Megatest

;;======================================================================
;; setting/getting a lock on the db for only one server per db
;;
;;  NOTE:
;;       These operate directly on the disk file, NOT on the inmemory db
;;       The lockname is the filename (can have many to one, run-id to fname 
;;======================================================================

(define (with-lock-db dbfile proc)
  (let* ((dbh (db:open-run-db dbfile db:initialize-db))
	 (res (proc dbh dbfile)))
    (sqlite3:finalize! dbh)
    res))

;; called before db is open?
;;
(define (db:get-iam-server-lock dbh dbfname)
  (sqlite3:with-transaction
   dbh
   (lambda ()
     (let* ((locker (db:get-locker dbh dbfname)))
       (if locker
	   #f
	   (db:take-lock dbh dbfname))))))

	     
;; (exn sqlite3) 
(define (db:get-locker dbh dbfname)
  (condition-case
   (sqlite3:first-row dbh "SELECT owner_pid,owner_host,event_time FROM locks WHERE lockname=%;" dbfname)
   (exn (sqlite3) #f)))