[EPIC] Sequencing API

[Manav-Aggarwal]

• EPIC: Separate SignedHeader and Data into 2 different blobs #829
• Separate Sequencer and Executor into different functions
• Refactor sequencer like an endpoint so that it can:
  • Accept a Tx
  • create a batch post to DA
  • pull/subscribe for batch
• Refactor executor to:
  • Subscribe/pull batch
  • Talk to verifier for validating the batch
  • pull block time from sequencer header
  • Execute the batch to produce a header
• Implement batch verifier
  • Runs Shared Sequencer Light node
  • Runs DA light node
  • Verifies:
    • Batch is part of canonical SS chain
    • Batch is published to DA

[Manav-Aggarwal]

Needs from Astria:

• API links on:
  • pulling batch from the SS
  • code pointers from the conductor on where this is happening
• Getting Merkle proofs from the SS Namespace
• Verification of Merkle proofs
• Serialization/Deserialization and decompression of batch data
• Composer submission to SS
• pull block time from sequencer header

@joroshiba

[joroshiba]

For grabbing data from the sequencer: we have a grpc service withGetFilteredSequencerBlock which returns the transactions and proofs required to validate data for a single rollup. Protobufs are posted to buf, directly link to rpc definition here

Data posting to celestia is generally batched, serialized as protobuf data and compressed via brotli with a compression setting of 5. There are, from the view of an individual rollup, two batches: Sequencer Metadata and Rollup Data

This documentation needs some updating with new data shapes, but the gist is correct: https://github.com/astriaorg/astria/blob/main/specs/data-flow-and-verification.md

Transactions can be submitted to composer (essentially a gas station) via grpc: https://buf.build/astria/composer-apis/docs/main:astria.composer.v1alpha1. The "rollup id" here is also used by conductor for knowing which rollup to read from sequencer and which namespace to read on celestia.