Pre-deploying contracts to testnets

Explanation of the pre_built_artifacts

Normally when building the application against a local development network we deploy the contracts at compile time. However when targeting a test network this isn't very practical as deployment takes a long time.

To speed up the developer workflow, we have deployed the contracts in advance to the following test networks using truffle:

• Ropsten

• Kovan

• Rinkeby

The truffle artifacts created from the deployments are located here:

/contracts/pre_built_artifacts/

When the TARGET_NETWORK environment variable is set to a test network, webpack will use the predeployed artifacts instead of trying to deploy the contracts at compile time:

webpack.config.prod.js

    new webpack.NormalModuleReplacementPlugin(
      /.*\/build\/contracts\/.*\.json/,
      function (resource) {
        if (process.env.TARGET_NETWORK !== 'development') {
          resource.request = resource.request.replace(/.*\/build\/contracts/, paths.appContractArtifacts);
        }
      }),

If we are targeting a development network, this snippet will use the artifacts that truffle just created at compile time. Otherwise it replaces all references to /build/contracts/*.json files to the predeployed artifacts in /contract/pre_built_artifacts folder.

Deploying Contracts to a Test Network

There's a few steps to follow to deploy and create the pre-deployed artifacts:

1. Delete the /build/contract folder. This removes any existing artifacts that might be there and contain references to development network.

2. Set TARGET_NETWORK in your .env file to your desired test network.

3. Run yarn deployContracts

4. Repeat step 2 and 3 for any other test networks you want to pre deploy to.

5. Copy the .json files from /build/contracts to the /contract/pre_built_artifacts folder.

6. Remove unecessary fields from these .json files: we only need abi, bytecode and networks.

7. Check in the updated artifacts to source control.