Metadata-Version: 1.0
Name: buildout.recipe.isolation
Version: 0.2.0
Summary: Recipe for isolating Python distributions (packages and scripts).
Home-page: http://weblion.psu.edu/trac/weblion/browser/weblion/buildout.recipe.isolation
Author: Michael Mulich | WebLion Group, Penn State University
Author-email: support@weblion.psu.edu
License: GPL 2
Description: ================
        Isolation Recipe
        ================
        
        This buildout recipe's sole purpose is to isolate distribution packages and
        there dependencies. This recipe was originally developed to be used in the
        packaging of Zope2 for the Debian operating system. The recipe can additionally
        be used to populate a Python enviroment (or virtual environment). This can be
        handy in situations where buildout is required to build the application, but
        the developer/system administrator wants to use the application in a typical
        Python environment.
        
        Isolation of distributions
        ==========================
        
        The `buildout.recipe.isolation` recipe can be used to isolate distributions and
        their dependencies in a single directory. The recipe takes a number of options:
        
        dists
        A list of distributions to isolate given as one or more setuptools
        requirement strings. Each requirements string should be given on a
        separate line. The default is to use the part name as the distribution.
        
        exclude-dists (optional)
        A list of distributions that should be excluded from the isolation.
        
        dists-location (optional)
        A directory location where the isolated distributions should be put.
        This option
        defaults to a location in the buildout parts directory under the section
        name where the recipe is being used.
        
        scripts-location (optional)
        A directory location where the distribution scripts should be isolated.
        This option defaults to a location in the buildout parts directory under
        the part (or section) name followed by '-scripts' (e.g. for a part
        named *isolated* the default scripts directory name would be
        `isolated-scripts`).
        
        .. _pth_location_opt:
        
        pth-location (optional)
        A directory location where a `.pth` file will be created for this isolation.
        This option defaults to a location in the buildout parts directory under
        the part (or section) name followed by '-pth' (e.g. for a part named
        *isolated*, the default pth directory name would be `isolated-pth`).
        
        __ pth_file_location_opt_
        
        The final name of the pth file will be the part name with a `.pth`
        extension. To reference the resulting `.pth` file, use the
        `pth-file-location`__ options.
        
        .. _pth_file_location_opt:
        
        pth-file-location (reference only)
        A location where the `.pth` file lives. The resulting `.pth` file is used
        during the script generation process to provide a list of distributions
        that are isolated somewhere else on the filesystem.
        
        .. note:: This option can only be referenced. Later versions of this recipe
        may provide a means to change the pth filename.
        
        extra-pth (optional)
        A list of `.pth` files to include as part of the script initialization.
        
        This option resolves dependency issues caused by dependency isolation.
        For instance, if you are using `exclude-dists` and those distributions
        that are being exluded are required to run a script, you probably want
        to include the `.pth` file with locations to those dependencies.
        
        exclude-own-pth (optional)
        A boolean option, that when set will exclude the in context part's generated
        `.pth` file from inclusion in scripts. This option is closely tied to
        pth-file-location and extra-pth. This option is false by default.
        
        The reason this option has been included is because the locations in the
        `.pth` file main already be included in the python path via the `.pth`
        file's location in site-packages.
        
        executable (optional)
        The location of the Python executable. By default this is `sys.executable`.
        
        The executable specified is not executed in the recipe. The location is
        used as the shebang line during the scripts generation.
        
        .. _stage_locally_opt:
        
        stage-locally (optional)
        A boolean option to specify whether we should stage the resources or
        put them in there final destination. If this option is true, the values
        specified for `dist-location`, `script-location` and `pth-location` are
        used to generate the resources, but the resources are placed in
        the default parts locations. This option is handy for staged installation.
        
        Recipe deliverables
        -------------------
        
        - A directory that contains a specified distribution(s) package and its
        dependency package(s).
        - A directory that contains a `.pth` file, which lists the absolute path
        for each package in the isolation context.
        - A directory that contains the scripts that have been generated from the
        distribution(s) package and its dependency packages.
        
        How it works
        ============
        
        
        
        We have a sample buildout.  Let's update it's configuration file to
        install the demo package.
        
        >>> write(sample_buildout, 'buildout.cfg',
        ... """
        ... [buildout]
        ... parts = demo
        ...
        ... [demo]
        ... recipe = buildout.recipe.isolation
        ... dists = demo<0.3
        ... find-links = %(server)s
        ... index = %(server)s/index
        ... """ % dict(server=link_server))
        
        In this example, we limited ourselves to revisions before 0.3. We also
        specified where to find distributions using the find-links option.
        
        In order to control the distribution test data, we decided to use buildout's
        testing index, shown below::
        
        >>> print get(link_server),
        <html><body>
        <a href="bigdemo-0.1-py2.3.egg">bigdemo-0.1-pyN.N.egg</a><br>
        <a href="demo-0.1-py2.3.egg">demo-0.1-py2.3.egg</a><br>
        <a href="demo-0.2-py2.3.egg">demo-0.2-py2.3.egg</a><br>
        <a href="demo-0.3-py2.3.egg">demo-0.3-py2.3.egg</a><br>
        <a href="demo-0.4c1-py2.3.egg">demo-0.4c1-py2.3.egg</a><br>
        <a href="demoneeded-1.0.zip">demoneeded-1.0.zip</a><br>
        <a href="demoneeded-1.1.zip">demoneeded-1.1.zip</a><br>
        <a href="demoneeded-1.2c1.zip">demoneeded-1.2c1.zip</a><br>
        <a href="extdemo-1.4.zip">extdemo-1.4.zip</a><br>
        <a href="index/">index/</a><br>
        <a href="other-1.0-py2.3.egg">other-1.0-py2.3.egg</a><br>
        </body></html>
        
        We will be using this index through the testing structure and further
        explaining the relationships before each of these distributions.
        
        Let's run the buildout::
        
        >>> import os
        >>> print system(buildout), #doctest: +ELLIPSIS
        Installing demo.
        Getting distribution for 'demo<0.3'.
        Got demo 0.2.
        Getting distribution for 'demoneeded'.
        install_dir ...
        Got demoneeded 1.2c1.
        demo: Copying demo to the destination directory.
        demo: Copying demoneeded to the destination directory.
        demo: Generated script '/sample-buildout/parts/demo-scripts/demo'.
        
        Now, if we look at the buildout parts directory for the isolation::
        
        >>> ls(sample_buildout, 'parts/demo')
        -  demo-0.2-py2.3.egg
        d  demoneeded-1.2c1-py2.3.egg
        
        These distributions have been entered into a `.pth` file as well. This file
        is not directly useful to the buildout, but has it's place in a Python
        environment. The contents of the `.pth` file will be the absolute path for each
        of the distributions that have been installed into the isolation. Let's have
        a look::
        
        >>> cat(sample_buildout, 'parts/demo-pth', 'demo.pth')
        /sample-buildout/parts/demo/demo-0.2-py2.6.egg
        /sample-buildout/parts/demo/demoneeded-1.2c1-py2.6.egg
        
        __ pth_file_location_opt_
        
        By default the name of the `.pth` files will be the name of the buildout
        section, which in this case is demo. You can change the location of the
        `.pth` file using the `pth-file-location`__ option.
        
        .. note:: When using the `pth-file-location` option, the directory that the
        `.pth` file will reside, must exist prior to running the buildout.
        If directory  does not exist, an `IOError` will be raised and the
        buildout will fail.
        
        Dependency exclusion
        --------------------
        
        Let's now try a buildout with a slightly larger example that we can use to
        illustrate the exclude dependencies from a certain isolation.
        
        Let's create a new buildout configuration based on the previous one. This
        configuration is setup to isolate the bigdemo distribution and its
        dependencies, but exclude the demoneeded dependency.
        
        >>> write(sample_buildout, 'buildout.cfg',
        ... """
        ... [buildout]
        ... parts =
        ...     demoneeded
        ...     demo
        ... find-links = %(server)s
        ... index = %(server)s/index
        ...
        ... [demoneeded]
        ... recipe = buildout.recipe.isolation
        ... dists = demoneeded
        ...
        ... [demo]
        ... recipe = buildout.recipe.isolation
        ... dists = bigdemo
        ... exclude-dists = ${demoneeded:dists}
        ... """ % dict(server=link_server))
        
        >>> print system(buildout), #doctest: +ELLIPSIS
        Uninstalling demo.
        Installing demoneeded.
        demoneeded: Copying demoneeded to the destination directory.
        Installing demo.
        Getting distribution for 'bigdemo'.
        Got bigdemo 0.1.
        Getting distribution for 'demo'.
        Got demo 0.4c1.
        demo: Copying demo to the destination directory.
        demo: Copying bigdemo to the destination directory.
        demo: Generated script '/sample-buildout/parts/demo-scripts/demo'.
        
        Check the isolated results:
        
        >>> ls(sample_buildout, 'parts/demo')
        -  bigdemo-0.1-py2.6.egg
        -  demo-0.4c1-py2.6.egg
        >>> ls(sample_buildout, 'parts/demoneeded')
        d  demoneeded-1.2c1-py2.6.egg
        
        Script generation
        -----------------
        
        Some distributions supply command-line scripts with there packages. Buildout
        typically generates these scripts for us, because it needs to supply the built
        packages to to script. It does this by injecting the distribution locations
        into the Python system path. In some cases we do not want to inject anything
        into the Python system path, because we may have deposited the generated .pth
        file in a virtual environment's site-packages directory. While in other cases,
        we might want to supply our .pth file as a mean for import resolution. Let's
        take a closer look at both cases.
        
        For the general case, we will likely want to supply our .pth file to the
        script. Additionally, we will probably want to supply any .pth files that
        dependent isolations may have generated. Here is an example.
        
        >>> import sys
        >>> write(sample_buildout, 'buildout.cfg',
        ... """
        ... [buildout]
        ... parts =
        ...     demoneeded
        ...     demo
        ... find-links = %(server)s
        ... index = %(server)s/index
        ...
        ... [demoneeded]
        ... recipe = buildout.recipe.isolation
        ... dists = demoneeded
        ...
        ... [demo]
        ... recipe = buildout.recipe.isolation
        ... dists = bigdemo
        ... exclude-dists = ${demoneeded:dists}
        ... extra-pth = ${demoneeded:pth-file-location}
        ... executable = %(python)s
        ... """ % dict(server=link_server, python=sys.executable))
        >>> print system(buildout), #doctest: +ELLIPSIS
        Uninstalling demo.
        Uninstalling demoneeded.
        Installing demoneeded.
        demoneeded: Copying demoneeded to the destination directory.
        Installing demo.
        demo: Copying demo to the destination directory.
        demo: Copying bigdemo to the destination directory.
        demo: Generated script '/sample-buildout/parts/demo-scripts/demo'.
        
        The resulting script should have two .pth files in it. The demo.pth file has
        been defined and generated from the recipe in context. The demoneeded.pth file
        was generated by the demoneeded section and pulled in using the extra-pth
        recipe option.
        
        >>> if sys.platform == 'win32':
        ...    script_name = 'demo-script.py'
        ... else:
        ...    script_name = 'demo'
        >>> script_dir = 'parts/demo-scripts'
        >>> f = open(os.path.join(sample_buildout, script_dir, script_name))
        >>> shebang = f.readline().strip()
        >>> if shebang[:3] == '#!"' and shebang[-1] == '"':
        ...     shebang = '#!'+shebang[3:-1]
        >>> shebang == '#!' + os.path.realpath(sys.executable)
        True
        >>> print f.read(), # doctest: +NORMALIZE_WHITESPACE
        <BLANKLINE>
        import sys
        def pth_injector(pth_file):
        path_file = open(pth_file, 'r')
        sys.path[0:0] = [line
        for line in path_file.read().split('\n')
        if line is not None]
        <BLANKLINE>
        pth_files = ['/sample-buildout/parts/demo-pth/demo.pth', '/sample-buildout/parts/demoneeded-pth/demoneeded.pth']
        for pth in pth_files:
        pth_injector(pth)
        <BLANKLINE>
        import eggrecipedemo
        <BLANKLINE>
        if __name__ == '__main__':
        eggrecipedemo.main()
        >>> f.close()
        
        The second case is where we have deposited the .pth files into a virtual
        environment. Let's setup a *fake* virtual environment structure inside the
        buildout structure for demonstration sake.
        
        >>> virtenv = os.path.join(sample_buildout, 'virtenv')
        >>> mkdir(virtenv)
        >>> mkdir(virtenv, 'bin')
        >>> mkdir(virtenv, 'lib')
        >>> mkdir(virtenv, 'lib', 'python2.6')
        >>> mkdir(virtenv, 'lib', 'python2.6', 'site-packages')
        >>> site_pkgs = os.path.join(virtenv, 'lib', 'python2.6', 'site-packages')
        
        All we really need for the purpose of this demonstration is the site-packages
        directory.
        
        >>> write(sample_buildout, 'buildout.cfg',
        ... """
        ... [buildout]
        ... parts =
        ...     demoneeded
        ...     demo
        ... find-links = %(server)s
        ... index = %(server)s/index
        ...
        ... [demoneeded]
        ... recipe = buildout.recipe.isolation
        ... dists = demoneeded
        ... pth-file-location = %(site_pkgs)s
        ...
        ... [demo]
        ... recipe = buildout.recipe.isolation
        ... dists = bigdemo
        ... exclude-dists = ${demoneeded:dists}
        ... pth-file-location = %(site_pkgs)s
        ... exclude-own-pth = trUE
        ... python = %(python)s
        ... """ % dict(server=link_server, python=sys.executable,
        ...     site_pkgs=site_pkgs))
        >>> print system(buildout), #doctest: +ELLIPSIS
        Uninstalling demo.
        Uninstalling demoneeded.
        Installing demoneeded.
        demoneeded: Copying demoneeded to the destination directory.
        Installing demo.
        demo: Copying demo to the destination directory.
        demo: Copying bigdemo to the destination directory.
        demo: Generated script '/sample-buildout/parts/demo-scripts/demo'.
        
        Now if we print out the demo script, we'll find no mention of the .pth files.
        
        >>> f = open(os.path.join(sample_buildout, script_dir, script_name))
        >>> shebang = f.readline().strip()
        >>> if shebang[:3] == '#!"' and shebang[-1] == '"':
        ...     shebang = '#!'+shebang[3:-1]
        >>> shebang == '#!' + os.path.realpath(sys.executable)
        True
        >>> print f.read(), # doctest: +NORMALIZE_WHITESPACE
        <BLANKLINE>
        import eggrecipedemo
        <BLANKLINE>
        if __name__ == '__main__':
        eggrecipedemo.main()
        >>> f.close()
        
        Why does this work? If we were to use the virtual environments Python
        executable, it would load the site-packages directory and any .pth files in
        it. This would in turn load the modules we built using the buildout.
        
        .. note:: We aren't actually using the virtual environments Python executable
        in this test case, but it is a simple matter of changing the executable
        value in the system_python section of this buildout.cfg.
        
        Staging the isolation
        ---------------------
        
        __ stage_locally_opt_
        
        In some situations it is handy to build the packages locally before
        transfering these resources to a final destination. To do this we stage the
        isolation process with the `stage-locally`__ option.
        
        This option will allow you to set the `dists-location`, `scripts-location` and
        `pth-file-location` as final destinations, but place the results in their
        default build location. The default build location, if you recall, is in the
        buildout's parts directory.
        
        .. note:: The following example isn't necessarily useful beyond the test that
        it satisfies. If you're trying to figure out how to use the staging parts
        of this recipe and run into issues or parts you don't understand, please
        feel free to contact the author (see the package metadata for the address).
        
        Let's have a look at how this works by creating similar buildout to those about
        execept now we are setting the `stage-locally` option to `true`::
        
        
        >>> write(sample_buildout, 'buildout.cfg',
        ... """
        ... [buildout]
        ... parts =
        ...     demo
        ... find-links = %(server)s
        ... index = %(server)s/index
        ...
        ... [demo]
        ... recipe = buildout.recipe.isolation
        ... dists = bigdemo
        ... dists-location = %(site_pkgs)s
        ... scripts-location = %(bin_dir)s
        ... pth-location = %(site_pkgs)s
        ... executable = %(python)s
        ... stage-locally = true
        ... """ % dict(server=link_server,
        ...	           bin_dir=os.path.join(virtenv, 'bin'),
        ...	    	   python=os.path.join(virtenv, 'bin', 'python'),
        ...     	   site_pkgs=site_pkgs))
        >>> print system(buildout), #doctest: +ELLIPSIS
        Uninstalling demo.
        Uninstalling demoneeded.
        Installing demo.
        demo: Copying demo to the staging directory.
        demo: Copying demoneeded to the staging directory.
        demo: Copying bigdemo to the staging directory.
        demo: Can't find the executable on the filesystem. Perhaps this setup is not destine to be used on this machine. So we are using the given executable value /sample-buildout/virtenv/bin/python as is.
        demo: Generated script '/sample-buildout/parts/demo-scripts/demo'.
        
        To verify that things have been staged, let's have a closer look at the demo
        script to verify everything went as planned. For one, we expect the script
        to be in the parts directory::
        
        >>> parts_dir = os.path.join(sample_buildout, 'parts')
        >>> demo_script = os.path.join(parts_dir, 'demo-scripts', 'demo')
        >>> os.path.exists(demo_script)
        True
        >>> cat(demo_script)
        #!/sample-buildout/virtenv/bin/python
        <BLANKLINE>
        import sys
        def pth_injector(pth_file):
        path_file = open(pth_file, 'r')
        sys.path[0:0] = [line
        for line in path_file.read().split('\n')
        if line is not None]
        <BLANKLINE>
        pth_files = ['/sample-buildout/virtenv/lib/python2.6/site-packages/demo.pth']
        for pth in pth_files:
        pth_injector(pth)
        <BLANKLINE>
        import eggrecipedemo
        <BLANKLINE>
        if __name__ == '__main__':
        eggrecipedemo.main()
        
        And also we want to check that the pth locations are correct and that the pth
        itself is in the staging area with parts::
        
        >>> demo_pth = os.path.join(parts_dir, 'demo-pth', 'demo.pth')
        >>> cat(demo_pth)
        /sample-buildout/virtenv/lib/python2.6/site-packages/demo-0.4c1-py2.1.egg
        /sample-buildout/virtenv/lib/python2.6/site-packages/demoneeded-1.2c1-py2.1.egg
        /sample-buildout/virtenv/lib/python2.6/site-packages/bigdemo-0.1-py2.1.egg
        
        
        Issues and help
        ---------------
        
        If you have issues or need assistance, file a bug report on `WebLion's project
        site <http://www.weblion.psu.edu/trac/weblion>`_ or contact us via `IRC <irc://irc.freenode.net/#weblion>`_ or email.
        
Keywords: development build
Platform: UNKNOWN
Classifier: Framework :: Buildout
Classifier: Intended Audience :: Developers
Classifier: License :: OSI Approved :: Zope Public License
Classifier: Topic :: Software Development :: Build Tools
Classifier: Topic :: Software Development :: Libraries :: Python Modules
Classifier: Development Status :: 4 - Beta
