Bootstrapping a buildout gives its own
independent of its Python environment. There are 2 reasons you might use this:
- Enable automatic Buildout upgrade (or downgrade).
buildoutscript is local to the buildout, then Buildout will check for newest versions of Buildout and its dependencies that are consistent with any version pins and install any that are different, in which case, it restarts to use the new versions.
Doing automatic upgrades allows buildouts to be more independent of their environments and more repeatable.
Using a local
buildoutscript may be necessary for a project that pins the version of Buildout itself and the pinned version is different from the version in the Python environment.
- Avoid modifying the python environment.
From a philosophical point of view, Buildout has tried to be isolated from its environment, and requiring the Python environment to be modified, by installing Buildout, was inconsistent.
Before virtualenv existed, it might not have been possible to modify the environment without building Python from source.
Unfortunately, doing this requires using a bootstrap script.
Local bootstrapping using the
You can use the bootstrap command of a
buildout script installed in your Python environment to boostrap
the buildout in the current directory:
If you have any other buildouts that have local
buildout scripts, you
can use their
In this case, the buildout being bootstrapped will have the same Python environment as the buildout that was used to bootstrap it.
Using a bootstrapping script¶
If you download:
And then run it:
It will download the software needed to run Buildout and install it in the current directory.
This has been the traditional approach to bootstrapping Buildout.
It was the best approach for a long time because the
easy_install commands usually weren’t available. In the early
easy_install was installed, it was likely to have an
incompatible version of setuptools, because Buildout and setuptools
were evolving rapidly, sometimes in lock step.
This approach fails from time to time, due to changes in setuptools or the package index and has been a source of breakage when automated systems depended on it.
It’s also possible that this approach will stop being supported.
Buildout’s bootstrapping script relies on setuptools’ bootstrap
script, which was used to bootstrap
easy_install. Now that pip is
ubiquitous, there’s no reason to bootstrap
setuptools’ bootstrapping script exists solely to support Buildout.
At some point, that may become too much of a maintenance burden, and
there may not be Buildout volunteers motivated to create a new
Bootstrapping requires a
init creates one¶
Normally, when bootstrapping, the local directory must have a
If you don’t have one, you can use the init command instead:
This can be used with the bootstrapping script as well:
python bootstrap-buildout.py init
This creates an empty Buildout configuration:
[buildout] parts =
If you know you’re going to use some packages, you can supply
requirements on the command line after
buildout init bobo six
In which case it will generate and run a buildout that uses them. The command above would generate a buildout configuration file:
[buildout] parts = py [py] recipe = zc.recipe.egg interpreter = py eggs = bobo six
This can provide an easy way to experiment with a package without adding it to your Python environment or creating a virtualenv.