Event Driven Ethereum using Lambdas and Parameter Store

This is a deployable SAM repository that deploys:

1. Lambda on a 15min schedule that checks for mutations on a smart contract
2. Notifies a SQS/SNS/S3 It uses Parameter store to determine what needs checking and to store block height.

The intention of this tool was to abstract part of the event processing logic away from bots.

Production recommendation

Isolated accounts with unique RPC (Infura/Alchemy/Pokt.Network) endpoints for a low-cost approach. Archive node endpoints If working with >50 watched contracts, consider running the lambda more often by changing the CloudWatch event trigger.

Gotchas

1. At-least once message delivery, do your own idempotency if working e.g. with transactional operations.

Required parameters:

1. /ede/config/mainnet = Ethereum RPC endpoint.
2. /ede/config/gnosis = Gnosis RPC endpoint.
3. Various VPC/Subnet parameters, see template.yaml.

Write ABI

I use a dynamodb to store the ABI of the contracts. The key in dynamo should match "ContractName" in SSM

Watching a contract

/ede/tasks/mainnet/<ContractName>/<Event>/<ContractAddress>

Example: /ede/tasks/mainnet/ProofOfHumanity/AddSubmission/0xC5E9dDebb09Cd64DfaCab4011A0D5cEDaf7c9BDb This watches a ProofOfHumanity contract at 0xC5.. Your SSM can be tagged with SQS or SNS to receive notifications in form of the tx hash.