[loader] Make recipe engine support examples/ module subdir

recipe_modules/step/example.py

-# Copyright 2013 The LUCI Authors. All rights reserved.
-# Use of this source code is governed under the Apache License, Version 2.0
-# that can be found in the LICENSE file.
-
-from recipe_engine import recipe_api, config
-
-DEPS = [
-  'context',
-  'path',
-  'properties',
-  'step',
-]
-
-
-RETURN_SCHEMA = config.ReturnSchema(
-  test_me=config.Single(int)
-)
-
-
-PROPERTIES = {
-  'bad_return': recipe_api.Property(default=False),
-  'access_invalid_data': recipe_api.Property(default=False),
-  'timeout': recipe_api.Property(default=0, kind=int),
-}
-
-
-def RunSteps(api, bad_return, access_invalid_data, timeout):
-  if bad_return:
-    return RETURN_SCHEMA.new(test_me='this should fail')
-  elif timeout:
-    # Timeout causes the recipe engine to raise an exception if your step takes
-    # longer to run than you allow. Units are seconds.
-    if timeout == 1:
-      api.step('timeout', ['sleep', '20'], timeout=1)
-    elif timeout == 2:
-      try:
-        api.step('caught timeout', ['sleep', '20'], timeout=1)
-      except api.step.StepTimeout:
-        return RETURN_SCHEMA(test_me=4)
-
-
-  # TODO(martinis) change this
-  # The api.step object is directly callable.
-  api.step('hello', ['echo', 'Hello World'])
-  api.step('hello', ['echo', 'Why hello, there.'])
-
-  # You can change the current working directory as well
-  api.step('mk subdir', ['mkdir', '-p', 'something'])
-  with api.step.context({'cwd': api.path['start_dir'].join('something')}):
-    api.step('something', ['bash', '-c', 'echo Why hello, there, in a subdir.'])
-
-  # By default, all steps run in 'start_dir', or the cwd of the recipe engine
-  # when the recipe begins. Because of this, setting cwd to start_dir doesn't
-  # show anything in particular in the expectations.
-  with api.step.context({'cwd': api.path['start_dir']}):
-    api.step('start_dir ignored', ['bash', '-c', 'echo what happen'])
-
-  # You can also manipulate various aspects of the step, such as env.
-  # These are passed straight through to subprocess.Popen.
-  # Also, abusing bash -c in this way is a TERRIBLE IDEA DON'T DO IT.
-  with api.context(env={'friend': 'Darth Vader'}):
-    api.step('goodbye', ['bash', '-c', 'echo Good bye, $friend.'])
-
-  # You can modify environment in terms of old environment. Environment
-  # variables are substituted in for expressions of the form %(VARNAME)s.
-  with api.context(env={'PATH': api.path.pathsep.join(
-      [str(api.step.package_repo_resource()), '%(PATH)s'])}):
-    api.step('recipes help', ['recipes.py', '--help'])
-
-  # Finally, you can make your step accept any return code
-  api.step('anything is cool', ['bash', '-c', 'exit 3'],
-           ok_ret='any')
-
-  # We can manipulate the step presentation arbitrarily until we run
-  # the next step.
-  step_result = api.step('hello', ['echo', 'hello'])
-  step_result.presentation.status = api.step.EXCEPTION
-  step_result.presentation.logs['the reason'] = ['The reason\nit failed']
-
-  # Without a command, a step can be used to present some data from the recipe.
-  step_result = api.step('Just print stuff', cmd=None)
-  step_result.presentation.logs['more'] = ['More stuff']
-
-  try:
-    api.step('goodbye', ['echo', 'goodbye'])
-    # Modifying step_result now would raise an AssertionError.
-  except api.step.StepFailure:
-    # Raising anything besides StepFailure or StepWarning causes the build to go
-    # purple.
-    raise ValueError('goodbye must exit 0!')
-
-  try:
-    api.step('warning', ['echo', 'warning'])
-  except api.step.StepFailure as e:
-    e.result.presentation.status = api.step.WARNING
-    raise api.step.StepWarning(e.message)
-
-
-  # Aggregate failures from tests!
-  try:
-    with recipe_api.defer_results():
-      api.step('testa', ['echo', 'testa'])
-      api.step('testb', ['echo', 'testb'])
-  except recipe_api.AggregatedStepFailure as f:
-    raise api.step.StepFailure("You can catch step failures.")
-
-  # Some steps are needed from an infrastructure point of view. If these
-  # steps fail, the build stops, but doesn't get turned red because it's
-  # not the developers' fault.
-  try:
-    api.step('cleanup', ['echo', 'cleaning', 'up', 'build'], infra_step=True)
-  except api.step.InfraFailure as f:
-    assert f.result.presentation.status == api.step.EXCEPTION
-
-  # Run a step through a made-up wrapper program.
-  api.step('application', ['echo', 'main', 'application'],
-           wrapper=['python', '-c', 'import sys; print sys.argv'])
-
-  if access_invalid_data:
-    result = api.step('no-op', ['echo', 'I', 'do', 'nothing'])
-    # Trying to access non-existent attributes on the result should raise.
-    _ = result.json.output
-
-  return RETURN_SCHEMA(test_me=3)
-
-
-def GenTests(api):
-  yield (
-      api.test('basic') +
-      api.step_data('anything is cool', retcode=3)
-    )
-
-  # If you don't have the expect_exception in this test, you will get something
-  # like this output.
-  # ======================================================================
-  # ERROR: step:example.exceptional (..../exceptional.json)
-  # ----------------------------------------------------------------------
-  # Traceback (most recent call last):
-  #   <full stack trace ommitted>
-  #   File "annotated_run.py", line 537, in run
-  #     retcode = steps_function(api)
-  #   File "recipe_modules/step/example.py", line 39, in RunSteps
-  #     raise ValueError('goodbye must exit 0!')
-  # ValueError: goodbye must exit 0!
-
-  yield (
-      api.test('exceptional') +
-      api.step_data('goodbye (2)', retcode=1) +
-      api.expect_exception('ValueError')
-    )
-
-  yield (
-      api.test('warning') +
-      api.step_data('warning', retcode=1)
-    )
-
-  yield (
-      api.test('defer_results') +
-      api.step_data('testa', retcode=1)
-    )
-
-  yield (
-      api.test('invalid_access') +
-      api.properties(access_invalid_data=True) +
-      api.expect_exception('StepDataAttributeError')
-    )
-
-  yield (
-      api.test('infra_failure') +
-      api.step_data('cleanup', retcode=1)
-    )
-
-  yield (
-      api.test('bad_return') +
-      api.properties(bad_return=True) +
-      api.expect_exception('TypeError')
-    )
-
-  yield (
-      api.test('timeout') +
-      api.properties(timeout=1) +
-      api.step_data('timeout', times_out_after=20)
-    )
-
-  yield (
-      api.test('catch_timeout') +
-      api.properties(timeout=2) +
-      api.step_data('caught timeout', times_out_after=20)
-    )