Remove old clock entries

Question

I'm clocking the time spent on daily tasks like email and for that I have a "Daily Routine" TODO entry. Clocking in this task adds a new clock line everyday, leading to a very populated CLOCK drawer. I'd like to limit its size by either a maximum number of clock entries by removing the older ones or better, removing the entries older than some date. Ideally, I'd like to find a function that tidies the clock drawer of an entry, to be added to the clock-in or clock-out hook.

Any idea how to achieve that ?

Answer 1

Have a look at org-clock-remove-empty-clock-drawer. It uses org-map-tree and a regular expression based on org-clock-drawer-name to find the :LOGBOOK: drawers.

You can use the same logic to get point to the start of :LOGBOOK: and then handle all CLOCK: entries on a line-by-line basis. To parse the timestamps, you can use org-ts-regexp-both and org-element-timestamp-parser. Afterwards, you can use kill-whole-line to get rid of the entry.

So in short:

1. Find the next :LOGBOOK: via re-search-forward
2. Go forward a single line
3. Check the start of the line.
   • If it starts with :END:, stop the clock handling for the current drawer
   • If it starts with CLOCK:, search for the next timestamp.
     1. If it's too old, remove the whole line with kill-whole-line.
     2. Otherwise continue to the next line
   • goto 3.

Answer 2

Here is what I came up with:

(defun jc-org-clock-remove-old-clock-entries (n)
  "Remove clock entries whose end is older than N weeks in current subtree.
Skip over dangling clock entries."
  (interactive "nnumber of weeks: ")
  (save-excursion
    (org-back-to-heading t)
    (org-map-tree
     (lambda ()
       (let ((drawer (re-search-forward org-clock-drawer-start-re (save-excursion (org-end-of-subtree)) t))
         (case-fold-search t))
     (when drawer
       (let ((re org-clock-line-re)
         (end (save-excursion (re-search-forward org-clock-drawer-end-re (save-excursion (org-end-of-subtree)) nil)))
         )
         (while (re-search-forward re end t)
           (skip-chars-forward " \t\r")
           (looking-at org-tr-regexp-both)
           (when (>= (/ (time-to-number-of-days (org-time-since (match-string-no-properties 2))) 7) (float n)) (kill-whole-line))
           ))))))
    (org-clock-remove-empty-clock-drawer)
    ))

It should work if your clocking uses either a specific :CLOCK: drawer or the default :LOGBOOK: drawer, according to the value of the org-clock-into-drawer variable.