How to use the buildbot.plugins.util function in buildbot

# Copyright 2018 The WPT Dashboard Project. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

from buildbot.plugins import steps
from buildbot.plugins import util
import os


class WptRunStep(steps.ShellCommand):
    name = util.Interpolate(
        'WPT Run ' +
        '(%(prop:browser_name)s, %(prop:this_chunk)s of %(prop:total_chunks)s)'
    )

    def __init__(self, *args, **kwargs):
        kwargs['name'] = self.name
        kwargs['command'] = self.makeWptRunCommand
        kwargs['logfiles'] = {
            'sauce-connect-log': {
                'filename': '/var/log/sauce-connect/sc.log',
                'follow': True
            },
            'xvfb-log': {
                'filename': '/var/log/xvfb/xvfb.log',
                'follow': True
            }

command=["/bin/sh", "find.sh"],
                                       workdir="build/files/"))

    factory.addStep(steps.ShellCommand(name="Building kernel",
                                       command=["/bin/sh", "../build-kernel.sh", arch],
                                       workdir="build/files/linux-" + version + "/",
                                       haltOnFailure=True))

    factory.addStep(steps.ShellCommand(name="Building modules",
                                       command=["/bin/sh", "../build-kernel.sh", arch, "modules"],
                                       workdir="build/files/linux-" + version + "/",
                                       haltOnFailure=True))

    factory.addStep(steps.ShellCommand(name="Booting with QEMU",
                                       command=["/usr/bin/python", "qemu_check.py", arch,
                                                util.Property('buildername'), util.Property('buildnumber')],
                                       workdir="build/files/", timeout=3600))

    factory.addStep(steps.ShellCommand(name="Cleanup",
                                       command=["/bin/sh", "clean.sh"],
                                       workdir="build/", 
                                       alwaysRun=True))

    return factory

def __init__(self, name, **kwargs):
            kwargs = self.extract_attrs(name, **kwargs)
            return worker.HyperLatentWorker.__init__(
                self,
                name,
                kube_config=kube_config,
                image=util.Interpolate("%(prop:DOCKER_IMAGE:-buildbot/metabbotcfg)s"),
                masterFQDN="buildbot.buildbot.net",
                **kwargs)

def test_gentoo_sources():
    factory = util.BuildFactory()
    factory.addStep(steps.GitHub(name="Fetching repository",
                                 repourl=pull_repourl,
                                 mode='incremental', workdir="build/gentoo", shallow=50))
    factory.addStep(steps.FileDownload(mastersrc="config/files/qemu_check.py",
                                       workerdest="files/qemu_check.py"))
    factory.addStep(steps.FileDownload(mastersrc="config/files/stabilize-packages.py",
                                       workerdest="files/stabilize-packages.py"))
    factory.addStep(steps.FileDownload(mastersrc="config/files/clean.sh",
                                       workerdest="clean.sh",
                                       alwaysRun=True))
    factory.addStep(steps.FileDownload(mastersrc="config/files/clean.py",
                                       workerdest="clean.py",
                                       alwaysRun=True))
    factory.addStep(steps.ShellCommand(name="Stabilizing package",
                                       command=filterFiles,
                                       workdir="build/files/"))

def getPushChangeFilter(self):
        filt = dict(repository=self.repository)
        if self.branch is not None:
            filt['branch'] = self.branch
        return util.ChangeFilter(**filt)

def __init__(self, *args, project, repository, button_name=None,
                 label=None, **kwargs):
        """Improves the default form of ForceScheduler"""
        codebase = util.CodebaseParameter(
            codebase='',
            label='',
            project=util.FixedParameter(name='project', default=project),
            repository=util.FixedParameter(name='repository',
                                           default=repository),
            branch=util.StringParameter(name='branch',
                                        default='master',
                                        required=True),
            # required, otherwise status push reporter fails with a
            # non-descriptive exception
            revision=util.StringParameter(name='revision', default='HEAD',
                                          required=True)
        )
        kwargs['buttonName'] = button_name or f'Build {project}'
        kwargs['label'] = label or f'Manual {project} build'
        super().__init__(*args, codebases=[codebase], **kwargs)

def mkcoveragefactory():
    f = util.BuildFactory()
    f.addSteps([
        gitStep,
        VirtualenvSetup(name='virtualenv setup',
                        no_site_packages=True,
                        virtualenv_packages=['coverage', 'mock',
                                             '--editable=master',
                                             '--editable=slave'],
                        virtualenv_dir='sandbox',
                        haltOnFailure=True),
        steps.ShellCommand(command=textwrap.dedent("""
            PYTHON=sandbox/bin/python;
            sandbox/bin/coverage run --rcfile=common/coveragerc \
                sandbox/bin/trial buildbot.test buildslave.test \
                || exit 1;
            sandbox/bin/coverage html -i --rcfile=.coveragerc \
                -d /home/buildbot/www/buildbot.buildbot.net/static/coverage \

def __init__(self, *args, project, repository, button_name=None,
                 label=None, **kwargs):
        """Improves the default form of ForceScheduler"""
        codebase = util.CodebaseParameter(
            codebase='',
            label='',
            project=util.FixedParameter(name='project', default=project),
            repository=util.FixedParameter(name='repository',
                                           default=repository),
            branch=util.StringParameter(name='branch',
                                        default='master',
                                        required=True),
            # required, otherwise status push reporter fails with a
            # non-descriptive exception
            revision=util.StringParameter(name='revision', default='HEAD',
                                          required=True)
        )
        kwargs['buttonName'] = button_name or f'Build {project}'
        kwargs['label'] = label or f'Manual {project} build'
        super().__init__(*args, codebases=[codebase], **kwargs)

),
        hideStepIf=lambda results, s: results == SKIPPED or results == SUCCESS,
    )

    # load builders.json with definitions on how to build things
    parent_path = os.path.dirname(__file__)
    with open(os.path.join(parent_path, "volk_builders.json"), "r") as builders_file:
        build_config = json.loads(builders_file.read())

    trigger_builds = custom_steps.BuildTrigger(
        name="trigger the right builders",
        build_config=build_config,
        schedulerNames=["trigger"],
        runner="pull",
        set_properties={
            "pr_base": util.Property("github.base.ref"),
            "src_dir": util.Interpolate(os.path.join(
                _PULL_SRC_BASE, "%(prop:github.number)s"))
        },
        updateSourceStamp=False,
        waitForFinish=True
    )

    factory = util.BuildFactory()
    factory.addStep(create_src)
    factory.addStep(clone_step)
    factory.addStep(rm_src_dir)
    factory.addStep(copy_src)
    factory.addStep(trigger_builds)
    return factory