[Zope] CoreSession + Non-undoable databases

[Chris McDonough]

Excellent, I'll add these notes to the HowTo.  I really appreciate it.

CJ Kucera wrote:

> On Tue Oct  9 12:43:16 2001, Chris McDonough wrote:
> 
>>Ugh!  This isn't as easy as it should be.
>>
> 
> Excellent; thanks for your help.  It appears to be working.
> Some notes:
> 
>   1) BerkeleyDB installs by default into /usr/local/BerkeleyDB.3.2
>      (obviously if you're installing a different version that'll be
>      slightly different).  This means that to compile bsddb3 you have
>      to do the following:
> 
>         $ python setup.py build_ext --inplace --berkeley-db=/usr/local...
> 
>      What the bsdbb3 README files don't tell you is that you have to
>      pass in the --berkeley-db= line to the "python setup.py install"
>      command as well, or it won't be built properly.  To find out if
>      it's been built properly, cd into "bsddb3/{arch}/bsddb3" [1] and:
> 
>         $ nm _db.so | grep db_create
> 
>      If you get a line like "000242e0 T db_create" you're okay.  If you
>      get one like "     U db_create" there's problems because it wasn't
>      linked properly.  The "_db.so" created inside the "build" directory
>      during the initial "build_ext" step doesn't seem to actually have
>      anything to do with anything; the one under "bsddb3" gets compiled
>      at the "install" step.
> 
>   2) The bsddb3Storage READMEs are a little obtuse.  [2] When you've
>      untarred the package, you'll have a "bsddb3Storage" directory with
>      just .py files in it.  THAT's the directory to copy into
>      {ZOPE_HOME}/lib/python/Products.
> 
>   3) Also, the "custom_zodb.sample" mentioned in the docs doesn't
>      actually exist.  It's "custom_zodb.py" in the current release
>      (1.0beta4), and the syntax of the file doesn't work in Python < 2
>      (so if you're using Python 2, you should be okay).  The
>      custom_zodb.py I ended up using is here:
> 
> 
>>from bsddb3Storage.Packless import Packless
>>#from bsddb3Storage.Minimal  import Minimal  as ConcreteStorage
>>#from bsddb3Storage.Full     import Full     as ConcreteStorage
>>
>>import os
>>env = os.path.join('var', 'bsddb3Storage')
>>
>>Storage = Packless(name='BerkeleyStorage', env=env)
>>
> 
>      Note that the "env" line is telling the BerkeleyDB that it's
>      data directory will be in "var/bsddb3Storage" (your Data.fs
>      is in "var").
> 
>   4) When you've created the "sessionData" folder in BerkeleyDB,
>      shut down your temporary Zope instance and I recommend tarring
>      up the bsddb3Storage directory under var, to move it over to
>      your "real" zope instance.  For instance:
> 
>        $ cd $TEMP_ZOPE/var; tar zcvf ../berkeleydb.tgz bsddb3Storage
> 
>   5) Here's the correct syntax for "Extensions/sessionDB":
> 
> 
>>import ZODB
>>from bsddb3Storage import Packless
>>
>>def getSessionDB():
>>  return ZODB.DB(Packless.Packless('session','berkeleyStorage'))
>>
> 
>      Note that "berkeleyStorage" is the name of the directory where
>      the BerkeleyDB is going to be located (was "var/bsddb3Storage"
>      on your "temp" Zope instance earlier).  So, using my tarfile from
>      before, here's basically what I did:
> 
>        $ cd $ZOPE_HOME; tar zxf ../temp_zope/berkeleydb.tgz
>        $ mv bsddb3Storage berkeleyStorage
> 
>      So for me, I put the BerkeleyDB Storage directory in the same
>      directory as var, lib, zpasswd.py, etc . . .
> 
>   6) When it's been inserted into your tree, for all intents and
>      purposes it looks EXACTLY like just a regular folder, as far
>      as I can tell, which threw me off.  There's even an "undo"
>      tab and everything.  So be careful; there doesn't seem to be
>      an indication that it's actually an Externally Mounted
>      folder as opposed to a regular one.
> 
> In any case, after all that it appears to be working.  You might
> want to update your HOWTO with what I've mentioned here.
> 
> Thanks very much!
> 
> -CJ
> 
> [1] Replace "{arch}" with the directory there.  On my system, it was
>     "lib.linux-i686-1.5"
> 
> [2] I lie.  They're astonishingly useless.  The READMEs distributed
>     with 1.0beta4 are actually the 1.0beta3 files, which may account
>     or most if not all of the problems.  Under the "docs" directory
>     there's a "PacklessReadme.txt" that you're much better off not
>     reading.  It makes references like "Once you've untarred the
>     product, you should have a subdirectory named
>     'PacklessBerkeley3Storage'" which turn out to be patently false.
>     So anyway . . . [3]
> 
> [3] I'm being a bit harsh; they're not really THAT bad, just overly
>     confusing at times. :)
> 
> WOW: Rapacious           | A priest advised Voltaire on his death bed to
> apocalyptech.com/wow     |  renounce the devil.  Replied Voltaire, "This
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> 


-- 
Chris McDonough                    Zope Corporation
http://www.zope.org             http://www.zope.com
"Killing hundreds of birds with thousands of stones"