Make metric expiration time configurable

lading/src/bin/lading.rs

@@ -210,6 +210,10 @@ struct Opts {
     /// whether to ignore inspector configuration, if present, and not run the inspector
     #[clap(long)]
     disable_inspector: bool,
+    /// the time, in seconds, to consider a metric expired and not to be included in the capture
+    /// If set to 0, metrics will never expire
+    #[clap(long, default_value_t = 0)]
+    capture_metric_expiration_seconds: u64,
     /// Extra sub commands
     #[clap(subcommand)]
     extracmds: Option<ExtraCommands>,
@@ -304,8 +308,13 @@ fn get_config(ops: &Opts, config: Option<String>) -> Result<Config, Error> {
             global_labels: options_global_labels.inner,
         };
     } else if let Some(ref capture_path) = ops.capture_path {
+        let metric_expiration_duration = match ops.capture_metric_expiration_seconds {
+            0 => None,
+            _ => Some(std::time::Duration::from_secs(ops.capture_metric_expiration_seconds)),
+        };
         config.telemetry = Telemetry::Log {
             path: capture_path.parse().map_err(|_| Error::CapturePath)?,
+            metric_expiration_duration,
             global_labels: options_global_labels.inner,
         };
     } else {
@@ -386,9 +395,11 @@ async fn inner_main(
         Telemetry::Log {
             path,
             global_labels,
+            metric_expiration_duration,
         } => {
             let mut capture_manager = CaptureManager::new(
                 path,
+                metric_expiration_duration,
                 shutdown_watcher.register()?,
                 experiment_started_watcher.clone(),
                 target_running_watcher.clone(),

lading/src/captures.rs

@@ -75,6 +75,7 @@ impl CaptureManager {
     /// Function will error if the underlying capture file cannot be opened.
     pub async fn new(
         capture_path: PathBuf,
+        metric_expiration_duration: Option<Duration>,
         shutdown: lading_signal::Watcher,
         experiment_started: lading_signal::Watcher,
         target_running: lading_signal::Watcher,
@@ -94,7 +95,7 @@ impl CaptureManager {
                 recency: Recency::new(
                     quanta::Clock::new(),
                     MetricKindMask::COUNTER | MetricKindMask::GAUGE,
-                    Some(Duration::from_secs(2)),
+                    metric_expiration_duration,
                 ),
             }),
             global_labels: FxHashMap::default(),

lading/src/config.rs

@@ -80,6 +80,8 @@ pub enum Telemetry {
         path: PathBuf,
         /// Additional labels to include in every metric
         global_labels: FxHashMap<String, String>,
+        /// Time to consider metrics 'expired' and not to be included in the log
+        metric_expiration_duration: Option<std::time::Duration>,
     },
 }