feat: add uptime metric

Author: Leandros

src/collector.rs

@@ -12,8 +12,7 @@ use smol::lock::RwLock;
 
 use crate::config::UserConfig;
 use crate::metrics::collector::{
-    CpuStatsCollector, DiskStatsCollector, FilesystemStatsCollector, MemoryStatsCollector,
-    NetworkStatsCollector, NodeInfoCollector, PressureCollector, SystemdUnitStateCollector,
+    CpuStatsCollector, DiskStatsCollector, FilesystemStatsCollector, MemoryStatsCollector, NetworkStatsCollector, NodeInfoCollector, NodeUptimeCollector, PressureCollector, SystemdUnitStateCollector
 };
 use crate::metrics::Metric;
 
@@ -54,6 +53,10 @@ impl Collector {
             let collector = Box::new(NodeInfoCollector::new()?);
             inner.metrics.push(collector);
         }
+        {
+            let collector = Box::new(NodeUptimeCollector::default());
+            inner.metrics.push(collector);
+        }
 
         if metrics.cpu_seconds.enabled || metrics.loadavg.enabled {
             // TODO: Fix disabling of CPU seconds.

src/metrics/collector.rs

@@ -411,8 +411,6 @@ struct NodeInfoLabels {
     hostname: String,
     /// CPU architecture
     arch: String,
-    /// Uptime as seconds
-    uptime: String,
 }
 
 impl NodeInfoCollector {
@@ -422,7 +420,6 @@ impl NodeInfoCollector {
         let labels = NodeInfoLabels {
             hostname: info.hostname.clone(),
             arch: info.arch.clone(),
-            uptime: format!("{}", info.uptime.as_secs()),
         };
         let metric = Family::<NodeInfoLabels, Gauge>::default();
         metric.get_or_create(&labels).set(1);
@@ -572,3 +569,26 @@ impl Metric for DiskStatsCollector {
         })
     }
 }
+
+#[derive(Debug, Default)]
+pub struct NodeUptimeCollector {
+    metric: Gauge<u64, AtomicU64>,
+}
+
+impl Metric for NodeUptimeCollector {
+    fn register(&self, registry: &mut prometheus_client::registry::Registry) {
+        registry.register(
+            "litemon_node_uptime",
+            "Uptime in seconds",
+            self.metric.clone(),
+        );
+    }
+
+    fn collect(&self) -> DynFuture<'_, Result<()>> {
+        Box::pin(async move {
+            let info = NodeInfo::new()?;
+            self.metric.set(info.uptime.as_secs());
+            Ok(())
+        })
+    }
+}