Buld script for Python project (virtualenv, pip with requirement file, pylint, py.test, coverage, Jenkins CI) which could be executed from both system and virtual environment

build_tasks.py

import os
import sys

# One or several build tasks could be executed from Jenkins CI as following:
# #!/bin/bash
# cd $WORKSPACE/release_system/src/build/
# python -c 'from build_tasks import *; code_analysis(); run_tests()'


class BuildEnvironment(object):
    def __init__(self):
        self.project_dir = os.path.abspath(os.path.join(os.path.dirname(__file__), '../..'))
        self.source_dir = os.path.join(self.project_dir, 'src')
        self.root_init_path = os.path.join(self.source_dir, '__init__.py')
        self.virtualenv_dir = os.path.join(self.project_dir, 'env')
        self.coverage_config_path = os.path.join(self.project_dir, 'src/build/coverage_config.ini')
        self.build_report_dir = os.path.join(self.project_dir, 'build_output/reports')
        self.test_report_path = os.path.join(self.build_report_dir, 'test_report.xml')
        self.pylint_report_path = os.path.join(self.build_report_dir, 'pylint_report.txt')
        self.pylint_suppress_csv = 'C0111,R0903,W0232,R0201,W0511'


build_env = BuildEnvironment()


def setup_virtual_environment_win32():
    """Create Python virtual environment if it not exists or re-create if outdated."""
    if not os.path.exists(build_env.virtualenv_dir):
        os.chdir(build_env.project_dir)
        os.system('virtualenv env --no-site-packages')
        activate_virtual_environment()
        os.system('pip install --requirement=pip_requires.txt --download-cache=pip_download_cache')


def activate_virtual_environment():
    """ Activates virtual environment in the same way as activate.bat or activate.sh from virtualenv package """
    if not hasattr(sys, 'real_prefix') or 'VIRTUAL_ENV' not in os.environ:
        activate_this = '{0}/env/bin/activate_this.py'.format(build_env.project_dir)
        virtual_env_path = '{0}/env/bin:'.format(build_env.project_dir)
        if os.name == 'nt':
            activate_this = '{0}/env/Scripts/activate_this.py'.format(build_env.project_dir)
            virtual_env_path = '{0}\env\Scripts;'.format(build_env.project_dir)

        execfile(activate_this, dict(__file__=activate_this))
        path = os.environ['PATH']
        os.environ['PATH'] = virtual_env_path + path


def code_analysis():
    """
    Runs PyLint code analysis tool and suppress it's error code with simple echo printing.
    Otherwise each build will be failed because of code style issues.
    """
    activate_virtual_environment()

    if not os.path.exists(build_env.build_report_dir):
        os.makedirs(build_env.build_report_dir)

    os.chdir(build_env.source_dir)
    os.system('pylint --max-line-length=120 --output-format=parseable --disable={0} {1} >> {2}'.format(
        build_env.pylint_suppress_csv,
        build_env.source_dir,
        build_env.pylint_report_path))

    print('pylint code analysis was completed')


def run_tests():
    """
    Runs unit tests with enabled code coverage.
    Produces JUnit-compatible test run report and two coverage reports - Cobertura-compatible xml and Html report
    """
    activate_virtual_environment()

    if not os.path.exists(build_env.build_report_dir):
        os.makedirs(build_env.build_report_dir)

    os.chdir(build_env.source_dir)

    # NOTE that PyLint requires __init__.py file in project root BUT py.test must be executed without this file.
    # Root module's init file must be renamed before running test; otherwise ImportError occurs because
    # all modules will have names like 'src.common', 'src.data_access' instead of just 'common', 'data_access'.
    root_init_temp_path = build_env.root_init_path + '.tmp'
    os.rename(build_env.root_init_path, root_init_temp_path)

    os.system('py.test . --cov=. --cov-report=xml --cov-report=html --junitxml={0} --cov-config={1}'.format(
        build_env.test_report_path,
        build_env.coverage_config_path))

    os.rename(root_init_temp_path, build_env.root_init_path)

if __name__ == '__main__':
    run_tests()