Expose relay version metric (#1750)

* expose relay version metric

* spelling

* and clippy

* clippy

* typo

* use version directly and determine git commit

* typos and leftovers

relays/bin-substrate/Cargo.toml

@@ -15,6 +15,7 @@ hex = "0.4"
 log = "0.4.17"
 num-format = "0.4"
 num-traits = "0.2"
+rbtag = "0.3"
 structopt = "0.3"
 signal-hook = "0.3.14"
 signal-hook-async-std = "0.2.2"

relays/bin-substrate/src/cli/mod.rs

@@ -21,6 +21,7 @@ use std::convert::TryInto;
 use async_std::prelude::*;
 use codec::{Decode, Encode};
 use futures::{select, FutureExt};
+use rbtag::BuildInfo;
 use signal_hook::consts::*;
 use signal_hook_async_std::Signals;
 use structopt::{clap::arg_enum, StructOpt};
@@ -254,17 +255,30 @@ pub struct PrometheusParams {
 	pub prometheus_port: u16,
 }
 
-impl From<PrometheusParams> for relay_utils::metrics::MetricsParams {
-	fn from(cli_params: PrometheusParams) -> relay_utils::metrics::MetricsParams {
-		if !cli_params.no_prometheus {
+/// Struct to get git commit info and build time.
+#[derive(BuildInfo)]
+struct SubstrateRelayBuildInfo;
+
+impl PrometheusParams {
+	/// Tries to convert CLI metrics params into metrics params, used by the relay.
+	pub fn into_metrics_params(self) -> anyhow::Result<relay_utils::metrics::MetricsParams> {
+		let metrics_address = if !self.no_prometheus {
 			Some(relay_utils::metrics::MetricsAddress {
-				host: cli_params.prometheus_host,
-				port: cli_params.prometheus_port,
+				host: self.prometheus_host,
+				port: self.prometheus_port,
 			})
-			.into()
 		} else {
-			None.into()
-		}
+			None
+		};
+
+		let relay_version = option_env!("CARGO_PKG_VERSION").unwrap_or("unknown");
+		let relay_commit = SubstrateRelayBuildInfo.get_build_commit();
+		relay_utils::metrics::MetricsParams::new(
+			metrics_address,
+			relay_version.into(),
+			relay_commit.into(),
+		)
+		.map_err(|e| anyhow::format_err!("{:?}", e))
 	}
 }
 

relays/bin-substrate/src/cli/relay_headers.rs

@@ -77,7 +77,8 @@ where
 		let target_transactions_mortality = data.target_sign.target_transactions_mortality;
 		let target_sign = data.target_sign.to_keypair::<Self::Target>()?;
 
-		let metrics_params: relay_utils::metrics::MetricsParams = data.prometheus_params.into();
+		let metrics_params: relay_utils::metrics::MetricsParams =
+			data.prometheus_params.into_metrics_params()?;
 		GlobalMetrics::new()?.register_and_spawn(&metrics_params.registry)?;
 
 		let target_transactions_params = substrate_relay_helper::TransactionParams {

relays/bin-substrate/src/cli/relay_headers_and_messages/mod.rs

@@ -110,7 +110,7 @@ impl<Left: ChainWithTransactions + CliChain, Right: ChainWithTransactions + CliC
 		right: BridgeEndCommonParams<Right>,
 	) -> anyhow::Result<Self> {
 		// Create metrics registry.
-		let metrics_params = shared.prometheus_params.clone().into();
+		let metrics_params = shared.prometheus_params.clone().into_metrics_params()?;
 		let metrics_params = relay_utils::relay_metrics(metrics_params).into_params();
 
 		Ok(Self { shared, left, right, metrics_params })

relays/bin-substrate/src/cli/relay_messages.rs

@@ -83,7 +83,7 @@ where
 			source_to_target_headers_relay: None,
 			target_to_source_headers_relay: None,
 			lane_id: data.lane.into(),
-			metrics_params: data.prometheus_params.into(),
+			metrics_params: data.prometheus_params.into_metrics_params()?,
 		})
 		.await
 		.map_err(|e| anyhow::format_err!("{}", e))

relays/bin-substrate/src/cli/relay_parachains.rs

@@ -98,7 +98,8 @@ where
 			target_transaction_params,
 		);
 
-		let metrics_params: relay_utils::metrics::MetricsParams = data.prometheus_params.into();
+		let metrics_params: relay_utils::metrics::MetricsParams =
+			data.prometheus_params.into_metrics_params()?;
 		GlobalMetrics::new()?.register_and_spawn(&metrics_params.registry)?;
 
 		parachains_relay::parachains_loop::run(

relays/utils/src/metrics.rs

@@ -99,6 +99,39 @@ impl Default for MetricsAddress {
 }
 
 impl MetricsParams {
+	/// Creates metrics params from metrics address.
+	pub fn new(
+		address: Option<MetricsAddress>,
+		relay_version: String,
+		relay_commit: String,
+	) -> Result<Self, PrometheusError> {
+		const BUILD_INFO_METRIC: &str = "substrate_relay_build_info";
+
+		let registry = Registry::new();
+		register(
+			Gauge::<U64>::with_opts(
+				Opts::new(
+					BUILD_INFO_METRIC,
+					"A metric with a constant '1' value labeled by version",
+				)
+				.const_label("version", &relay_version)
+				.const_label("commit", &relay_commit),
+			)?,
+			&registry,
+		)?
+		.set(1);
+
+		log::info!(
+			target: "bridge",
+			"Exposed {} metric: version={} commit={}",
+			BUILD_INFO_METRIC,
+			relay_version,
+			relay_commit,
+		);
+
+		Ok(MetricsParams { address, registry })
+	}
+
 	/// Creates metrics params so that metrics are not exposed.
 	pub fn disabled() -> Self {
 		MetricsParams { address: None, registry: Registry::new() }
@@ -112,12 +145,6 @@ impl MetricsParams {
 	}
 }
 
-impl From<Option<MetricsAddress>> for MetricsParams {
-	fn from(address: Option<MetricsAddress>) -> Self {
-		MetricsParams { address, registry: Registry::new() }
-	}
-}
-
 /// Returns metric name optionally prefixed with given prefix.
 pub fn metric_name(prefix: Option<&str>, name: &str) -> String {
 	if let Some(prefix) = prefix {