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zc.buildout recipe for installing cx_Oracle

Project description

gocept.cxoracle - A zc.buildout recipe to easily get cx_Oracle running

An example buildout might look like this:

[buildout]
develop = .
parts = python-oracle cx_Oracle test
python = python-oracle

[python-oracle]
recipe = gocept.cxoracle
instant-client = .../instantclient-basiclite-macosx-10.2.0.4.0.zip
instant-sdk = .../instantclient-sdk-macosx-10.2.0.4.0.zip

[cx_Oracle]
recipe = zc.recipe.egg:custom
egg = cx_Oracle

[test]
recipe = zc.recipe.testrunner
eggs = test.some.egg

gocept.cxoracle - A zc.buildout recipe to easily get cx_Oracle running

The main purpose is to set up the environment required to build a cx_Oracle egg and then provide a loader which sets environment variables required to load the shared libraries.

Oracle doesn’t allow the libraries required to be distributed freely. That means that they must be downloaded by the user or developer from http://www.oracle.com/technology/software/tech/oci/instantclient/index.html

Two archives are required per architecture / operating system:

  1. Instant client basic lite
  2. The SDK
>>> import os.path
>>> basiclite = os.path.join(
...     os.path.dirname(__file__), 'basiclite-linux.zip')
>>> sdk = os.path.join(
...     os.path.dirname(__file__), 'sdk-linux.zip')

Both files have to be configured in the buildout:

>>> write("buildout.cfg", """
... [buildout]
... parts = python-oracle
... python = python-oracle
...
... [python-oracle]
... recipe = gocept.cxoracle
... instant-client = %(basiclite)s
... instant-sdk = %(sdk)s
...
... """ % {'basiclite': basiclite,
...        'sdk': sdk}
... )
>>> print system(buildout),
Installing python-oracle.

We have an oracle-home now in the parts. It contains the contents of both archives mixed together plus a symlink for libclntsh.so -> libclntsh.so.10.1:

>>> ls('parts', 'python-oracle')
-  BASIC_LITE_README
-  classes12.jar
-  genezi
-  libclntsh.so
-  libclntsh.so.10.1
-  libnnz10.so
-  libocci.so.10.1
-  libociicus.so
-  libocijdbc10.so
-  ojdbc14.jar
d  sdk
>>> import os
>>> os.path.islink(os.path.join('parts', 'python-oracle', 'libclntsh.so'))
True
>>> os.readlink(os.path.join('parts', 'python-oracle', 'libclntsh.so'))
'.../parts/python-oracle/libclntsh.so.10.1'

In the bin directory there is a wrapper which sets the LD_LIBRARY_PATH (or DYLD_LIBRARY_PATH on darwin) and the ORACLE_HOME environment variables:

>>> ls('bin')
-  buildout
-  python-oracle

The wrapper can be called like any python interpreter:

>>> system(os.path.join('bin', 'python-oracle') +
...     """ -c "import os; print os.environ['ORACLE_HOME']" """)
'.../parts/python-oracle\n'
>>> script = '''\
... import os
... import sys
... if sys.platform == 'darwin':
...     varname = 'DYLD_LIBRARY_PATH'
... else:
...     varname = 'LD_LIBRARY_PATH'
... print os.environ[varname]
... '''
>>> system(os.path.join('bin', 'python-oracle') +
...     """ -c "%s" """ % script)
'.../parts/python-oracle\n'

On Mac OS X / Darwin the libraries are not called .so but .dylib. The recipe handles this correctly:

>>> basiclite = os.path.join(
...     os.path.dirname(__file__), 'basiclite-darwin.zip')
>>> sdk = os.path.join(
...     os.path.dirname(__file__), 'sdk-darwin.zip')

Both files have to be configured in the buildout:

>>> write("buildout.cfg", """
... [buildout]
... parts = python-oracle
... python = python-oracle
...
... [python-oracle]
... recipe = gocept.cxoracle
... instant-client = %(basiclite)s
... instant-sdk = %(sdk)s
...
... """ % {'basiclite': basiclite,
...        'sdk': sdk}
... )
>>> print system(buildout),
Uninstalling python-oracle.
Installing python-oracle.

The archives are merged as for linux, the a symlink is libclntsh.dylib -> libclntsh.dylib.10.1 this time:

>>> ls('parts', 'python-oracle')
    -  BASIC_LITE_README
    -  classes12.jar
    -  genezi
    -  libclntsh.dylib
    -  libclntsh.dylib.10.1
    -  libnnz10.dylib
    -  libocci.dylib.10.1
    -  libociicus.dylib
    -  libocijdbc10.dylib
    -  libocijdbc10.jnilib
    -  ojdbc14.jar
    d  sdk
>>> import os
>>> os.path.islink(os.path.join('parts', 'python-oracle', 'libclntsh.dylib'))
True
>>> os.readlink(os.path.join('parts', 'python-oracle', 'libclntsh.dylib'))
'.../parts/python-oracle/libclntsh.dylib.10.1'

When an archive cannot be extracted we’ll get an informative error:

>>> write("buildout.cfg", """
... [buildout]
... parts = python-oracle
... python = python-oracle
...
... [python-oracle]
... recipe = gocept.cxoracle
... instant-client = /does/not/exist
... instant-sdk = %(sdk)s
...
... """ % {'sdk': sdk}
... )
>>> print system(buildout),
Uninstalling python-oracle.
Installing python-oracle.
While:
  Installing python-oracle.
<BLANKLINE>
An internal error occured due to a bug in either zc.buildout or in a
recipe being used:
Traceback (most recent call last):
    ...
Exception: Extraction of file '/does/not/exist' failed.

Changes

0.1.1 (2008-08-29)

  • Fixed brown bag release 0.1

0.1 (2008-08-29)

  • first release

Project details


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