ETH Event Listener (Google Cloud Run)

Simple NodeJS based, event listener for ethereum based blockchains.

Goals

• Dockerised - DONE
• Google Cloud Run Application - DONE
• Node JS based - DONE
• Web3 JS based - DONE
• Multiple options for consuming events e.g. native subscribe, inbound webhooks from 3rd parties etc - DONE
• Ability to define many contracts to watch - DONE
• Ability to POST matched events from specific contracts to a configured endpoint - DONE
• Ability to write matched events from specific contracts to a file - DONE
• Ability to write matched events from specific contracts to a Google Cloud DB
• Ability to re-start if the process dies
• General EVM network compatibility - e.g. mainnet, ropsten, rinkeby, koven, Görli, POA, xDAI

General Architecture

• event-listener
  • scrapes and listens for event from a set of configured smart contracts
  • Found events are handled by a set of available handlers which can write top files, DB or post to endpoints such as event-processor-api
  • Stateful implementations maintain the current last block scrapped from the network
• event-processor-api is a simple serverless and statelsss API
  • New events are handle accordingly and persisted to Cloud DB

Google Cloud Run Setup

• gcloud init and login/auth

• Select create new configuration

  • Select koda-eth-event-listener

• After setting up both accounts run

  • gcloud config configurations list and you should see something similar to this

• You can view and change the properties of your active configuration using the following commands:

$ gcloud config list
$ gcloud config set

• gcloud config configurations list

Deployment

• ./build_image.sh - build and push new Docker image to GCP repo