l2-deployment

# L2 Deployment Patterns ## L2 Gas Economics L2 transaction cost = L2 execution gas + L1 data posting cost | Operation | L1 (Ethereum) | L2 (Base/OP/Arb) | Savings | |-----------|:------------:|:----------------:|:-------:| | ETH transfer | ~$0.50 | ~$0.0003 | 99.9% | | ERC-20 transfer | ~$2.00 | ~$0.001 | 99.9% | | Uniswap swap | ~$8.00 | ~$0.002-0.003 | 99.9% | | NFT mint | ~$5.00 | ~$0.002 | 99.9% | | Contract deploy | ~$50-500 | ~$0.05-0.50 | 99% | Post-EIP-4844 (blobs), L1 data costs dropped 10-100x for L2s. ## L2-Specific Considerations ### PUSH0 Opcode Compatibility PUSH0 was introduced in the Shanghai upgrade (EVM version). Some L2s may lag behind on EVM version support: ```toml # foundry.toml — set EVM version explicitly for L2 [profile.default] evm_version = "cancun" # Base, Optimism, Arbitrum all support cancun # If targeting an L2 that doesn't support cancun: # evm_version = "paris" # No PUSH0 ``` ### Block Time Differences | Chain | Block Time | Implication | |-------|-----------|-------------| | Ethereum | ~12s | Standard | | Base | 2s | Faster confirmations | | Optimism | 2s | Faster confirmations | | Arbitrum | ~0.25s | Near-instant | Avoid hardcoding time assumptions based on block numbers. ### L2-Specific Addresses ```solidity // Optimism / Base predeploys (same addresses on all OP Stack chains) address constant L2_CROSS_DOMAIN_MESSENGER = 0x4200000000000000000000000000000000000007; address constant L2_STANDARD_BRIDGE = 0x4200000000000000000000000000000000000010; address constant L2_TO_L1_MESSAGE_PASSER = 0x4200000000000000000000000000000000000016; address constant WETH = 0x4200000000000000000000000000000000000006; address constant L1_BLOCK = 0x4200000000000000000000000000000000000015; address constant GAS_PRICE_ORACLE = 0x420000000000000000000000000000000000000F; // Arbitrum system addresses address constant ARB_SYS = 0x0000000000000000000000000000000000000064; address constant ARB_RETRYABLE_TX = 0x000000000000000000000000000000000000006E; ``` ## Foundry Multi-L2 Deployment Script ```solidity // SPDX-License-Identifier: MIT pragma solidity ^0.8.20; import {Script, console2} from "forge-std/Script.sol"; import {MyProtocol} from "../src/MyProtocol.sol"; contract DeployL2 is Script { struct L2Config { string rpcAlias; uint256 chainId; address weth; address usdc; } function getConfigs() internal pure returns (L2Config[] memory) { L2Config[] memory configs = new L2Config[](3); configs[0] = L2Config({ rpcAlias: "base", chainId: 8453, weth: 0x4200000000000000000000000000000000000006, usdc: 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 }); configs[1] = L2Config({ rpcAlias: "optimism", chainId: 10, weth: 0x4200000000000000000000000000000000000006, usdc: 0x0b2C639c533813f4Aa9D7837CAf62653d097Ff85 }); configs[2] = L2Config({ rpcAlias: "arbitrum", chainId: 42161, weth: 0x82aF49447D8a07e3bd95BD0d56f35241523fBab1, usdc: 0xaf88d065e77c8cC2239327C5EDb3A432268e5831 }); return configs; } function run() external { uint256 deployerKey = vm.envUint("DEPLOYER_PRIVATE_KEY"); L2Config[] memory configs = getConfigs(); for (uint256 i = 0; i < configs.length; i++) { L2Config memory cfg = configs[i]; console2.log("Deploying to chain:", cfg.chainId); vm.createSelectFork(cfg.rpcAlias); vm.startBroadcast(deployerKey); MyProtocol protocol = new MyProtocol(cfg.weth, cfg.usdc); console2.log(" Deployed at:", address(protocol)); vm.stopBroadcast(); } } } ``` ```bash # Deploy to all L2s forge script script/DeployL2.s.sol --broadcast --multi --verify ``` ## L1 Data Cost Estimation On OP Stack chains (Base, Optimism), query the gas price oracle: ```solidity interface IGasPriceOracle { function getL1Fee(bytes memory data) external view returns (uint256); function getL1GasUsed(bytes memory data) external view returns (uint256); } IGasPriceOracle oracle = IGasPriceOracle(0x420000000000000000000000000000000000000F); uint256 l1Fee = oracle.getL1Fee(txData); ``` On Arbitrum, L1 data costs are embedded in the gas price. ## Bridge Integration ### OP Stack Bridge (Base / Optimism) ```solidity interface IL2StandardBridge { function bridgeETHTo(address to, uint32 minGasLimit, bytes calldata extraData) external payable; function bridgeERC20To( address localToken, address remoteToken, address to, uint256 amount, uint32 minGasLimit, bytes calldata extraData ) external; } // Bridge ETH from L2 to L1 IL2StandardBridge(0x4200000000000000000000000000000000000010).bridgeETHTo{value: amount}( recipient, 200_000, "" ); ``` ### Arbitrum Bridge ```solidity interface IArbSys { function withdrawEth(address destination) external payable returns (uint256); function sendTxToL1(address destination, bytes calldata data) external payable returns (uint256); } // Withdraw ETH from Arbitrum to L1 IArbSys(0x0000000000000000000000000000000000000064).withdrawEth{value: amount}(recipient); ``` ## Testing on Forked L2s ```solidity function setUp() public { vm.createSelectFork("base", 20_000_000); } function test_swapOnBase() public { address whale = 0x...; // Known USDC holder on Base vm.startPrank(whale); // Interact with real Base contracts vm.stopPrank(); } ``` ## L2 Deployment Checklist - [ ] Set correct `evm_version` in `foundry.toml` for target L2 - [ ] Use L2-specific WETH and token addresses (not mainnet addresses) - [ ] Account for different block times in time-based logic - [ ] Test on forked L2 before deploying - [ ] Estimate L1 data costs for gas-sensitive operations - [ ] Verify contracts on the correct L2 block explorer - [ ] Configure bridge integration if cross-chain messaging needed - [ ] Test with L2-specific gas prices (much lower than L1) - [ ] Check L2 predeploy addresses for system contracts - [ ] Deploy to testnet first (Base Sepolia, OP Sepolia, Arbitrum Sepolia)