Avoiding the build to fail if prometheus fail

src/algebra/metrics.rs

@@ -1,42 +1,55 @@
-use anyhow::anyhow;
 use metrics_exporter_prometheus::PrometheusBuilder;
 
 pub const SUCCESSFULLY_REFRESHED_GAUGE: &str = "successfully_refreshed";
 pub const FAILED_TO_REFRESH_GAUGE: &str = "failed_to_refresh";
 pub const REFRESH_TOTAL: &str = "refresh_total";
 
 #[derive(Clone, Debug)]
-pub struct Metrics;
+pub struct Metrics {
+    is_installed: bool,
+}
 
 impl Metrics {
     pub fn new() -> anyhow::Result<Self> {
-        PrometheusBuilder::new().install().map_err(|e| {
-            tracing::error!("Failed to install prometheus exporter: {}", e);
-            anyhow!(e)
-        })?;
-
-        metrics::describe_gauge!(
-            SUCCESSFULLY_REFRESHED_GAUGE,
-            "The number of successfully refreshed connections"
-        );
-
-        metrics::describe_gauge!(
-            FAILED_TO_REFRESH_GAUGE,
-            "The number of failed to refresh connections"
-        );
-
-        metrics::describe_gauge!(REFRESH_TOTAL, "The total number of refreshes");
-
-        Ok(Self)
+        let metric = PrometheusBuilder::new()
+            .install()
+            .map_err(|e| {
+                tracing::error!("Failed to install prometheus exporter: {}", e);
+            })
+            .ok();
+
+        if metric.is_some() {
+            metrics::describe_gauge!(
+                SUCCESSFULLY_REFRESHED_GAUGE,
+                "The number of successfully refreshed connections"
+            );
+
+            metrics::describe_gauge!(
+                FAILED_TO_REFRESH_GAUGE,
+                "The number of failed to refresh connections"
+            );
+
+            metrics::describe_gauge!(REFRESH_TOTAL, "The total number of refreshes");
+
+            Ok(Self { is_installed: true })
+        } else {
+            Ok(Self {
+                is_installed: false,
+            })
+        }
     }
 
     pub fn add_refreshed(&self, value: u64) {
-        metrics::increment_gauge!(SUCCESSFULLY_REFRESHED_GAUGE, value as f64);
-        metrics::increment_gauge!(REFRESH_TOTAL, value as f64);
+        if self.is_installed {
+            metrics::increment_gauge!(SUCCESSFULLY_REFRESHED_GAUGE, value as f64);
+            metrics::increment_gauge!(REFRESH_TOTAL, value as f64);
+        }
     }
 
     pub fn add_failed_to_refresh(&self, value: u64) {
-        metrics::increment_gauge!(FAILED_TO_REFRESH_GAUGE, value as f64);
-        metrics::increment_gauge!(REFRESH_TOTAL, value as f64);
+        if self.is_installed {
+            metrics::increment_gauge!(FAILED_TO_REFRESH_GAUGE, value as f64);
+            metrics::increment_gauge!(REFRESH_TOTAL, value as f64);
+        }
     }
 }

src/algebra/refresh.rs

@@ -79,12 +79,17 @@ pub async fn refresh(
     let (successes, failures): (Vec<_>, Vec<_>) =
         results.into_iter().partition(|result| result.is_ok());
 
-    tracing::info!("Refreshed {} connections: {:?}", successes.len(), successes);
-    tracing::info!(
-        "Failed to refresh {} connections: {:?}",
-        failures.len(),
-        failures
-    );
+    if !successes.is_empty() {
+        tracing::info!("Refreshed {} connections: {:?}", successes.len(), successes);
+    }
+
+    if !failures.is_empty() {
+        tracing::info!(
+            "Failed to refresh {} connections: {:?}",
+            failures.len(),
+            failures
+        );
+    }
 
     metrics.add_refreshed(successes.len() as u64);
     metrics.add_failed_to_refresh(failures.len() as u64);