Wire Protocols

GasHammer communicates with Nitro and between its own components through four wire protocols. This page documents each protocol’s usage, message format, and configuration.

JSON-RPC (Edge → Nitro)

Standard Ethereum JSON-RPC over HTTP. Used for transaction submission and state queries.

Endpoint: Sequencer (port 8547) or Gateway (port 8547).

Methods Used

Method	Direction	Purpose
`eth_sendRawTransaction`	Edge → Sequencer	Submit signed transactions
`eth_getTransactionReceipt`	Edge → Gateway	Poll for confirmation
`eth_blockNumber`	Edge → Gateway	Current L2 block height
`eth_chainId`	Edge → Sequencer	Health check and chain validation
`eth_gasPrice`	Edge → Gateway	Current gas price
`eth_getTransactionCount`	Edge → Gateway	Nonce recovery on failure
`eth_call`	Edge → Gateway	Read-only contract calls
`eth_getLogs`	Monitor → L1	L1 event queries

Request Format

{
  "jsonrpc": "2.0",
  "method": "eth_sendRawTransaction",
  "params": ["0x<signed_tx_rlp>"],
  "id": 1
}

Headers

Every request includes:

Header	Value
`User-Agent`	`GasHammer/<version> (<build_sha>)`
`X-Powered-By`	`GasHammer/<version>`
`X-GasHammer-Version`	`<version>`
`X-GasHammer-Build`	`<build_sha>`

WebSocket Feed (Edge → Feed Relay)

The sequencer feed is a one-way WebSocket stream from the feed relay (port 9642) to the edge. Messages are JSON-encoded BroadcastMessage envelopes.

Message Format

{
  "version": 1,
  "messages": [
    {
      "sequenceNumber": 12345,
      "message": {
        "header": {
          "kind": 3,
          "poster": "0x...",
          "blockNumber": 100,
          "timestamp": 1700000000,
          "requestId": "0x...",
          "l1BaseFeeEstimate": "0x..."
        },
        "l2Msg": "0x..."
      },
      "signature": "0x..."
    }
  ],
  "confirmedSequenceNumberMessage": {
    "sequenceNumber": 12340
  }
}

Reconnection

On disconnect, the feed consumer reconnects with exponential backoff:

Attempt	Delay
1	1s + jitter
2	2s + jitter
3	4s + jitter
n	min(2^n, 30)s + jitter

gRPC (Edge ↔ Hive)

Internal communication between edges and the hive uses gRPC with Protocol Buffers. Definitions are in proto/gashammer/v1/.

Service: HiveEdge

RPC	Direction	Description
`RegisterEdge`	Edge → Hive	Register with capabilities
`Heartbeat`	Edge → Hive	Periodic health signal
`StreamTelemetry`	Edge → Hive	Bidirectional event stream
`ControlStream`	Hive → Edge	Run start/stop commands

Proto Files

File	Contents
`hive_edge.proto`	`HiveEdge` service, `RegisterEdgeRequest/Response`, `ControlMessage`
`telemetry.proto`	`TelemetryEvent`, `TelemetryBatch`, event payload messages
`types.proto`	Shared types: `RunId`, `EdgeId`, `PhaseConfig`, `EdgeStatus`

Transport

Default port: 9090
TLS: mTLS recommended for production (configured via tls.cert_path, tls.key_path, tls.ca_path)
Keepalive: 30s interval

L1 JSON-RPC (Monitor → L1 Geth)

The L1 monitor polls an Ethereum L1 node for Nitro contract events.

Methods Used

Method	Purpose
`eth_blockNumber`	Current L1 block for range queries
`eth_getLogs`	Fetch `SequencerBatchDelivered` and assertion events
`eth_call`	Read `batchCount()` and `latestConfirmed()`

Event Signatures

Event	Signature Hash
`SequencerBatchDelivered(uint256,bytes32,bytes32,bytes32,uint256,(uint64,uint64),uint8)`	Computed via `keccak256`
`AssertionCreated(bytes32,...)`	Computed via `keccak256`
`AssertionConfirmed(bytes32,...)`	Computed via `keccak256`

All signature hashes are verified non-zero and mutually distinct in unit tests.

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