openrelay/blockmonitorng repository overview

Monitors an Ethereum RPC server for new blocks, emitting messages containing the block number, block hash, and block bloom filter for each block. Handles restarts and chain reorganizations fairly gracefully.

This block monitor can be subscribed to by downstream services, which can check the bloom filter for events. This means downstream services only have to hit the RPC server when it is likely that there are events for it to find, and otherwise they can just monitor the channel for new blocks.