Prometheus metrics service (#522)

* A wrapper crate for prometheus client

* Initial integration of metrics for mempool

* Merge mempool metrics imports

* Add cli flag to enable metrics

* Add nomos metrics service for serving metrics

* Use nomos prometheus metrics in the node

* Rename metrics to registry where applicable

* Expose metrics via http

* Featuregate the metrics service

* Style and fail on encode error

* Add metrics cargo feature for mempool

Cargo.toml

@@ -3,6 +3,7 @@ members = [
     "nomos-core",
     "nomos-libp2p",
     "nomos-services/api",
+    "nomos-metrics",
     "nomos-services/log",
     "nomos-services/metrics",
     "nomos-services/network",

nodes/nomos-node/Cargo.toml

@@ -23,7 +23,8 @@ nomos-core = { path = "../../nomos-core" }
 nomos-network = { path = "../../nomos-services/network", features = ["libp2p"] }
 nomos-api = { path = "../../nomos-services/api" }
 nomos-log = { path = "../../nomos-services/log" }
-nomos-mempool = { path = "../../nomos-services/mempool", features = ["mock", "libp2p"] }
+nomos-mempool = { path = "../../nomos-services/mempool", features = ["mock", "libp2p", "metrics"] }
+nomos-metrics = { path = "../../nomos-metrics" }
 nomos-http = { path = "../../nomos-services/http", features = ["http"] }
 carnot-consensus = { path = "../../nomos-services/carnot-consensus", features = ["libp2p"] }
 nomos-storage = { path = "../../nomos-services/storage", features = ["sled"] }

nodes/nomos-node/src/api.rs

@@ -3,10 +3,13 @@ use std::{fmt::Debug, hash::Hash};
 use axum::{
     extract::{Query, State},
     http::HeaderValue,
-    response::Response,
+    response::{IntoResponse, Response},
     routing, Json, Router, Server,
 };
-use hyper::header::{CONTENT_TYPE, USER_AGENT};
+use hyper::{
+    header::{CONTENT_TYPE, USER_AGENT},
+    Body, StatusCode,
+};
 use overwatch_rs::overwatch::handle::OverwatchHandle;
 use serde::{de::DeserializeOwned, Deserialize, Serialize};
 use tower_http::{
@@ -24,7 +27,7 @@ use nomos_network::backends::libp2p::Libp2p;
 use nomos_storage::backends::StorageSerde;
 
 use nomos_api::{
-    http::{cl, consensus, da, libp2p, mempool, storage},
+    http::{cl, consensus, da, libp2p, mempool, metrics, storage},
     Backend,
 };
 
@@ -123,6 +126,7 @@ where
             .route("/storage/block", routing::post(block::<S, T>))
             .route("/mempool/add/tx", routing::post(add_tx::<T>))
             .route("/mempool/add/cert", routing::post(add_cert))
+            .route("/metrics", routing::get(get_metrics))
             .with_state(handle);
 
         Server::bind(&self.settings.address)
@@ -350,3 +354,29 @@ async fn add_cert(
         nomos_core::da::certificate::Certificate::hash
     ))
 }
+
+#[utoipa::path(
+    get,
+    path = "/metrics",
+    responses(
+        (status = 200, description = "Get all metrics"),
+        (status = 500, description = "Internal server error", body = String),
+    )
+)]
+async fn get_metrics(State(handle): State<OverwatchHandle>) -> Response {
+    match metrics::gather(&handle).await {
+        Ok(encoded_metrics) => Response::builder()
+            .status(StatusCode::OK)
+            .header(
+                CONTENT_TYPE,
+                HeaderValue::from_static("text/plain; version=0.0.4"),
+            )
+            .body(Body::from(encoded_metrics))
+            .unwrap()
+            .into_response(),
+        Err(e) => axum::response::IntoResponse::into_response((
+            hyper::StatusCode::INTERNAL_SERVER_ERROR,
+            e.to_string(),
+        )),
+    }
+}

nodes/nomos-node/src/config.rs

@@ -10,8 +10,6 @@ use crate::{Carnot, Tx, Wire, MB16};
 use clap::{Parser, ValueEnum};
 use color_eyre::eyre::{self, eyre, Result};
 use hex::FromHex;
-#[cfg(feature = "metrics")]
-use metrics::{backend::map::MapMetricsBackend, types::MetricsData, MetricsService};
 use nomos_api::ApiService;
 use nomos_libp2p::{secp256k1::SecretKey, Multiaddr};
 use nomos_log::{Logger, LoggerBackend, LoggerFormat};
@@ -115,14 +113,18 @@ pub struct DaArgs {
     da_voter: Option<String>,
 }
 
+#[derive(Parser, Debug, Clone)]
+pub struct MetricsArgs {
+    #[clap(long = "with-metrics", env = "WITH_METRICS")]
+    pub with_metrics: bool,
+}
+
 #[derive(Deserialize, Debug, Clone, Serialize)]
 pub struct Config {
     pub log: <Logger as ServiceData>::Settings,
     pub network: <NetworkService<Libp2p> as ServiceData>::Settings,
     pub http: <ApiService<AxumBackend<Tx, Wire, MB16>> as ServiceData>::Settings,
     pub consensus: <Carnot as ServiceData>::Settings,
-    #[cfg(feature = "metrics")]
-    pub metrics: <MetricsService<MapMetricsBackend<MetricsData>> as ServiceData>::Settings,
     pub da: <DataAvailability as ServiceData>::Settings,
 }
 

nodes/nomos-node/src/lib.rs

@@ -29,13 +29,17 @@ use nomos_mempool::{
     backend::mockpool::MockPool, Certificate as CertDiscriminant, MempoolService,
     Transaction as TxDiscriminant,
 };
+#[cfg(feature = "metrics")]
+use nomos_metrics::Metrics;
 use nomos_network::backends::libp2p::Libp2p;
 use nomos_storage::{
     backends::{sled::SledBackend, StorageSerde},
     StorageService,
 };
 
-pub use config::{Config, ConsensusArgs, DaArgs, HttpArgs, LogArgs, NetworkArgs, OverlayArgs};
+pub use config::{
+    Config, ConsensusArgs, DaArgs, HttpArgs, LogArgs, MetricsArgs, NetworkArgs, OverlayArgs,
+};
 use nomos_core::{
     da::certificate::select::FillSize as FillSizeWithBlobsCertificate,
     tx::select::FillSize as FillSizeWithTx,
@@ -89,10 +93,10 @@ pub struct Nomos {
     >,
     consensus: ServiceHandle<Carnot>,
     http: ServiceHandle<ApiService<AxumBackend<Tx, Wire, MB16>>>,
-    #[cfg(feature = "metrics")]
-    metrics: ServiceHandle<MetricsService<MapMetricsBackend<MetricsData>>>,
     da: ServiceHandle<DataAvailability>,
     storage: ServiceHandle<StorageService<SledBackend<Wire>>>,
+    #[cfg(feature = "metrics")]
+    metrics: ServiceHandle<Metrics>,
     system_sig: ServiceHandle<SystemSig>,
 }
 

nodes/nomos-node/src/main.rs

@@ -1,7 +1,9 @@
 use full_replication::{Blob, Certificate};
+#[cfg(feature = "metrics")]
+use nomos_metrics::MetricsSettings;
 use nomos_node::{
-    Config, ConsensusArgs, DaArgs, HttpArgs, LogArgs, NetworkArgs, Nomos, NomosServiceSettings,
+    Config, ConsensusArgs, DaArgs, HttpArgs, LogArgs, MetricsArgs, NetworkArgs, Nomos,
-    OverlayArgs, Tx,
+    NomosServiceSettings, OverlayArgs, Tx,
 };
 
 use clap::Parser;
@@ -40,6 +42,9 @@ struct Args {
     /// Overrides da config.
     #[clap(flatten)]
     da_args: DaArgs,
+    /// Overrides metrics config.
+    #[clap(flatten)]
+    metrics_args: MetricsArgs,
 }
 
 fn main() -> Result<()> {
@@ -51,6 +56,7 @@ fn main() -> Result<()> {
         network_args,
         consensus_args,
         overlay_args,
+        metrics_args,
     } = Args::parse();
     let config = serde_yaml::from_reader::<_, Config>(std::fs::File::open(config)?)?
         .update_da(da_args)?
@@ -60,6 +66,14 @@ fn main() -> Result<()> {
         .update_overlay(overlay_args)?
         .update_network(network_args)?;
 
+    let registry = cfg!(feature = "metrics")
+        .then(|| {
+            metrics_args
+                .with_metrics
+                .then(nomos_metrics::NomosRegistry::default)
+        })
+        .flatten();
+
     let app = OverwatchRunner::<Nomos>::run(
         NomosServiceSettings {
             network: config.network,
@@ -71,6 +85,7 @@ fn main() -> Result<()> {
                     topic: String::from(nomos_node::CL_TOPIC),
                     id: <Tx as Transaction>::hash,
                 },
+                registry: registry.clone(),
             },
             da_mempool: nomos_mempool::Settings {
                 backend: (),
@@ -78,10 +93,11 @@ fn main() -> Result<()> {
                     topic: String::from(nomos_node::DA_TOPIC),
                     id: cert_id,
                 },
+                registry: registry.clone(),
             },
             consensus: config.consensus,
             #[cfg(feature = "metrics")]
-            metrics: config.metrics,
+            metrics: MetricsSettings { registry },
             da: config.da,
             storage: nomos_storage::backends::sled::SledBackendSettings {
                 db_path: std::path::PathBuf::from(DEFAULT_DB_PATH),

nomos-metrics/Cargo.toml

@@ -0,0 +1,16 @@
+[package]
+name = "nomos-metrics"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+async-trait = "0.1"
+futures = "0.3"
+overwatch-rs = { git = "https://github.com/logos-co/Overwatch", rev = "2f70806" }
+overwatch-derive = { git = "https://github.com/logos-co/Overwatch", rev = "ac28d01" }
+prometheus-client = "0.22.0"
+tracing = "0.1"
+tokio = { version = "1", features = ["sync", "macros"] }
+serde = { version = "1", features = ["derive"] }

nomos-metrics/src/lib.rs

@@ -0,0 +1,119 @@
+pub use prometheus_client::{self, *};
+
+// std
+use std::fmt::{Debug, Error, Formatter};
+use std::sync::{Arc, Mutex};
+// crates
+use futures::StreamExt;
+use overwatch_rs::services::life_cycle::LifecycleMessage;
+use overwatch_rs::services::{
+    handle::ServiceStateHandle,
+    relay::RelayMessage,
+    state::{NoOperator, NoState},
+    ServiceCore, ServiceData,
+};
+use prometheus_client::encoding::text::encode;
+use prometheus_client::registry::Registry;
+use tokio::sync::oneshot::Sender;
+use tracing::error;
+// internal
+
+// A wrapper for prometheus_client Registry.
+// Lock is only used during services initialization and prometheus pull query.
+pub type NomosRegistry = Arc<Mutex<Registry>>;
+
+pub struct Metrics {
+    service_state: ServiceStateHandle<Self>,
+    registry: NomosRegistry,
+}
+
+#[derive(Clone, Debug)]
+pub struct MetricsSettings {
+    pub registry: Option<NomosRegistry>,
+}
+
+pub enum MetricsMsg {
+    Gather { reply_channel: Sender<String> },
+}
+
+impl RelayMessage for MetricsMsg {}
+
+impl Debug for MetricsMsg {
+    fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error> {
+        match self {
+            Self::Gather { .. } => {
+                write!(f, "MetricsMsg::Gather")
+            }
+        }
+    }
+}
+
+impl ServiceData for Metrics {
+    const SERVICE_ID: &'static str = "Metrics";
+    type Settings = MetricsSettings;
+    type State = NoState<Self::Settings>;
+    type StateOperator = NoOperator<Self::State>;
+    type Message = MetricsMsg;
+}
+
+#[async_trait::async_trait]
+impl ServiceCore for Metrics {
+    fn init(service_state: ServiceStateHandle<Self>) -> Result<Self, overwatch_rs::DynError> {
+        let config = service_state.settings_reader.get_updated_settings();
+
+        Ok(Self {
+            service_state,
+            registry: config.registry.ok_or("No registry provided")?,
+        })
+    }
+
+    async fn run(self) -> Result<(), overwatch_rs::DynError> {
+        let Self {
+            mut service_state,
+            registry,
+        } = self;
+        let mut lifecycle_stream = service_state.lifecycle_handle.message_stream();
+        loop {
+            tokio::select! {
+                Some(msg) = service_state.inbound_relay.recv() => {
+                    let MetricsMsg::Gather{reply_channel} = msg;
+
+                    let mut buf = String::new();
+                    {
+                        let reg = registry.lock().unwrap();
+                        // If encoding fails, we need to stop trying process subsequent metrics gather
+                        // requests. If it succeds, encode method returns empty unit type.
+                        _ = encode(&mut buf, &reg).map_err(|e| std::io::Error::new(std::io::ErrorKind::Other, e))?;
+                    }
+
+                    reply_channel
+                        .send(buf)
+                        .unwrap_or_else(|_| tracing::debug!("could not send back metrics"));
+                }
+                Some(msg) = lifecycle_stream.next() =>  {
+                    if Self::should_stop_service(msg).await {
+                        break;
+                    }
+                }
+            }
+        }
+        Ok(())
+    }
+}
+
+impl Metrics {
+    async fn should_stop_service(message: LifecycleMessage) -> bool {
+        match message {
+            LifecycleMessage::Shutdown(sender) => {
+                if sender.send(()).is_err() {
+                    error!(
+                        "Error sending successful shutdown signal from service {}",
+                        Self::SERVICE_ID
+                    );
+                }
+                true
+            }
+            LifecycleMessage::Kill => true,
+        }
+    }
+}

nomos-services/api/Cargo.toml

@@ -19,6 +19,7 @@ carnot-consensus = { path = "../carnot-consensus" }
 nomos-network = { path = "../../nomos-services/network" }
 nomos-da = { path = "../../nomos-services/data-availability" }
 nomos-mempool = { path = "../../nomos-services/mempool", features = ["mock", "libp2p", "openapi"] }
+nomos-metrics = { path = "../../nomos-metrics" }
 nomos-storage = { path = "../../nomos-services/storage", features = ["sled"] }
 nomos-libp2p = { path = "../../nomos-libp2p" }
 full-replication = { path = "../../nomos-da/full-replication" }

nomos-services/api/src/http/metrics.rs

@@ -0,0 +1,18 @@
+use nomos_metrics::{Metrics, MetricsMsg};
+use tokio::sync::oneshot;
+
+pub async fn gather(
+    handle: &overwatch_rs::overwatch::handle::OverwatchHandle,
+) -> Result<String, super::DynError> {
+    let relay = handle.relay::<Metrics>().connect().await?;
+    let (sender, receiver) = oneshot::channel();
+
+    relay
+        .send(MetricsMsg::Gather {
+            reply_channel: sender,
+        })
+        .await
+        .map_err(|(e, _)| e)?;
+
+    Ok(receiver.await?)
+}

nomos-services/api/src/http/mod.rs

@@ -4,4 +4,5 @@ pub mod consensus;
 pub mod da;
 pub mod libp2p;
 pub mod mempool;
+pub mod metrics;
 pub mod storage;

nomos-services/mempool/Cargo.toml

@@ -10,6 +10,7 @@ async-trait = "0.1"
 bincode = { version = "2.0.0-rc.2", features = ["serde"] }
 futures = "0.3"
 linked-hash-map = { version = "0.5.6", optional = true }
+nomos-metrics = { path = "../../nomos-metrics" }
 nomos-network = { path = "../network" }
 nomos-core = { path = "../../nomos-core" }
 overwatch-rs = { git = "https://github.com/logos-co/Overwatch", rev = "2f70806" }
@@ -34,6 +35,7 @@ blake2 = "0.10"
 default = []
 mock = ["linked-hash-map", "nomos-network/mock", "rand", "nomos-core/mock"]
 libp2p = ["nomos-network/libp2p"]
+metrics = []
 
 # enable to help generate OpenAPI
 openapi = ["dep:utoipa", "serde_json"]

nomos-services/mempool/src/lib.rs

@@ -1,4 +1,6 @@
 pub mod backend;
+#[cfg(feature = "metrics")]
+pub mod metrics;
 pub mod network;
 
 /// Re-export for OpenAPI
@@ -15,6 +17,9 @@ use std::{
 
 // crates
 use futures::StreamExt;
+#[cfg(feature = "metrics")]
+use metrics::Metrics;
+use nomos_metrics::NomosRegistry;
 use tokio::sync::oneshot::Sender;
 // internal
 use crate::network::NetworkAdapter;
@@ -42,6 +47,8 @@ where
     service_state: ServiceStateHandle<Self>,
     network_relay: Relay<NetworkService<N::Backend>>,
     pool: P,
+    #[cfg(feature = "metrics")]
+    metrics: Option<Metrics>,
     // This is an hack because SERVICE_ID has to be univoque and associated const
     // values can't depend on generic parameters.
     // Unfortunately, this means that the mempools for certificates and transactions
@@ -162,10 +169,18 @@ where
     fn init(service_state: ServiceStateHandle<Self>) -> Result<Self, overwatch_rs::DynError> {
         let network_relay = service_state.overwatch_handle.relay();
         let settings = service_state.settings_reader.get_updated_settings();
+
+        #[cfg(feature = "metrics")]
+        let metrics = settings
+            .registry
+            .map(|reg| Metrics::new(reg, service_state.id()));
+
         Ok(Self {
             service_state,
             network_relay,
             pool: P::new(settings.backend),
+            #[cfg(feature = "metrics")]
+            metrics,
             _d: PhantomData,
         })
     }
@@ -195,6 +210,8 @@ where
         loop {
             tokio::select! {
                 Some(msg) = service_state.inbound_relay.recv() => {
+                    #[cfg(feature = "metrics")]
+                    if let Some(metrics) = &self.metrics { metrics.record(&msg) }
                     Self::handle_mempool_message(msg, &mut pool, &mut network_relay, &mut service_state).await;
                 }
                 Some((key, item )) = network_items.next() => {
@@ -317,4 +334,5 @@ where
 pub struct Settings<B, N> {
     pub backend: B,
     pub network: N,
+    pub registry: Option<NomosRegistry>,
 }

nomos-services/mempool/src/metrics.rs

@@ -0,0 +1,80 @@
+// std
+use std::fmt::Debug;
+// crates
+use nomos_metrics::{
+    metrics::{counter::Counter, family::Family},
+    prometheus_client::{self, encoding::EncodeLabelSet, encoding::EncodeLabelValue},
+    NomosRegistry,
+};
+use overwatch_rs::services::ServiceId;
+// internal
+use crate::MempoolMsg;
+
+#[derive(Debug, Clone, Hash, PartialEq, Eq, EncodeLabelValue)]
+enum MempoolMsgType {
+    Add,
+    View,
+    Prune,
+    MarkInBlock,
+}
+
+impl<I, K> From<&MempoolMsg<I, K>> for MempoolMsgType
+where
+    I: 'static + Debug,
+    K: 'static + Debug,
+{
+    fn from(event: &MempoolMsg<I, K>) -> Self {
+        match event {
+            MempoolMsg::Add { .. } => MempoolMsgType::Add,
+            MempoolMsg::View { .. } => MempoolMsgType::View,
+            MempoolMsg::Prune { .. } => MempoolMsgType::Prune,
+            MempoolMsg::MarkInBlock { .. } => MempoolMsgType::MarkInBlock,
+            _ => unimplemented!(),
+        }
+    }
+}
+
+#[derive(Debug, Clone, Hash, PartialEq, Eq, EncodeLabelSet)]
+struct MessageLabels {
+    label: MempoolMsgType,
+}
+
+pub(crate) struct Metrics {
+    messages: Family<MessageLabels, Counter>,
+}
+
+impl Metrics {
+    pub(crate) fn new(registry: NomosRegistry, discriminant: ServiceId) -> Self {
+        let mut registry = registry
+            .lock()
+            .expect("should've acquired the lock for registry");
+        let sub_registry = registry.sub_registry_with_prefix(discriminant);
+
+        let messages = Family::default();
+        sub_registry.register(
+            "messages",
+            "Messages emitted by the Mempool",
+            messages.clone(),
+        );
+
+        Self { messages }
+    }
+
+    pub(crate) fn record<I, K>(&self, msg: &MempoolMsg<I, K>)
+    where
+        I: 'static + Debug,
+        K: 'static + Debug,
+    {
+        match msg {
+            MempoolMsg::Add { .. }
+            | MempoolMsg::View { .. }
+            | MempoolMsg::Prune { .. }
+            | MempoolMsg::MarkInBlock { .. } => {
+                self.messages
+                    .get_or_create(&MessageLabels { label: msg.into() })
+                    .inc();
+            }
+            _ => {}
+        }
+    }
+}

nomos-services/mempool/tests/mock.rs

@@ -64,6 +64,7 @@ fn test_mockmempool() {
             mockpool: Settings {
                 backend: (),
                 network: (),
+                registry: None,
             },
             logging: LoggerSettings::default(),
         },