rust

Rust + Solana (Anchor) Best Practices

Program Structure

• Structure Solana programs using Anchor framework standards
• Place program entrypoint logic in lib.rs, not main.rs
• Organize handlers into modules (e.g., initialize, update, close)
• Separate state definitions, errors, instructions, and utils
• Group reusable logic under a utils module (e.g., account validation)
• Use declare_id!() to define program ID

Anchor Framework

• Use #[derive(Accounts)] for all instruction contexts
• Validate accounts strictly using constraint macros (e.g., #[account(mut)], seeds, bump])
• Define all state structs with #[account] and #[derive(AnchorSerialize, AnchorDeserialize)]
• Prefer Init, Close, Realloc, Mut, and constraint macros to avoid manual deserialization
• Use ctx.accounts to access validated context accounts
• Handle CPI (Cross-Program Invocation) calls via Anchor’s CPI helpers

Serialization

• Use Borsh or Anchor's custom serializer (not Serde) for on-chain data
• Always include #[account(zero_copy)] or #[repr(C)] for packed structures
• Avoid floating point types — use u64, u128, or fixed-point math
• Zero out or close unused accounts to reduce rent costs

Testing

• Write tests in TypeScript using Anchor’s Mocha + Chai setup (tests/*.ts)
• Use anchor.workspace.MyProgram to load deployed contracts
• Use provider.simulate() to inspect failed txs
• Spin up a local validator (anchor test) and reset between tests
• Airdrop SOL to wallets with provider.connection.requestAirdrop(...)
• Validate program logs using tx.confirmation.logMessages

Solana SDK (Manual)

• Use solana_program crate when not using Anchor (bare-metal programs)
• Carefully deserialize accounts using AccountInfo, try_from_slice_unchecked
• Use solana_program::msg! for lightweight debugging logs
• Verify accounts via is_signer, is_writable, key == expected
• Never panic! Use ProgramError::Custom(u32) or ErrorCode enums

Security Patterns

• Always validate msg.sender/signer with account_info.is_signer
• Prevent replay attacks via seeds, bump, and unique PDAs
• Use strict size checks before reallocating or deserializing
• Avoid unsafe unchecked casting; prefer Anchor deserialization
• For CPIs, validate target_program against expected program ID
• When using randomness, never rely on timestamps — use oracles or off-chain VRFs

Performance

• Prefer zero-copy deserialization when accounts are large
• Minimize compute usage; avoid loops and recursion
• Avoid memory reallocations mid-instruction
• Use #[account(zero_copy)] and #[repr(packed)] for tight layout
• Profile compute units with solana logs and anchor run

Dev Workflow

• Use anchor init to scaffold projects
• Add Anchor IDL support for front-end usage (JSON ABI)
• Use anchor build, anchor deploy, anchor test consistently
• Use separate Anchor.toml environments for devnet/mainnet/localnet
• Format all Rust code with cargo fmt, lint with cargo clippy
• Keep Cargo.lock checked into programs/ but not root

Documentation

• Use /// Rust doc comments for all instructions and accounts
• Include doc examples for each instruction
• Document PDA derivation logic and bump seed expectations
• Maintain up-to-date README.md with test commands and deployment steps

Wallet & Network Handling

• Use anchorProvider.wallet.publicKey for signer verification in tests
• Do not hardcode keypairs — use env-based loading (process.env.ANCHOR_WALLET)
• Deploy with clear cluster targets (localnet, devnet, mainnet)
• Use anchor keys sync to propagate program ID changes
• Commit target/idl/ and target/types/ to share with front end

CI/CD & Deploy

• Use GitHub Actions with solana-cli, anchor-cli, and node installed
• Run anchor test in CI for every PR
• Use solana program deploy with explicit --program-id on production deploys
• Upload IDLs to a central registry (e.g., GitHub, IPFS, or anchor.cloud)