Annotation protobuf code can now dump final.

recipe_engine/stream_logdog.py

Index: recipe_engine/stream_logdog.py
diff --git a/recipe_engine/stream_logdog.py b/recipe_engine/stream_logdog.py
index f7835ecc0c6d2e9fad2a27b2c15d015807163134..4aec670aba8a0b858bd3bdb756d903e72436e742 100644
--- a/recipe_engine/stream_logdog.py
+++ b/recipe_engine/stream_logdog.py
@@ -268,7 +268,7 @@ class StreamEngine(stream.StreamEngine):
 
 
   def __init__(self, client=None, streamserver_uri=None, name_base=None,
-               ignore_triggers=False, environment=None):
+               dump_path=None, ignore_triggers=False, environment=None):
     """Initializes a new LogDog/Annotation StreamEngine.
 
     Args:
@@ -281,6 +281,8 @@ class StreamEngine(stream.StreamEngine):
           None, a StreamClient will be created through probing.
       name_base (str or None): The default stream name prefix that will be added
           to generated LogDog stream names. If None, no prefix will be applied.
+      dump_path (str or None): If provided, a filesystem path where the final
+          recipe annotation protobuf binary will be dumped.
       ignore_triggers (bool): Triggers are not supported in LogDog annotation
           streams. If True, attempts to trigger will be silently ignored. If
           False, they will cause a NotImplementedError to be raised.
@@ -292,6 +294,7 @@ class StreamEngine(stream.StreamEngine):
     self._client = client
     self._streamserver_uri = streamserver_uri
     self._name_base = _StreamName(name_base)
+    self._dump_path = dump_path
     self._ignore_triggers = ignore_triggers
     self._env = environment or _Environment.probe()
 
@@ -363,7 +366,7 @@ class StreamEngine(stream.StreamEngine):
     self._check()
 
     # Shut down our annotation monitor and close our annotation stream.
-    self._annotation_monitor.flush_and_join()
+    last_step_data = self._annotation_monitor.flush_and_join()
     self._annotation_stream.close()
 
     # Clear our client and state. We are now closed.
@@ -371,6 +374,11 @@ class StreamEngine(stream.StreamEngine):
     self._client = None
     self._astate = None
 
+    # If requested, write out the last step data.
+    if self._dump_path and last_step_data:
+      with open(self._dump_path, 'wb') as fd:

[nodir, 2016/09/28 23:02:22]

please swap these two lines, so in the worst case we have an empty file (which
is still a valid protobuf)

[dnj, 2016/09/28 23:04:11]

Done.

+        fd.write(last_step_data)
+
   def _check(self):
     if self._astate is None:
       return
@@ -511,10 +519,14 @@ class _AnnotationMonitor(object):
 
   def flush_and_join(self):
     """Flushes any remaining updates and blocks until the monitor is complete.
+
+    Returns (pb.Step): The final Step protobuf, or None if no step data was
+        sent.
     """
     # Mark that we're finished and signal our event.
     with self._lock:
       self._flush_now_locked(datetime.datetime.now())
+      return self._last_flush_data
 
   @property
   def latest(self):