// Copyright (C) Parity Technologies (UK) Ltd.

// This file is part of Polkadot.

// Polkadot is free software: you can redistribute it and/or modify

// it under the terms of the GNU General Public License as published by

// the Free Software Foundation, either version 3 of the License, or

// (at your option) any later version.

// Polkadot is distributed in the hope that it will be useful,

// but WITHOUT ANY WARRANTY; without even the implied warranty of

// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License

// along with Polkadot.  If not, see <http://www.gnu.org/licenses/>.

//! Metrics helpers

//!

//! Collects a bunch of metrics providers and related features such as

//! `Metronome` for usage with metrics collections.

//!

//! This crate also reexports Prometheus metric types which are expected to be implemented by

//! subsystems.

#![deny(missing_docs)]

#![deny(unused_imports)]

pub use metered;

/// Cyclic metric collection support.

pub mod metronome;

pub use self::metronome::Metronome;

#[cfg(feature = "runtime-metrics")]

pub mod runtime;

#[cfg(feature = "runtime-metrics")]

pub use self::runtime::logger_hook;

/// Export a dummy logger hook when the `runtime-metrics` feature is not enabled.

#[cfg(not(feature = "runtime-metrics"))]

/// This module reexports Prometheus types and defines the [`Metrics`](metrics::Metrics) trait.

pub mod metrics {

	/// Reexport Substrate Prometheus types.

	pub use prometheus_endpoint as prometheus;

	/// Subsystem- or job-specific Prometheus metrics.

	///

	/// Usually implemented as a wrapper for `Option<ActualMetrics>`

	/// to ensure `Default` bounds or as a dummy type ().

	/// Prometheus metrics internally hold an `Arc` reference, so cloning them is fine.

	pub trait Metrics: Default + Clone {

		/// Try to register metrics in the Prometheus registry.

		fn try_register(

			registry: &prometheus::Registry,

		) -> Result<Self, prometheus::PrometheusError>;

		/// Convenience method to register metrics in the optional Prometheus registry.

		///

		/// If no registry is provided, returns `Default::default()`. Otherwise, returns the same

		/// thing that `try_register` does.

			}

	}

	// dummy impl

	impl Metrics for () {

	}

}

#[cfg(all(feature = "runtime-metrics", not(feature = "runtime-benchmarks"), test))]

mod tests;