Integrate Chainlink Data Streams SDK with Foundry by creating a FFI test
Start by creating a new Foundry project by running the forge init command.
Then install the @chainlink/contracts package by running the following command:
forge install smartcontractkit/chainlink-brownie-contractsand setting the remappings to @chainlink/contracts/=lib/chainlink-brownie-contracts/contracts/src/.
Your foundry.toml file should look like this:
# foundry.toml
[profile.default]
src = "src"
out = "out"
libs = ["lib"]
remappings = [
'@chainlink/contracts/=lib/chainlink-brownie-contracts/contracts/',
]
# See more config options https://github.com/foundry-rs/foundry/blob/master/crates/config/README.md#all-optionsCreate a .env file in the root of the project with the following content:
ARBITRUM_SEPOLIA_RPC_URL = https://arb-sepolia.g.alchemy.com/v2/<YOUR_ALCHEMY_KEY>
API_KEY = <YOUR_DATA_STREAMS_API_KEY>
USER_SECRET = <YOUR_DATA_STREAMS_USER_SECRET>
Create a new contract in the src directory called Example.sol with the content below. This is a simple contract that accepts a signed report from a Data Streams DON, verifies it using the Verifier contract, pays for verification in LINK and returns the verified price of the ETH/USD feed on Arbitrum Sepolia.
// SPDX-License-Identifier: MIT
pragma solidity 0.8.19;
import {Common} from "@chainlink/contracts/src/v0.8/llo-feeds/libraries/Common.sol";
import {IVerifierFeeManager} from "@chainlink/contracts/src/v0.8/llo-feeds/interfaces/IVerifierFeeManager.sol";
import {IRewardManager} from "@chainlink/contracts/src/v0.8/llo-feeds/interfaces/IRewardManager.sol";
import {OwnerIsCreator} from "@chainlink/contracts/src/v0.8/shared/access/OwnerIsCreator.sol";
import {IERC20} from "@chainlink/contracts/src/v0.8/vendor/openzeppelin-solidity/v4.8.3/contracts/interfaces/IERC20.sol";
/**
* THIS IS AN EXAMPLE CONTRACT THAT USES UN-AUDITED CODE FOR DEMONSTRATION PURPOSES.
* DO NOT USE THIS CODE IN PRODUCTION.
*/
// Custom interfaces for IVerifierProxy and IFeeManager
interface IVerifierProxy {
/**
* @notice Verifies that the data encoded has been signed.
* correctly by routing to the correct verifier, and bills the user if applicable.
* @param payload The encoded data to be verified, including the signed
* report.
* @param parameterPayload Fee metadata for billing. For the current implementation this is just the abi-encoded fee token ERC-20 address.
* @return verifierResponse The encoded report from the verifier.
*/
function verify(bytes calldata payload, bytes calldata parameterPayload)
external
payable
returns (bytes memory verifierResponse);
function s_feeManager() external view returns (IVerifierFeeManager);
}
interface IFeeManager {
/**
* @notice Calculates the fee and reward associated with verifying a report, including discounts for subscribers.
* This function assesses the fee and reward for report verification, applying a discount for recognized subscriber addresses.
* @param subscriber The address attempting to verify the report. A discount is applied if this address
* is recognized as a subscriber.
* @param unverifiedReport The report data awaiting verification. The content of this report is used to
* determine the base fee and reward, before considering subscriber discounts.
* @param quoteAddress The payment token address used for quoting fees and rewards.
* @return fee The fee assessed for verifying the report, with subscriber discounts applied where applicable.
* @return reward The reward allocated to the caller for successfully verifying the report.
* @return totalDiscount The total discount amount deducted from the fee for subscribers
*/
function getFeeAndReward(address subscriber, bytes memory unverifiedReport, address quoteAddress)
external
returns (Common.Asset memory, Common.Asset memory, uint256);
function i_linkAddress() external view returns (address);
function i_rewardManager() external view returns (address);
}
contract Example is OwnerIsCreator {
/**
* @dev Represents a data report from a Data Streams feed for v3 schema (crypto feeds).
* The `price`, `bid`, and `ask` values are carried to either 8 or 18 decimal places, depending on the feed.
* For more information, see https://docs.chain.link/data-streams/crypto-feeds and https://docs.chain.link/data-streams/reference/report-schema
*/
struct ReportV3 {
bytes32 feedId; // The feed ID the report has data for.
uint32 validFromTimestamp; // Earliest timestamp for which price is applicable.
uint32 observationsTimestamp; // Latest timestamp for which price is applicable.
uint192 nativeFee; // Base cost to validate a transaction using the report, denominated in the chain’s native token (e.g., WETH/ETH).
uint192 linkFee; // Base cost to validate a transaction using the report, denominated in LINK.
uint32 expiresAt; // Latest timestamp where the report can be verified onchain.
int192 price; // DON consensus median price (8 or 18 decimals).
int192 bid; // Simulated price impact of a buy order up to the X% depth of liquidity utilisation (8 or 18 decimals).
int192 ask; // Simulated price impact of a sell order up to the X% depth of liquidity utilisation (8 or 18 decimals).
}
IVerifierProxy public s_verifier;
constructor(address verifier) {
s_verifier = IVerifierProxy(verifier);
}
function verifyReportAndReturnEthUsdFeedPrice(bytes calldata fullReport) external onlyOwner returns (int192) {
( /* bytes32[3] reportContextData */ , bytes memory reportData) = abi.decode(fullReport, (bytes32[3], bytes));
// Handle billing
IFeeManager feeManager = IFeeManager(address(s_verifier.s_feeManager()));
IRewardManager rewardManager = IRewardManager(address(feeManager.i_rewardManager()));
address feeTokenAddress = feeManager.i_linkAddress();
(Common.Asset memory fee,,) = feeManager.getFeeAndReward(address(this), reportData, feeTokenAddress);
// Approve rewardManager to spend this contract's balance in fees
IERC20(feeTokenAddress).approve(address(rewardManager), fee.amount);
// Verify the report
bytes memory verifiedReportData = s_verifier.verify(fullReport, abi.encode(feeTokenAddress));
ReportV3 memory verifiedReportV3 = abi.decode(verifiedReportData, (ReportV3));
return verifiedReportV3.price;
}
function withdrawToken(address beneficiary, address token) public onlyOwner {
uint256 amount = IERC20(token).balanceOf(address(this));
IERC20(token).transfer(beneficiary, amount);
}
}In the root of the Foundry project create the new get_latest_eth_usd_report.rs file with the following content:
use chainlink_data_streams_report::feed_id::ID;
use chainlink_data_streams_sdk::client::Client;
use chainlink_data_streams_sdk::config::Config;
use dotenv::dotenv;
use std::env;
use std::error::Error;
#[tokio::main]
async fn get_latest_eth_usd_report() -> Result<(), Box<dyn Error>> {
dotenv().ok();
let api_key = env::var("API_KEY").expect("API_KEY must be set in .env");
let user_secret = env::var("USER_SECRET").expect("USER_SECRET must be set in .env");
let rest_url = "https://api.testnet-dataengine.chain.link";
let ws_url = "wss://api.testnet-dataengine.chain.link/ws";
let eth_usd_feed_id =
ID::from_hex_str("0x000359843a543ee2fe414dc14c7e7920ef10f4372990b79d6361cdc0dd1ba782")
.unwrap();
// Initialize the configuration
let config = Config::new(
api_key.to_string(),
user_secret.to_string(),
rest_url.to_string(),
ws_url.to_string(),
)
.build()?;
// Initialize the client
let client = Client::new(config)?;
// Make a GET request to "/api/v1/reports/latest?feedID={feed_id}"
match client.get_latest_report(eth_usd_feed_id).await {
Ok(response) => {
let full_report_payload = &response.report.full_report;
println!("{:?}", &full_report_payload);
}
Err(e) => {
eprintln!("Error fetching latest report: {}", e);
}
}
Ok(())
}
fn main() {
let _ = get_latest_eth_usd_report();
}Then create the Cargo.toml file with the following content. Make sure to replace the path to the data-streams-sdk library with the correct path on your local machine (where you git cloned the repository). After publishing the library to crates.io, you can replace the path with the published version.
[package]
name = "get_latest_eth_usd_report"
version = "0.0.1"
edition = "2021"
[dependencies]
chainlink-data-streams-report = "1.2.1"
chainlink-data-streams-sdk = { version = "1.2.1", features = ["rest"] }
dotenv = "0.15"
tokio = { version = "1", features = ["full"] }
[[bin]]
name = "get_latest_eth_usd_report"
path = "get_latest_eth_usd_report.rs"Finally, make sure running the script does not return any errors:
cargo runIn the test directory of the Foundry project, create a new file called Example.t.sol with the following content:
// SPDX-License-Identifier: UNLICENSED
pragma solidity ^0.8.0;
import {Test, console} from "forge-std/Test.sol";
import {Example, IERC20} from "../src/Example.sol";
contract ExampleTest is Test {
address constant LINK_FAUCET = 0x4281eCF07378Ee595C564a59048801330f3084eE;
Example public example;
function setUp() public {
string memory ARBITRUM_SEPOLIA_RPC_URL = vm.envString("ARBITRUM_SEPOLIA_RPC_URL");
vm.createSelectFork(ARBITRUM_SEPOLIA_RPC_URL);
address verifierProxyArbitrumSepolia = 0x2ff010DEbC1297f19579B4246cad07bd24F2488A;
example = new Example(verifierProxyArbitrumSepolia);
}
function requestLinkFromFaucet(address to) public returns (bool success) {
address linkTokenArbitrumSepolia = 0xb1D4538B4571d411F07960EF2838Ce337FE1E80E;
vm.startPrank(LINK_FAUCET);
success = IERC20(linkTokenArbitrumSepolia).transfer(to, 20 ether);
vm.stopPrank();
}
function getLatestReportFromDataStreamsDon() public returns (string memory) {
string[] memory cmds = new string[](3);
cmds[0] = "cargo";
cmds[1] = "run";
cmds[2] = "get_latest_eth_usd_report";
bytes memory output = vm.ffi(cmds);
// remove string quotes
bytes memory result = new bytes(output.length - 2);
for (uint256 i = 1; i < output.length - 1; i++) {
result[i - 1] = output[i];
}
return string(result);
}
function test_happy_path() public {
assertEq(block.chainid, 421614); // Arbitrum Sepolia Chain ID
bool success = requestLinkFromFaucet(address(example));
require(success, "Failed to request LINK from faucet");
string memory result = getLatestReportFromDataStreamsDon();
bytes memory payload = vm.parseBytes(result);
// bytes memory payload =
// hex"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";
int192 price = example.verifyReportAndReturnEthUsdFeedPrice(payload);
console.log("price", price);
assertGt(price, 0);
}
}Finally, run the test by executing the following command:
forge test --ffi -vvv