acquia_purge 7.x-1.0

I'm excited to announce version 7.x-1.0 of the Acquia Purge module, its first stable release ever!

Since the last version 7 months ago, the installation statistic of the module went up to 1,322 instances (1756 downloads) as of the last measurement point on August 24th 2014. Although no big problems got reported since, many smaller annoyances and use-case related things found their ways up into the issue queue. I would like to thank everyone for their issue-queue contributions as this enables improvements to find their way back into many more Drupal sites.

Action requiring changes

• Please run update.php or drush updb immediately!
  Several changes have been made that require updates, for instance a renamed permission and variables that got deleted. Therefore run the updates straight away or else proper functioning of Acquia Purge cannot be guaranteed.
• Version 2.0-rc2 or higher now required for the Cache Expiration module (137455, 2290791, 2239045)
  Support for the 7.x-1.x branch of Expire has stopped and only versions on the 2.X branch are supported with the minimum requirement of 2.0-rc2.
• Rules integration improved drastically and CHANGED (2189819, 2239043)
  Your rules will not break once upgraded to version 7.x-1.0 but will start to emit warning in your logs as we introduced the new rule action Clear pages on Acquia Cloud. The new rule action supports URLs, paths and tokens equally and is better documented on-screen to better aid administrators. The rule action from the expire module (Clear URL(s) from the page cache) is now no longer visible in the Rules interface, as Acquia Purge reimplemented and renamed it.

Notable improvements & features

• Optional SSL-support (2100327)
  It is now possible to purge http:// and https:// URLs or only https:// or only http://, the latter being the default mode. Sites upgrading won't see this feature enabled by default until configured so in settings.php, see README.txt.
• Optional cron-driven processing mode (2194387, 2228949)
  The module can now be put into cron-based processing mode which will disable the on-screen progress-bar immediately. Its recommended to put the cron interval of your general cron short, something like 5-10 minutes, see README.txt.
• Optional ability to reduce logging verbosity
  Some sites saw millions of log messages for the Acquia Purge module, which isn't always very helpful. Site administrators can now - after a weeks long and successfully running implementation - decide to disable logging for successful purges, failures will always be reported, see README.txt. Even without enabling this setting, diagnostic errors that were found will now end up in the logs much less (only once per full queue run).
• Deduplication of the queue
  Although its almost impossible to accurately prevent items from ending up in the queue more than once (as that would bombard the database with queries), it is a lot less likely now. Items will be deduplicated when they go into the queue and quickly dismissed when duplicates are processed (when coming out of the queue). When the site is using Memcached, the deduplication effort becomes much more accurate as it keeps a in-memory log of queued items since the last queue clear or drush ap-forget.
• Memcached or file-backed state data storage (2205015)
  Acquia Purge now no longer stores any of its queue state information (totals, counters, etc) using variable_set() which meant that your site would wipe the variables cache anytime purging occurred. Instead, Acquia Purge will now leverage a special Memcache bin which won't get cleared as part of cache wipes and drush cc all invocations. When your site already leverages memory based caching, Acquia Purge will automatically use it for storing its own (small footprint) data or when your site is on database caching, it will fall back to a file based state storage mechanism which is slightly slower.
• Improved+new diagnostic tests, drush ap-diagnosis cleanup.
  Both in order to support the module and to help aid users with a relatively complex problem to solve (doing load balancer clearing instead of short TTL's) its important to have better and more granular tests to predict what is and can go wrong. Many of the lessons learned from the issue queue found their way back into the diagnostic runtime tests, but still keeping them relatively lightweight. The drush ap-diagnosis command also received a visual cleanup since it reports many more things now. The diagnostic report is also available now on the Expire configuration page.
• Safety shutdown
  When the queue is under extreme loads or when too many errors occurred in row, the module now shuts down and will no longer continue to hammer the server. Running drush ap-diagnosis will explain why the shutdown occurred and also highlight other configuration issues.
• Editorial experience improves with "variations"
  Acquia Purge isn't only used in a fully automated fashion, but drush ap-purge and the manual purge form are clearly getting used as well. One thing that users found cumbersome was that clearing a certain path would also require them to purge same versions of that path (e.g. alias and with trailing slash) that Varnish would also see as uniquely different object. With variations, the system will automatically purge more then asked for when used by editorial users (so not when Expire purges system content) and by doing so, speed up their daily work. If desired, this feature can be disabled, see README.txt
• Editorial experience improves with two "manual purge" blocks (2305309)
  Administrative and editorial use now improves with the introduction of a block called Manual purge form (current page) and another block named Manual purge form (paths). Either of those blocks can be assigned to users with less privileges as the site administrator - who's the only one able to access the main manual purge form - but offers the same feature set, visually simplified.
• Drush ap-purge improved
  It is now possible to purge multiple paths at once with drush ap-purge by encapsulating spaced arguments in quotes, e.g.: drush ap-purge "<front> news node/4". The command got rewritten to the slightly changed API's and now uses process forking to batch process the queue when purging.
• API: hook_acquia_purge_domains_alter()
  It is now possible to alter the domains that are going to be purged in the active context, for instance in less common configuration with domains and subpaths.
• API: hook_acquia_purge_variations_alter()
  The new variations feature allows editorial users to purge variations on the paths they wanted to purge. This hook allows site builders to expand or reduce the list of variations per given path.

Notable bug-fixes

• Capacity calculation improved, respected and reported now
  Acquia Purge attempts to only purge as much as it can from the queue depending on the available PHP resources it has and how work it needs to do. When you wrote your own code against Acquia Purge, a while loop calling _acquia_purge_queue_pop() will no longer endlessly run until the queue is empty but when the capacity calculation thinks its going to run out resources or execution time, this means for instance that Cron-based processing and through drush ap-process is a little faster then through the UI (but not significant). The diagnostic report now reports the slowdown factor which is a reliable indicator of how badly configured the module is, good values are between 2-6.
• Unified input-validation and cleanup.
  In previous versions there were several different and contracting ways of how HTTP-paths got validated, some times (e.g. URLs and wildcards) passed validation and ended up in the queue, while it would not happen at other points. This is now history as validation rules (and user feedback thereof) is now fed back to the user on drush ap-purge, rules, the manual purge form and items are passed upon when expire would attempt to purge something invalid for Acquia Purge to work with (e.g. full URLs).
• False purge failures fixed
  It happened regularly that Acquia Purge instances would report failing purges - with queue looping as result - while in reality the items were purged on the load balancer. This should now be fixed as the HTTP code weighs the response code from the load balancers over the success indication from CURL.
• Better support for Authcache (2330805)
  When using the authcache module, the diagnostic system will no longer shut the whole system down when the page cache is disabled as required by Authcache. However, that use case is experimental and not broadly tested yet (nor recommended).
• Better support for localization (2271983)
  Domains are now better extracted from Drupal and no longer include strings like en or fr when the locale module is in use.
• AJAX forms no longer cause the on-screen progress bar to go mad
  As soon as Acquia Purge's on-screen processing widget is done with purging your queue, it will unset its Javascript behavior. This means that when your on pages with AJAX-driven forms (e.g. with the new manual purge form blocks somewhere), the notification won't just show up and act weird.