op-fault-detector

Fault detector is a service that identifies mismatches between a local view of the Optimism or superchain network and L2 output proposals published to Ethereum. Here is the reference to the original implementation of the fault monitoring service from Optimism.

How it works

The state root of the block is published to the L2OutputOracle contract on Ethereum. The L2OutputOracle is inferred from the portal contract.

In the application, we take the state root of the given block as reported by an Optimism node, compute outputRoot from it and compare it with the outputRoot as published to L2OutputOracle contract on Ethereum.

Installation

git clone https://github.com/liskhq/op-fault-detector
make install

Running Fault Detector

Copy config.yaml file at the root path and use any name with .yaml extension or edit existing config.yaml file to set configuration for the application.

To run with default config,

faultdetector

To run with custom config file,

faultdetector --config /PATH/TO/YOUR/CUSTOM/CONFIG

To build and run from source code

Build

make build

Run

make run-app

if want to provide custom config file, for example, my-config.yaml, run,

make run-app config=/path/to/my-config.yaml

View all available commands by running make help and view the commands with options as below.

build: Builds the application and create a binary at ./bin/

install: Installs faultdetector cmd and creates executable at $GOPATH/bin/

docker-build: Builds docker image

docker-run: Runs docker image, use `make docker-run config={PATH_TO_CONFIG_FILE}` to provide custom config and to provide slack access token use `make docker-run slack_access_token={ACCESS_TOKEN}`

format: Runs gofmt on the repo

godocs: Runs godoc and serves via endpoint

help: Show help for each of the Makefile recipes

lint: Runs golangci-lint on the repo

run-app: Runs the application, use `make run-app config={PATH_TO_CONFIG_FILE}` to provide custom config

test: Runs tests

Config

The configuration file is used to configure the application. Currently, the default configuration is found under ./config.yaml. To provide custom config, edit the ./config.yaml or create own and provide it while running the application make run-app config={PATH_TO_CUSTOM_CONFIG_FILE}.

Config paths:

Config file can be placed in any of the paths below and will be read without giving --config flag,

• .
• ..
• $HOME/.op-fault-detector

Below is the default config file,

# General system configurations
system:
  log_level: "info"

# API related configurations
api:
  server:
    host: "127.0.0.1"
    port: 8080
  base_path: "/api"
  register_versions:
    - v1

# Faultdetector configurations
fault_detector:
  l1_rpc_endpoint: "https://rpc.notadegen.com/eth"
  l2_rpc_endpoint: "https://mainnet.optimism.io/"
  start_batch_index: -1
  l2_output_oracle_contract_address: "0x0000000000000000000000000000000000000000"

System Config

• system.log_level: Set log level of the application, by default info and available options are warn, debug, error and fatal

API Config

• api.server.host: Host of application
• api.server.port: Port of application
• api.base_path: Base path for the API
• register_versions: Versions for APIs

Fault Detector Config

• fault_detector.l1_rpc_endpoint: RPC endpoint for L1 chain.
• fault_detector.l2_rpc_endpoint: RPC endpoint for L2 chain.
• fault_detector.start_batch_index: Provide batch_index to start from. If not provided, it will pick default -1 and then application will find the first unfinalized batch index that has not yet passed the fault proof window.
• fault_detector.l2_output_oracle_contract_address: Deployed L2OutputOracle contract address used to retrieve necessary info for output verification. Only provided for the chains other than Optimism and Lisk Superchain.

API and Metrics

API

• Status API exposed via {api.server.host}:{api.server.port}/api/v1/status
• Metrics is exposed at {api.server.host}:{api.server.port}/metrics
• {api.server.host} in config.yaml defaults to 127.0.0.1
• {api.server.port} in config.yaml defaults to 8080

Metrics

- fault_detector_highest_output_index      prometheus.Gauge     Highest known output index
- fault_detector_is_state_mismatch         prometheus.Gauge     0 if state is ok, 1 if state is mismatched
- fault_detector_api_connection_failure    prometheus.Gauge     Number of API RPC calls failed for L1 and L2 nodes

Notification Service

When the state root for the proposed batch index on L2OutputOracle doesn't match the local view, user can also get notifications on Slack. This is an optional feature that can be enabled by following steps,

• Set configuration as below,

notification:
  enable: true
  slack:
    channel_id: "YOUR_CHANNEL_ID"

channel_id can be found on Slack, reference Locate your Slack URL or ID.

• Set environment variable SLACK_ACCESS_TOKEN_KEY,

export SLACK_ACCESS_TOKEN_KEY="{SLACK_ACCESS_TOKEN}"

Access token for Slack can be found in Slack application, reference How to quickly get and use a Slack API token.

• Run app faultdetector or faultdetector --config /PATH/TO/CUSTOM/CONFIG/FILE

To run notification service with docker.

• Run make docker-run config={/PATH/TO/CUSTOM/CONFIG/FILE} slack_access_token={ACCESS_TOKEN}