Substrate Faucet pallet

The Faucet pallet allows an account to claim a pre-configured number of tokens up to a certain number of times, and not faster than a configured interval.

When an account claims tokens from the faucet, the pallet will mint new tokens and credit them to requestor account's balance, and the token's total issuance will be updated accordingly. The operation of claiming tokens is feeless so the requesting account does not need to have any fund to submit the transaction.

This is a simple & effective way to distribute tokens on dev / test PoA chains, but it should be not be used in any case on a public network (which require more elaborate token distribution schemes baked by a solid cryptoeconomics model).

Usage

Claim tokens from the faucet

To claim tokens from the faucet, an account must send a transaction with a faucet.claimTokens extrinsic. The call is feeless so no fee will be charged for the transaction, and the requestor account's balance will be credited with the number of tokens as configured in the FaucetDripAmount parameter of the pallet's Config trait in your runtime.

Configure your runtime

Runtime Cargo.toml

To add this pallet to your runtime, simply include the following to your runtime's Cargo.toml file:

[dependencies.pallet-faucet]
default_features = false
version = '1.0.0'

and update your runtime's std feature to include this pallet:

std = [
    # --snip--
    'pallet-faucet/std',
]

Runtime lib.rs

You should implement it's Config trait like so:

parameter_types! {
    // Example configuration values.
    // Note: UNITS & DAYS constants might not be defined in your runtime.
    // 
    // The amount of token that "drips" from the faucet for every claim.
	pub const FaucetDripAmount: Balance = 1000 * UNITS;
    // The minimum period, as a number of blocks, between consecutive claims of a given account.
	pub const MinBlocksBetweenClaims: BlockNumber = 1 * DAYS;
    // The maximum number of times an account can claim tokens from the faucet.
	pub const MaxClaimsPerAccount: u32 = 3;
}

impl pallet_faucet::Config for Runtime {
	type Currency = Balances;
	type DripAmount = FaucetDripAmount;
	type Event = Event;
	type MaxClaimsPerAccount = MaxClaimsPerAccount;
	type MinBlocksBetweenClaims = MinBlocksBetweenClaims;
}

and include it in your construct_runtime! macro:

Faucet: pallet_faucet::{Pallet, Call, Storage, Event<T>},

Genesis Configuration

This pallet does not have any genesis configuration.

Testing

Run the tests with:

```
cargo test
```

Reference Docs

You can view the reference docs for this pallet by running:

cargo doc --open

License

The Faucet pallet is licensed under Apache 2.