Contract Deployment
To add contracts to your application, we'll start by creating a new aztec-nargo project. We'll then compile the contracts, and write a simple script to deploy them to our Sandbox.
info
Follow the instructions here to install aztec-nargo if you haven't done so already.
Initialize Aztec project
Create a new contracts folder, and from there, initialize a new project called token:
mkdir contracts && cd contracts
aztec-nargo new --contract token
Then, open the contracts/token/Nargo.toml configuration file, and add the aztec.nr and value_note libraries as dependencies:
[dependencies]
aztec = { git="https://github.com/AztecProtocol/aztec-packages/", tag="aztec-packages-v0.68.0", directory="noir-projects/aztec-nr/aztec" }
authwit = { git="https://github.com/AztecProtocol/aztec-packages/", tag="aztec-packages-v0.68.0", directory="noir-projects/aztec-nr/authwit"}
compressed_string = {git="https://github.com/AztecProtocol/aztec-packages/", tag="aztec-packages-v0.68.0", directory="noir-projects/aztec-nr/compressed-string"}
Last, copy-paste the code from the Token contract into contracts/token/main.nr:
token_all
mod types;
mod test;
use dep::aztec::macros::aztec;
// Minimal token implementation that supports `AuthWit` accounts.
// The auth message follows a similar pattern to the cross-chain message and includes a designated caller.
// The designated caller is ALWAYS used here, and not based on a flag as cross-chain.
// message hash = H([caller, contract, selector, ...args])
// To be read as `caller` calls function at `contract` defined by `selector` with `args`
// Including a nonce in the message hash ensures that the message can only be used once.
#[aztec]
contract Token {
// Libs
use std::meta::derive;
use dep::compressed_string::FieldCompressedString;
use dep::aztec::{
context::{PrivateCallInterface, PrivateContext},
encrypted_logs::{
encrypted_event_emission::encode_and_encrypt_event_unconstrained,
encrypted_note_emission::encode_and_encrypt_note_unconstrained,
},
macros::{
events::event,
functions::{initializer, internal, private, public, view},
storage::storage,
},
oracle::random::random,
prelude::{
AztecAddress, FunctionSelector, Map, PublicContext, PublicImmutable, PublicMutable,
},
protocol_types::{point::Point, traits::Serialize},
};
use dep::uint_note::uint_note::UintNote;
use dep::authwit::auth::{
assert_current_call_valid_authwit, assert_current_call_valid_authwit_public,
compute_authwit_nullifier,
};
use crate::types::balance_set::BalanceSet;
// In the first transfer iteration we are computing a lot of additional information (validating inputs, retrieving
// keys, etc.), so the gate count is already relatively high. We therefore only read a few notes to keep the happy
// case with few constraints.
global INITIAL_TRANSFER_CALL_MAX_NOTES: u32 = 2;
// All the recursive call does is nullify notes, meaning the gate count is low, but it is all constant overhead. We
// therefore read more notes than in the base case to increase the efficiency of the overhead, since this results in
// an overall small circuit regardless.
global RECURSIVE_TRANSFER_CALL_MAX_NOTES: u32 = 8;
#[derive(Serialize)]
#[event]
struct Transfer {
from: AztecAddress,
to: AztecAddress,
amount: Field,
}
#[storage]
struct Storage<Context> {
admin: PublicMutable<AztecAddress, Context>,
minters: Map<AztecAddress, PublicMutable<bool, Context>, Context>,
balances: Map<AztecAddress, BalanceSet<Context>, Context>,
total_supply: PublicMutable<U128, Context>,
public_balances: Map<AztecAddress, PublicMutable<U128, Context>, Context>,
symbol: PublicImmutable<FieldCompressedString, Context>,
name: PublicImmutable<FieldCompressedString, Context>,
decimals: PublicImmutable<u8, Context>,
}
#[public]
#[initializer]
fn constructor(admin: AztecAddress, name: str<31>, symbol: str<31>, decimals: u8) {
assert(!admin.is_zero(), "invalid admin");
storage.admin.write(admin);
storage.minters.at(admin).write(true);
storage.name.initialize(FieldCompressedString::from_string(name));
storage.symbol.initialize(FieldCompressedString::from_string(symbol));
storage.decimals.initialize(decimals);
}
#[public]
fn set_admin(new_admin: AztecAddress) {
assert(storage.admin.read().eq(context.msg_sender()), "caller is not admin");
storage.admin.write(new_admin);
}
#[public]
#[view]
fn public_get_name() -> FieldCompressedString {
storage.name.read()
}
#[private]
#[view]
fn private_get_name() -> FieldCompressedString {
storage.name.read()
}
#[public]
#[view]
fn public_get_symbol() -> pub FieldCompressedString {
storage.symbol.read()
}
#[private]
#[view]
fn private_get_symbol() -> pub FieldCompressedString {
storage.symbol.read()
}
#[public]
#[view]
fn public_get_decimals() -> pub u8 {
storage.decimals.read()
}
#[private]
#[view]
fn private_get_decimals() -> pub u8 {
storage.decimals.read()
}
#[public]
#[view]
fn get_admin() -> Field {
storage.admin.read().to_field()
}
#[public]
#[view]
fn is_minter(minter: AztecAddress) -> bool {
storage.minters.at(minter).read()
}
#[public]
#[view]
fn total_supply() -> Field {
storage.total_supply.read().to_integer()
}
#[public]
#[view]
fn balance_of_public(owner: AztecAddress) -> Field {
storage.public_balances.at(owner).read().to_integer()
}
#[public]
fn set_minter(minter: AztecAddress, approve: bool) {
assert(storage.admin.read().eq(context.msg_sender()), "caller is not admin");
storage.minters.at(minter).write(approve);
}
#[public]
fn mint_to_public(to: AztecAddress, amount: Field) {
assert(storage.minters.at(context.msg_sender()).read(), "caller is not minter");
let amount = U128::from_integer(amount);
let new_balance = storage.public_balances.at(to).read().add(amount);
let supply = storage.total_supply.read().add(amount);
storage.public_balances.at(to).write(new_balance);
storage.total_supply.write(supply);
}
#[public]
fn transfer_in_public(from: AztecAddress, to: AztecAddress, amount: Field, nonce: Field) {
if (!from.eq(context.msg_sender())) {
assert_current_call_valid_authwit_public(&mut context, from);
} else {
assert(nonce == 0, "invalid nonce");
}
let amount = U128::from_integer(amount);
let from_balance = storage.public_balances.at(from).read().sub(amount);
storage.public_balances.at(from).write(from_balance);
let to_balance = storage.public_balances.at(to).read().add(amount);
storage.public_balances.at(to).write(to_balance);
}
#[public]
fn burn_public(from: AztecAddress, amount: Field, nonce: Field) {
if (!from.eq(context.msg_sender())) {
assert_current_call_valid_authwit_public(&mut context, from);
} else {
assert(nonce == 0, "invalid nonce");
}
let amount = U128::from_integer(amount);
let from_balance = storage.public_balances.at(from).read().sub(amount);
storage.public_balances.at(from).write(from_balance);
let new_supply = storage.total_supply.read().sub(amount);
storage.total_supply.write(new_supply);
}
#[private]
fn transfer_to_public(from: AztecAddress, to: AztecAddress, amount: Field, nonce: Field) {
if (!from.eq(context.msg_sender())) {
assert_current_call_valid_authwit(&mut context, from);
} else {
assert(nonce == 0, "invalid nonce");
}
// TODO: constrain encryption below - we are using unconstrained here only because of the following Noir issue
// https://github.com/noir-lang/noir/issues/5771
storage.balances.at(from).sub(from, U128::from_integer(amount)).emit(
encode_and_encrypt_note_unconstrained(&mut context, from, from),
);
Token::at(context.this_address())._increase_public_balance(to, amount).enqueue(&mut context);
}
#[private]
fn transfer(to: AztecAddress, amount: Field) {
let from = context.msg_sender();
let amount = U128::from_integer(amount);
// We reduce `from`'s balance by amount by recursively removing notes over potentially multiple calls. This
// method keeps the gate count for each individual call low - reading too many notes at once could result in
// circuits in which proving is not feasible.
// Since the sum of the amounts in the notes we nullified was potentially larger than amount, we create a new
// note for `from` with the change amount, e.g. if `amount` is 10 and two notes are nullified with amounts 8 and
// 5, then the change will be 3 (since 8 + 5 - 10 = 3).
let change = subtract_balance(
&mut context,
storage,
from,
amount,
INITIAL_TRANSFER_CALL_MAX_NOTES,
);
storage.balances.at(from).add(from, change).emit(encode_and_encrypt_note_unconstrained(
&mut context,
from,
from,
));
storage.balances.at(to).add(to, amount).emit(encode_and_encrypt_note_unconstrained(
&mut context,
to,
from,
));
// We don't constrain encryption of the note log in `transfer` (unlike in `transfer_in_private`) because the transfer
// function is only designed to be used in situations where the event is not strictly necessary (e.g. payment to
// another person where the payment is considered to be successful when the other party successfully decrypts a
// note).
Transfer { from, to, amount: amount.to_field() }.emit(
encode_and_encrypt_event_unconstrained(&mut context, to, from),
);
}
#[contract_library_method]
fn subtract_balance(
context: &mut PrivateContext,
storage: Storage<&mut PrivateContext>,
account: AztecAddress,
amount: U128,
max_notes: u32,
) -> U128 {
let subtracted = storage.balances.at(account).try_sub(amount, max_notes);
// Failing to subtract any amount means that the owner was unable to produce more notes that could be nullified.
// We could in some cases fail early inside try_sub if we detected that fewer notes than the maximum were
// returned and we were still unable to reach the target amount, but that'd make the code more complicated, and
// optimizing for the failure scenario is not as important.
assert(subtracted > U128::from_integer(0), "Balance too low");
if subtracted >= amount {
// We have achieved our goal of nullifying notes that add up to more than amount, so we return the change
subtracted - amount
} else {
// try_sub failed to nullify enough notes to reach the target amount, so we compute the amount remaining
// and try again.
let remaining = amount - subtracted;
compute_recurse_subtract_balance_call(*context, account, remaining).call(context)
}
}
// TODO(#7729): apply no_predicates to the contract interface method directly instead of having to use a wrapper
// like we do here.
#[no_predicates]
#[contract_library_method]
fn compute_recurse_subtract_balance_call(
context: PrivateContext,
account: AztecAddress,
remaining: U128,
) -> PrivateCallInterface<25, U128> {
Token::at(context.this_address())._recurse_subtract_balance(account, remaining.to_field())
}
// TODO(#7728): even though the amount should be a U128, we can't have that type in a contract interface due to
// serialization issues.
#[internal]
#[private]
fn _recurse_subtract_balance(account: AztecAddress, amount: Field) -> U128 {
subtract_balance(
&mut context,
storage,
account,
U128::from_integer(amount),
RECURSIVE_TRANSFER_CALL_MAX_NOTES,
)
}
/**
* Cancel a private authentication witness.
* @param inner_hash The inner hash of the authwit to cancel.
*/
#[private]
fn cancel_authwit(inner_hash: Field) {
let on_behalf_of = context.msg_sender();
let nullifier = compute_authwit_nullifier(on_behalf_of, inner_hash);
context.push_nullifier(nullifier);
}
#[private]
fn transfer_in_private(from: AztecAddress, to: AztecAddress, amount: Field, nonce: Field) {
if (!from.eq(context.msg_sender())) {
assert_current_call_valid_authwit(&mut context, from);
} else {
assert(nonce == 0, "invalid nonce");
}
let amount = U128::from_integer(amount);
// TODO: constrain encryption below - we are using unconstrained here only becuase of the following Noir issue
// https://github.com/noir-lang/noir/issues/5771
storage.balances.at(from).sub(from, amount).emit(encode_and_encrypt_note_unconstrained(
&mut context,
from,
from,
));
// TODO: constrain encryption below - we are using unconstrained here only becuase of the following Noir issue
// https://github.com/noir-lang/noir/issues/5771
storage.balances.at(to).add(to, amount).emit(encode_and_encrypt_note_unconstrained(
&mut context,
to,
from,
));
}
#[private]
fn burn_private(from: AztecAddress, amount: Field, nonce: Field) {
if (!from.eq(context.msg_sender())) {
assert_current_call_valid_authwit(&mut context, from);
} else {
assert(nonce == 0, "invalid nonce");
}
// TODO: constrain encryption below - we are using unconstrained here only becuase of the following Noir issue
// https://github.com/noir-lang/noir/issues/5771
storage.balances.at(from).sub(from, U128::from_integer(amount)).emit(
encode_and_encrypt_note_unconstrained(&mut context, from, from),
);
Token::at(context.this_address())._reduce_total_supply(amount).enqueue(&mut context);
}
// Transfers token `amount` from public balance of message sender to a private balance of `to`.
#[private]
fn transfer_to_private(to: AztecAddress, amount: Field) {
// `from` is the owner of the public balance from which we'll subtract the `amount`.
let from = context.msg_sender();
let token = Token::at(context.this_address());
// We prepare the private balance increase (the partial note).
let hiding_point_slot = _prepare_private_balance_increase(from, to, &mut context, storage);
// At last we finalize the transfer. Usage of the `unsafe` method here is safe because we set the `from`
// function argument to a message sender, guaranteeing that he can transfer only his own tokens.
token._finalize_transfer_to_private_unsafe(from, amount, hiding_point_slot).enqueue(
&mut context,
);
}
/// Prepares an increase of private balance of `to` (partial note). The increase needs to be finalized by calling
/// some of the finalization functions (`finalize_transfer_to_private`, `finalize_mint_to_private`).
/// Returns a hiding point slot.
#[private]
fn prepare_private_balance_increase(to: AztecAddress, from: AztecAddress) -> Field {
// TODO(#9887): ideally we'd not have `from` here, but we do need a `from` address to produce a tagging secret
// with `to`.
_prepare_private_balance_increase(from, to, &mut context, storage)
}
/// This function exists separately from `prepare_private_balance_increase` solely as an optimization as it allows
/// us to have it inlined in the `transfer_to_private` function which results in one less kernel iteration.
///
/// TODO(#9180): Consider adding macro support for functions callable both as an entrypoint and as an internal
/// function.
#[contract_library_method]
fn _prepare_private_balance_increase(
from: AztecAddress, // sender of the tag: TODO(#9887): this is not great?
to: AztecAddress,
context: &mut PrivateContext,
storage: Storage<&mut PrivateContext>,
) -> Field {
let to_note_slot = storage.balances.at(to).set.storage_slot;
// We create a setup payload with unpopulated/zero `amount` for 'to'
// TODO(#7775): Manually fetching the randomness here is not great. If we decide to include randomness in all
// notes we could just inject it in macros.
let note_randomness = unsafe { random() };
let note_setup_payload = UintNote::setup_payload().new(to, note_randomness, to_note_slot);
// We get the keys and encrypt the log of the note
let setup_log = note_setup_payload.encrypt_log(context, to, from);
// Using the x-coordinate as a hiding point slot is safe against someone else interfering with it because
// we have a guarantee that the public functions of the transaction are executed right after the private ones
// and for this reason the protocol guarantees that nobody can front-run us in consuming the hiding point.
// This guarantee would break if `finalize_transfer_to_private` was not called in the same transaction. This
// however is not the flow we are currently concerned with. To support the multi-transaction flow we could
// introduce a `from` function argument, hash the x-coordinate with it and then repeat the hashing in
// `finalize_transfer_to_private`.
// We can also be sure that the `hiding_point_slot` will not overwrite any other value in the storage because
// in our state variables we derive slots using a different hash function from multi scalar multiplication
// (MSM).
let hiding_point_slot = note_setup_payload.hiding_point.x;
// We don't need to perform a check that the value overwritten by `_store_point_in_transient_storage_unsafe`
// is zero because the slot is the x-coordinate of the hiding point and hence we could only overwrite
// the value in the slot with the same value. This makes usage of the `unsafe` method safe.
Token::at(context.this_address())
._store_payload_in_transient_storage_unsafe(
hiding_point_slot,
note_setup_payload.hiding_point,
setup_log,
)
.enqueue(context);
hiding_point_slot
}
/// Finalizes a transfer of token `amount` from public balance of `from` to a private balance of `to`.
/// The transfer must be prepared by calling `prepare_private_balance_increase` first and the resulting
/// `hiding_point_slot` must be passed as an argument to this function.
#[public]
fn finalize_transfer_to_private(amount: Field, hiding_point_slot: Field) {
let from = context.msg_sender();
_finalize_transfer_to_private(from, amount, hiding_point_slot, &mut context, storage);
}
/// This is a wrapper around `_finalize_transfer_to_private` placed here so that a call
/// to `_finalize_transfer_to_private` can be enqueued. Called unsafe as it does not check `from` (this has to be
/// done in the calling function).
#[public]
#[internal]
fn _finalize_transfer_to_private_unsafe(
from: AztecAddress,
amount: Field,
hiding_point_slot: Field,
) {
_finalize_transfer_to_private(from, amount, hiding_point_slot, &mut context, storage);
}
#[contract_library_method]
fn _finalize_transfer_to_private(
from: AztecAddress,
amount: Field,
hiding_point_slot: Field,
context: &mut PublicContext,
storage: Storage<&mut PublicContext>,
) {
// TODO(#8271): Type the amount as U128 and nuke the ugly cast
let amount = U128::from_integer(amount);
// First we subtract the `amount` from the public balance of `from`
let from_balance = storage.public_balances.at(from).read().sub(amount);
storage.public_balances.at(from).write(from_balance);
// Then we finalize the partial note with the `amount`
let finalization_payload =
UintNote::finalization_payload().new(context, hiding_point_slot, amount);
// At last we emit the note hash and the final log
finalization_payload.emit();
}
/// Mints token `amount` to a private balance of `to`. Message sender has to have minter permissions (checked
/// in the enqueued call).
#[private]
fn mint_to_private(
from: AztecAddress, // sender of the tag: TODO(#9887): this is not great?
to: AztecAddress,
amount: Field,
) {
let token = Token::at(context.this_address());
// We prepare the partial note to which we'll "send" the minted amount.
let hiding_point_slot = _prepare_private_balance_increase(from, to, &mut context, storage);
// At last we finalize the mint. Usage of the `unsafe` method here is safe because we set the `from`
// function argument to a message sender, guaranteeing that only a message sender with minter permissions
// can successfully execute the function.
token
._finalize_mint_to_private_unsafe(context.msg_sender(), amount, hiding_point_slot)
.enqueue(&mut context);
}
/// Finalizes a mint of token `amount` to a private balance of `to`. The mint must be prepared by calling
/// `prepare_private_balance_increase` first and the resulting
/// `hiding_point_slot` must be passed as an argument to this function.
///
/// Note: This function is only an optimization as it could be replaced by a combination of `mint_to_public`
/// and `finalize_transfer_to_private`. It is however used very commonly so it makes sense to optimize it
/// (e.g. used during token bridging, in AMM liquidity token etc.).
#[public]
fn finalize_mint_to_private(amount: Field, hiding_point_slot: Field) {
assert(storage.minters.at(context.msg_sender()).read(), "caller is not minter");
_finalize_mint_to_private(amount, hiding_point_slot, &mut context, storage);
}
#[public]
#[internal]
fn _finalize_mint_to_private_unsafe(
from: AztecAddress,
amount: Field,
hiding_point_slot: Field,
) {
// We check the minter permissions as it was not done in `mint_to_private` function.
assert(storage.minters.at(from).read(), "caller is not minter");
_finalize_mint_to_private(amount, hiding_point_slot, &mut context, storage);
}
#[contract_library_method]
fn _finalize_mint_to_private(
amount: Field,
hiding_point_slot: Field,
context: &mut PublicContext,
storage: Storage<&mut PublicContext>,
) {
let amount = U128::from_integer(amount);
// First we increase the total supply by the `amount`
let supply = storage.total_supply.read().add(amount);
storage.total_supply.write(supply);
// Then we finalize the partial note with the `amount`
let finalization_payload =
UintNote::finalization_payload().new(context, hiding_point_slot, amount);
// At last we emit the note hash and the final log
finalization_payload.emit();
}
/// Called by fee payer contract (FPC) to set up a refund for a user during the private fee payment flow.
#[private]
fn setup_refund(
user: AztecAddress, // A user for which we are setting up the fee refund.
max_fee: Field, // The maximum fee a user is willing to pay for the tx.
nonce: Field, // A nonce to make authwitness unique.
) {
// 1. This function is called by FPC when setting up a refund so we need to support the authwit flow here
// and check that the user really permitted fee_recipient to set up a refund on their behalf.
assert_current_call_valid_authwit(&mut context, user);
// 2. Deduct the max fee from user's balance. The difference between max fee and the actual tx fee will
// be refunded to the user in the `complete_refund(...)` function.
let change = subtract_balance(
&mut context,
storage,
user,
U128::from_integer(max_fee),
INITIAL_TRANSFER_CALL_MAX_NOTES,
);
// Emit the change note.
storage.balances.at(user).add(user, change).emit(encode_and_encrypt_note_unconstrained(
&mut context,
user,
user,
));
// 3. Prepare the partial note for the refund.
let user_point_slot = _prepare_private_balance_increase(user, user, &mut context, storage);
// 4. Set the public teardown function to `complete_refund(...)`. Public teardown is the only time when a public
// function has access to the final transaction fee, which is needed to compute the actual refund amount.
let fee_recipient = context.msg_sender(); // FPC is the fee recipient.
context.set_public_teardown_function(
context.this_address(),
comptime { FunctionSelector::from_signature("complete_refund((Field),Field,Field)") },
[fee_recipient.to_field(), user_point_slot, max_fee],
);
}
// TODO(#9375): Having to define the note log length here is very unfortunate as it's basically impossible for
// users to derive manually. This will however go away once we have a real transient storage since we will not need
// the public call and instead we would do something like `context.transient_storage_write(slot, payload)` and that
// will allow us to use generics and hence user will not need to define it explicitly. We cannot use generics here
// as it is an entrypoint function.
#[public]
#[internal]
fn _store_payload_in_transient_storage_unsafe(
slot: Field,
point: Point,
setup_log: [Field; 9],
) {
context.storage_write(slot, point);
context.storage_write(slot + aztec::protocol_types::point::POINT_LENGTH as Field, setup_log);
}
// TODO(#7728): even though the max_fee should be a U128, we can't have that type in a contract interface due
// to serialization issues.
/// Executed as a public teardown function and is responsible for completing the refund in a private fee payment
/// flow.
#[public]
#[internal]
fn complete_refund(fee_recipient: AztecAddress, user_slot: Field, max_fee: Field) {
// TODO(#7728): Remove the next line
let max_fee = U128::from_integer(max_fee);
let tx_fee = U128::from_integer(context.transaction_fee());
// 1. We check that user funded the fee payer contract with at least the transaction fee.
// TODO(#7796): we should try to prevent reverts here
assert(max_fee >= tx_fee, "max fee not enough to cover tx fee");
// 2. We compute the refund amount as the difference between funded amount and the tx fee.
// TODO(#10805): Introduce a real exchange rate
let refund_amount = max_fee - tx_fee;
// 3. We send the tx fee to the fee recipient in public.
_increase_public_balance_inner(fee_recipient, tx_fee.to_field(), storage);
// 4. We construct the user note finalization payload with the refund amount.
let user_finalization_payload =
UintNote::finalization_payload().new(&mut context, user_slot, refund_amount);
// 5. At last we emit the user finalization note hash and the corresponding note log.
user_finalization_payload.emit();
// --> Once the tx is settled user and fee recipient can add the notes to their pixies.
}
/// Internal ///
/// TODO(#9180): Consider adding macro support for functions callable both as an entrypoint and as an internal
/// function.
#[public]
#[internal]
fn _increase_public_balance(to: AztecAddress, amount: Field) {
_increase_public_balance_inner(to, amount, storage);
}
#[contract_library_method]
fn _increase_public_balance_inner(
to: AztecAddress,
amount: Field,
storage: Storage<&mut PublicContext>,
) {
let new_balance = storage.public_balances.at(to).read().add(U128::from_integer(amount));
storage.public_balances.at(to).write(new_balance);
}
#[public]
#[internal]
fn _reduce_total_supply(amount: Field) {
// Only to be called from burn.
let new_supply = storage.total_supply.read().sub(U128::from_integer(amount));
storage.total_supply.write(new_supply);
}
/// Unconstrained ///
pub(crate) unconstrained fn balance_of_private(owner: AztecAddress) -> pub Field {
storage.balances.at(owner).balance_of().to_field()
}
}
Source code: noir-projects/noir-contracts/contracts/token_contract/src/main.nr#L1-L749
Helper files
info
Remove the mod test; line from contracts/token/src/main.nr as we will not be using TXE tests in this tutorial.
The Token contract also requires some helper files. You can view the files here (GitHub link). Copy the types.nr and the types folder into contracts/token/src.
Compile your contract
We'll now use aztec-nargo to compile.
Now run the following from your contract folder (containing Nargo.toml):
aztec-nargo compile
Deploy your contracts
Let's now write a script for deploying your contracts to the Sandbox. We'll create a Private eXecution Environment (PXE) client, and then use the ContractDeployer class to deploy our contracts, and store the deployment address to a local JSON file.
Create a new file src/deploy.mjs. We import the contract artifacts we have generated plus the dependencies we'll need, and then we can deploy the contracts by adding the following code to the src/deploy.mjs file.
// src/deploy.mjs
import { getInitialTestAccountsWallets } from '@aztec/accounts/testing';
import { Contract, createPXEClient, loadContractArtifact, waitForPXE } from '@aztec/aztec.js';
import TokenContractJson from "../contracts/token/target/token-Token.json" assert { type: "json" };
import { writeFileSync } from 'fs';
const TokenContractArtifact = loadContractArtifact(TokenContractJson);
const { PXE_URL = 'http://localhost:8080' } = process.env;
async function main() {
const pxe = createPXEClient(PXE_URL);
await waitForPXE(pxe);
const [ownerWallet] = await getInitialTestAccountsWallets(pxe);
const ownerAddress = ownerWallet.getAddress();
const token = await Contract.deploy(ownerWallet, TokenContractArtifact, [ownerAddress, 'TokenName', 'TKN', 18])
.send()
.deployed();
console.log(`Token deployed at ${token.address.toString()}`);
const addresses = { token: token.address.toString() };
writeFileSync('addresses.json', JSON.stringify(addresses, null, 2));
}
main().catch((err) => {
console.error(`Error in deployment script: ${err}`);
process.exit(1);
});
Here, we are using the Contract class with the compiled artifact to send a new deployment transaction. The deployed method will block execution until the transaction is successfully mined, and return a receipt with the deployed contract address.
Note that the token's constructor() method expects an owner address to set as the contract admin. We are using the first account from the Sandbox for this.
info
If you are using the generated typescript classes, you can drop the generic ContractDeployer in favor of using the deploy method of the generated class, which will automatically load the artifact for you and type-check the constructor arguments. See the How to deploy a contract page for more info.
Run the snippet above as node src/deploy.mjs, and you should see the following output, along with a new addresses.json file in your project root:
Token deployed to 0x2950b0f290422ff86b8ee8b91af4417e1464ddfd9dda26de8af52dac9ea4f869
Next steps
Now that we have our contracts set up, it's time to actually start writing our application that will be interacting with them.