In this guide, we're going to walk through the details of setting up the chainbridge-core-example in order to showcase the chainbridge-core library.
The chainbridge-core is the project that was born from the existing version of Chainbridge. It was built to improve the maintainability and modularity of the current solution. The fundamental distinction is that chainbridge-core is more of a framework rather than a stand-alone application.
In other words, it's a library, and therefore contains no main.go file. Therefore, we need some sort of example that will allow us to source files and packages from the chainbridge-core library.
For this case, we have created the chainbridge-core-example.
As the name suggests, this is an example application (CLI) that serves two purposes:
- It allows us to issue commands to our ChainBridge contracts
- It serves the unique distinction as a bridge relayer
Before anything further can be done, we need to download and install some necessary software.
The above section helps you to install the chainbridge-core-example which internally sources the chainbridge-core but it makes no mention of how to assist with local development efforts.
Say we are working on parts of the chainbridge-core and wish to test functionality (outside of unit/integration tests) by building the CLI with our local changes. This can easily be made possible by adding a single line to our go.mod within the chainbridge-core-example.
module github.com/ChainSafe/chainbridge-core-example
go 1.16
// replace existing version with local
replace github.com/ChainSafe/chainbridge-core => ../chainbridge-core
// the same can be done when working with various ChainBridge modules
replace github.com/ChainSafe/chainbridge-celo-module => ../chainbridge-celo-module
require (
github.com/ChainSafe/chainbridge-core v0.0.0-20210922142450-7e66fa42a68e
github.com/ChainSafe/chainbridge-celo-module v0.0.0-20210812101441-b6d7ad422a53
...
)
In this step we will start one geth instance and an instance of celo.
We chose these two networks because during the installation section we checked out the evm-celo-dev branch; therefore, the assumption is we will be bridging the Ethereum and Celo networks.
Within the evm-celo-dev branch you will find a docker-compose.e2e.yml file; we use this in order to start the chains for local development.
docker-compose -f ./docker-compose.e2e.yml up -VWithin the chainbridge-core-example config directory of the evm-celo-dev branch you will find two JSON configuration files. Both of these will require some slight customizations since likely the from, bridge, erc20Handler and endpoint fields will need to be updated to your own local development needs.
config_celo.json
{
"name": "celo",
"id": "0",
"endpoint": "ws://localhost:8546",
"from": "",
"bridge": "",
"erc20Handler": "",
"gasLimit": "9000000",
"maxGasPrice": "20000000000",
"blockConfirmations": "10"
}config_evm.json
{
"name": "ethereum",
"id": "1",
"endpoint": "ws://localhost:8545",
"from": "",
"bridge": "",
"erc20Handler": "",
"gasLimit": "9000000",
"maxGasPrice": "20000000000",
"blockConfirmations": "10"
}Note: You will notice that the id field within both configs is different- this is a requirement; both chains must not share the same id!
Now that we have properly installed the chainbridge-core-example, have seen how to customize its module sourcing for our local development needs as well as have some local networks running via Docker, we can now use the CLI for either issuing commands to the networks we are seeking to bridge, or by running the software as a bridge relayer if the contracts are already deployed.
This step describes how to use the chainbridge-core-example CLI we previously configured in order to serve as a relayer for the networks we are seeking to bridge.
Notable flags:
--config: Path to JSON configuration files directory (default ".")
--testkey: Applies a predetermined test keystore to the chain
--fresh: Disables loading from blockstore at start. Opts will still be used if specified. (default: false)
./chainbridge-core-example run --config /path/to/your/config/directory --testkey alice --freshThe following resources can be referenced for further explanation in either of these areas.