" -gt 0 ]; then
+ printf %s\\n "$*" >>"${LOGFILE}"
+ elif [ "$ll" -le "$LOGLEVEL" ]; then
+ tee -a "${LOGFILE}"
+ elif [ ! "$#" -gt 0 ]; then
+ cat
+ fi
+}
+
+die(){
+ [ "$#" -gt 0 ] && logmsg 1 "$@"
+ exit 1
+}
+panic(){ logmsg 2 "$@"; }
+error(){ logmsg 3 "$@"; }
+debug(){ logmsg 4 "$@"; }