Deploying contracts

There are two main ways of working with contracts in the SDK: deploying a contract with SDK or using the SDK to interact with existing contracts.

Deploying a contract binary

Once you've written a contract in Sway and compiled it with forc build, you'll have in your hands two important artifacts: the compiled binary file and the JSON ABI file.

Note: Read here for more on how to work with Sway.

Below is how you can deploy your contracts using the SDK. For more details about each component in this process, read The abigen macro, The FuelVM binary file, and The JSON ABI file.

First, the Contract::load_from function is used to load a contract binary with a LoadConfiguration. If you are only interested in a single instance of your contract, use the default configuration: LoadConfiguration::default(). After the contract binary is loaded, you can use the deploy() method to deploy the contract to the blockchain.

        // This helper will launch a local node and provide a test wallet linked to it
        let wallet = launch_provider_and_get_wallet().await?;

        // This will load and deploy your contract binary to the chain so that its ID can
        // be used to initialize the instance
        let contract_id = Contract::load_from(
            "../../packages/fuels/tests/contracts/contract_test/out/debug/contract_test.bin",
            LoadConfiguration::default(),
        )?
        .deploy(&wallet, TxPolicies::default())
        .await?;

        println!("Contract deployed @ {contract_id}");

Alternatively, you can use LoadConfiguration to configure how the contract is loaded. LoadConfiguration let's you:

• Load the same contract binary with Salt to get a new contract_id
• Change the contract's storage slots
• Update the contract's configurables

  Note: The next section will give more information on how configurables can be used.

Additionally, you can set custom TxParameters when deploying the loaded contract.

        // Optional: Add `Salt`
        let rng = &mut StdRng::seed_from_u64(2322u64);
        let salt: [u8; 32] = rng.gen();

        // Optional: Configure storage
        let key = Bytes32::from([1u8; 32]);
        let value = Bytes32::from([2u8; 32]);
        let storage_slot = StorageSlot::new(key, value);
        let storage_configuration =
            StorageConfiguration::default().add_slot_overrides([storage_slot]);
        let configuration = LoadConfiguration::default()
            .with_storage_configuration(storage_configuration)
            .with_salt(salt);

        // Optional: Configure deployment parameters
        let tx_policies = TxPolicies::default()
            .with_gas_price(0)
            .with_script_gas_limit(1_000_000)
            .with_maturity(0);

        let contract_id_2 = Contract::load_from(
            "../../packages/fuels/tests/contracts/contract_test/out/debug/contract_test.bin",
            configuration,
        )?
        .deploy(&wallet, tx_policies)
        .await?;

        println!("Contract deployed @ {contract_id_2}");

After the contract is deployed, you can use the contract's methods like this:

        // This will generate your contract's methods onto `MyContract`.
        // This means an instance of `MyContract` will have access to all
        // your contract's methods that are running on-chain!
        abigen!(Contract(
            name = "MyContract",
            abi = "packages/fuels/tests/contracts/contract_test/out/debug/contract_test-abi.json"
        ));

        // This is an instance of your contract which you can use to make calls to your functions
        let contract_instance = MyContract::new(contract_id_2, wallet);

        let response = contract_instance
            .methods()
            .initialize_counter(42) // Build the ABI call
            .call() // Perform the network call
            .await?;

        assert_eq!(42, response.value);

        let response = contract_instance
            .methods()
            .increment_counter(10)
            .call()
            .await?;

        assert_eq!(52, response.value);