Development guide

So you want to extend EasyBuild? Great idea!

There are three major parts to EasyBuild:

• build.py: the main script which sets up the rest of the application and determines the build-order, this is called through easybuild.sh which sets a correct Python environment before starting
• apps: the general Application class and a collection of more specific subclasses
• buildsoft: utilities for building
  • asyncprocess
  • buildLog: wrapper around Python's logger
  • config: proxy for the Configuration
  • fileTools: file management and running commands
  • moduleGenerator: generates module-files
  • modules: interface to the module command
  • repository: interface to the configured source control system such as pySVN subversion or the filesystem.
  • toolkit: toolkit setup and configuration

How to build a custom Application-class

First check if the available functionality is already available in EasyBuild. Some application-classes are very flexible and might be sufficient for your needs. If not, go ahead and create a new class inheriting from Application or a subclass of that (you can get a quick overview of all available classes using --dump-classes).

Each step in the build-process consists out of one or more methods which you can override. If you want to skip a step, just implement it with pass. See Easyconfig files for options for each step in the default implementation.

1. Generate installation path and create build directory
   • genInstallDir
   • makeBuilDir
2. Unpack source in the build directory
   • unpackSrc
3. Apply patches
   • applyPatch
4. Configure
   • prepare toolkit (using self.tk.prepare)
   • startFrom: Change the build directory
   • configure
5. Make
   • make
6. Test (run make test or variants)
   • test
7. Install
   • makeInstallDir
   • makeInstall
8. Packages
   • packages
9. Generate modulefiles
   • postproc
10. Cleanup
    • cleanup
11. Test installation
    • runTests

Adding specification-options

Specification files are read by the importCfg-method. Instead of overriding this method, it's highly recommended to extend the datastructure that method uses to process your specification options. To do so, create the following extra_options method:

from easybuild.framework.easyconfig import CUSTOM
from easybuild.easyblocks.application import Application

    def __init__(self, *args, **kwargs):
        Application.__init__(self, *args, **kwargs)

    @staticmethod
    def extra_options():
        extra_vars = [

                      ('importdeps', [None, 'A list of modules to import when configuring', CUSTOM]),
                      ('config-key', [<default>, <description>, CUSTOM ]),
                      (..., [..., ..., CUSTOM]),
                     ]
        return Application.extra_options(extra_vars)

Afterwards you can read the requested configuration using getCfg. If a key was not set, the default value will be returned.

Testing

Unittests should be added (if possible) for each added feature. You can run the unittests with python -m easybuild.test.suite

Adding more unittests should be done by creating a new test module, adding a suite() method which returns a TestSuite object with all the testcases in it.

In easybuild/test/suite.py you should add it to the list of modules then, so it will be included when somebody runs the suite.

Regression test

To run a full regression test: first append the easybuild directory to the PYTHONPATH. Also, set your MODULEPATH to something which doesn't have dependencies installed. then run python easybuild/scripts/regtest.py. (see -h) for specific options.

output will be placed in the current directory in easybuild-test-TIMESTAMP. You can aggregate the results into a single xml file. by using the -a option.

Make sure to populate the easybuild_config.py with settings that make sense for the regression tester.

The final xml will contain JUnit-compatible xml. Per build there is either a failure (with reason). the buildstats for each application and also a summary in a top comment.