advanced.md

Advanced Topics

Configuration for non-buidler, non-truffle projects

The reporter's only strict requirements are:

• Mocha
• The Ethereum client it connects to is in a separate process and accepts calls over http. (You cannot use ganache-core as an in-process provider, for example.)

Apart from that, it should be possible to run the reporter in any environment by configuring the following:

• The root directory to begin searching for .sol files in via the src option.

• The client url the reporter uses to send calls.

• The method the reporter uses to acquire necessary info from solc compilation artifacts. Truffle and Buidler are supported out of the box but you can also use the artifactType option to define a function which meets your use case. This method receives a contract name (ex: MetaCoin) and must return an object as below:

// Example function
function myArtifactProcessor(contractName){...}

// Output
{
  // Required
  abi: []
  bytecode: "0xabc.." // solc: "0x" + contract.evm.bytecode.object

  // Optional
  deployedBytecode: "0xabc.." // solc: "0x" + contract.evm.deployedBytecode.object
  metadata: {
    compiler: {
      version: "0.5.8"
    },
    settings: {
      optimizer: {
        enabled: true,
        runs: 500
      }
    }
  }
}

Example artifact handlers can be found here.

Resolving method identities when using proxy contracts

Many projects use a proxy contract strategy like EtherRouter or ZeppelinOS to manage their upgradeability requirements. In practice this means method calls are routed through the proxy's fallback function and forwarded to the contract system's current implementation.

You can define a helper method for the proxyResolver option which makes matching methods to contracts in these cases possible. The reporter automatically detects proxy use when methods are called on a contract whose ABI does not include their signature. It then invokes proxyResolver to make additional calls to the router contract and establish the true identity of the transaction target.

Resources

• An implementation for EtherRouter.
• The code which consumes the proxyResolver.

PRs are welcome if you have a proxy mechanism you'd like supported by default.

Gas Reporter JSON output

The gas reporter now writes the data it collects to a JSON file at ./gasReporterOutput.json whenever the environment variable CI is set to true. An example of this output is here. You may find it useful as an input to more complex / long running gas analyses, better CI integrations, etc.