sauna.reload 0.1.0

Introduction

sauna.reload is an attempt to recreate plone.reload without the issues it has. Like being unable to reload new grokked views or portlet code.

sauna.reload does reloading by using a fork loop. So actually it does not reload the code, but restarts small part of Zope2.

It does following on Zope2 startup:

1. Defers loading of your development packages by hooking into PEP 302 loader and changing their z3c.autoinclude target module

2. Starts a watcher thread which monitors changes in your development py-files

3. Stops loading of Zope2 in zope.processlifetime.IProcessStarting event by stepping into a infinite loop; Just before this, tries to load all non-developed dependencies of your development packages (resolved by z3c.autoinclude)

4. It forks a new child and lets it pass the loop

5. Loads all your development packages invoking z3c.autoinclude. This is fast!

6. And now every time when the watcher thread detects a change in development files it will signal the child to shutdown and the child will signal the parent to fork new a child when it is just about to close itself

7. Just before dying, the child saves Data.fs.index to help the new child to see the changes in ZODB (by loading the saved index)

8. GOTO 4

Installing

Add this package to your buildout eggs and add following zope-conf-additional line to you instance part of buildout.cfg:

[instance]
recipe = plone.recipe.zope2instance
...
zope-conf-additional = %import sauna.reload

Using

Fork loop is not active by default. You can activate it by setting RELOAD_PATH environment variable to your development product path(s). In most setups src is what you want:

RELOAD_PATH=src bin/instance fg

Or if you want to optimize load speed you can directly specify only some of your development products:

RELOAD_PATH=src/my.product:src/my.another.product bin/instance fg

Known issues

• Currently reloading is limited to new style z3c.autoincluded Python packages and does not cover old-style Products.XXX namespaced packages or Five-packages (e.g. does not reload Archetypes yet)

• Currently only FileStorage (ZODB) is supported

• The watcher (watchdog) does not compile on OS X Lion 10.7. Snowleopard is fine

TODOs

• Be able to reload oldschool (Products.XXX and Five) packages too

• Test it!

• Find out the limitations

• Document why it is hard to reload plone core packages

Authors

• Esa-Matti Suuronen (esa-matti aet suuronen.org)

• Asko Soukka (asko.soukka aet iki.fi)

• Mikko Ohtamaa (idea)

• Andreas Jung (approved in IRC)

300 kg of beer was consumed to create this package (at least). Also several kilos of firewood, one axe, one chainsaw and one boat.

0.1.0 - 2011-08-03

• First experimental release.