Enhance rotatelogs-compress.sh script, fix for symlinked log directories

_sources/scripts/rotatelogs-compress.sh

@@ -1,30 +1,48 @@
 #!/bin/bash
+# Enable extended globbing for +([0-9]) pattern.
+shopt -s extglob
 
 # Returns common prefix of two strings
 common_prefix() {
   local n=0
-  while [[ "${1:n:1}" == "${2:n:1}" ]]; do
+  # Compare strings char-by-char and stop at first mismatch/end.
+  while [[ -n "${1:n:1}" && "${1:n:1}" == "${2:n:1}" ]]; do
     ((n++))
   done
   echo "${1:0:n}"
 }
 
 new_log_file="${1}"
 file_to_compress="${2}"
+commonFilePrefix=""
 if [ -n "$new_log_file" ] && [ -n "$file_to_compress" ] && [ "$new_log_file" != "$file_to_compress" ]; then
-    new_log_file_basename=$(basename "$new_log_file")
-    file_to_compress_basename=$(basename "$file_to_compress")
-    commonFilePrefix=$(common_prefix "$new_log_file_basename" "$file_to_compress_basename" | sed 's/[0-9]*$//')
+    new_log_file_basename=$(basename -- "$new_log_file")
+    file_to_compress_basename=$(basename -- "$file_to_compress")
+    commonFilePrefix=$(common_prefix "$new_log_file_basename" "$file_to_compress_basename")
+    # Trim trailing digits
+    commonFilePrefix="${commonFilePrefix%%+([0-9])}"
 fi
+
+# Fallback: derive prefix from file_to_compress basename to avoid empty prefix ("*") in find filters.
+if [ -z "$commonFilePrefix" ] && [ -n "$file_to_compress" ]; then
+    file_to_compress_basename=$(basename -- "$file_to_compress")
+    # Trim trailing digits
+    commonFilePrefix="${file_to_compress_basename%%+([0-9])}"
+fi
+
 compress_exit_code=0
 
 if [[ "${file_to_compress}" ]]; then
     # wait random number of seconds before compressing to avoid to compress log files simultaneously (especially for wiki farms)
-    if [ "$LOG_FILES_COMPRESS_DELAY" -eq 0 ]; then
-        DELAY=0
-    else
+    # Use random delay only when env value is a valid positive integer.
+    if [[ "${LOG_FILES_COMPRESS_DELAY:-0}" =~ ^[0-9]+$ ]] && [ "${LOG_FILES_COMPRESS_DELAY:-0}" -gt 0 ]; then
         DELAY=$RANDOM
-        ((DELAY %= "$LOG_FILES_COMPRESS_DELAY"))
+        ((DELAY %= LOG_FILES_COMPRESS_DELAY))
+    else
+        if [ -n "${LOG_FILES_COMPRESS_DELAY:-}" ] && ! [[ "${LOG_FILES_COMPRESS_DELAY}" =~ ^[0-9]+$ ]]; then
+            echo "LOG_FILES_COMPRESS_DELAY is not a non-negative integer (${LOG_FILES_COMPRESS_DELAY:-}), using 0."
+        fi
+        DELAY=0
     fi
     echo "Wait for $DELAY seconds before compressing ${file_to_compress}"
     sleep "$DELAY"
@@ -44,14 +62,28 @@ if [[ "${file_to_compress}" ]]; then
         echo "File ${file_to_compress} does not exist".
     fi
 
-    # remove old log files
-    if [ -n "$LOG_FILES_REMOVE_OLDER_THAN_DAYS" ] && [ "$LOG_FILES_REMOVE_OLDER_THAN_DAYS" != false ]; then
-        LOG_DIRECTORY=$(dirname "${file_to_compress}")
-        find "$LOG_DIRECTORY" -type f -mtime "+$LOG_FILES_REMOVE_OLDER_THAN_DAYS" -iname "$commonFilePrefix*" ! -iname ".*" ! -iname "*.current" -exec rm -f {} \;
-    fi
+    LOG_DIRECTORY="$(dirname -- "$file_to_compress")"
+    # Keep exactly one trailing slash (needed for symlink directory handling).
+    LOG_DIRECTORY="${LOG_DIRECTORY%/}/"
+
+    # Empty prefix would expand to "*" and affect unrelated files.
+    if [ -n "$commonFilePrefix" ]; then
+        # remove old log files
+        if [ -n "${LOG_FILES_REMOVE_OLDER_THAN_DAYS:-}" ] && [ "${LOG_FILES_REMOVE_OLDER_THAN_DAYS}" != false ]; then
+            # Validate mtime value before passing it to find.
+            if [[ "${LOG_FILES_REMOVE_OLDER_THAN_DAYS}" =~ ^[0-9]+$ ]]; then
+                find "$LOG_DIRECTORY" -type f -mtime "+$LOG_FILES_REMOVE_OLDER_THAN_DAYS" -iname "$commonFilePrefix*" ! -iname ".*" ! -iname "*.current" -exec rm -f {} \;
+            else
+                echo "LOG_FILES_REMOVE_OLDER_THAN_DAYS is not a non-negative integer (${LOG_FILES_REMOVE_OLDER_THAN_DAYS}), skipping old log removal."
+            fi
+        fi
 
-    # compress uncompressed old log files
-    find "$LOG_DIRECTORY" -type f -mtime "+2" -iname "$commonFilePrefix*" ! -iname ".*" ! -iname "*.current" ! -iname "*.gz" ! -iname "*.zip" -exec tar --gzip --create --remove-files --absolute-names --transform 's/.*\///g' --file {}.tar.gz {} \;
+        # compress uncompressed old log files
+        find "$LOG_DIRECTORY" -type f -mtime "+2" -iname "$commonFilePrefix*" ! -iname ".*" ! -iname "*.current" ! -iname "*.gz" ! -iname "*.zip" ! -iname "*.tar" -exec tar --gzip --create --remove-files --absolute-names --transform 's/.*\///g' --file {}.tar.gz {} \;
+    else
+        echo "commonFilePrefix is empty, skipping cleanup/compression find operations."
+    fi
 fi
 
+shopt -u extglob
 exit ${compress_exit_code}