Add CURRENT_TIMESTAMP annotation

scripts/common/annotator.py

Index: scripts/common/annotator.py
diff --git a/scripts/common/annotator.py b/scripts/common/annotator.py
index 8fcb5ebc02ba7e2aa3554c2c54cafb7ae9155f85..ddac1f2ce4c6ba3498071ccf054fc0c36674af08 100755
--- a/scripts/common/annotator.py
+++ b/scripts/common/annotator.py
@@ -6,6 +6,7 @@
 
 import os
 import sys
+import time
 import traceback
 
 # These are maps of annotation key -> number of expected arguments.
@@ -32,6 +33,14 @@ CONTROL_ANNOTATIONS = {
 }
 
 STREAM_ANNOTATIONS = {
+    # CURRENT_TIMESTAMP has one parameter, current Unix timestamp, which in
+    # practice specifies timestamp of the following annotation.
+    # The following annotation MUST be emitted immediately,
+    # however there is no requirement for the annotation after the next one
+    # to be emitted immediately. Annotation parsers must not consider
+    # CURRENT_TIMESTAMP for annotations that follow the annotation which is next
+    # after the CURRENT_TIMESTAMP.
+    'CURRENT_TIMESTAMP': 1,
     'HALT_ON_FAILURE': 0,
     'HONOR_ZERO_RETURN_CODE': 0,
     'SEED_STEP': 1,
@@ -197,11 +206,11 @@ class StructuredAnnotationStep(StepCommands, StepControlCommands):
     self.control = StepControlCommands(self.stream, self.flush_before)
     self.emitted_logs = set()
 
-
   def __enter__(self):
     return self.step_started()
 
   def step_started(self):
+    self.annotation_stream.emit_current_timestamp()
     self.control.step_started()
     return self
 
@@ -211,6 +220,7 @@ class StructuredAnnotationStep(StepCommands, StepControlCommands):
     if exc_type:
       self.step_exception_occured(exc_type, exc_value, tb)
 
+    self.annotation_stream.emit_current_timestamp()
     self.control.step_closed()
     self.annotation_stream.current_step = ''
     return not exc_type
@@ -223,6 +233,7 @@ class StructuredAnnotationStep(StepCommands, StepControlCommands):
 
   def step_ended(self):
     self.annotation_stream.step_cursor(self.annotation_stream.current_step)
+    self.annotation_stream.emit_current_timestamp()
     self.control.step_closed()
     self.annotation_stream.current_step = ''
 
@@ -253,10 +264,15 @@ class StructuredAnnotationStream(AnnotationPrinter):
 
   def __init__(self, stream=sys.stdout,
                flush_before=sys.stderr,
-               seed_steps=None):  # pylint: disable=W0613
+               seed_steps=None,  # pylint: disable=W0613
+               time_fn=None):
     super(StructuredAnnotationStream, self).__init__(stream=stream,
                                                      flush_before=flush_before)
     self.current_step = ''
+    self.time_fn = time_fn or time.time
+
+  def emit_current_timestamp(self):
+    self.current_timestamp(self.time_fn())
 
   def step(self, name):
     """Provide a context with which to execute a step."""