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EVM Localnet with Metamask Wallet

This tutorial is for how to set up your Metamask wallet to use with EVM localnet on Bittensor. You must run either this step or EVM Testnet with Metamask Wallet tutorial before you can run other tutorials in this section.

blog post: EVM on Bittensor

If you are new to EVM, try this blog post for a simplified explanation.

Key values:

Step 1. Run EVM-enabled localnet​

git clone https://github.com/opentensor/subtensor
./scripts/localnet.sh

Step 2. Set Chain ID​

The bare local network doesn't have the Chain ID setup and it needs to be configured with an admin extrinsic. Use sudo section of Polkadot AppsUI to call this extrinsic to set the ChainID to 945 (to simulate Testnet) or 964 (to simulate Mainnet):

adminUtils >> sudoSetEvmChainId

Step 3. Create a Metamask wallet​

  1. If you don't already have it, install Metamask wallet browser extension.
  2. Create a new account.

Step 4. Add EVM localnet to Metamask​

Follow the below steps:

  1. Open Metamask Wallet extension on your browser. Click on the drop-down Select a network menu at the top left.
  2. Click on + Add a Custom Network button.
  3. Enter the following details:
    • Network name: "Subtensor Local"
    • Default RPC URL: http://localhost:9944/
    • Chain ID: 964 or 945, depending on your setting in Step 2
    • Currency symbol: TAO
  4. Click Save.
  5. Click on Select a network again and switch to the Subtensor Local network.

With the above steps, you have successfully configured your Metamask wallet with the EVM localnet.

Step 5. Configure private key and RPC endpoint​

Stop. Did you install the dependencies?

Before you proceed, make sure you finished the Install step.

In this step you will copy the private key from your Metamask wallet account and paste it into the configuration file in the repo. This step will ensure that you are not prompted with password each and every step as you run these tutorials.

  1. Navigate to the examples directory of the EVM-Bittensor repo:

    cd examples

  2. Create config.js file by copying the config-example.js file:

    cp config-example.js config.js

  3. On Metamask wallet extension, your wallet account will have a H160 account address, starting with the 0x prefix (for example: 0x7E5F4552091A69125d5DfCb7b8C2659029395Bdf), and also your wallet account name.

  4. Click on your wallet account name, which will open the drop-down menu.

  5. Click on the ⋮ (three vertical dots, i.e., vertical ellipsis) next to the wallet account and select Account details. It will open a view with a QR code, your wallet account H160 address and a Show private key button.

  6. Click on the Show private key button, enter the password. You will then see the private key for your wallet account. Copy this private key.

  7. Paste this private key into ethPrivateKey string in your config.js file as shown below (mangled for security):

    const ethPrivateKey = "02c1c4112233snipsnipsnipgh933aca491e090e0b7xxyy1b124b86d9382b01a8";

  8. Finally, edit the module.exports section of the config.js file to use the localnet URLs, as shown below:

    module.exports = {
    ethPrivateKey,
    subSeed,
    rpcUrl: rpcUrlLocal,
    wsUrl: wsUrlLocal,
    }

Save the config.js file. Now your setup is ready to run the tutorials with EVM localnet.

Step 6 (Optional). Disable white list for contract deployment​

If you are planning to deploy contracts locally, you need to disable the premission control. This can be done with the following extrinsic in sudo section of Polkadot AppsUI:

evm >> disableWhitelist

Select Yes and then click Submit Sudo.