Module instrument 

Conditional instrumentation support for profiling.

This module provides tracing integration when the profiling feature is enabled. When disabled, instrumentation compiles to zero-cost no-ops.

Features

• profiling - Base feature enabling tracing spans (no backend)
• trace-file - Trace file output in Chrome JSON (.json) or Perfetto (.pftrace) format

Usage

For method-level instrumentation, use the #[cfg_attr] pattern:

#[cfg_attr(feature = "profiling", tracing::instrument(skip(self)))]
pub async fn my_method(&self) -> Result<T, Error> {
    // ...
}

For manual span creation within functions:

#[cfg(feature = "profiling")]
let _span = tracing::info_span!("operation_name", field = value).entered();

// ... code to profile

#[cfg(feature = "profiling")]
drop(_span);  // Optional: explicitly end span early

Trace Output

When built with the trace-file feature, traces can be written to files:

• .json extension → Chrome JSON format (viewable in Perfetto UI)
• .pftrace extension → Native Perfetto format (viewable in Perfetto UI)

Use --trace-file path.json or --trace-file path.pftrace to select format.

Modules

instrument

Attach a span to a std::future::Future.

Macros

debug

Constructs an event at the debug level.

debug_span

Constructs a span at the debug level.

error

Constructs an event at the error level.

error_span

Constructs a span at the error level.

info

Constructs an event at the info level.

info_span

Constructs a span at the info level.

trace

Constructs an event at the trace level.

trace_span

Constructs a span at the trace level.

warn

Constructs an event at the warn level.

warn_span

Constructs a span at the warn level.

Structs

Level

Describes the level of verbosity of a span or event.

Span

A handle representing a span, with the capability to enter the span if it exists.

Traits

Instrument

Attaches spans to a std::future::Future.

Attribute Macros

instrument

Instruments a function to create and enter a tracing span every time the function is called.