How to develop a network or chain agnostic subgraph?

Question

Multichain applications setup a network/chain config that could be simplified to an object where each key is a unique ID for a supported chain such as the chainId as follows:

// typescript:
enum ChainIds {
  Ethereum = 1,
  BSC = 56,
  AVAX = 43114,
};

const NetworkConfig = {
  [ChainIds.Ethereum]: {
    blockTime: 15_000, // 15s/block
    gasLimit: 15_000_000 // 15m/block
  },
  [ChainIds.BSC]: {
    blockTime: 3_000, // 3s/block
    gasLimit: 100_000_000 // 100m/block
  },
  [ChainIds.AVAX]: {
    blockTime: 3_000, // 3s/block
    gasLimit: 8_000_000 // 8m/block
  },
};

const chainId = 1; // how to get the chainId in subgraph environment

const gasPerS = NetworkConfig[chainId].gasLimit/NetworkConfig[chainId].blockTime;

This is one way of developing a subgraph in a network agnostic way, however I couldn't find any way to get the chainId from within a subgraph in thegraphs documentation. Is it possible to do so and if not how could/should a subgraph be developed in a chain agnostic manner.

Answer 1

The network name can be accessed via dataSource as follows:

import { dataSource } from "@graphprotocol/graph-ts";

const chainName = dataSource.network(); // returns network name

const chainId = ChainIds[chainName];

The list of network's supported on the graphs hosted service can be found here.

You can also configure the data source addresses listed in the subgraph.yaml for multiple networks using a networks.json config as shown in thegraph's docs.