Merge pull request #2877 from coreos-inc/joseph.schorr/QS-24/step-parsing

Fix parsing of Dockerfile steps in newer versions of Docker

buildman/component/buildcomponent.py

@@ -11,6 +11,7 @@ from trollius import From, Return
 
 from buildman.server import BuildJobResult
 from buildman.component.basecomponent import BaseComponent
+from buildman.component.buildparse import extract_current_step
 from buildman.jobutil.buildjob import BuildJobLoadException
 from buildman.jobutil.buildstatus import StatusHandler
 from buildman.jobutil.workererror import WorkerError
@@ -269,9 +270,7 @@ class BuildComponent(BaseComponent):
     current_status_string = str(fully_unwrapped.encode('utf-8'))
 
     if current_status_string and phase == BUILD_PHASE.BUILDING:
-      step_increment = re.search(r'Step ([0-9]+) :', current_status_string)
-      if step_increment:
-        current_step = int(step_increment.group(1))
+      current_step = extract_current_step(current_status_string)
 
     # Parse and update the phase and the status_dict. The status dictionary contains
     # the pull/push progress, as well as the current step index.

buildman/component/buildparse.py

@@ -0,0 +1,15 @@
+import re
+
+def extract_current_step(current_status_string):
+  """ Attempts to extract the current step numeric identifier from the given status string. Returns the step
+      number or None if none.
+  """
+  # Older format: `Step 12 :`
+  # Newer format: `Step 4/13 :`
+  step_increment = re.search(r'Step ([0-9]+)/([0-9]+) :', current_status_string)
+  if step_increment:
+    return int(step_increment.group(1))
+
+  step_increment = re.search(r'Step ([0-9]+) :', current_status_string)
+  if step_increment:
+    return int(step_increment.group(1))

buildman/component/test/test_buildparse.py

@@ -0,0 +1,16 @@
+import pytest
+
+from buildman.component.buildparse import extract_current_step
+
+
+@pytest.mark.parametrize('input,expected_step', [
+  ("", None),
+  ("Step a :", None),
+  ("Step 1 :", 1),
+  ("Step 1 : ", 1),
+  ("Step 1/2 : ", 1),
+  ("Step 2/17 : ", 2),
+  ("Step 4/13 : ARG somearg=foo", 4),
+])
+def test_extract_current_step(input, expected_step):
+  assert extract_current_step(input) == expected_step