Source code for mcap_protobuf.reader

"""the :py:mod:`mcap_protobuf.reader` module is deprecated. For similar functionality,
instantiate the :py:class:`mcap.reader.McapReader` with a
:py:class:`mcap_protobuf.decoder.DecoderFactory` instance, eg:

>>> from mcap.reader import make_reader
>>> from mcap_protobuf.decoder import DecoderFactory
>>> reader = make_reader(open("proto.mcap", "rb"), decoder_factories=[DecoderFactory()])
>>> for schema_, channel_, message_, proto_msg in reader.iter_decoded_messages():
>>>     print(proto_msg)
import warnings
from datetime import datetime
from os import PathLike
from typing import IO, Any, Dict, Iterable, Iterator, Optional, Union

from mcap.reader import McapReader, make_reader
from mcap.records import Channel, Message

from .decoder import DecoderFactory

warnings.warn(__doc__, DeprecationWarning)

[docs]def read_protobuf_messages( source: Union[str, bytes, PathLike[str], McapReader, IO[bytes]], topics: Optional[Iterable[str]] = None, start_time: Optional[Union[int, datetime]] = None, end_time: Optional[Union[int, datetime]] = None, log_time_order: bool = True, reverse: bool = False, ) -> Iterator["McapProtobufMessage"]: """High-level generator that reads protobuf messages out of an MCAP. :param source: some source of MCAP file data. Supply a stream of bytes, an McapReader instance, or the path to a valid MCAP file in the filesystem. :param topics: an optional list of topics to read from the MCAP file. :param start_time: if not None, messages logged before this time will not be included. :param end_time: if not None, messages logged at this timestamp or after will not be included. :param log_time_order: if True, messages will be yielded in ascending log time order. If False, messages will be yielded in the order they appear in the MCAP file. :param reverse: if both ``log_time_order`` and ``reverse`` are True, messages will be yielded in descending log time order. :yields: an McapProtobufMessage instance for each protobuf message in the MCAP file. .. note:: this generator assumes the source MCAP contains only Protobuf-encoded messages. If you need to decode protobuf messages from a file containing other encodings, use the :py:func:`mcap.reader.McapReader.iter_messages()` function to iterate through Message records in your MCAP, and decode the protobuf messages with the :py:class:`mcap_protobuf.decoder.Decoder` class. """ if start_time is not None and isinstance(start_time, datetime): start_time = int(start_time.timestamp() * 1e9) if end_time is not None and isinstance(end_time, datetime): end_time = int(end_time.timestamp() * 1e9) fd = None if ( isinstance(source, PathLike) or isinstance(source, str) or isinstance(source, bytes) ): fd = open(source, "rb") reader = make_reader(fd, decoder_factories=[DecoderFactory()]) elif isinstance(source, McapReader): reader = source else: reader = make_reader(source, decoder_factories=[DecoderFactory()]) try: for schema, channel, message, proto_msg in reader.iter_decoded_messages( topics, start_time, end_time, log_time_order, reverse ): assert schema is not None yield McapProtobufMessage( proto_msg=proto_msg, message=message, channel=channel, ) finally: if fd is not None: fd.close()
[docs]class McapProtobufMessage: """Contains a single protobuf message and associated metadata from an MCAP file. :ivar proto_msg: the decoded protobuf message. :ivar sequence_count: the message sequence count if included in the MCAP, or 0 otherwise. :ivar topic: the topic that the message was published on. :ivar channel_metadata: the metadata associated with this protobuf topic, if any. :ivar log_time_ns: the time this message was logged by the recorder, as a POSIX nanosecond timestamp. :ivar publish_time_ns: the time this message was published, as a POSIX nanosecond timestamp. """ def __init__(self, proto_msg: Any, message: Message, channel: Channel): self.proto_msg = proto_msg self.sequence_count: int = message.sequence self.topic: str = channel.topic self.channel_metadata: Dict[str, str] = channel.metadata self.log_time_ns: int = message.log_time self.publish_time_ns: int = message.publish_time @property def log_time(self) -> datetime: """The timestamp representing when this message was logged by the recorder.""" return datetime.fromtimestamp(float(self.log_time_ns) / 1e9) @property def publish_time(self) -> datetime: """The timestamp representing when this message was published.""" return datetime.fromtimestamp(float(self.publish_time_ns) / 1e9)