Setup

1. create a .env file like below:

   INFURA_API_KEY =
   DEPLOYMENT_ACCOUNT_KEY =
   

   *ask for values to the team and pass them

2. navigate to your repo directory and install the dependencies:

   npm install
   

Deploy to a Local Ganache Instance That Mirrors the Mainnet

1. Install the Ganache CLI

   npm install -g ganache-cli
   

2. Fork and mirror mainnet into your Ganache instance. You can fork mainnet and use each protocol's production contracts and production ERC20 tokens. Replace INFURA_API_KEY with the value in the following and run:

   ganache-cli --fork https://mainnet.infura.io/v3/INFURA_API_KEY -i 1
   

3. In a new terminal window in your repo directory, run:

   truffle console
   

4. Migrate your FlashLoan contract to your instance of Ganache with:

   migrate --reset
   

   *After a few minutes, your contract will be deployed.

Deploy to the Mainnet

1. Run:

   truffle console --network mainnet
   

2. You are now connected to the mainnet. Now, use the migrate command to deploy your contract:

   migrate --reset
   

   You might get the error below:

   /aave-flash-loans/node_modules/@trufflesuite/web3-provider-engine/index.js:219
      number:           ethUtil.toBuffer(jsonBlock.number),
                                                   ^
   TypeError: Cannot read property 'number' of null
   

Interact With the Contract

Call your contract's flashLoan function within the truffle console.

let instance = await FlashLoan.deployed()
const DAI = "0x6b175474e89094c44da98b954eedeac495271d0f";
const amount = 20; // specify the amount
const USDC = "0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48";
await instance.flashLoan(DAI, amount, USDC)

If your implementation is correct, then the transaction will succeed. If it fails/reverts, a reason will be given.

*Make sure that this contract has enough of _reserve funds of a token you borrow to payback the _fee.

*if the above operation takes an unreasonably long time or timesout, try CTRL+C to exit the Truffle console, run truffle console again, then try this step agin. You may need to wait a few blocks before your node can 'see' the deployed contract.

EOA Address

We are using this EOA address 0xcc84e428b30ea976f932d77293df4ba8edd7307f.

Known issues

No access to archive state errors

If you are using Ganache to fork a network, then you may have issues with the blockchain archive state every 30 minutes. This is due to your node provider (i.e. Infura) only allowing free users access to 30 minutes of archive state. You can either 1) upgrade to a paid plan or 2) restart your ganache instance and redploy your contracts.

Unable to debug executeOperation() with mainnet ganache fork

The Truffle debugger does not work too well with proxy / complex calls. You may find that the Truffle debugger returns an error such as:

TypeError: Cannot read property 'version' of undefined
at ...

• In this case you can try calling your executeOperation() function directly, instead of having Aave's LendingPool contract invoke the function. This will allow you to debug the function directly, however you will need to supply the relevant parameters (e.g. _amount, _fee, _reserve, etc).
• Alternatively, see the 'Troubleshooting' link.

Versions

$ truffle --version
Truffle v5.1.51
$ ganache-cli --version
Ganache CLI v6.12.1 (ganache-core: 2.13.1)

Troubleshooting

See our Troubleshooting Errors documentation.

Examples

• Here is an example transaction that followed the above steps on Ropsten using Dai.

• Here is an example transaction that followed the above steps on Ropsten using ETH.