hardhat-external-plugin

This plug-in it is used to add external contract already deployed dependencies to the project.

Hardhat external plugin.

What

This plugin will help you with:

• For verified contracts it is possible to fetch abi from blockchain explorer and register as a model.
• Once registered a model, it is possible to register multiple instances (contract addreses) for a model.
• For each model it is possible to generate typechain classes.

Installation

npm install @sebasgoldberg/hardhat-external

Import the plugin in your hardhat.config.js:

require("@sebasgoldberg/hardhat-external");

Or if you are using TypeScript, in your hardhat.config.ts:

import "@sebasgoldberg/hardhat-external";

Optional plugins

• @typechain/hardhat

Tasks

external-add-model

In the following example we register the model BridgeToken using the abi found in the address 0xd586E7F844cEa2F87f50152665BCbc2C279D8d70. This model is registered in the test group (the group is optional). Aditionally, at the same time it is registered an instance BridgeDAIe, that it is going to use the same address, and the model BridgeToken.

$ npx hardhat external-add-model --address 0xd586E7F844cEa2F87f50152665BCbc2C279D8d70 --group test --instance BridgeDAIe --model BridgeToken

external-add-instance

In case we want to register multiple instance with the same model, we use external-add-instance.

In the following example we register an instance BridgeWETHe, that it is going to use the address 0x49D5c2BdFfac6CE2BFdB6640F4F80f226bc10bAB, and the model BridgeToken. Note that to be possible to find the BridgeToken model, it is necessary to pass the group test as a parameter.

$ npx hardhat external-add-instance --instance BridgeWETHe --model BridgeToken --group test --address 0x49D5c2BdFfac6CE2BFdB6640F4F80f226bc10bAB

Environment extensions

This plugin extends the Hardhat Runtime Environment by adding an external field whose type is External.

To get the Contract instance for both instances registered above, we simply do the following:

import { BridgeToken } from '../typechain-types'
// ...
const BridgeWETHe: BridgeToken = hre.external.getContract('BridgeWETHe', 'test') as BridgeToken
const BridgeDAIe: BridgeToken = hre.external.getContract('BridgeDAIe', 'test') as BridgeToken

Note that we are using the specific contract type BridgeToken generated using typechain.

Configuration

The models are created for each network (defined in taks using --network parameter).

In case the models registered for one network are the same for another network, it is possible to specify this with an alias. For this, we use @sebasgoldberg/hardhat-network-alias plugin.

In the following example, the models are registered for the hardhat network, and we want to use the same models for the localhost network.

const config: HardhatUserConfig = {
  // ...
  networkAliases:{
    "external-plugin": { // Note that the group must be "external-plugin".
      'localhost': 'hardhat'
    }
  }
  // ...

Note above that the group for aliases must be "external-plugin".

Additionally, by default all information related to models and instances are saved in the external folder.

If you need to change the path of this folder you can specify a relative or an absolute path:

const config: HardhatUserConfig = {
  // ...
  external:{
    path: 'other/location/for/external/plugin'
  },
  // ...