feat: prometheus metrics

Prometheus metrics exposed at /metrics

Cargo.lock

@@ -1207,6 +1207,7 @@ dependencies = [
  "lazy_static",
  "nonzero_ext",
  "parse_duration",
+ "prometheus",
  "r2d2",
  "r2d2_sqlite",
  "rand 0.8.5",
@@ -1545,6 +1546,21 @@ dependencies = [
  "unicode-ident",
 ]
 
+[[package]]
+name = "prometheus"
+version = "0.13.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "449811d15fbdf5ceb5c1144416066429cf82316e2ec8ce0c1f6f8a02e7bbcf8c"
+dependencies = [
+ "cfg-if",
+ "fnv",
+ "lazy_static",
+ "memchr",
+ "parking_lot",
+ "protobuf",
+ "thiserror",
+]
+
 [[package]]
 name = "prost"
 version = "0.11.6"
@@ -1578,6 +1594,12 @@ dependencies = [
  "prost",
 ]
 
+[[package]]
+name = "protobuf"
+version = "2.28.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "106dd99e98437432fed6519dedecfade6a06a73bb7b2a1e019fdd2bee5778d94"
+
 [[package]]
 name = "quanta"
 version = "0.9.3"

Cargo.toml

@@ -43,6 +43,7 @@ rand = "0.8"
 const_format = "0.2.28"
 regex = "1"
 async-trait = "0.1.60"
+prometheus = "0.13.3"
 
 [dev-dependencies]
 anyhow = "1"

src/db.rs

@@ -3,6 +3,7 @@ use crate::config::Settings;
 use crate::error::{Error, Result};
 use crate::event::Event;
 use crate::notice::Notice;
+use crate::server::NostrMetrics;
 use governor::clock::Clock;
 use governor::{Quota, RateLimiter};
 use r2d2;
@@ -29,15 +30,15 @@ pub const DB_FILE: &str = "nostr.db";
 /// # Panics
 ///
 /// Will panic if the pool could not be created.
-pub async fn build_repo(settings: &Settings) -> Arc<dyn NostrRepo> {
+pub async fn build_repo(settings: &Settings, metrics: NostrMetrics) -> Arc<dyn NostrRepo> {
     match settings.database.engine.as_str() {
-        "sqlite" => {Arc::new(build_sqlite_pool(settings).await)},
+        "sqlite" => {Arc::new(build_sqlite_pool(settings, metrics).await)},
         _ => panic!("Unknown database engine"),
     }
 }
 
-async fn build_sqlite_pool(settings: &Settings) -> SqliteRepo {
-    let repo = SqliteRepo::new(settings);
+async fn build_sqlite_pool(settings: &Settings, metrics: NostrMetrics) -> SqliteRepo {
+    let repo = SqliteRepo::new(settings, metrics);
     repo.start().await.ok();
     repo.migrate_up().await.ok();
     repo

src/repo/sqlite.rs

@@ -9,6 +9,7 @@ use crate::repo::sqlite_migration::{STARTUP_SQL,upgrade_db};
 use crate::utils::{is_hex, is_lower_hex};
 use crate::nip05::{Nip05Name, VerificationRecord};
 use crate::subscription::{ReqFilter, Subscription};
+use crate::server::NostrMetrics;
 use hex;
 use r2d2;
 use r2d2_sqlite::SqliteConnectionManager;
@@ -35,6 +36,8 @@ pub const DB_FILE: &str = "nostr.db";
 
 #[derive(Clone)]
 pub struct SqliteRepo {
+    /// Metrics
+    metrics: NostrMetrics,
     /// Pool for reading events and NIP-05 status
     read_pool: SqlitePool,
     /// Pool for writing events and NIP-05 verification
@@ -49,7 +52,7 @@ pub struct SqliteRepo {
 
 impl SqliteRepo {
     // build all the pools needed
-    #[must_use] pub fn new(settings: &Settings) -> SqliteRepo {
+    #[must_use] pub fn new(settings: &Settings, metrics: NostrMetrics) -> SqliteRepo {
         let maint_pool = build_pool(
             "maintenance",
             settings,
@@ -82,6 +85,7 @@ impl SqliteRepo {
         let write_in_progress = Arc::new(Mutex::new(0));
 
         SqliteRepo {
+	    metrics,
             read_pool,
             write_pool,
             maint_pool,
@@ -235,13 +239,18 @@ impl NostrRepo for SqliteRepo {
     }
     /// Persist event to database
     async fn write_event(&self, e: &Event) -> Result<u64> {
+	let start = Instant::now();
         let _write_guard = self.write_in_progress.lock().await;
         // spawn a blocking thread
         let mut conn = self.write_pool.get()?;
         let e = e.clone();
-        task::spawn_blocking(move || {
+        let event_count = task::spawn_blocking(move || {
             SqliteRepo::persist_event(&mut conn, &e)
-        }).await?
+        }).await?;
+	self.metrics
+            .write_events
+            .observe(start.elapsed().as_secs_f64());
+	event_count
     }
 
     /// Perform a database query using a subscription.
@@ -259,6 +268,7 @@ impl NostrRepo for SqliteRepo {
     ) -> Result<()> {
         let pre_spawn_start = Instant::now();
         let self=self.clone();
+	let metrics=self.metrics.clone();
         task::spawn_blocking(move || {
             {
                 // if we are waiting on a checkpoint, stop until it is complete
@@ -392,6 +402,9 @@ impl NostrRepo for SqliteRepo {
             } else {
                 warn!("Could not get a database connection for querying");
             }
+	    metrics
+		.query_sub
+		.observe(pre_spawn_start.elapsed().as_secs_f64());
             let ok: Result<()> = Ok(());
             ok
         });

src/server.rs

@@ -13,6 +13,7 @@ use crate::info::RelayInfo;
 use crate::nip05;
 use crate::notice::Notice;
 use crate::subscription::Subscription;
+use prometheus::{CounterVec, Encoder, Histogram, HistogramOpts, Opts, Registry, TextEncoder};
 use futures::SinkExt;
 use futures::StreamExt;
 use governor::{Jitter, Quota, RateLimiter};
@@ -55,6 +56,8 @@ async fn handle_web_request(
     broadcast: Sender<Event>,
     event_tx: tokio::sync::mpsc::Sender<SubmittedEvent>,
     shutdown: Receiver<()>,
+    registry: Registry,
+    metrics: NostrMetrics,
 ) -> Result<Response<Body>, Infallible> {
     match (
         request.uri().path(),
@@ -116,6 +119,7 @@ async fn handle_web_request(
                                     broadcast,
                                     event_tx,
                                     shutdown,
+                                    metrics,
                                 ));
                             }
                             // todo: trace, don't print...
@@ -168,6 +172,18 @@ async fn handle_web_request(
                .body(Body::from("Please use a Nostr client to connect."))
                .unwrap())
         }
+        ("/metrics", false) => {
+            let mut buffer = vec![];
+            let encoder = TextEncoder::new();
+            let metric_families = registry.gather();
+            encoder.encode(&metric_families, &mut buffer).unwrap();
+
+            Ok(Response::builder()
+               .status(StatusCode::OK)
+               .header("Content-Type", "text/plain")
+               .body(Body::from(buffer))
+               .unwrap())
+        }
         (_, _) => {
             //handle any other url
             Ok(Response::builder()
@@ -293,8 +309,35 @@ pub fn start_server(settings: &Settings, shutdown_rx: MpscReceiver<()>) -> Resul
         // overwhelming this will drop events and won't register
         // metadata events.
         let (metadata_tx, metadata_rx) = broadcast::channel::<Event>(4096);
+
+        // setup prometheus registry
+        let registry = Registry::new();
+
+        let query_sub = Histogram::with_opts(HistogramOpts::new(
+            "query_sub",
+            "Subscription response times",
+        ))
+        .unwrap();
+        let write_events = Histogram::with_opts(HistogramOpts::new(
+            "write_event",
+            "Event writing response times",
+        ))
+        .unwrap();
+        let connections = CounterVec::new(
+            Opts::new("connections", "New connections"),
+            vec!["origin"].as_slice(),
+        )
+        .unwrap();
+        registry.register(Box::new(query_sub.clone())).unwrap();
+        registry.register(Box::new(write_events.clone())).unwrap();
+        registry.register(Box::new(connections.clone())).unwrap();
+        let metrics = NostrMetrics {
+            query_sub,
+            write_events,
+            connections,
+        };
         // build a repository for events
-        let repo = db::build_repo(&settings).await;
+        let repo = db::build_repo(&settings, metrics.clone()).await;
         // start the database writer task.  Give it a channel for
         // writing events, and for publishing events that have been
         // written (to all connected clients).
@@ -360,6 +403,8 @@ pub fn start_server(settings: &Settings, shutdown_rx: MpscReceiver<()>) -> Resul
             let event = event_tx.clone();
             let stop = invoke_shutdown.clone();
             let settings = settings.clone();
+            let registry = registry.clone();
+            let metrics = metrics.clone();
             async move {
                 // service_fn converts our function into a `Service`
                 Ok::<_, Infallible>(service_fn(move |request: Request<Body>| {
@@ -371,6 +416,8 @@ pub fn start_server(settings: &Settings, shutdown_rx: MpscReceiver<()>) -> Resul
                         bcast.clone(),
                         event.clone(),
                         stop.subscribe(),
+                        registry.clone(),
+                        metrics.clone(),
                     )
                 }))
             }
@@ -451,6 +498,7 @@ async fn nostr_server(
     broadcast: Sender<Event>,
     event_tx: mpsc::Sender<SubmittedEvent>,
     mut shutdown: Receiver<()>,
+    metrics: NostrMetrics,
 ) {
     // the time this websocket nostr server started
     let orig_start = Instant::now();
@@ -510,6 +558,17 @@ async fn nostr_server(
         "cid: {}, origin: {:?}, user-agent: {:?}",
         cid, origin, user_agent
     );
+
+    // Measure connections per origin
+    let mut metric_map: HashMap<&str, &str> = HashMap::new();
+    metric_map.insert("origin", origin.as_str());
+
+    metrics
+        .connections
+        .get_metric_with(&metric_map)
+        .unwrap()
+        .inc();
+
     loop {
         tokio::select! {
             _ = shutdown.recv() => {
@@ -723,3 +782,10 @@ async fn nostr_server(
         orig_start.elapsed()
     );
 }
+
+#[derive(Clone)]
+pub struct NostrMetrics {
+    pub query_sub: Histogram,
+    pub write_events: Histogram,
+    pub connections: CounterVec,
+}