Display Docker build errors when builds fail (Fixes #35)

src/rocker/core.py

@@ -305,30 +305,38 @@ def base_image_exists(base_image, docker_client=None, output_callback=None):
  # Re-raise other non-404 API errors from inspect
  raise
 
-def docker_build(docker_client = None, output_callback = None, **kwargs):
+def docker_build(docker_client=None, output_callback=None, **kwargs):
  image_id = None
 
  if not docker_client:
  docker_client = get_docker_client()
+
  kwargs['decode'] = True
+
  for line in docker_client.build(**kwargs):
- output = line.get('stream', '').rstrip()
- if not output:
- # print("non stream data", line)
- continue
- if output_callback is not None:
- output_callback(output)
+ stream = line.get('stream', '').rstrip()
+ error = line.get('error', '').rstrip()
 
- match = re.match(r'Successfully built ([a-z0-9]{12})', output)
- if match:
- image_id = match.group(1)
+ if stream:
+ if output_callback:
+ output_callback(stream)
+
+ match = re.match(r'Successfully built ([a-z0-9]{12})', stream)
+ if match:
+ image_id = match.group(1)
+
+ if error:
+ if output_callback:
+ output_callback(error)
+ print(error)
+ return None
 
  if image_id:
  return image_id
- else:
- print("no more output and success not detected")
- return None
 
+ print("no more output and success not detected")
+ return None
+
 def docker_remove_image(
  image_id,
  docker_client = None,
@@ -398,6 +406,8 @@ def __init__(self, active_extensions, cliargs, base_image):
  self.dockerfile = generate_dockerfile(active_extensions, self.cliargs, base_image)
  self.image_id = None
 
+ self.output_callback = lambda output: print("build > %s" % output)
+
  def build(self, **kwargs):
  with tempfile.TemporaryDirectory() as td:
  df = os.path.join(td, 'Dockerfile')
@@ -429,7 +439,7 @@ def build(self, **kwargs):
  try:
  self.image_id = docker_build(
  **arguments,
- output_callback=lambda output: print("building > %s" % output)
+ output_callback=self.output_callback
  )
  if self.image_id:
  self.built = True

test/test_core.py

@@ -306,3 +306,74 @@ def test_docker_cmd_nocleanup(self):
  self.assertIn('--rm', dig.generate_docker_cmd(nocleanup=''))
 
  self.assertNotIn('--rm', dig.generate_docker_cmd(nocleanup='true'))
+
+
+
+class BrokenBuildSnippet(RockerExtension):
+ @staticmethod
+ def get_name():
+ return 'broken_snippet'
+
+ def __init__(self):
+ self._env_subs = None
+ self.name = BrokenBuildSnippet.get_name()
+
+
+ def get_environment_subs(self):
+ if not self._env_subs:
+ self._env_subs = {}
+ return self._env_subs
+
+ def get_preamble(self, cliargs):
+ return ''
+
+ def get_snippet(self, cliargs):
+ snippet = "BAD KEYWORD for a dockerfile"
+ return snippet #empy_expand(snippet, self.get_environment_subs())
+
+ @staticmethod
+ def register_arguments(parser, defaults):
+ parser.add_argument(name_to_argument(BrokenBuildSnippet.get_name()),
+ action='store_true',
+ default=defaults.get('broken_snippet', None),
+ help="test a broken snippet")
+
+class BrokenBuiildTest(unittest.TestCase):
+
+ def setUp(self):
+ # Work around interference between empy Interpreter
+ # stdout proxy and test runner. empy installs a proxy on stdout
+ # to be able to capture the information.
+ # And the test runner creates a new stdout object for each test.
+ # This breaks empy as it assumes that the proxy has persistent
+ # between instances of the Interpreter class
+ # empy will error with the exception
+ # "em.Error: interpreter stdout proxy lost"
+ em.Interpreter._wasProxyInstalled = False
+
+ @pytest.mark.docker
+ def test_broken_snippet_extension(self):
+
+ # # Test build args
+ # mock_cliargs = {'shm_size_build': '2g'}
+ # build_args = p.get_build_args(mock_cliargs)
+ # self.assertEqual(build_args, {'shm_size': '2g'})
+
+ extension_manager = RockerExtensionManager()
+ extension_manager.available_plugins = {'broken_snippet': BrokenBuildSnippet}
+ active_extensions = extension_manager.get_active_extensions({'user': True, 'broken_snippet': BrokenBuildSnippet, 'extension_blacklist': ['ssh']})
+ self.assertTrue(active_extensions)
+
+ # Confirm successful build baseline
+ mock_cli_args = {'broken_snippet': False}
+ dig = DockerImageGenerator([], mock_cli_args, 'ubuntu:bionic')
+ self.assertNotIn('BAD KEYWORD', dig.dockerfile)
+ self.assertEqual(dig.build(), 0)
+
+ # Add broken build which breaks
+ mock_cli_args = {'broken_snippet': True}
+ dig = DockerImageGenerator(active_extensions, mock_cli_args, 'ubuntu:bionic')
+ # dig.output_callback = lambda output: print("OVERRIDE build > %s" % output)
+ self.assertIn('BAD KEYWORD', dig.dockerfile)
+ self.assertEqual(dig.build(), 1)
+ # TODO(tfoote) capture the console output by passing in a custom output_callback and assert we see the error there