Extension and Recipes

This package is composed of an extension to zc.buildout and a recipe. We recommend you use both during the creation of your own package-based recipes. Here is a typical buildout.cfg file that can be used to setup the development of your own package, and which we normally ship with all Bob-based packages:

parts = scripts
develop = .
eggs = <PACKAGE>
extensions = bob.buildout
newest = false
verbose = true

recipe = bob.buildout:scripts

Replace <PACKAGE> by your package name and you should be ready to run the buildout application. If you’re curious about zc.buildout and how to structure your recipe to take full advantage of it, we advise you seek documentation on that package on its website or by searching the internet.

The above setup will include all required material for building both simple python or python/C/C++ packages from Bob.

By using extension bob.buildout on the buildout section of your recipe, you ensure the current package will be built taking into consideration all required environment/compiler settings required by Bob. This extension is strictly required for packages containing C/C++ bindings, but it is harmless to include it in Python-only packages.

The section scripts define a list of scripts that will be installed on the bin directory. By default, we make sure all packages listed in buildout.eggs are available, as well as typical packages required for development such as sphinx, for documentation building, nose for running your test suite and coverage, for code coverage reporting. You may augment the eggs entry on the buildout section if you’d like further packages to be installed on your development environment. It is your call. An example package that is often listed there is ipdb - the iPython based python debugger. The syntax of the eggs entry on the buildout section is one package per line.

The entry develop on the buildout section indicates to buildout the root directories of packages that it should take, prioritarily, before considering potential versions installed on base python (conda) environment. It typically says just . (dot), as we’re typically willing to only make buildout aware of our local checkout. It can include more directories (one per line), if we’d like to cross-develop more packages. That is what we do, for example, when using the extension mr.developer (see: Bob Package Development development). For each package listed in develop, buildout will run the equivalent of cd <dir> && python setup.py develop on each package before trying to resolve the dependencies in eggs. It will then consider those locally installed packages in final load-path scheme for your applications.

In case you’re curious, the buildout.newest flag is internal to zc.buildout. It instructs the setuptools machinery to consider or not versions of packages currently installed. If newest=true, then only the absolute newest packages in PyPI can satisfy the build. By default, we let this setting to false indicating that what is currently installed will be sufficient. Only change it if you know the implications. Note, for example, in this case, you may not be testing anymore, exclusively, against a Bob-agreed set of dependencies.

The remainder flags and options are explained next.

Supported extension options

Here is a list of supported options for the bob.buildout. They should appear in the buildout section of your recipe. They are considered for as long as bob.buildout is listed as an extension.


If set, buildout it will output the compilation commands while compiling the module. This flag should go into the buildout section of your recipe. Accepted values are true or false.(the default).


A list of directories where this recipe will look for installed software, such as compiled libraries and header files. It is important if you’re compiling a package that requires external software such as ffmpeg or blitz++ header files to be available. It is the same as setting the environment variable BOB_PREFIX_PATH to a list of paths containing externally installed software. As a side-effect, setting BOB_PREFIX_PATH also sets, internally, PKG_CONFIG_PATH to a list of directories following where to search for pkg-config files.

You typically don’t need to set this manually since bob.extension is smart enough to figure out where to find external libraries. This is even more true if you’re using conda-based installations as the bootstrapping environment of your buildout.


If set, the module will be compiled with debugging symbols and with optimization turned off. If debug is set to true, this is equivalent to appending the environment variables CFLAGS and CXXFLAGS with -O0 -g. By default, the value is false. This setting is advised if you are compiling python C/C++ bindings and would like to debug C/C++ code locally.


The name of another section on your configuration file that contains the names and values of environment variables that should be set before any possible build takes place. This section is named, by default, environ. That is, if you provide a section named environ on your buildout recipe, then you don’t need to explicitly specify its name using this flag.

If a section named environ (or whatever lists the environ override on the buildout section of your recipe) exists, it is read and the environment variables are set before the specified packages are built. You can use variable substitution on this section. Here is an an example:


Notice there is some functionality overlap between the previous flags and the use of section environ. While it is more flexible, you must understand the consequences of setting both prefixes and debug, together with environ. The rule is simple: values set on the environ section have precedence to debug and prefixes. If you set debug and CFLAGS (or CXXFLAGS) in the environ section, for example, then the values on the final CFLAGS variable would be -O0 -g followed by environ’s CFLAGS settings. Analogously, the paths defined by environ’s BOB_PREFIX_PATH and PKG_CONFIG_PATH are prepended to those listed in prefixes, if that is also set.

The scripts recipe

By using the recipe bob.buildout:scripts on one of the sections of your recipe, you ensure the scripts generated by the recipe will be built taking into consideration all installed packages from your base python environment (typically a conda-based installation). If you don’t use the bob.buildout:scripts recipe, zc.buildout, by default, assumes no packages are availabe on the python installation and may download/recompile all dependencies from scratch.

By default, this recipe will use the eggs defined at the buildout section called eggs, but that can be overriden locally. It generates these scripts:


A pre-configured python interpreter taking into consideration all eggs and development packages on your recipe.

gdb-python or lldb-python

A pre-configured python interpreter, prefixed with gdb (or lldb on a MacOS system) to make debugging easier. Use it like you use python.


A test runner called nosetests will be created on the bin directory of buildout.


A test coverage application called coverage will be created on the bin directory of buildout.

sphinx-build and friends

Several sphinx utilities will be created on the bin directory of buildout.

Other package scripts

Package scripts will be created taking into account the prefixes established for this section or globally (as a second priority).

Supported recipe options

The scripts recipe supports the following options (mostly for experts - read don’t use them unless you know what you’re doing):


Overrides or sets the list of prefixes in buildout.prefixes. If not given, the value of this property defaults to buildout.prefixes. Both can be empty, which makes this recipe default to using standard available paths.


The eggs option specifies a list of eggs to use for building the scripts of this recipe. Each string must be given on a separate line. If not given, the value of this property defaults to buildout.eggs.


If set to the string true, scripts will be generated for all required eggs in addition to the eggs specifically named. By default, it is false to avoid the clutter it may cause on very high-level packages, with numerous dependencies exporting scripts.


The name of a script to generate that allows access to a Python interpreter that has the path set based on the eggs installed. If you don’t specify anything, the default value python will be used.


Extra paths to be appended in a generated script. To prepend, use the prefixes entry.


These are extra flags that are appended to the given nosetests command line, automatically. Use this to preset arguments you like running all the time like -v, for example.