Procedural macros for the aetos metrics library.
This crate provides the #[metrics] attribute macro and #[derive(Label)] macro
for generating Prometheus metrics rendering code.
Label Validation
The #[metrics] macro validates that the label attribute is not used on common
scalar primitive types (u64, f64, i32, etc.). Using label on these types will
produce a compile error:
error: the 'label' attribute is not supported on scalar types like u64, f64, etc.
Labels are only supported on collection types that implement IntoIterator.
Note: This validation only catches common primitive types. Type aliases and custom wrapper types are not detected and will silently ignore labels.
See the main aetos crate documentation for usage examples.