Chainlink DataStreamsFeed.sol Reference Repo

A minimal example of deploying and operating a Chainlink Data Streams consumer contract.
This repository contains an opinionated wrapper around the community-maintained DataStreamsFeed.sol implementation from Adrastia.

The goal is to give you a quick, copy-pasteable starting point for:

• deploying your own on-chain DataStreamsFeed instance,
• funding the feed contract with LINK, and
• pushing fresh price data on-chain via an off-chain pushengine.

DYOR! This project is a community endeavour – audit the code and contracts before moving real value.

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1 · Prepare the environment

What	Why	Where to get it
Verifier Proxy address	Every chain has a dedicated contract that validates Data Streams reports.	See the Verifier Addresses table in the Chainlink Docs
LINK & native tokens	You'll pay the verification fee in LINK and gas in the native token.	Faucets · LINK contracts
RPC URL	Foundry & cast need it to send txs.	Chainlist
Private key	Account that will own the feed and pay fees.	Export from your wallet → store in .env as PRIVATE_KEY=<hex>

Docker-compose spins up a Redis instance, so make sure Docker Desktop (or Docker Engine) and the Redis CLI are installed on your machine.

Create a .env file in the repo root, then load it into the current shell:

cat >.env <<EOF
PRIVATE_KEY=<0xYOUR_PRIVATE_KEY>
RPC_URL_AVAX_FUJI=<https://...>
RPC_URL_ARBITRUM_SEPOLIA=<https://...>
RPC_URL_ETHEREUM_MAINNET=<https://...>
EOF

source .env

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2 · Install & configure

# dependencies
pnpm add --save-dev @openzeppelin/contracts @chainlink/contracts

# install Foundry if you haven't yet
curl -L https://foundry.paradigm.xyz | bash && foundryup

foundry.toml already contains the required remappings:

remappings = [
  "@openzeppelin/contracts/=node_modules/@openzeppelin/contracts/",
  "@chainlink/contracts/=node_modules/@chainlink/contracts/",
  "forge-std/=lib/forge-std/src/"
]

RPC endpoints are also pre-configured (see [rpc_endpoints]). Edit them if you prefer different providers.

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3 · Customise your feed contract

DataStreamsFeed constructor

constructor(
    address verifierProxy_,
    bytes32 _feedId,
    uint8   _decimals,
    uint32  _maxReportExpirationSeconds,
    string  memory _description
)

Fill in:

1. verifierProxy_ – the address from step 1.
2. _feedId – 32-byte identifier of the stream you want to mirror (e.g. ETH/USD).
   Example: 0x000359843a543ee2fe414dc14c7e7920ef10f4372990b79d6361cdc0dd1ba782.
3. _decimals – usually 18.
4. _maxReportExpirationSeconds – the maximum allowed window between a report's observation time and its expiresAt.
   • If a report's expiresAt is greater than observationsTimestamp + _maxReportExpirationSeconds, the update will revert.
   • Example deploy scripts default to 30 days, but you should set this to what makes sense for your deployment.
5. _description – human-readable label, e.g. "ETH / USD Feed".

Edit the deploy scripts with your values, or pass them as CLI arguments (see below).

Where to set the expiration window in scripts:

• script/DeployDataStreamsFeed.s.sol: uint32 maxExpiration = 30 days; is passed to the constructor.
• script/DeployDataStreamsFeedWithRoleAssign.s.sol: uint32 maxExpiration = 30 days; is passed to the constructor.

---

4 · Deploy & fund

Deploy the contract

forge script script/DeployDataStreamsFeed.s.sol:DeployDataStreamsFeed \
  --rpc-url $RPC_URL_AVAX_FUJI \
  --private-key $PRIVATE_KEY \
  --broadcast

Fund the contract with LINK

After deployment transfer some testnet LINK to the feed contract address so it can pay verification fees:

# Example using cast to transfer 5 LINK (18 decimals)
cast send $LINK_TOKEN "transfer(address,uint256)" \
     <DEPLOYED_FEED_ADDRESS> 5000000000000000000 \
     --rpc-url $RPC_URL_AVAX_FUJI \
     --private-key $PRIVATE_KEY

(Optional) Verify the contract on RouteScan/Etherscan

forge verify-contract \
  --chain-id 43113 \
  --verifier etherscan \
  --verifier-url "https://api.routescan.io/v2/network/testnet/evm/43113/etherscan/api" \
  <DEPLOYED_FEED_ADDRESS> \
  src/feed/DataStreamsFeed.sol:DataStreamsFeed \
  --flatten \
  --etherscan-api-key <YOUR_API_KEY>

---

5 · Run the pushengine

Follow these steps to bring an off-chain 📡 pushengine online.

# 1 · clone & enter
git clone -b https://github.com/hack-bg/push-engine.git push-engine
cd push-engine

# 2 · env vars
cp .env.example .env            # create your own copy
# open .env and fill in PRIVATE_KEY, RPC urls, etc.

# 3 · required – create the runtime config
cp config-chainlink-verify-example.yml config.yml      # customise as needed

# 4 · deps & run
pnpm install                      # or pnpm install
docker compose up -d            # starts redis + node + ui

# 5 · UI
open http://localhost:3000       # dashboard

The pushengine continuously listens for deviation on the ETH/USD feed and, on trigger, calls:

verifyAndUpdateReport(bytes rawReport, bytes parameterPayload)

on every target contract defined in config.yml.

Minimal working config.yml

# --- Feeds (off-chain subscriptions) ----------------------------
feeds:
  - name: "ETH/USD"
    feedId: "0x000359843a543ee2fe414dc14c7e7920ef10f4372990b79d6361cdc0dd1ba782"

# --- Defaults ---------------------------------------------------
chainId: 1301          # default target chain – Unichain Sepolia in this file
gasCap: "150000"
interval: "*/30 * * * * *"  # every 30 s
priceDeltaPercentage: 0.01   # 0.01 %

# --- RPC & Currency metadata -----------------------------------
chains:
  # Avalanche Fuji
  - id: 43113
    name: "Avalanche Fuji Network"
    currencyName: "Fuji AVAX"
    currencySymbol: "AVAX"
    currencyDecimals: 18
    rpc: "https://api.avax-test.network/ext/bc/C/rpc"
    testnet: true

  # Arbitrum Sepolia
  - id: 421614
    name: "Arbitrum Sepolia"
    currencyName: "Arbitrum Sepolia Ether"
    currencySymbol: "ETH"
    currencyDecimals: 18
    rpc: "https://sepolia-rollup.arbitrum.io/rpc"
    testnet: true

  # Unichain Sepolia
  - id: 1301
    name: "Unichain Sepolia"
    currencyName: "Unichain"
    currencySymbol: "UNI"
    currencyDecimals: 18
    rpc: "https://unichain-sepolia.drpc.org"
    testnet: true

# --- Data-Streams Verifier addresses ----------------------------
verifierAddresses:
  - chainId: 43113  # Fuji
    address: "0x2bf612C65f5a4d388E687948bb2CF842FFb8aBB3"
  - chainId: 421614 # Arbitrum Sepolia
    address: "0x2ff010DEbC1297f19579B4246cad07bd24F2488A"
  - chainId: 1301   # Unichain Sepolia
    address: "0x60fAa7faC949aF392DFc858F5d97E3EEfa07E9EB"

# --- Target contracts (on-chain writes) -------------------------
targetChains:
  - chainId: 43113     # Fuji
    targetContracts:
      - feedId: "0x000359843a543ee2fe414dc14c7e7920ef10f4372990b79d6361cdc0dd1ba782"
        address: "0xb3DCAB3217cC2f8f19A9CAa555f5f7C8BB5cB749"
        functionName: verifyAndUpdateReport
        functionArgs: [rawReport, parameterPayload]
        skipVerify: false
        abi:
          - inputs: [{internalType: bytes,name: unverifiedReportData,type: bytes},{internalType: bytes,name: parameterPayload,type: bytes}]
            name: verifyAndUpdateReport
            outputs: []
            stateMutability: nonpayable
            type: function

  - chainId: 421614    # Arbitrum Sepolia
    targetContracts:
      - feedId: "0x000359843a543ee2fe414dc14c7e7920ef10f4372990b79d6361cdc0dd1ba782"
        address: "0x180473Ff989D30F0eDB4a159174C1964A504854D"
        functionName: verifyAndUpdateReport
        functionArgs: [rawReport, parameterPayload]
        skipVerify: false
        abi: *id001

  - chainId: 1301       # Unichain Sepolia
    targetContracts:
      - feedId: "0x000359843a543ee2fe414dc14c7e7920ef10f4372990b79d6361cdc0dd1ba782"
        address: "0x74CD225023c01D6B6244913F6Ce2B899482944f3"
        functionName: verifyAndUpdateReport
        functionArgs: [rawReport, parameterPayload]
        skipVerify: false
        abi: *id001

The YAML uses an anchor *id001 so the ABI block isn't repeated three times.

Need help?

• Full pushengine docs → README
• Example configs → config-chainlink-example.yml in that repo.

Once the service is running you can watch log output in logs/ or the browser dashboard.

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Reference deployments

Network	Address	Explorer
Avalanche Fuji	0xb3DCAB3217cC2f8f19A9CAa555f5f7C8BB5cB749	https://testnet.snowtrace.io/address/0xb3DCAB3217cC2f8f19A9CAa555f5f7C8BB5cB749
Arbitrum Sepolia	0x180473Ff989D30F0eDB4a159174C1964A504854D	https://testnet.routescan.io/address/0x180473Ff989D30F0eDB4a159174C1964A504854D/contract/421614/code
Unichain Sepolia	0x74CD225023c01D6B6244913F6Ce2B899482944f3	https://testnet.routescan.io/address/0x74CD225023c01D6B6244913F6Ce2B899482944f3/contract/1301/code

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Troubleshooting

• Gas estimation too high → adjust gasCap in foundry.toml or pushengine config.
• LINK balance 0 → top up the feed contract via faucet.

Happy building! 🚀

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Security notice – This repository contains a lightly-patched version of Adrastia's DataStreamsFeed.sol. The code has not been audited by Chainlink Labs. A comprehensive, independent security review is strongly recommended before any production use.