Bridge Daemon
An overview of the Bridge Daemon
The
Bridge Daemon is implemented in the same way as other daemons in the dYdX Chain open source software. Specifically, the daemon:- will be run in process as go routines, and
- will use gRPC for communication with the main application.
- 1.Application initializes gRPC server
- 2.The daemon initializes gRPC client
- 1.need to make a connection to
localhost:9090for query service - 2.need to make a connection to unix socket for private daemon service
Let
n be the nextRecognizedEventId on the in-memory BridgeEvents struct on thex/bridge module.Let
c be the ProposeParams.MaxBridgesPerBlock parameter on the x/bridge module.For each Ethereum node endpoint configured, use the
eth_getLogs RPC call with the following parameters:address:BridgeContractAddresstopics: [sha256(LogBridge(…)), [n,n+1, … ,n+c-1]]from_block:"ethereum block height of last recognized bridge event"to_block:"finalized"
For each event returned by each of the Ethereum nodes, send a single, batched
AddBridgeEventsRequest to the server with the events in-order.To prevent hogging resources (from the validator itself or the remote Ethereum Node), the go routine can sleep until the next iteration. It can use the
ProposeParams.ProposeDelayDuration parameter on the x/bridge module to determine a suitable sleep time. Ideally it would sleep for no more than about half of this interval.These should be configurable by a validator.
EthereumNodeRpcEndpoint : The daemon maintains an Ethereum node RPC endpoint.Ideally, this should be a list of RPC endpoints and every RPC query will be sent to each node and daemon will only proceed if each node provides the same response. However, if a validator hosts its own Ethereum node, then it can use a single endpoint. All 16 private-testnet validators who responded to a dYdX survey indicated that they will host their own Ethereum full nodes.
BridgeContractAddress : The bridge contract to query logs from.
// BridgeService defines the gRPC service used by bridge daemon.
service BridgeService {
// Sends a list of newly recognized bridge events.
rpc AddBridgeEvents(AddBridgeEventsRequest)
returns (AddBridgeEventsResponse);
}
// AddBridgeEventsRequest is a request message that contains a list of new bridge
// events. The events should be contiguous and sorted by (unique) id.
message AddBridgeEventsRequest {
repeated dydxprotocol.bridge.BridgeEvent bridge_events = 1
[ (gogoproto.nullable) = false ];
}
// AddBridgeEventsResponse is a response message for BridgeEventRequest.
message AddBridgeEventsResponse {}