Turpentine is a Magento extension to improve Magento's compatibility with Varnish, a very-fast caching reverse-proxy. By default, Varnish doesn't cache requests with cookies and Magento sends the frontend cookie with every request causing a (near) zero hit-rate for Varnish's cache. Turpentine provides Varnish configuration files (VCLs) to work with Magento and modifies Magento's behaviour to significantly improve the cache hit rate.

Note that this extension is still in beta so use on a production site should be considered carefully. There are already some sites using it in production, but it is certainly not stable yet (ESI support brought significant changes to how it works).

• Full Magento Page Caching
• Requires very little configuration for impressive results
• Able to apply new Varnish VCLs (configurations) on the fly, without restarting/changing Varnish's config files or flushing the cache
• Exclude URL paths, request parameters (__SID, __store, etc) from caching
• Configure cache TTL by URL and individual block's TTL
• Ability to force static asset (css, js, etc) caching
• Supports multiple Varnish instances for clustered usage
• Hole-punching via Varnish ESI support
• Automatic cache clearing on actions (clearing product/catalog/cms page after saving)
• Non-root Magento installs (i.e. putting Magento in /store/ instead of /)
• Web crawler support for warming the cache
• SSL support through Pound

• Magento Community Edition 1.6+ (earlier versions may work but have not been tested) or Magento Enterprise Edition 1.11+
• Varnish 2.1+ (including 3.0+)

See the Installation and Usage pages.

If you have an issue, please read the FAQ then if you still need help, open a bug report in GitHub's issue tracker.

The extension works in two parts, page caching and block (ESI) caching. A simplified look at how they work:

For pages, Varnish first checks whether the visitor sent a frontend cookie. If they didn't, then they are served a served a new page from the backend (Magento), regardless of whether that page is already cached. This is so they get a new session from Magento. If they already already have a frontend cookie, then they get a (non-session-specific) page from the backend, with any session-specific blocks (defined by the ESI policies) filled in via ESI. Note that this is bypassed for clients identified as crawlers (see the Crawler IP Addresses and Crawler User Agents settings).

For blocks, the extension listens for the core_block_abstract_to_html_before event in Magento. When this event is triggered, the extension looks at the block attached to it and if an ESI policy has been defined for the block then the block's template is replaced with a simple ESI template that tells Varnish to pull the block content from a separate URL. Varnish then does another request to that URL to get the content for that block, which can be cached separately from the page and may differ between different visitors/clients.

• This extension is currently in beta. There are some sites using it in production but you should carefully test it on your own dev site before pushing to production.
• Turpentine will not help (directly) with the speed of "actions" like adding things to the cart or checking out. It only caches, so it can only speed up page load speed for site browsing. It will remove a lot of load on the backend though so for heavily loaded sites it can free up enough backend resources to have a noticeable effect on "actions".
• By design, the first request from a new visitor will not serve them a cached page (it will be passed through to the backend so they get a unique session), so the page load speed will the same as normal (without Varnish/Turpentine). The second request will also be somewhat faster than normal, but not full cached-page speed as the ESI blocks will need to be regenerated and cached for the visitor's new session. Any further requests will be at full cached-page speed (assuming the pages are already in the cache).
• Varnish 2.1 Caveats: Due to technical limitations, some features are not available when using Varnish 2.1:
  • TTL extension on cache hits does not work
  • External ESI requests are not blocked
  • Per-block TTLs are not honored, all ESI blocks use their default TTL

• Logging and statistics will show all requests as coming from the same IP address (usually localhost/127.0.0.1). It should be possible to work around this using Apache's mod_remoteip or mod_rpaf.
• Changing to a different store language has no effect

See the Demo Sites wiki page.

If you use Turpentine (on a production site), feel free to add your site to the list!

The code is licensed under GPLv2+, much of the ESI-specific code is taken from Hugues Alary's Magento-Varnish extension, which is licensed as GPLv3.