@ora-io/rek

Rek: Reliable ETH Kit

Event Cross-Check

• used for cross-checking missing events using eth getLogs
• note: cross-check interval shouldn't < 5min, otherwise rpc call would be expensive. Recommend set to 1 hour + 50 blocks (for redundancy check).

BaseCrossChecker

• onMissingLog: FnOnMissingLog: the callback function that will be called when there's a missing log found;
• ignoreLogs?: SimpleLog[] : it allows users to pass in the txhash list (,log index list) that already processed, let the crosschecker to ignore then.

crossCheckRange

crossCheckRetro

crossCheckFrom

AutoCrossCheck

Conceptually it supports 'catchup', 'realtime', 'mix' modes, controled by fromBlock and toBlock;

• realtime mode: run over the latest block data; enter when fromBlock and toBlock are NOT present; starts from latestblocknum and never ends, always waits until latestblocknum >= lastcheckpoint + batchBlocksCount;
• catchup mode: run over historical block data; enter when fromBlock and toBlock is present; starts from fromBlock and ends at toBlock;
• mix mode: start in catchup mode and transit to realtime mode; enter when fromBlock is present and toBlock is NOT; auto-transit when lastcheckpoint > latestblocknum - batchBlocksCount;

i.e. It starts with 'realtime' mode by default.

Options:

• store?: the Store used to cache the <txhash, logindex> that already processed.
• batchBlocksCount?: how many blocks to get per getLogs check, in readtime mode it waits until the new block num >= batchBlocksCount.
• intervalMsMin?: mostly for limiting getLogs calling rate in catchup mode; how long does it take at least between 2 checks
• blockIntervalMs?: the block interval (in ms) of the given chain, default: 12000 for eth
• delayBlockFromLatest?: mostly for realtime mode; each time cc wait until latest height > toBlock + delayBlockFromLatest
• fromBlock?: once specified, it means start catching up from historical blocks
• toBlock?: once specified, it means the crosscheck isn't infinite and will end at this height; need fromBlock present if this set

Usage

const acc = new AutoCrossChecker(provider)
await acc.start({
  onMissingLog,
  ignoreLogs,
  fromBlock: 20003371, // optional, empty to start from latest
  toBlock: 20003371, // optional, empty to enter continueous cc
  address: CONTRACT_ADDRESS,
  topics,
  batchBlocksCount: 1,
  intervalMsMin: 3000,
})