Update packages every nth day! (Very hacky)

init.el

@@ -35,7 +35,35 @@ PACKAGE is installed and the current version is deleted."
                          (package-desc-vers (cdr pkg-desc)))))
       (package-install package))))
 
-(package-refresh-contents)
+(defvar days-between-updates 1)
+(defvar do-package-update-on-init t)
+
+(require 'time-stamp)
+;; Open the 'user-init-file' and write any changes.
+(with-temp-file user-init-file
+  ;; Insert it's original content's.
+  (insert-file-contents user-init-file)
+  (forward-line time-stamp-line-limit)
+  (let ((bound (point)))
+    (goto-char (point-min))
+    ;; We search for the time-stamp.
+    (let ((start (re-search-forward time-stamp-start bound t))
+          (end (re-search-forward time-stamp-end bound t)))
+      (when (and start end)
+        ;; Assuming we have found a time-stamp, we check determine if it's
+        ;; time to update.
+        (setq do-package-update-on-init
+              (<= days-between-updates
+                  (days-between
+                   (current-time-string)
+                   (buffer-substring-no-properties start end))))
+        ;; Remember to update the time-stamp.
+        (when do-package-update-on-init
+          (time-stamp))))))
+
+(when do-package-update-on-init
+  (package-refresh-contents))
+
 (dolist (package
          '(ac-geiser         ; Auto-complete backend for geiser
            ac-slime          ; An auto-complete source using slime completions
@@ -59,7 +87,8 @@ PACKAGE is installed and the current version is deleted."
            pretty-lambdada   ; the word `lambda' as the Greek letter.
            smex              ; M-x interface with Ido-style fuzzy matching.
            ))
-  (upgrade-or-install-package package))
+  (when do-package-update-on-init
+    (upgrade-or-install-package package)))
 
 (dolist (feature
          '(auto-compile             ; auto-compile .el files

init.org

@@ -83,12 +83,57 @@
            (package-install package))))
    #+END_SRC
 
+   The =package-refresh-contents= function downloads archive descriptions,
+   this is a major bottleneck in this configuration. To avoid this we can
+   try to only check for updates once every day or so. Here are to
+   variables. The first specifies how often we should check for updates. The
+   second specifies wither one should update during the initialization.
+
+   #+BEGIN_SRC emacs-lisp :tangle yes
+     (defvar days-between-updates 1)
+     (defvar do-package-update-on-init t)
+   #+END_SRC
+
+   The tricky part is figuring out when the last time the Emacs was updated!
+   Here is a hacky way of doing it, using [[http://www.gnu.org/software/emacs/manual/html_node/emacs/Time-Stamps.html][time-stamps]]. By adding a
+   time-stamp to the init file, we can search for it and determine wither or
+   not to do an update. After that we must run the =time-stamp=-function to
+   update the time-stamp. Note that if there is no time-stamp in the
+   init-file then packages will be updated every time you start Emacs.
+
+   #+BEGIN_SRC emacs-lisp :tangle yes
+     (require 'time-stamp)
+     ;; Open the 'user-init-file' and write any changes.
+     (with-temp-file user-init-file
+       ;; Insert it's original content's.
+       (insert-file-contents user-init-file)
+       (forward-line time-stamp-line-limit)
+       (let ((bound (point)))
+         (goto-char (point-min))
+         ;; We search for the time-stamp.
+         (let ((start (re-search-forward time-stamp-start bound t))
+               (end (re-search-forward time-stamp-end bound t)))
+           (when (and start end)
+             ;; Assuming we have found a time-stamp, we check determine if it's
+             ;; time to update.
+             (setq do-package-update-on-init
+                   (<= days-between-updates
+                       (days-between
+                        (current-time-string)
+                        (buffer-substring-no-properties start end))))
+             ;; Remember to update the time-stamp.
+             (when do-package-update-on-init
+               (time-stamp))))))
+   #+END_SRC
+
    Now we can use the function above to make sure packages are installed and
    up to date. Here are some packages I find useful (some of these
    configurations are also dependent on them).
 
    #+BEGIN_SRC emacs-lisp :tangle yes
-     (package-refresh-contents)
+     (when do-package-update-on-init
+       (package-refresh-contents))
+
      (dolist (package
               '(ac-geiser         ; Auto-complete backend for geiser
                 ac-slime          ; An auto-complete source using slime completions
@@ -112,7 +157,8 @@
                 pretty-lambdada   ; the word `lambda' as the Greek letter.
                 smex              ; M-x interface with Ido-style fuzzy matching.
                 ))
-       (upgrade-or-install-package package))
+       (when do-package-update-on-init
+         (upgrade-or-install-package package)))
    #+END_SRC
 
 ** Require