gordon-platform

Purpose

Runtime library crate every Gordon v7 service composes. Provides outbound HTTP with retry and circuit breaking, inbound Axum trace-context middleware, tracing-subscriber initialisation, Postgres LISTEN/NOTIFY pub/sub for manager-internal channels, and the full W3C TraceContext struct. Extracted from the legacy combined library to separate runtime plumbing from near-frozen wire contracts. A telemetry tweak no longer forces a major bump across five services.

Version + status

0.4.0 — moderate churn. Drift ceiling: 2 minors max. Default features are empty; each consumer enables only what it uses.

Feature flags

Feature	Activates
http	Outbound Client, RetryPolicy, CircuitBreakerConfig
http-middleware	Axum inbound middleware for W3C trace-context propagation (implies http)
telemetry	tracing-subscriber init with JSON / pretty formatters and env-driven filters
ipc	Postgres LISTEN/NOTIFY publisher + subscriber
time	Injectable Clock + TestClock for virtual-sleep test support

Public surface

• http — Client (reqwest-backed), RetryPolicy, CircuitBreakerConfig. Per-host breaker registry backed by parking_lot::Mutex — the critical section never crosses .await.
• http-middleware — Axum Layer that extracts a W3C traceparent from inbound requests and injects a TraceContext into extensions. Derives a stable trace_id from an X-Request-Id header via SHA-256 when no traceparent is present.
• telemetry — init(filter) wires tracing-subscriber with JSON formatter for production and pretty formatter for development, driven by RUST_LOG.
• ipc — Publisher + Subscriber over LISTEN/NOTIFY. Manager-internal channels (bot lifecycle events, deploy state) stay off the NATS bus by design.
• trace — TraceContext: full W3C traceparent v00 struct (parse, format, child-span derive). Moved here from gordon-kernel at the kernel 2.0 batch (DP-15a, 2026-05-17). Runtime callers (HTTP middleware, span emission, pg-NOTIFY stamping) are runtime concerns and belong in this crate. The wire scalar TraceId stays in gordon-kernel so gordon-protocol is not forced to depend on gordon-platform.
• time — Clock trait + TestClock impl for deterministic time in tests.

Dependencies of note

• gordon-kernel (^2) — TraceId + GordonError taxonomy.
• gordon-domain (^1) — domain types referenced by some IPC channel payloads.
• axum (optional, http-middleware) — tower-compatible middleware layer.
• sqlx (optional, ipc) — Postgres LISTEN/NOTIFY driver.
• parking_lot (optional, http) — Mutex for the per-host breaker registry.

Invariants

• Zero #[allow(...)].
• No domain types in default surface. A pure-runtime crate — if a type names a strategy, market, order, or intent concept, it belongs in gordon-domain or gordon-protocol.
• Default features are empty. Never enable features in gordon-platform itself. Consumers opt in.
• TraceContext ownership. Since kernel 2.0, the full W3C traceparent struct lives here. New trace-runtime helpers belong in trace.rs; wire validation helpers belong in gordon-kernel::trace.
• No service binaries. Library crate only — no main.rs.

Where it lives

• Repo: gordon-platform/
• kellnr: https://kellnr.lepaux.com/crates/gordon-platform (LAN-only)

Related

• gordon-kernel — TraceId scalar; TraceContext moved here at 2.0.
• gordon-bus — IPC (ipc feature) complements NATS for manager-internal channels.
• gordon-domain — domain types referenced by IPC payloads.