How to set FeeCalculator value to use BaseFee or FixedGasPrice in pallet_evm config?

Question

I was trying to add Frontier into my parachain as a dependency... then I got this error

     Compiling parachain-template-runtime v0.1.0 (/mnt/sda3/polkadot/substrate-parachain-template-evm/runtime)
  error[E0412]: cannot find type `BaseFee` in this scope
     --> /mnt/sda3/polkadot/substrate-parachain-template-evm/runtime/src/lib.rs:415:23
      |
  415 |     type FeeCalculator = BaseFee;
      |                          ^^^^^^^ not found in this scope

But I don't know how to import this BaseFee because I could not find where it was imported from in the Frontier repository's template/runtime/src/lib.rs: https://github.com/paritytech/frontier/blob/polkadot-v0.9.25/template/runtime/src/lib.rs#L330

impl pallet_evm::Config for Runtime {
    type FeeCalculator = BaseFee;//from Frontier template, where is this declared?
    //type FeeCalculator = FixedGasPrice;//from moombeam;
    //type FeeCalculator = ();//From JoshOrndorff
...
}

or should I use the FixedGasPrice from Moombeam?

pub struct FixedGasPrice;
impl FeeCalculator for FixedGasPrice {
    fn min_gas_price() -> (U256, Weight) {
        (
            (1 * currency::GIGAWEI * currency::SUPPLY_FACTOR).into(),
            1u64,
        )
}

What is the difference? It seems I can use FixedGasPrice to set the minimum gasPrice...

so that the user must pay 1 * currency::GIGAWEI * currency::SUPPLY_FACTOR for every 1u64 amount of Weight. right?

Answer 1

Adding pallet_base_fee in the construct_runtime! somehow imports this BaseFee variable:

construct_runtime!(
    ...
    {
    BaseFee: pallet_base_fee,
}