moneta_fn 0.2.0

A set of macros to function profiling
Documentation

A set of macros to function profiling

Contains some convenient macros to analyze function execution, like count to know how many times a function was called, trace to log when entering/exiting from a function and what are its arguments, and cache for pure functions cache.

Features

Feature Description Additional dependencies
count Makes available a macro count! to get how many times a function was called None
trace Prints when entering/exiting in a tagged function and its arguments None
cache Implements memoization for a tagged function lazy_static and hashbrown
visible Changes the cache storage and counter visibility None

Each feature can be forbided, forced or setted to global config (setted by features) in the attribute declaration. E.g:

#[moneta_fn::moneta(cache = "forbid", visible = "forbid", count = "force")]
fn foo(a: u8) -> u8 {
    unimplemented!()
}

Dependencies

cache requires that both lazy_static and hashbrown are enabled in the target module. When enabled in a function, it also requires that all parameters implement the Debug trait and Clone for the return type.

Wait... Why Debug for parameters and not Clone?

Consider these scenarios:

#[moneta_fn::moneta]
fn foo<'a, T>(lhs: &'a T, rhs: &'a T) -> T {
    unimplemented!()
}

It's hard to create cache storage with generic keys and lifetimes, once it can't be parsed in an equivalent format for a global RwLock.

Furthermore, it allows some optimizations for liked types:

#[moneta_fn::moneta]
fn foo<T: AsRef<str> + Debug>(lhs: T, rhs: T) -> T {
    unimplemented!()
}

I don't want trace/count/cache in my release builds. How do I disable it?

There isn't yet a good way to enable/disable specific features in different profiles. You'll need to set default-features to false and define which features you want. E.g:

[dependencies]
moneta_fn = { version = "*", default-features = false, features = ["cache", "count", "time"] }

Another way to do it, is using a setting a default feature.

[dependencies]
moneta_fn = { version = "*", default-features = false, features = ["cache", "count", "time"] }

[features]
default = ["debug_mode"]
debug_mode = ["moneta_fn/trace"]

And when compiling with a profile relase, use --no-default-features

cargo build --release --no-default-features

How do I enable/disable trace/count/cache for just one function?

Set trace/count/cache as force/forbid

#[moneta_fn::moneta(cache = "forbid")] // Will not update cache storage
fn foo(a: u8) -> u8 {
    unimplemented!()
}

Will count!/get_cache! calls break when the count/cache feature is disabled?

No. The counting or cache will just not be updated.