## 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:
```js
// 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](https://github.com/cgewecke/eth-gas-reporter/blob/master/lib/artifactor.js).
### Resolving method identities when using proxy contracts
Many projects use a proxy contract strategy like
[EtherRouter](https://github.com/PeterBorah/ether-router) or
[ZeppelinOS](https://docs.zeppelinos.org/docs/start.html) 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](https://github.com/cgewecke/eth-gas-reporter/blob/master/lib/etherRouter.js) for EtherRouter.
- The [code](https://github.com/cgewecke/eth-gas-reporter/blob/master/lib/transactionWatcher.js) 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](https://github.com/cgewecke/eth-gas-reporter/blob/master/docs/gasReporterOutput.md).
You may find it useful as an input to more complex / long running gas analyses, better CI integrations, etc.
