Add log levels to Minecraft backup script

roles/minecraft/files/minecraft-backup.sh

@@ -7,18 +7,50 @@ SCRATCH=$(mktemp -p /var/tmp -d minecraft.XXXXXXXXXX)
 NICE=15
 TAR=minecraft-$(date +%Y-%m-%d).tar
 WAIT=30
+VERBOSE=${VERBOSE:-4}
+
+declare -A LOG_LEVELS
+LOG_LEVELS=(
+    [emerg]=0
+    [alert]=1
+    [crit]=2
+    [err]=3
+    [warning]=4
+    [notice]=5
+    [info]=6
+    [debug]=7
+)
+
+log() {
+    local LEVEL
+    local TS
+
+    LEVEL=$1
+    TS="$(date -Is)"
+    shift
+
+    if [[ $VERBOSE -ge ${LOG_LEVELS[$LEVEL]} ]]; then
+        if [[ $# -ge 2 ]]; then
+            local FMT=$1
+            shift
+            printf "%s [%s] ${FMT}\n" "${TS}" "$LEVEL" "$@"
+        else
+            echo "${TS} [$LEVEL]" "$@"
+        fi
+    fi
+}
 
 finish() {
-    printf "Cleaning up ...\n"
+    log info "Cleaning up"
     rm -rf "$SCRATCH"
     if ! systemctl -q is-active "$SERVICE"; then
-        start_server
+        start_server $SERVICE
     fi
 }
 trap finish EXIT
 
 error_exit() {
-    printf "%s\n" "$1"
+    log crit "$1"
     exit 1
 }
 
@@ -27,14 +59,14 @@ stop_server() {
     local attempts="${2:-$WAIT}"
 
     if ! systemctl -q is-active "$unit"; then
-        printf "%s is already stopped\n" "$unit"
+        log warning "%s is already stopped\n" "$unit"
         return 0
     fi
 
     systemctl -q stop "$unit"
 
     while systemctl -q is-active "$unit"; do
-        printf "Waiting for %s to stop ... (%s)\n" "$unit" "$attempts"
+        log warning "Waiting for %s to stop ... (%s)\n" "$unit" "$attempts"
         ((attempts--))
         if ((attempts == 0)); then
             return 1
@@ -50,14 +82,14 @@ start_server() {
     local attempts="${2:-$WAIT}"
 
     if systemctl -q is-active "$unit"; then
-        printf "%s is already started\n" "$unit"
+        log warning "%s is already started\n" "$unit"
         return 0
     fi
 
     systemctl -q start "$unit"
 
     while ! systemctl -q is-active "$unit"; do
-        printf "Waiting for %s to start ... (%d)\n" "$unit" "$attempts"
+        log warning "Waiting for %s to start ... (%d)\n" "$unit" "$attempts"
         ((attempts--))
         if ((attempts == 0)); then
             return 1
@@ -74,7 +106,7 @@ open_files() {
     local attempts="${2:-$WAIT}"
 
     while (($(lsof +D "$dir" | wc -l) > 0)); do
-        printf "Waiting for open files ... (%d)\n" "$attempts"
+        log warning "Waiting for open files ... (%d)\n" "$attempts"
         ((attempts--))
         if ((attempts == 0)); then
             return 1
@@ -87,26 +119,32 @@ open_files() {
 
 
 main() {
-    if ! stop_server; then
+    log info "Stopping %s service" $SERVICE
+    if ! stop_server $SERVICE; then
         error_exit "Failed to stop $SERVICE"
     fi
 
-    if ! open_files; then
+    log info "Checking for open files"
+    if ! open_files $VAR_DIR; then
         error_exit "Open files exist in $VAR_DIR"
     fi
 
+    log info "Starting backup"
     if ! tar -cf "$SCRATCH/$TAR" -C "$VAR_DIR" world; then
         error_exit "Archive failed"
     fi
 
-    if ! start_server; then
+    log info "Starting %s service" $SERVICE
+    if ! start_server $SERVICE; then
         error_exit "Failed to start $SERVICE"
     fi
 
+    log info "Compressing $TAR"
     if ! nice -n "$NICE" xz -9 "$SCRATCH/$TAR"; then
         error_exit "Failed to compress $SCRATCH/$TAR"
     else
         mv "$SCRATCH/$TAR.xz" "$BACKUP_DIR"
+        log info "Symlinking current archive"
         ln -nfs "$BACKUP_DIR/$TAR.xz" "$BACKUP_DIR/minecraft-latest.tar.xz"
     fi
 }