hick-trace

Tracing-or-noop diagnostic macro shim and backend-agnostic stats/metrics primitives for the hick mDNS stack.

hick-trace is an internal support crate: all of the mDNS crates in the [hick] family depend on it, and downstream code normally enables its features indirectly through those crates (e.g. hick/tracing, mdns-proto/stats).

Macros

Five log-level macros are always available as hick_trace::<name>!(...): trace!, debug!, info!, warn!, error!. When the tracing Cargo feature is enabled they delegate to the real [tracing] crate; otherwise they discard every argument without emitting code.

Three span macros — trace_span!, debug_span!, info_span! — follow the same pattern. Without tracing they return a NoopSpan that supports .entered() / .enter(), so call sites compile in both configurations.

Feature flags

Feature	Description
`tracing`	Delegate macros to the real [`tracing`] crate (emit structured events/spans).
`stats`	Enable [`stats::Stats`] and [`stats::StatsSnapshot`]: `no_std`-safe atomic counters and gauges. Requires `portable-atomic` on targets without native 64-bit atomics. Available on bare-metal.
`metrics`	Forward every counter/gauge update to the [`metrics`] facade (Prometheus/StatsD exporters). Implies `stats`; requires `std`. Not available on bare-metal (`no_std`) targets — use `stats` + `defmt` for embedded observability instead.

`stats` module

stats::Stats owns one AtomicU64 per metric. Call stats.snapshot() to get a StatsSnapshot (plain Copy struct of u64 fields). All loads use Relaxed ordering — sufficient for periodic reporting.

Counters: packets_rx, packets_tx, bytes_rx, bytes_tx, packets_dropped, parse_errors, send_errors, questions_rx, answers_rx, answers_collected, answers_suppressed_kas, duplicate_questions_suppressed, responses_tx, probes_tx, announcements_tx, goodbyes_tx, conflicts, renames, cache_inserts, cache_refreshes, cache_evictions, cache_expirations, queries_started, queries_done, queries_timeout, services_registered, services_established.

Gauges: cache_size, queries_active, services_active (each with incr_* / decr_* / set_* methods).

Feature-forwarding in downstream crates

Each crate in the hick family exposes feature names that forward to hick-trace:

std crates (hick-reactor, hick-compio, the [hick] facade for std targets): expose tracing, stats, and metrics.
bare-metal crates (hick-smoltcp, hick-embassy, mdns-proto): expose tracing, stats, and defmt. The metrics feature is not forwarded from bare-metal crates because it requires std.

License

hick-trace is under the terms of both the MIT license and the Apache License (Version 2.0).

See LICENSE-APACHE, LICENSE-MIT for details.