Transform a Batch into Frames

note

This example performs the reverse transformation as the frames-to-batch example.

caution

Steps and handling of types with respect to chain tip, ordering of frames, re-orgs, and more are not covered by this example. This example solely demonstrates the most trivial way to transform an individual [Batch][batch] into [Frame][frame]s.

This example walks through transforming a [Batch][batch] into [Frame][frame]s.

Effectively, this example demonstrates the encoding process from an L2 batch into the serialized bytes that are posted to the data availability layer.

Walkthrough

The high level transformation is the following.

Batch -> decompressed batch data -> ChannelOut -> frames[] -> bytes[]

Given the [Batch][batch], the first step to encode the batch using the [Batch::encode()][encode-batch] method. The output bytes need to then be compressed prior to adding them to the [ChannelOut][channel-out].

note

The [ChannelOut][channel-out] type also provides a method for adding the [Batch][batch] itself, handling encoding and compression, but this method is not available yet.

Once compressed using the [compress_brotli][compress-brotli] method, the compressed bytes can be added to a newly constructed [ChannelOut][channel-out]. As long as the [ChannelOut][channel-out] has [ready_bytes()][ready-bytes], [Frame][frame]s can be constructed using the [ChannelOut::output_frame()][output-frame] method, specifying the maximum frame size.

Once [Frame][frame]s are returned from the [ChannelOut][channel-out], they can be [Frame::encode][encode-frame] into raw, serialized data ready to be batch-submitted to the data-availability layer.

Running this example:

  • Clone the examples repository: git clone git@github.com:op-rs/kona.git
  • Run: cargo run --example batch_to_frames
#![allow(unused)]
fn main() {
{{#include ../../../crates/protocol/protocol/examples/batch_to_frames.rs}}
}