Lock file create and remove improvements (#2183)

* changed the locking function to better support multiple servers running at once and sharing the same config

* helper function testing now runs inside of container

Co-authored-by: Brennan Kinney <5098581+polarathene@users.noreply.github.com>

target/scripts/check-for-changes.sh

@@ -6,8 +6,6 @@
 LOG_DATE=$(date +"%Y-%m-%d %H:%M:%S ")
 _notify 'task' "${LOG_DATE} Start check-for-changes script."
 
-SCRIPT_NAME="$(basename "$0")"
-
 # ? ––––––––––––––––––––––––––––––––––––––––––––– Checks
 
 cd /tmp/docker-mailserver || exit 1
@@ -40,9 +38,6 @@ while true
 do
   LOG_DATE=$(date +"%Y-%m-%d %H:%M:%S ")
 
-  # Lock configuration while working
-  create_lock "${SCRIPT_NAME}"
-
   # get chksum and check it, no need to lock config yet
   _monitored_files_checksums >"${CHKSUM_FILE}.new"
   cmp --silent -- "${CHKSUM_FILE}" "${CHKSUM_FILE}.new"
@@ -53,6 +48,7 @@ do
   if [ $? -eq 1 ]
   then
     _notify 'inf' "${LOG_DATE} Change detected"
+    create_lock # Shared config safety lock
     CHANGED=$(grep -Fxvf "${CHKSUM_FILE}" "${CHKSUM_FILE}.new" | sed 's/^[^ ]\+  //')
 
     # Bug alert! This overwrites the alias set by start-mailserver.sh
@@ -227,11 +223,12 @@ s/$/ regexp:\/etc\/postfix\/regexp/
 
     # prevent restart of dovecot when smtp_only=1
     [[ ${SMTP_ONLY} -ne 1 ]] && supervisorctl restart dovecot
+
+    remove_lock
   fi
 
   # mark changes as applied
   mv "${CHKSUM_FILE}.new" "${CHKSUM_FILE}"
-  remove_lock "${SCRIPT_NAME}"
 
   sleep 1
 done