Developing Programs in Rust

Solana programs are primarily developed using the Rust programming language. This page focuses on writing Solana programs in Rust without using the Anchor framework, an approach often referred to as writing "native Rust" programs.

Native Rust development provides developers with direct control over their Solana programs. However, this approach requires more manual setup and boilerplate code compared to using the Anchor framework. This method is recommended for developers who:

Seek granular control over program logic and optimizations
Want to learn the underlying concepts before moving to higher-level frameworks

For beginners, we recommend starting with the Anchor framework. See the Anchor section for more information.

Prerequisites

For detailed installation instructions, visit the installation page.

Before you begin, ensure you have the following installed:

Rust: The programming language for building Solana programs.
Solana CLI: Command-line tool for Solana development.

Getting Started

The example below covers the basic steps to create your first Solana program written in Rust. We'll create a minimal program that prints "Hello, world!" to the program log.

Create a new Program

First, create a new Rust project using the standard cargo init command with the --lib flag.

Terminal

cargo init hello_world --lib

Navigate to the project directory. You should see the default src/lib.rs and Cargo.toml files

Terminal

cd hello_world

Next, add the solana-program dependency. This is the minimum dependency required to build a Solana program.

Terminal

cargo add solana-program@1.18.26

Next, add the following snippet to Cargo.toml. If you don't include this config, the target/deploy directory will not be generated when you build the program.

Cargo.toml

[lib]
crate-type = ["cdylib", "lib"]

Your Cargo.toml file should look like the following:

Cargo.toml

[package]
name = "hello_world"
version = "0.1.0"
edition = "2021"

[lib]
crate-type = ["cdylib", "lib"]

[dependencies]
solana-program = "1.18.26"

Next, replace the contents of src/lib.rs with the following code. This is a minimal Solana program that prints "Hello, world!" to the program log when the program is invoked.

The msg! macro is used in Solana programs to print a message to the program log.

lib.rs

use solana_program::{
    account_info::AccountInfo, entrypoint, entrypoint::ProgramResult, msg, pubkey::Pubkey,
};

entrypoint!(process_instruction);

pub fn process_instruction(
    _program_id: &Pubkey,
    _accounts: &[AccountInfo],
    _instruction_data: &[u8],
) -> ProgramResult {
    msg!("Hello, world!");
    Ok(())
}

Build the Program

Next, build the program using the cargo build-sbf command.

Terminal

cargo build-sbf

This command generates a target/deploy directory containing two important files:

A .so file (e.g., hello_world.so): This is the compiled Solana program that will be deployed to the network as a "smart contract".
A keypair file (e.g., hello_world-keypair.json): The public key of this keypair is used as the program ID when deploying the program.

To view the program ID, run the following command in your terminal. This command prints the public key of the keypair at the specified file path:

Terminal

solana address -k ./target/deploy/hello_world-keypair.json

Example output:

4Ujf5fXfLx2PAwRqcECCLtgDxHKPznoJpa43jUBxFfMz

Test the Program

Next, test the program using the solana-program-test crate. Add the following dependencies to Cargo.toml.

Terminal

cargo add solana-program-test@1.18.26 --dev
cargo add solana-sdk@1.18.26 --dev
cargo add tokio --dev

Add the following test to src/lib.rs, below the program code. This is a test module that invokes the hello world program.

lib.rs

#[cfg(test)]
mod test {
    use solana_program_test::*;
    use solana_sdk::{
        instruction::Instruction, pubkey::Pubkey, signature::Signer, transaction::Transaction,
    };

    #[tokio::test]
    async fn test_hello_world() {
        let program_id = Pubkey::new_unique();
        let mut program_test = ProgramTest::default();
        program_test.add_program("hello_world", program_id, None);
        let (mut banks_client, payer, recent_blockhash) = program_test.start().await;
        // Create instruction
        let instruction = Instruction {
            program_id,
            accounts: vec![],
            data: vec![],
        };
        // Create transaction with instruction
        let mut transaction = Transaction::new_with_payer(&[instruction], Some(&payer.pubkey()));

        // Sign transaction
        transaction.sign(&[&payer], recent_blockhash);

        let transaction_result = banks_client.process_transaction(transaction).await;
        assert!(transaction_result.is_ok());
    }
}

Run the test using the cargo test-sbf command. The program log will display "Hello, world!".

Terminal

cargo test-sbf

Example output:

Terminal

running 1 test
[2024-10-18T21:24:54.889570000Z INFO  solana_program_test] "hello_world" SBF program from /hello_world/target/deploy/hello_world.so, modified 35 seconds, 828 ms, 268 µs and 398 ns ago
[2024-10-18T21:24:54.974294000Z DEBUG solana_runtime::message_processor::stable_log] Program 1111111QLbz7JHiBTspS962RLKV8GndWFwiEaqKM invoke [1]
[2024-10-18T21:24:54.974814000Z DEBUG solana_runtime::message_processor::stable_log] Program log: Hello, world!
[2024-10-18T21:24:54.976848000Z DEBUG solana_runtime::message_processor::stable_log] Program 1111111QLbz7JHiBTspS962RLKV8GndWFwiEaqKM consumed 140 of 200000 compute units
[2024-10-18T21:24:54.976868000Z DEBUG solana_runtime::message_processor::stable_log] Program 1111111QLbz7JHiBTspS962RLKV8GndWFwiEaqKM success
test test::test_hello_world ... ok

test result: ok. 1 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.13s

Deploy the Program

Next, deploy the program. When developing locally, we can use the solana-test-validator.

First, configure the Solana CLI to use the local Solana cluster.

Terminal

solana config set -ul

Example output:

Config File: /.config/solana/cli/config.yml
RPC URL: http://localhost:8899
WebSocket URL: ws://localhost:8900/ (computed)
Keypair Path: /.config/solana/id.json
Commitment: confirmed

Open a new terminal and run the solana-test-validators command to start the local validator.

Terminal

solana-test-validator

While the test validator is running, run the solana program deploy command in a separate terminal to deploy the program to the local validator.

Terminal

solana program deploy ./target/deploy/hello_world.so

Example output:

Program Id: 4Ujf5fXfLx2PAwRqcECCLtgDxHKPznoJpa43jUBxFfMz
Signature:
5osMiNMiDZGM7L1e2tPHxU8wdB8gwG8fDnXLg5G7SbhwFz4dHshYgAijk4wSQL5cXiu8z1MMou5kLadAQuHp7ybH

You can inspect the program ID and transaction signature on Solana Explorer. Note that the cluster on Solana Explorer must also be localhost. The "Custom RPC URL" option on Solana Explorer defaults to http://localhost:8899.

Invoke the Program

Next, we'll demonstrate how to invoke the program using a Rust client.

First create an examples directory and a client.rs file.

Terminal

mkdir -p examples
touch examples/client.rs

Add the following to Cargo.toml.

Cargo.toml

[[example]]
name = "client"
path = "examples/client.rs"

Add the solana-client dependency.

Terminal

cargo add solana-client@1.18.26 --dev

Add the following code to examples/client.rs. This is a Rust client script that funds a new keypair to pay for transaction fees and then invokes the hello world program.

example/client.rs

use solana_client::rpc_client::RpcClient;
use solana_sdk::{
    commitment_config::CommitmentConfig,
    instruction::Instruction,
    pubkey::Pubkey,
    signature::{Keypair, Signer},
    transaction::Transaction,
};
use std::str::FromStr;

#[tokio::main]
async fn main() {
    // Program ID (replace with your actual program ID)
    let program_id = Pubkey::from_str("4Ujf5fXfLx2PAwRqcECCLtgDxHKPznoJpa43jUBxFfMz").unwrap();

    // Connect to the Solana devnet
    let rpc_url = String::from("http://127.0.0.1:8899");
    let client = RpcClient::new_with_commitment(rpc_url, CommitmentConfig::confirmed());

    // Generate a new keypair for the payer
    let payer = Keypair::new();

    // Request airdrop
    let airdrop_amount = 1_000_000_000; // 1 SOL
    let signature = client
        .request_airdrop(&payer.pubkey(), airdrop_amount)
        .expect("Failed to request airdrop");

    // Wait for airdrop confirmation
    loop {
        let confirmed = client.confirm_transaction(&signature).unwrap();
        if confirmed {
            break;
        }
    }

    // Create the instruction
    let instruction = Instruction::new_with_borsh(
        program_id,
        &(),    // Empty instruction data
        vec![], // No accounts needed
    );

    // Add the instruction to new transaction
    let mut transaction = Transaction::new_with_payer(&[instruction], Some(&payer.pubkey()));
    transaction.sign(&[&payer], client.get_latest_blockhash().unwrap());

    // Send and confirm the transaction
    match client.send_and_confirm_transaction(&transaction) {
        Ok(signature) => println!("Transaction Signature: {}", signature),
        Err(err) => eprintln!("Error sending transaction: {}", err),
    }
}

Before running the script, replace the program ID in the code snippet above with the one for your program.

You can get your program ID by running the following command.

Terminal

solana address -k ./target/deploy/hello_world-keypair.json

#[tokio::main]
async fn main() {
-     let program_id = Pubkey::from_str("4Ujf5fXfLx2PAwRqcECCLtgDxHKPznoJpa43jUBxFfMz").unwrap();
+     let program_id = Pubkey::from_str("YOUR_PROGRAM_ID).unwrap();
    }
}

Run the client script with the following command.

Terminal

cargo run --example client

Example output:

Transaction Signature: 54TWxKi3Jsi3UTeZbhLGUFX6JQH7TspRJjRRFZ8NFnwG5BXM9udxiX77bAACjKAS9fGnVeEazrXL4SfKrW7xZFYV

You can inspect the transaction signature on Solana Explorer (local cluster) to see "Hello, world!" in the program log.

Update the Program

Solana programs can be updated by redeploying to the same program ID. Update the program in src/lib.rs to print "Hello, Solana!" instead of "Hello, world!".

lib.rs

pub fn process_instruction(
    _program_id: &Pubkey,
    _accounts: &[AccountInfo],
    _instruction_data: &[u8],
) -> ProgramResult {
-   msg!("Hello, world!");
+   msg!("Hello, Solana!");
    Ok(())
}

Test the updated program by running the cargo test-sbf command.

Terminal

cargo test-sbf

You should see "Hello, Solana!" in the program log.

Terminal

running 1 test
[2024-10-23T19:28:28.842639000Z INFO  solana_program_test] "hello_world" SBF program from /code/misc/delete/hello_world/target/deploy/hello_world.so, modified 4 minutes, 31 seconds, 435 ms, 566 µs and 766 ns ago
[2024-10-23T19:28:28.934854000Z DEBUG solana_runtime::message_processor::stable_log] Program 1111111QLbz7JHiBTspS962RLKV8GndWFwiEaqKM invoke [1]
[2024-10-23T19:28:28.936735000Z DEBUG solana_runtime::message_processor::stable_log] Program log: Hello, Solana!
[2024-10-23T19:28:28.938774000Z DEBUG solana_runtime::message_processor::stable_log] Program 1111111QLbz7JHiBTspS962RLKV8GndWFwiEaqKM consumed 140 of 200000 compute units
[2024-10-23T19:28:28.938793000Z DEBUG solana_runtime::message_processor::stable_log] Program 1111111QLbz7JHiBTspS962RLKV8GndWFwiEaqKM success
test test::test_hello_world ... ok

test result: ok. 1 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.14s

Run the cargo build-sbf command to generate an updated .so file.

Terminal

cargo build-sbf

Redeploy the program using the solana program deploy command.

Terminal

solana program deploy ./target/deploy/hello_world.so

Run the client code again and inspect the transaction signature on Solana Explorer to see "Hello, Solana!" in the program log.

Terminal

cargo run --example client

Close the Program

You can close your Solana program to reclaim the SOL allocated to the account. Closing a program is irreversible, so it should be done with caution.

To close a program, use the solana program close <PROGRAM_ID> command. For example:

Terminal

solana program close 4Ujf5fXfLx2PAwRqcECCLtgDxHKPznoJpa43jUBxFfMz
--bypass-warning

Example output:

Closed Program Id 4Ujf5fXfLx2PAwRqcECCLtgDxHKPznoJpa43jUBxFfMz, 0.1350588 SOL
reclaimed

Note that once a program is closed, its program ID cannot be reused. Attempting to deploy a program with a previously closed program ID will result in an error.

Error: Program 4Ujf5fXfLx2PAwRqcECCLtgDxHKPznoJpa43jUBxFfMz has been closed, use
a new Program Id

If you need to redeploy a program with the same source code after closing a program, you must generate a new program ID. To generate a new keypair for the program, run the following command:

Terminal

solana-keygen new -o ./target/deploy/hello_world-keypair.json --force

Alternatively, you can delete the existing keypair file (e.g. ./target/deploy/hello_world-keypair.json) and run cargo build-sbf again, which will generate a new keypair file.

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