[−][src]Attribute Macro tracing::instrument
#[instrument]
Instruments a function to create and enter a tracing
span every time
the function is called.
The generated span's name will be the name of the function. Any arguments
to that function will be recorded as fields using fmt::Debug
. To skip
recording a function's or method's argument, pass the argument's name
to the skip
argument on the #[instrument]
macro. For example,
skip
can be used when an argument to an instrumented function does
not implement fmt::Debug
, or to exclude an argument with a verbose
or costly Debug implementation. Note that:
- multiple argument names can be passed to
skip
. - arguments passed to
skip
do not need to implementfmt::Debug
.
Examples
Instrumenting a function:
#[instrument] pub fn my_function(my_arg: usize) { // This event will be recorded inside a span named `my_function` with the // field `my_arg`. tracing::info!("inside my_function!"); // ... }
Setting the level for the generated span:
#[instrument(level = "debug")] pub fn my_function() { // ... }
Overriding the generated span's target:
#[instrument(target = "my_target")] pub fn my_function() { // ... }
To skip recording an argument, pass the argument's name to the skip
:
struct NonDebug; #[instrument(skip(non_debug))] fn my_function(arg: usize, non_debug: NonDebug) { // ... }
If tracing_futures
is specified as a dependency in Cargo.toml
,
async fn
s may also be instrumented:
#[instrument] pub async fn my_function() -> Result<(), ()> { // ... }