Hermes management, API specification and implementation (bootstrap)

[ancazamfir]

Crate

relayer

Summary

Define the architecture for hermes operation management and implement it. Specify the initial APIs and implement a demo sample.

Problem Definition

Current hermes operation is defined via the configuration file loaded at startup, cannot be changed programmatically or reloaded dynamically.

Proposal

• Write a specification for the required APIs, including:

  • query, add, delete chain configuration
  • query, add, delete(or disable) relaying policy elements (e.g. “relay between chains A and B”, “relay on connection X for chain A”, etc.). This is evolving but at minimum specify the ones currently supported.
  • all queries currently supported by the CLIs: keys, clients, connections, channels, packets
  • all operations supported by the CLIs (mainly create/ update client, connections and channels)

• Decide on a client/ server architecture, be it REST or other, based on the above.

• Server implementation and the APIs for query, create and update client.

Acceptance Criteria

Ability to interact with hermes via the agreed APIs and architecture to query, create, update clients.

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[andynog]

I can work with @romac and others to evaluate from the technical side what's the best framework/crate to use for a REST API if we're going with that.

[andynog]

Things to consider for HTTP server crate:

Had a discussion with @romac and here are things we need to consider:

• Do we need Async/Await support?
• Assumption this will be a REST API
• Need Middleware support (e.g. auth, logging, telemetry, rate-limiting, caching)?
• What are the Performance requirements (reqs/sec?)
• Is the REST crate maintained / lots of maintainers / starts ?
• What's the footprint, number of dependencies ?
• Can we add it as via a feature in the relayer cli crate?
• Does it support OpenAPI/Swagger docs?
• How do we make it to interact with the relayer crate?
• Are there big Serialize/Deserialize efforts required to support API request/response?

Next steps:

• Investigate crates
• Create feature/comparison matrix

Options:

Non-async:

• https://lib.rs/crates/rouille

Async:

• https://lib.rs/crates/tide
• https://lib.rs/crates/warp