Add summary source metadata to the TB summary writer output (#6002)

Specifies source metadata for event files as
`tensorboard.summary.writer.event_file_writer` for the TB summary
writer.

Author: groszewn

tensorboard/summary/writer/event_file_writer.py

@@ -90,7 +90,11 @@ def __init__(
 
         # Initialize an event instance.
         _event = event_pb2.Event(
-            wall_time=time.time(), file_version="brain.Event:2"
+            wall_time=time.time(),
+            file_version="brain.Event:2",
+            source_metadata=event_pb2.SourceMetadata(
+                writer="tensorboard.summary.writer.event_file_writer"
+            ),
         )
         self.add_event(_event)
         self.flush()

tensorboard/summary/writer/event_file_writer_fsspec_test.py

@@ -81,6 +81,10 @@ def test_async_writer_without_write(self):
         r.GetNext()
         s = event_pb2.Event.FromString(r.record())
         self.assertEqual(s.file_version, "brain.Event:2")
+        self.assertEqual(
+            s.source_metadata.writer,
+            "tensorboard.summary.writer.event_file_writer",
+        )
 
 
 if __name__ == "__main__":

tensorboard/summary/writer/event_file_writer_test.py

@@ -64,6 +64,10 @@ def test_async_writer_without_write(self):
         r.GetNext()
         s = event_pb2.Event.FromString(r.record())
         self.assertEqual(s.file_version, "brain.Event:2")
+        self.assertEqual(
+            s.source_metadata.writer,
+            "tensorboard.summary.writer.event_file_writer",
+        )
 
 
 class AsyncWriterTest(tb_test.TestCase):