roboto.domain.topics.mcap_topic_reader
Module Contents
McapTopicReader
Bases: roboto.domain.topics.topic_reader.TopicReader
Private interface for retrieving topic data stored in MCAP files.
Uses HTTP Range requests to efficiently fetch only required chunks from remote storage, avoiding full file downloads.
Parameters
roboto_client Optional[roboto.signed_url_resolver Optional[SignedUrlResolver]McapTopicReader.accepts()
Parameters
message_paths_to_representations collections.Return type
McapTopicReader.get_data()
Yield (log_time, record) pairs from the mappings’ MCAP files in log-time order.
Each record merges the projected fields of one message from every file whose next message has that log time.
Parameters
message_paths_to_representations collections.The message paths to read. Each MessagePathRepresentationMapping pairs message paths with the representation whose associated MCAP file stores them; a mapping whose representation is not associated with a file is skipped.
start_time Optional[int]Inclusive lower bound on message log time in nanoseconds, or None for unbounded.
end_time Optional[int]Exclusive upper bound on message log time in nanoseconds, or None for unbounded.
timestamp_message_path_representation_mapping Optional[roboto.Not read; each row’s timestamp is the log time of the messages it merges.
topic_name Optional[str]Read only messages on MCAP channels of this topic, or on every channel when None.
Yields
The log time in nanoseconds and the merged record.
Raises
topic_name is given and a file’s summary lists no channel on that topic.
Return type
McapTopicReader.get_data_as_df()
Parameters
message_paths_to_representations collections.start_time Optional[int]end_time Optional[int]timestamp_message_path_representation_mapping Optional[roboto.Return type
RobotoClientUrlResolver
A SignedUrlResolver that fetches signed URLs via the Roboto API.
Parameters
roboto_client roboto.SignedUrlResolver
Bases: Protocol
Resolves a file ID to a signed download URL.