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Merged
TheJokr merged 1 commit into from
Nov 7, 2025
Merged

Add unprefixed flag to #[metrics] macro #153

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108 changes: 98 additions & 10 deletions foundations-macros/src/metrics/mod.rs
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Original file line number Diff line number Diff line change
@@ -1,7 +1,8 @@
use darling::util::Flag;
use darling::FromMeta;
use proc_macro::TokenStream;
use proc_macro2::Span;
use quote::{quote, ToTokens};
use quote::{format_ident, quote, ToTokens};
use syn::punctuated::Punctuated;
use syn::{
parse_macro_input, parse_quote, Attribute, ExprStruct, Ident, LitStr, Path, Token, Type,
Expand All @@ -13,13 +14,15 @@ mod validation;

#[derive(FromMeta)]
struct MacroArgs {
unprefixed: Flag,
#[darling(default = "Self::default_crate_path")]
crate_path: Path,
}

impl Default for MacroArgs {
fn default() -> Self {
Self {
unprefixed: Flag::default(),
crate_path: Self::default_crate_path(),
}
}
Expand Down Expand Up @@ -86,8 +89,11 @@ pub(crate) fn expand(args: TokenStream, item: TokenStream) -> TokenStream {

fn expand_from_parsed(args: MacroArgs, extern_: Mod) -> proc_macro2::TokenStream {
let MacroArgs {
unprefixed,
crate_path: foundations,
} = &args;
let with_service_prefix =
format_ident!("{}", !unprefixed.is_present(), span = unprefixed.span());

let Mod {
attrs: mod_attrs,
Expand All @@ -107,24 +113,26 @@ fn expand_from_parsed(args: MacroArgs, extern_: Mod) -> proc_macro2::TokenStream
.iter()
.filter_map(|fn_| label_set_struct(foundations, fn_));

let registry_init = |var: &str, kind: &str| {
let registry_init = |var: &str, opt: bool| {
let var = Ident::new(var, Span::call_site());
let method = Ident::new(&format!("get_{kind}_subsystem"), Span::call_site());
let optional = format_ident!("{opt}");

quote! {
let #var = &mut *#foundations::telemetry::metrics::internal::Registries::#method(stringify!(#mod_name));
let #var = &mut *#foundations::telemetry::metrics::internal::Registries::get_subsystem(
stringify!(#mod_name), #optional, #with_service_prefix
);
}
};

let init_registry = fns
.iter()
.any(|fn_| !fn_.attrs.optional)
.then(|| registry_init("registry", "main"));
.then(|| registry_init("registry", false));

let init_opt_registry = fns
.iter()
.any(|fn_| fn_.attrs.optional)
.then(|| registry_init("opt_registry", "opt"));
.then(|| registry_init("opt_registry", true));

let metric_inits = fns.iter().map(|fn_| metric_init(foundations, fn_));

Expand Down Expand Up @@ -453,7 +461,7 @@ mod tests {
#[allow(non_upper_case_globals)]
static __oxy_Metrics: tarmac::reexports_for_macros::once_cell::sync::Lazy<__oxy_Metrics> =
tarmac::reexports_for_macros::once_cell::sync::Lazy::new(|| {
let registry = &mut *tarmac::telemetry::metrics::internal::Registries::get_main_subsystem(stringify!(oxy));
let registry = &mut *tarmac::telemetry::metrics::internal::Registries::get_subsystem(stringify!(oxy), false, true);

__oxy_Metrics {
connections_total: {
Expand Down Expand Up @@ -510,9 +518,83 @@ mod tests {
#[allow(non_upper_case_globals)]
static __oxy_Metrics: ::foundations::reexports_for_macros::once_cell::sync::Lazy<__oxy_Metrics> =
::foundations::reexports_for_macros::once_cell::sync::Lazy::new(|| {
let opt_registry = &mut *::foundations::telemetry::metrics::internal::Registries::get_opt_subsystem(stringify!(oxy));
let opt_registry = &mut *::foundations::telemetry::metrics::internal::Registries::get_subsystem(stringify!(oxy), true, true);

__oxy_Metrics {
connections_total: {
let metric = ::std::default::Default::default();

::foundations::reexports_for_macros::prometheus_client::registry::Registry::register(
opt_registry,
::std::stringify!(connections_total),
str::trim(" Total number of connections"),
::std::boxed::Box::new(::std::clone::Clone::clone(&metric))
);

metric
},
}
});

#[doc = " Total number of connections"]
#[must_use]
pub(crate) fn connections_total() -> Counter {
::std::clone::Clone::clone(&__oxy_Metrics.connections_total)
}
}
};

assert_eq!(actual, expected);
}

#[test]
fn expand_unprefixed_mixed() {
let attr = parse_attr! {
#[metrics(unprefixed)]
};

let src = parse_quote! {
pub(crate) mod oxy {
/// Total number of requests
pub(crate) fn requests_total() -> Counter;

/// Total number of connections
#[optional]
pub(crate) fn connections_total() -> Counter;
}
};

let actual = expand_from_parsed(attr, src).to_string();

let expected = code_str! {
pub(crate) mod oxy {
use super::*;

#[allow(non_camel_case_types)]
struct __oxy_Metrics {
requests_total: Counter,
connections_total: Counter,
}

#[allow(non_upper_case_globals)]
static __oxy_Metrics: ::foundations::reexports_for_macros::once_cell::sync::Lazy<__oxy_Metrics> =
::foundations::reexports_for_macros::once_cell::sync::Lazy::new(|| {
let registry = &mut *::foundations::telemetry::metrics::internal::Registries::get_subsystem(stringify!(oxy), false, false);
let opt_registry = &mut *::foundations::telemetry::metrics::internal::Registries::get_subsystem(stringify!(oxy), true, false);

__oxy_Metrics {
requests_total: {
let metric = ::std::default::Default::default();

::foundations::reexports_for_macros::prometheus_client::registry::Registry::register(
registry,
::std::stringify!(requests_total),
str::trim(" Total number of requests"),
::std::boxed::Box::new(::std::clone::Clone::clone(&metric))
);

metric
},
connections_total: {
let metric = ::std::default::Default::default();

Expand All @@ -528,6 +610,12 @@ mod tests {
}
});

#[doc = " Total number of requests"]
#[must_use]
pub(crate) fn requests_total() -> Counter {
::std::clone::Clone::clone(&__oxy_Metrics.requests_total)
}

#[doc = " Total number of connections"]
#[must_use]
pub(crate) fn connections_total() -> Counter {
Expand Down Expand Up @@ -596,7 +684,7 @@ mod tests {
#[allow(non_upper_case_globals)]
static __oxy_Metrics: ::foundations::reexports_for_macros::once_cell::sync::Lazy<__oxy_Metrics> =
::foundations::reexports_for_macros::once_cell::sync::Lazy::new(|| {
let registry = &mut *::foundations::telemetry::metrics::internal::Registries::get_main_subsystem(stringify!(oxy));
let registry = &mut *::foundations::telemetry::metrics::internal::Registries::get_subsystem(stringify!(oxy), false, true);

__oxy_Metrics {
connections_errors_total: {
Expand Down Expand Up @@ -691,7 +779,7 @@ mod tests {
#[allow(non_upper_case_globals)]
static __oxy_Metrics: ::foundations::reexports_for_macros::once_cell::sync::Lazy<__oxy_Metrics> =
::foundations::reexports_for_macros::once_cell::sync::Lazy::new(|| {
let registry = &mut *::foundations::telemetry::metrics::internal::Registries::get_main_subsystem(stringify!(oxy));
let registry = &mut *::foundations::telemetry::metrics::internal::Registries::get_subsystem(stringify!(oxy), false, true);

__oxy_Metrics {
connections_latency: {
Expand Down
110 changes: 52 additions & 58 deletions foundations/src/telemetry/metrics/internal.rs
View file
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Original file line number Diff line number Diff line change
Expand Up @@ -6,36 +6,53 @@ use prometheus_client::encoding::text::{encode, EncodeMetric};
use prometheus_client::registry::Registry;
use prometools::serde::InfoGauge;
use std::any::TypeId;
use std::borrow::Cow;
use std::collections::HashMap;
use std::ops::DerefMut;

static REGISTRIES: OnceCell<Registries> = OnceCell::new();

enum MetricsServiceName {
Prefix(String),
Label(String, String),
}

impl MetricsServiceName {
fn new(name: &str, format: ServiceNameFormat) -> Self {
let name = name.to_owned();
match format {
ServiceNameFormat::MetricPrefix => Self::Prefix(name),
ServiceNameFormat::LabelWithName(label) => Self::Label(label, name),
}
}
}

#[doc(hidden)]
pub struct Registries {
// NOTE: we intentionally use a lock without poisoning here to not
// panic the threads if they just share telemetry with failed thread.
main: parking_lot::RwLock<Registry>,
opt: parking_lot::RwLock<Registry>,
pub(super) info: parking_lot::RwLock<HashMap<TypeId, Box<dyn ErasedInfoMetric>>>,
extra_label: Option<(String, String)>,
service_name: MetricsServiceName,
extra_producers: parking_lot::RwLock<Vec<Box<dyn ExtraProducer>>>,
}

impl Registries {
pub(super) fn init(service_info: &ServiceInfo, settings: &MetricsSettings) {
let extra_label = match &settings.service_name_format {
ServiceNameFormat::MetricPrefix => None,
ServiceNameFormat::LabelWithName(name) => {
Some((name.clone(), service_info.name_in_metrics.clone()))
}
};
let service_name = MetricsServiceName::new(
&service_info.name_in_metrics,
settings.service_name_format.clone(),
);

// FIXME(nox): Due to prometheus-client 0.18 not supporting the creation of
// registries with specific label values, we use `MetricsServiceName::Label`
// directly in `Registries::get_subsystem`.
REGISTRIES.get_or_init(|| Registries {
main: new_registry(&service_info.name_in_metrics, &settings.service_name_format),
opt: new_registry(&service_info.name_in_metrics, &settings.service_name_format),
main: Default::default(),
opt: Default::default(),
info: Default::default(),
extra_label,
service_name,
extra_producers: Default::default(),
});
}
Expand Down Expand Up @@ -72,24 +89,31 @@ impl Registries {
encode_registry(buffer, &registry)
}

pub fn get_main_subsystem(subsystem: &str) -> impl DerefMut<Target = Registry> + '_ {
pub fn get_subsystem(
subsystem: &str,
optional: bool,
with_service_prefix: bool,
) -> impl DerefMut<Target = Registry> + 'static {
let registries = Self::get();
let registry = if optional {
&registries.opt
} else {
&registries.main
};

get_subsystem(
Self::get().main.write(),
subsystem,
registries.extra_label.clone(),
)
}

pub fn get_opt_subsystem(subsystem: &str) -> impl DerefMut<Target = Registry> + '_ {
let registries = Self::get();
let mut prefix = Cow::Borrowed(subsystem);
if with_service_prefix {
if let MetricsServiceName::Prefix(service) = &registries.service_name {
prefix = format!("{service}_{subsystem}").into();
}
}

get_subsystem(
Self::get().opt.write(),
subsystem,
registries.extra_label.clone(),
)
parking_lot::RwLockWriteGuard::map(registry.write(), move |mut reg| {
if let MetricsServiceName::Label(name, val) = &registries.service_name {
reg = reg.sub_registry_with_label((name.into(), val.into()));
}
reg.sub_registry_with_prefix(prefix)
})
}

pub fn add_extra_producer(&self, producer: Box<dyn ExtraProducer>) {
Expand All @@ -98,45 +122,15 @@ impl Registries {

pub(super) fn get() -> &'static Registries {
REGISTRIES.get_or_init(|| Registries {
main: new_registry("undefined", &ServiceNameFormat::MetricPrefix),
opt: new_registry("undefined", &ServiceNameFormat::MetricPrefix),
main: Default::default(),
opt: Default::default(),
info: Default::default(),
extra_label: None,
service_name: MetricsServiceName::Prefix("undefined".to_owned()),
extra_producers: Default::default(),
})
}
}

fn new_registry(
service_name_in_metrics: &str,
service_name_format: &ServiceNameFormat,
) -> parking_lot::RwLock<Registry> {
parking_lot::RwLock::new(match service_name_format {
ServiceNameFormat::MetricPrefix => match service_name_in_metrics {
"" => Registry::default(),
_ => Registry::with_prefix(service_name_in_metrics),
},
// FIXME(nox): Due to prometheus-client 0.18 not supporting the creation of
// registries with specific label values, we use this service identifier
// format directly in `Registries::get_main` and `Registries::get_optional`.
ServiceNameFormat::LabelWithName(_) => Registry::default(),
})
}

fn get_subsystem<'a>(
registry: parking_lot::RwLockWriteGuard<'a, Registry>,
subsystem: &str,
extra_label: Option<(String, String)>,
) -> impl DerefMut<Target = Registry> + 'a {
parking_lot::RwLockWriteGuard::map(registry, move |mut registry| {
if let Some((name, value)) = extra_label {
registry = registry.sub_registry_with_label((name.into(), value.into()));
}

registry.sub_registry_with_prefix(subsystem)
})
}

/// Build and version information
#[info_metric(crate_path = "crate")]
pub(super) struct BuildInfo {
Expand Down
4 changes: 3 additions & 1 deletion foundations/src/telemetry/metrics/mod.rs
View file
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Original file line number Diff line number Diff line change
Expand Up @@ -54,6 +54,9 @@ pub fn collect(settings: &MetricsSettings) -> Result<String> {
/// name becomes `<global prefix>_<module name>_<bodyless function name>`and function's
/// Rust doc comment is reported as metric description to Prometheus.
///
/// The `<global_prefix>` can be disabled by passing the `unprefixed` flag to the macro
/// invocation, like `#[metrics(unprefixed)]`. The module name is a mandatory prefix.
///
/// # Labels
/// Arguments of the bodyless functions become labels for that metric.
///
Expand Down Expand Up @@ -85,7 +88,6 @@ pub fn collect(settings: &MetricsSettings) -> Result<String> {
/// `collect_optional` argument of [`collect`] is set to `true`, or, in case the [telemetry server]
/// is used, if [`MetricsSettings::report_optional`] is set to `true`.
///
///
/// Can be used for heavy-weight metrics (e.g. with high cardinality) that don't need to be reported
/// on a regular basis.
///
Expand Down
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