loadpace-tower

Adaptive Tower services for clients balancing requests across a changing fleet.

Why this adapter exists

Tower's balancers decide which ready endpoint should receive a request, but a ready endpoint can still be the wrong place to send more work: it may already have a queue, its capacity may have changed, or its requests may be arriving faster than its service can complete them. A static limit either wastes spare capacity or applies the wrong limit to different endpoints.

loadpace-tower wraps each endpoint with the loadpace controller. It preserves Tower backpressure, paces dispatch with a per-endpoint GCRA schedule, and exposes predicted completion cost for P2C selection. This lets a dynamic discovery stream add and remove endpoints while each endpoint learns its own safe operating point.

loadpace-tower provides:

• AdaptiveEndpoint<S>, a bounded and paced tower::Service adapter;
• AdaptiveLayer, for wrapping services in a tower::ServiceBuilder stack;
• AdaptiveDiscovery, which wraps discovered services with fresh controller state; and
• LoadMetric, a predicted completion-cost metric for Tower's P2C balancer.

Intended deployment model

This adapter is for trusted microservice clients sharing private service endpoints. Congestion control assumes the other clients cooperate and run compatible pacing logic; it cannot enforce fairness against an unpaced or malicious peer.

It is not a primary rate limit, quota system, abuse-prevention boundary, or DDoS defense for a general-purpose public API. Keep those controls at the server or another trusted ingress boundary.

[dependencies]
loadpace = "0.1"
loadpace-tower = "0.1"

See the repository documentation for integration guidance and design details.