Custom Data Feed

You need to add a private key to the .env file. This is specifically required if you want to simulate chain writes (the key must be valid and funded).
If your workflow does not write on-chain, you can keep a dummy key:

CRE_ETH_PRIVATE_KEY=0000000000000000000000000000000000000000000000000000000000000001

If Bun is not already installed, follow the instructions at: https://bun.sh/docs/installation

From your project root, run:

bun install --cwd ./my-workflow

For local simulation to interact with a chain, specify RPC endpoints for the chains you interact with in project.yaml. This is required for submitting transactions and reading blockchain state.

Supported for local simulation (testnet/mainnet variants):

• Ethereum (ethereum-testnet-sepolia, ethereum-mainnet)
• Base (ethereum-testnet-sepolia-base-1, ethereum-mainnet-base-1)
• Avalanche (avalanche-testnet-fuji, avalanche-mainnet)
• Polygon (polygon-testnet-amoy, polygon-mainnet)
• BNB Chain (binance-smart-chain-testnet, binance-smart-chain-mainnet)
• Arbitrum (ethereum-testnet-sepolia-arbitrum-1, ethereum-mainnet-arbitrum-1)
• Optimism (ethereum-testnet-sepolia-optimism-1, ethereum-mainnet-optimism-1)

Add your RPCs under rpcs (example):

rpcs:
  - chain-name: ethereum-testnet-sepolia
    url: <Your RPC endpoint to ETH Sepolia>

For chain names, see the selectors list: chain-selectors/selectors.yml

Deploy the demo contracts: BalanceReader, MessageEmitter, ReserveManager, SimpleERC20. You can deploy to a local chain or a testnet using tools like Foundry.

For a quick start, you can also use the pre-deployed contract addresses on Ethereum Sepolia—no action required if you're just trying things out.

Configure config.json for the workflow:

• schedule: e.g. "*/30 * * * * *" (every 30 seconds), or any cron you prefer
• url: your off-chain data endpoint (custom data feed)
• tokenAddress: SimpleERC20 contract address
• porAddress: ReserveManager contract address
• proxyAddress: UpdateReservesProxySimplified contract address
• balanceReaderAddress: BalanceReader contract address
• messageEmitterAddress: MessageEmitter contract address
• chainSelectorName: human-readable chain name (see selectors YAML linked above)
• gasLimit: gas limit used for chain writes

Ensure workflow.yaml points to the config:

staging-settings:
  user-workflow:
    workflow-name: "my-workflow"
  workflow-artifacts:
    workflow-path: "./main.ts"
    config-path: "./config.json"
    secrets-path: ""

Run the command from the project root and pass the path to the workflow directory:

cre workflow simulate <path-to-workflow-directory>

Example (for my-workflow):

cre workflow simulate my-workflow

You'll see trigger options similar to:

🚀 Workflow simulation ready. Please select a trigger:
1. [email protected] Trigger
2. evm:ChainSelector:[email protected] LogTrigger

• Cron Trigger: choose 1 → the workflow executes on the schedule.
• Log Trigger: choose 2, then provide the example inputs:

Transaction Hash: 0x420721d7d00130a03c5b525b2dbfd42550906ddb3075e8377f9bb5d1a5992f8e
Log Event Index: 0

Add a private key to .env. This is required if your workflow performs chain writes (must be valid and funded). If your workflow does not write on-chain, you can use a dummy key:

CRE_ETH_PRIVATE_KEY=0000000000000000000000000000000000000000000000000000000000000001

Specify RPC endpoints for chains you interact with in project.yaml. This is needed to submit transactions and read state.

Supported for local simulation (testnet/mainnet variants):

• Ethereum (ethereum-testnet-sepolia, ethereum-mainnet)
• Base (ethereum-testnet-sepolia-base-1, ethereum-mainnet-base-1)
• Avalanche (avalanche-testnet-fuji, avalanche-mainnet)
• Polygon (polygon-testnet-amoy, polygon-mainnet)
• BNB Chain (binance-smart-chain-testnet, binance-smart-chain-mainnet)
• Arbitrum (ethereum-testnet-sepolia-arbitrum-1, ethereum-mainnet-arbitrum-1)
• Optimism (ethereum-testnet-sepolia-optimism-1, ethereum-mainnet-optimism-1)

Add your RPC under rpcs:

rpcs:
  - chain-name: ethereum-testnet-sepolia
    url: <Your RPC endpoint to ETH Sepolia>

Deploy the demo contracts: BalanceReader, MessageEmitter, ReserveManager, SimpleERC20 (locally or to a testnet using tools like Foundry).

For quick trials, you can use the pre-deployed addresses on Ethereum Sepolia:

• chain: ethereum-testnet-sepolia
• ReserveManager: 0x073671aE6EAa2468c203fDE3a79dEe0836adF032
• SimpleERC20: 0x4700A50d858Cb281847ca4Ee0938F80DEfB3F1dd
• BalanceReader: 0x4b0739c94C1389B55481cb7506c62430cA7211Cf
• MessageEmitter: 0x1d598672486ecB50685Da5497390571Ac4E93FDc

Source code lives under projectRoot/contracts/evm/src.

Generate Go bindings from ABIs (located in projectRoot/contracts/src/abi). Run this from your project root (where project.yaml is):

# Generate bindings for all contracts
cre generate-bindings evm

Bindings will appear under contracts/evm/src/generated/, e.g.:

• contracts/evm/src/generated/ierc20/IERC20.go
• contracts/evm/src/generated/reserve_manager/ReserveManager.go
• contracts/evm/src/generated/balance_reader/BalanceReader.go

(Template bindings are pre-generated; re-run only if ABIs/contracts change.)

Edit config.json:

• schedule: e.g. "*/3 * * * * *" (every 3 seconds) or your preferred cron
• url: your off-chain data endpoint (custom data feed)
• tokenAddress: SimpleERC20 address
• reserveManagerAddress: ReserveManager address
• balanceReaderAddress: BalanceReader address
• messageEmitterAddress: MessageEmitter address
• chainName: selected chain name (see selectors YAML linked above)
• gasLimit: gas limit used for chain writes

Ensure workflow.yaml points to the config:

staging-settings:
  user-workflow:
    workflow-name: "my-workflow"
  workflow-artifacts:
    workflow-path: "."
    config-path: "./config.json"
    secrets-path: ""

From your project root:

cre workflow simulate my-workflow

You'll see trigger options, e.g.:

🚀 Workflow simulation ready. Please select a trigger:
1. [email protected] Trigger
2. evm:ChainSelector:[email protected] LogTrigger

• Cron Trigger: choose 1 → the workflow executes immediately on the schedule.
• Log Trigger: choose 2 → provide the example inputs:

Transaction Hash: 0x420721d7d00130a03c5b525b2dbfd42550906ddb3075e8377f9bb5d1a5992f8e
Log Event Index: 0