EVM node

DipDup can connect to any EVM-compatible node via JSON-RPC. It can be used as a "last mile" datasource for EVM indexes (data that is not in Subsquid Network yet) or as a standalone datasource for handlers and hooks.

The example below shows how to connect to Alchemy nodes for Ethereum mainnet indexes. You can also use your own node, but make sure it has all the necessary data (e.g. archive node).

datasources:
  evm_node:
    kind: evm.node
    url: ${NODE_URL:-https://eth-mainnet.g.alchemy.com/v2}/${NODE_API_KEY:-''}
    ws_url: ${NODE_WS_URL:-wss://eth-mainnet.g.alchemy.com/v2}/${NODE_API_KEY:-''}

If you want to use the node as a last-mile datasource for EVM indexes, you should link it to the evm.subsquid definition.

datasources:
  subsquid:
    kind: evm.subsquid
    url: ${SUBSQUID_URL:-https://v2.archive.subsquid.io/network/ethereum-mainnet}
    node: evm_node

node field could also be a list of datasources; DipDup will use the random one for each request.

web3 client

web3.py is a popular Python library for interacting with Ethereum nodes. Every node datasource has a web3 client instance attached to it. You can use it in handlers and hooks to fetch data from the node and perform other actions.

To access the client, use web3 property of the datasource. The underlying web3 client is asynchronous, so you should use await keyword to call its methods.

web3: AsyncWeb3 = ctx.get_evm_node_datasource('evm_node').web3
contract = self.web3.eth.contract(...)
symbol = await contract.functions.symbol().call()

Each datasource has its own web3 client instance, so you can use it safely in parallel. web3 clients respect http configuration from the datasource config when making requests.