pyth-network_pyth-crosschain/apps/argus

Argus

Argus is a webservice that serves price updates according to the Pulse protocol. The webservice processes and delivers price updates to callers when permitted by the protocol. The service operates a keeper task that performs callback transactions for user requests.

A single instance of this service can simultaneously serve price updates for several different blockchains. Each blockchain is configured in config.yaml.

Build & Test

Argus uses Cargo for building and dependency management. Simply run cargo build and cargo test to build and test the project.

Command-Line Interface

The Argus binary has a command-line interface to perform useful operations on the contract, such as registering a new price provider, or requesting price updates. To see the available commands, simply run cargo run.

Hermes Integration

Argus integrates with the Hermes API to fetch price updates for fulfilling requests. When a price update request is received, Argus:

1. Retrieves the request details from the blockchain
2. Fetches the required price updates from Hermes using the /v2/updates/price/{publish_time} endpoint
3. Executes the callback on the Pulse contract with the fetched price updates

The Hermes client is implemented in the keeper/hermes.rs module and handles:

• Converting price IDs to the format expected by Hermes
• Fetching price updates from the Hermes API
• Parsing the response and converting it to the format expected by the Pulse contract
• Error handling and retries

Local Development

To start an instance of the webserver for local testing, you first need to perform a few setup steps:

1. Create a config.yaml file to point to the desired blockchains and Pulse contracts. Copy the content in config.sample.yaml and follow the directions inside to generate the necessary private keys and secrets.
2. Make sure the wallets you have generated in step (1) contain some gas tokens for the configured networks.
3. Run cargo run -- setup-provider to register a price provider for this service. This command will update the on-chain contracts such that the configured provider key is a price provider, and its on-chain configuration matches config.yaml.

Once you've completed the setup, simply run the following command to start the service:

RUST_LOG=INFO cargo run -- run

This command will start the webservice on localhost:34000.