Overview

Each "data source" within a subgraph manifest corresponds to an Ethereum contract on a specific network.

For example, the following data source pulls Compound v3 data for the USDC deployment:

specVersion: 0.0.5
schema:
  file: ./schema.graphql
dataSources:
  - kind: ethereum
    name: Comet
    network: mainnet
    source:
      address: "0xc3d688B66703497DAA19211EEdff47f25384cdc3"
      abi: Comet
      startBlock: 15331586
    mapping:
			...

See full specification for more details.

Adding a Data Source

To add a new data source to an existing subgraph, you can use the graph add CLI command:

graph add <address> [<subgraph-manifest default: "./subgraph.yaml">]

Options:

      --abi <path>              Path to the contract ABI (default: download from Etherscan)
      --contract-name           Name of the contract (default: Contract)
      --merge-entities          Whether to merge entities with the same name (default: false)
      --network-file <path>     Networks config file path (default: "./networks.json")

Proxy Contracts

EVM protocols often use a proxy contract that points to an implementation contract for the sake of upgradeability.

Event log and transaction data is associated with the proxy contract address, but need to be decoded using the implementation contract ABI. Because of this, you'll likely need to download the implementation contract ABI and associate it with the proxy contract address in your data source.

Factory Contracts

Another common pattern is to use factory or registry contracts that create and manage other smart contracts.

In order to handle sub-contracts that are dynamically created, you'll need to use Data Source Templates.