Setup
Contracts deployment
In this section, you will deploy the required contracts to the Polygon PoS and Polygon Edge chain with cb-sol-cli.
# Setup for cb-sol-cli command
$ git clone https://github.com/ChainSafe/chainbridge-deploy.git
$ cd chainbridge-deploy/cb-sol-cli
$ make install
Firstly, we will deploy contracts to the Polygon PoS chain by cb-sol-cli deploy command. --all flag makes the command deploy all the contracts, including Bridge, ERC20 Handler, ERC721 Handler, Generic Handler, ERC20, and ERC721 contract. In addition, it'll set the default relayer account address and the threshold
# Deploy all required contracts into Polygon PoS chain
$ cb-sol-cli deploy --all --chainId 99 \
--url https://rpc-mumbai.matic.today \
--gasPrice [GAS_PRICE] \
--privateKey [ADMIN_ACCOUNT_PRIVATE_KEY] \
--relayers [RELAYER_ACCOUNT_ADDRESS] \
--relayerThreshold 1
Learn about chainID and JSON-RPC URL here
caution
The default gas price in cb-sol-cli is 20000000 (0.02 Gwei). To set the appropriate gas price in a transaction, please set the value using the --gasPrice argument.
$ cb-sol-cli deploy --all --chainId 99 \
--url https://rpc-mumbai.matic.today \
--privateKey [ADMIN_ACCOUNT_PRIVATE_KEY] \
--relayers [RELAYER_ACCOUNT_ADDRESS] \
--relayerThreshold 1 \
# Set gas price to 5 Gwei
--gasPrice 5000000000
caution
The Bridge contract takes approximately 0x3f97b8 (4167608) gas to deploy. Please make sure the blocks being generated have enough block gas limit to contain the contract creation transaction. To learn more about changing block gas limit in Polygon Edge, please visit the Local Setup
Once the contracts have been deployed, you will get the following result:
Deploying contracts...
✓ Bridge contract deployed
✓ ERC20Handler contract deployed
✓ ERC721Handler contract deployed
✓ GenericHandler contract deployed
✓ ERC20 contract deployed
WARNING: Multiple definitions for safeTransferFrom
✓ ERC721 contract deployed
================================================================
Url: https://rpc-mumbai.matic.today
Deployer: <ADMIN_ACCOUNT_ADDRESS>
Gas Limit: 8000000
Gas Price: 20000000
Deploy Cost: 0.00029065308
Options
=======
Chain Id: <CHAIN_ID>
Threshold: <RELAYER_THRESHOLD>
Relayers: <RELAYER_ACCOUNT_ADDRESS>
Bridge Fee: 0
Expiry: 100
Contract Addresses
================================================================
Bridge: <BRIDGE_CONTRACT_ADDRESS>
----------------------------------------------------------------
Erc20 Handler: <ERC20_HANDLER_CONTRACT_ADDRESS>
----------------------------------------------------------------
Erc721 Handler: <ERC721_HANDLER_CONTRACT_ADDRESS>
----------------------------------------------------------------
Generic Handler: <GENERIC_HANDLER_CONTRACT_ADDRESS>
----------------------------------------------------------------
Erc20: <ERC20_CONTRACT_ADDRESS>
----------------------------------------------------------------
Erc721: <ERC721_CONTRACT_ADDRESS>
----------------------------------------------------------------
Centrifuge Asset: Not Deployed
----------------------------------------------------------------
WETC: Not Deployed
================================================================
Now we may deploy the contracts to the Polygon Edge chain.
# Deploy all required contracts into Polygon Edge chain
$ cb-sol-cli deploy --all --chainId 100 \
--url http://localhost:10002 \
--privateKey [ADMIN_ACCOUNT_PRIVATE_KEY] \
--relayers [RELAYER_ACCOUNT_ADDRESS] \
--relayerThreshold 1
Save the terminal outputs with the deployed smart contract addresses as we will need them for the next step.
Relayer setup
In this section, you will start a relayer to exchange data between 2 chains.
First, we need to clone and build the ChainBridge repository.
$ git clone https://github.com/ChainSafe/ChainBridge.git
$ cd chainBridge && make install
Next, You need to create config.json and set the JSON-RPC URLs, relayer address, and contracts address for each chain.
{
"chains": [
{
"name": "mumbai",
"type": "ethereum",
"id": "99",
"endpoint": "https://rpc-mumbai.matic.today",
"from": "<RELAYER_ACCOUNT_ADDRESS>",
"opts": {
"bridge": "<BRIDGE_CONTRACT_ADDRESS>",
"erc20Handler": "<ERC20_HANDLER_CONTRACT_ADDRESS>",
"erc721Handler": "<ERC721_HANDLER_CONTRACT_ADDRESS>",
"genericHandler": "<GENERIC_HANDLER_CONTRACT_ADDRESS>",
"minGasPrice": "1",
"http": "true"
}
},
{
"name": "polygon-edge",
"type": "ethereum",
"id": "100",
"endpoint": "http://localhost:10002",
"from": "<RELAYER_ACCOUNT_ADDRESS>",
"opts": {
"bridge": "<BRIDGE_CONTRACT_ADDRESS>",
"erc20Handler": "<ERC20_HANDLER_CONTRACT_ADDRESS>",
"erc721Handler": "<ERC721_HANDLER_CONTRACT_ADDRESS>",
"genericHandler": "<GENERIC_HANDLER_CONTRACT_ADDRESS>",
"minGasPrice": "1",
"http": "true"
}
}
]
}
To start a relayer, you need to import the private key corresponding to the relayer account address. You will need to input the password when you import private key. Once the import has been successful, the key will be stored under keys/<ADDRESS>.key.
# Import private key and store to local with encryption
$ chainbridge accounts import --privateKey [RELAYER_ACCOUNT_PRIVATE_KEY]
INFO[11-19|07:09:01] Importing key...
Enter password to encrypt keystore file:
> [PASSWORD_TO_ENCRYPT_KEY]
INFO[11-19|07:09:05] private key imported address=<RELAYER_ACCOUNT_ADDRESS> file=.../keys/<RELAYER_ACCOUNT_ADDRESS>.key
Then, you can start the relayer. You will need to input the same password you chose for storing the key in the beginning.
# Start relayer
$ chainbridge --config config.json --latest
INFO[11-19|07:15:19] Starting ChainBridge...
Enter password for key ./keys/<RELAYER_ACCOUNT_ADDRESS>.key:
> [PASSWORD_TO_DECRYPT_KEY]
INFO[11-19|07:15:25] Connecting to ethereum chain... chain=mumbai url=<JSON_RPC_URL>
Enter password for key ./keys/<RELAYER_ACCOUNT_ADDRESS>.key:
> [PASSWORD_TO_DECRYPT_KEY]
INFO[11-19|07:15:31] Connecting to ethereum chain... chain=polygon-edge url=<JSON_RPC_URL>
Once the relayer has begun, it will start to watch new blocks on each chain.