feat(sv-api): Add metric to report the latest synced block height.

Author: luizstacio

.env.sample

@@ -60,4 +60,4 @@ TESTNET_RELAYER_V2_LISTENING_CONTRACTS=0x01855B78C1f8868DE70e84507ec735983bf262d
 TESTNET_RELAYER_DA_DEPLOY_HEIGHT=5827607
 TESTNET_RELAYER_LOG_PAGE_SIZE=2000
 TESTNET_SYNC_HEADER_BATCH_SIZE=100
-TESTNET_RESERVED_NODES=/dns4/p2p-testnet.fuel.network/tcp/30333/p2p/16Uiu2HAmDxoChB7AheKNvCVpD4PHJwuDGn8rifMBEHmEynGHvHrf,/dns4/p2p-testnet.fuel.network/tcp/30333/p2p/16Uiu2HAmHnANNk4HjAxQV66BNCRxd2MBUU89ijboZkE69aLuSn1g,/dns4/p2p-testnet.fuel.network/tcp/30333/p2p/16Uiu2HAmVE468rpkh2X1kzz8qQXmqNFiPxU5Lrya28nZdbRUdVJX
+TESTNET_RESERVED_NODES=/dns/p2p-testnet.fuel.network/tcp/30333/p2p/16Uiu2HAm37z1CHm5XSyi1ChCm9wCxYg98wBn5o5LSXA4RdYnaL33,/dns/p2p-testnet.fuel.network/tcp/30334/p2p/16Uiu2HAmEcoBoXEeakKAuCdQ1rbh9WLdkJc5zM3rfdJbccagCY9F,/dns/p2p-testnet.fuel.network/tcp/30335/p2p/16Uiu2HAmH3gTJU5hekJxSmMugkXLzJV8tHhmiwmJi2rnZ2QkrdXM

Cargo.lock

@@ -25,6 +25,7 @@ dotenvy.workspace = true
 fuel-data-parser.workspace = true
 fuel-streams-core = { workspace = true, features = ["openapi"] }
 fuel-streams-domains.workspace = true
+fuel-streams-types.workspace = true
 fuel-web-utils.workspace = true
 num_cpus.workspace = true
 paste = "1.0.15"

services/api/Cargo.toml

@@ -4,7 +4,7 @@ use fuel_web_utils::{
 };
 use sv_api::{
     config::Config,
-    server::{routes::create_routes, state::ServerState},
+    server::{db_metrics, routes::create_routes, state::ServerState},
 };
 
 #[tokio::main]
@@ -18,6 +18,8 @@ async fn main() -> anyhow::Result<()> {
     let config = Config::load()?;
     let state = ServerState::new(&config).await?;
     let router = create_routes(&state);
+    db_metrics::spawn_block_height_monitor(&state).await;
+
     ServerBuilder::build(&state, config.api.port)
         .with_router(router)
         .run()

services/api/src/main.rs

@@ -3,8 +3,10 @@ use std::time::Duration;
 use async_trait::async_trait;
 use fuel_web_utils::{api_key::ApiKeyId, telemetry::metrics::TelemetryMetrics};
 use prometheus::{
+    register_gauge,
     register_histogram_vec,
     register_int_counter_vec,
+    Gauge,
     HistogramVec,
     IntCounterVec,
     Registry,
@@ -15,6 +17,7 @@ pub struct Metrics {
     pub registry: Registry,
     pub db_queries_error_rates: IntCounterVec,
     pub connection_duration: HistogramVec,
+    pub latest_block_height: Gauge,
 }
 
 impl Default for Metrics {
@@ -60,6 +63,12 @@ impl Metrics {
         )
         .expect("metric must be created");
 
+        let latest_block_height = register_gauge!(
+            format!("{}api_latest_block_height", metric_prefix),
+            "The latest block height in the database"
+        )
+        .expect("metric must be created");
+
         let registry =
             Registry::new_custom(prefix, None).expect("registry to be created");
         registry.register(Box::new(db_queries_error_rates.clone()))?;
@@ -69,6 +78,7 @@ impl Metrics {
             registry,
             db_queries_error_rates,
             connection_duration,
+            latest_block_height,
         })
     }
 
@@ -88,6 +98,10 @@ impl Metrics {
             .with_label_values(&[&user_id.to_string(), user_name])
             .observe(duration.as_secs_f64());
     }
+
+    pub fn update_latest_block_height(&self, height: u32) {
+        self.latest_block_height.set(height as f64);
+    }
 }
 
 #[cfg(test)]
@@ -124,4 +138,21 @@ mod tests {
         assert!(output.contains("timeout"));
         assert!(output.contains("1"));
     }
+
+    #[test]
+    fn test_latest_block_height_metric() {
+        let metrics = Metrics::random();
+
+        metrics.update_latest_block_height(123);
+
+        let metric_families = gather();
+        let mut buffer = Vec::new();
+        let encoder = TextEncoder::new();
+        encoder.encode(&metric_families, &mut buffer).unwrap();
+
+        let output = String::from_utf8(buffer.clone()).unwrap();
+
+        assert!(output.contains("api_latest_block_height"));
+        assert!(output.contains("123"));
+    }
 }

services/api/src/metrics.rs

@@ -0,0 +1,28 @@
+use fuel_streams_domains::blocks::Block;
+use fuel_streams_types::BlockHeight;
+use tokio::time::{sleep, Duration};
+
+use crate::server::state::ServerState;
+
+pub async fn spawn_block_height_monitor(state: &ServerState) {
+    let db = state.db.clone();
+    let telemetry = state.telemetry.clone();
+    tokio::spawn(async move {
+        let mut last_height = BlockHeight::from(0);
+        loop {
+            if let Ok(new_height) =
+                Block::find_last_block_height(&db, &Default::default()).await
+            {
+                if new_height > last_height {
+                    if let Some(metrics) = telemetry.base_metrics() {
+                        metrics.update_latest_block_height(
+                            new_height.into_inner(),
+                        );
+                    }
+                    last_height = new_height;
+                }
+            }
+            sleep(Duration::from_secs(10)).await;
+        }
+    });
+}

services/api/src/server/db_metrics.rs

@@ -1,3 +1,4 @@
+pub mod db_metrics;
 pub mod errors;
 pub mod handlers;
 pub mod middleware;