LCM Go

Performant, native Go LCM implementation with integrated support for protobuf and compression.

Installation

go get go.einride.tech/lcm

Usage

Receiver

	rx, err := lcm.ListenMulticastUDP(
		ctx,
		lcm.WithReceiveInterface("eth0"),
		lcm.WithReceiveProtos(&timestamppb.Timestamp{}),
	)
	if err != nil {
		panic(err) // TODO: Handle error.
	}
	if err := rx.ReceiveProto(ctx); err != nil {
		panic(err) // TODO: Handle error.
	}
	log.Println(rx.ProtoMessage())

Transmitter

	tx, err := lcm.DialMulticastUDP(
		ctx,
		lcm.WithTransmitInterface("eth0"),
	)
	if err != nil {
		panic(err) // TODO: Handle error.
	}
	if err := tx.TransmitProto(ctx, &timestamppb.Now()); err != nil {
		panic(err) // TODO: Handle error.
	}

Notable features

Protobuf messages

Protobuf messages can be transmitted and received, with encoding and decoding handled by the LCM stack.

Compression

The library can handle compression and decompression of messages at the channel-level, with the compression scheme indicated by a query-parameter on the channel name (similar to HTTP URLs).

For example an LZ4 compressed message transmitted over a channel named google.protobuf.Timestamp?z=lz4 will be automatically decompressed.

BPF filtering

When specifying a set of channels to receive from, the library will attempt to use BPF filters to only receive messages from those channels from the kernel.

However, since there is a limit of 255 instructions on BPF filters, if there are too many channels, it will fallback and listening to everything.

Notable missing features

Fragmented messages

This library currently does not support fragmented messages.