feat: add sequencer/rpc mode for flashblock preconfirmations#214
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fridrik01 wants to merge 5 commits intorezbera/use-modular-flashblocksfrom
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feat: add sequencer/rpc mode for flashblock preconfirmations#214fridrik01 wants to merge 5 commits intorezbera/use-modular-flashblocksfrom
fridrik01 wants to merge 5 commits intorezbera/use-modular-flashblocksfrom
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This PR adds flashblock preconfirmation support to bera-reth. It supersedes #202 and #214 which depended on an upstream reth PR ([paradigmxyz/reth#20122](paradigmxyz/reth#20122)) for the consumer plumbing. That created a hard dependency on an external merge timeline, and the upstream PR was ultimately closed after reth removed the optimism directory. This PR implements the entire pipeline natively within bera-reth so that all preconf and flashblock logic now lives entirely within bera-reth with no external dependencies or forks. In the preconf system, a node can run as either a sequencer (produces flashblocks) or an RPC consumer (subscribes to them), controlled by CLI flags. ## Sequencer A sequencer node builds blocks and streams progress over WebSocket. During block building, the payload builder executes transactions from the mempool in a loop and every 200 ms publishes a signed flashblock containing the transactions added since the last emission. When the engine calls `getPayload`, the deadline expires, or the gas limit is hit, the loop exits and a final flashblock is emitted with `is_last: true`. Each flashblock is BLS-signed over a message binding it to a specific chain, block number, payload ID, and index — not just the diff — so consumers can authenticate the stream without trusting the transport. The sequencer does not include computed roots (state root, receipts root) in the diff per BRIP-0007; consumers reconstruct those locally. Flags: `--sequencer-enabled`, `--flashblock-signing-key <path>`, `--flashblock-ws-addr <addr>` (default `0.0.0.0:8548`), `--flashblock-interval-ms <ms>` (default `200`). ## RPC consumer An RPC node connects to a sequencer's WebSocket endpoint (`--flashblocks-url <URL>`), receives the flashblock stream, assembles incoming diffs into in-progress block state, and re-executes transactions locally to compute state. The Eth JSON-RPC layer is then overridden so that methods like `eth_getTransactionReceipt`, `eth_getBlockByNumber`, `eth_call`, and `eth_gasPrice` serve flashblock-derived data for `latest` and `pending` queries. A staleness check ties flashblock data to the current canonical tip, preventing stale results during reorgs. The WebSocket client handles both raw JSON and brotli-compressed messages and automatically reconnects on disconnect. State root computation is deferred until near the end of the block time window to avoid redundant work on intermediate flashblocks. ## Test plan - See test plan in berachain/beacon-kit#3005
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Replaced with #228 |
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This PR adds flashblock support to bera-reth and introduces two modes:
Sequencer mode (
--sequencer-enabled)--flashblock-signing-key <path>Path to BLS secret key file (required)--flashblock-ws-addr <addr>WebSocket bind address (default:0.0.0.0:8548)--flashblock-interval-ms <ms>Emission interval (default:200)The payload builder runs a loop that (as in line with preconf notion doc):
--builder.deadline)Each flashblock contains:
Also, a single publisher broadcasts to all connected WebSocket subscribers.
RPC consumer mode (--flashblocks-url )
RPC nodes connect to a sequencer's WebSocket endpoint and subscribe to flashblocks. Incoming flashblocks are processed and used to override the Eth JSON-RPC layer so that latest and pending queries reflect sub-block state. Blocks, transaction counts, receipts, state, gas price, and call execution all serve in-progress flashblock data without the node needing to run as a sequencer.
Test plan
See test plan in berachain/beacon-kit#3005