ftw.chameleon 1.3.0 on PyPI

Table of Contents

Introduction
Enhancements
Compatibility
Installation
Environment variables
Development
Links
Copyright

Introduction

This package enhances the integration of Chameleon in Plone with five.pt.

In our deployments we have source checkouts (git) which are pulled on updates. This may cause templates to be updated on the next request in running instances, which may cause errors because the associated code was not yet reloaded because the zope instance was not yet rebooted. In order to make that more robust we use Chameleon with eager-loading enabled and auto-reload disabled, so that after an instance is started it will no longer read templates.

These options do not work as expected when using five.pt to integrate Chameleon in combination with ViewPageTemplateFile instances. ftw.chameleon contains enhancements for making that work well.

Enhancements

zope.pagetemplate is patched on Plone 4 so that it considers the CHAMELEON_RELOAD configuration: when CHAMELEON_RELOAD is disabled it does not trigger a recooking of the template even when it has changed. CHAMELEON_RELOAD is not available in Plone 5 as it already patches zope.pagetemplate to not recook templates unless Plone is run in debug mode.
When CHAMELEON_EAGER is enabled, all templates will be cooked on startup. This is done by explicitly cooking all known templates in a separate thread.
Fire an event when chameleon compiles templates.
Log warnings or raise exceptions when templates are compiled unexpectedly. This helps to pin-point problems with templates which are not cacheable.
When CHAMELEON_EAGER is enabled, the templates in portal_skins will be cooked after the first request on the Plone site.

Compatibility

Plone 4.3.x and Plone 5.1.x.

Installation

Buildout example for production:

[instance]
eggs +=
    ftw.chameleon
environment-vars +=
    CHAMELEON_EAGER true
    CHAMELEON_RELOAD false
    CHAMELEON_CACHE ${buildout:directory}/var/chameleon-cache
    FTW_CHAMELEON_RECOOK_WARNING true

Buildout example for development:

[instance]
eggs +=
    ftw.chameleon
environment-vars +=
    CHAMELEON_RELOAD true
    CHAMELEON_CACHE ${buildout:directory}/var/chameleon-cache

You need to make sure that the cache-directory exists. This can be done with buildout:

[buildout]
parts += chameleon-cache

[chameleon-cache]
directory = ${buildout:directory}/var/chameleon-cache
recipe = collective.recipe.shelloutput
commands =
    cmd1 = mkdir -p ${chameleon-cache:directory}

[instance]
environment-vars +=
    CHAMELEON_CACHE ${chameleon-cache:directory}

Environment variables

Name	Description	Values	Recommendation
`CHAMELEON_EAGER`	Parse and compile templates on startup.	`true`, `false`	`true`
`CHAMELEON_RELOAD` (Plone4 only)	Reload templates when they have changed.	`true`, `false`	`false`
`CHAMELEON_CACHE`	File system cache.	Path to cache directory.	`.../var/chameleon-cache`
`FTW_CHAMELEON_RECOOK_WARNING`	Warn when recooking templates.	`true`, `false`	`true`
`FTW_CHAMELEON_RECOOK_EXCEPTION`	Raise exception when recooking templates.	`true`, `false`	`true` when using Sentry.