Inspector Facet

A tool that allows you to inspect deployed EIP-2535 Diamond proxy contracts from your command line.

Inspector Facet was inspired by Louper.dev (GitHub).

Inspector Facet uses side information about facet ABIs to match the selectors that a Diamond proxy is serving to human-understandable information about the facets and the functions.

We support side information obtained from:

• brownie build artifacts
• foundry build artifacts
• hardhat build artifacts
• Etherscan/Polygonscan/etc.

Inspector Facet can build a complete audit log of all Diamond-related operations on an EIP2535 proxy contract. Use this functionality with the --timeline argument.

Installation

Inspector Facet is written in Python 3 and is distributed using PyPI: https://pypi.org/project/inspector-facet/

To install Inspector Facet, run:

pip install inspector-facet

Usage

inspector-facet --help

To use Inspector Facet:

With a brownie project

The following command produces human-readable output:

inspector-facet \
    --network <brownie network name for blockchain> \
    --address <address of diamond contract> \
    --project <path to brownie project> \
    --format human

The following command produces JSON output and can be used to inspect a Diamond contract programatically (e.g. as part of a CI/CD pipeline):

inspector-facet \
    --network <brownie network name for blockchain> \
    --address <address of diamond contract> \
    --project <path to brownie project> \
    --format json

With a foundry project

The following command produces human-readable output:

inspector-facet \
    --network <brownie network name for blockchain> \
    --address <address of diamond contract> \
    --project <path to foundry project> \
    --foundry \
    --format human

The following command produces JSON output and can be used to inspect a Diamond contract programatically (e.g. as part of a CI/CD pipeline):

inspector-facet \
    --network <brownie network name for blockchain> \
    --address <address of diamond contract> \
    --project <path to foundry project> \
    --foundry \
    --format json

With a hardhat project

inspector-facet \
    --network <brownie network name for blockchain> \
    --address <address of diamond contract> \
    --project <path to foundry project> \
    --hardhat \
    --format human

The following command produces JSON output and can be used to inspect a Diamond contract programatically (e.g. as part of a CI/CD pipeline):

inspector-facet \
    --network <brownie network name for blockchain> \
    --address <address of diamond contract> \
    --project <path to foundry project> \
    --hardhat \
    --format json

Non-standard build directories

The --build-dir command allows you to specify the name of the build directory in your brownie or foundry project in case you aren't using the standard directories (build/ for brownie and out/ for foundry).

To build an audit log of Diamond operations on an EIP2535 proxy contract

To build an audit log, you will need to crawl DiamondCut events from the blockchain. You can do this using moonworm.

First, you will need to install moonworm:

pip install moonworm

This should be done in a separate Python environment from inspector-facet because brownie pins its dependencies and doesn't play nice with other libraries (GitHub issue).

Once moonworm is installed, you can find the deployment block for your contract:

moonworm find-deployment -w <JSON RPC URL for blockchain node> -c <contract address> -t 0.5

Save the output of this command as START_BLOCK.

Then crawl the DiamondCut event data:

moonworm watch \
  -i inspector_facet/abis/DiamondCutFacetABI.json \
  -w <JSON RPC URL for blockchain node> \
  -c <contract address> \
  --start $START_BLOCK \
  --end <current block number> \
  --only-events \
  -o <output filename> \
  --min-blocks-batch 1000 \
  --max-blocks-batch 1000000

If you are crawling data from a POA chain (like Polygon), add --poa to the command above.

Then, invoke inspector-facet as:

inspector-facet \
  --crawldata <output filename> \
  --project <path to brownie project (should contain build artifacts in build/contracts)> \
  --format human \
  --timeline

Connecting to a blockchain

Internally, Inspector Facet uses brownie to work with any Ethereum-based blockchain. When you use inspector-facet, even with a hardhat project, inspector-facet will still use brownie to interact with any blockchain.

Any inspector-facet command that calls out to a blockchain will take a -n/--network argument. The value of this argument must be the name of a brownie network configured in your Python environment.

brownie is a dependency of inspector-facet and is automatically installed when you install inspector-facet.

To see a list of available brownie networks, activate the Python environment in which you installed inspector-facet and run:

brownie networks list

The output will look like this (truncated for brevity):

$ brownie networks list

Brownie v1.17.2 - Python development framework for Ethereum

The following networks are declared:

Ethereum
  ├─Mainnet (Infura): mainnet
  ├─Ropsten (Infura): ropsten
  ├─Rinkeby (Infura): rinkeby
  ├─Goerli (Infura): goerli
  └─Kovan (Infura): kovan

Ethereum Classic
  ├─Mainnet: etc
  └─Kotti: kotti

Arbitrum
  └─Mainnet: arbitrum-main
...

To view the details for any particular network, use:

brownie networks modify $NETWORK

For example:

$ brownie networks modify mainnet

$ brownie networks modify mainnet
Brownie v1.17.2 - Python development framework for Ethereum

SUCCESS: Network 'Mainnet (Infura)' has been modified
  └─Mainnet (Infura)
    ├─id: mainnet
    ├─chainid: 1
    ├─explorer: https://api.etherscan.io/api
    ├─host: https://mainnet.infura.io/v3/$WEB3_INFURA_PROJECT_ID
    └─multicall2: 0x5BA1e12693Dc8F9c48aAD8770482f4739bEeD696

If you want to connect to this network, using Infura, all you have to do is set your WEB3_INFURA_PROJECT_ID environment variable (get this information from your project dashboard on Infura) and set --network mainnet when you invoke inspector-facet.

For networks which have publicly available nodes, it's even more straightforward:

$ brownie networks modify etc
Brownie v1.17.2 - Python development framework for Ethereum

SUCCESS: Network 'Mainnet' has been modified
  └─Mainnet
    ├─id: etc
    ├─chainid: 61
    ├─explorer: https://blockscout.com/etc/mainnet/api
    └─host: https://www.ethercluster.com/etc

You don't need any additional environment variables.

Adding a custom network

To add your own network, use the brownie networks add command.

The signature for this command is:

brownie networks add <label> <network-name> chainid=<chain ID for network> host=<JSON RPC endpoint> explorer=<API URL for blockchain explorer>

The <label> is purely for organizational purposes and can be set to whatever string you want.

For example, if you wanted to add the public Polygon RPC service as a network, you would do:

brownie networks add Polygon matic chainid=137 host=https://polygon-rpc.com explorer=https://api.polygonscan.com/api

Support

You can get help in any of the following ways:

1. File an issue
2. Ask for help on Moonstream Discord