Macro sample 

sample!() { /* proc-macro */ }

Emit a metric sample.

Examples

Emit a metric sample from a value:

let my_metric = 42;

emit::sample!(value: my_metric);

In the above example, the name is inferred to be "my_metric" using the name of the identifier in the value control parameter.

The name can also be specified manually, and is required if value is not an identifier:

emit::sample!(name: "my_metric", value: 42);

Properties can be attached to metric samples:

let my_metric = 42;

let metric = emit::sample!(value: my_metric, props: emit::props! { my_property: "some value" });

Syntax

(control_param),*

where

• control_param: A Rust field-value with a pre-determined identifier (see below).

Control parameters

This macro accepts the following optional control parameters:

name	type	description
rt	impl emit::runtime::Runtime	The runtime to emit the metric sample through if sampler is unspecified.
sampler	impl emit::sampler::Sampler	The Sampler to pass the metric sample to.
mdl	impl Into<emit::Path>	The module the metric sample belongs to. If unspecified the current module path is used.
extent	impl emit::ToExtent	The extent to use on the metric sample. If unspecified the extent is left empty.
props	impl emit::Props	A set of properties to add to the metric sample.
value (required)	impl emit::ToValue	The value of the metric sample. If the value is an identifier then name will be inferred to be that identifier.
name (required if value is not an identifier)	impl emit::ToStr	The name of the metric being sampled. If unspecified, and value is an identifier, then the stringified identifier is used as the name.
agg	impl emit::ToStr	The aggregation of the metric sample. If unspecified, the default for the macro is used.
description	impl emit::ToStr	A description of the underlying data source. If unspecified the description is left empty.
unit	impl emit::ToStr	The measurement unit of the sample value. If unspecified the unit is left empty.