make buffer length configurable

Author: duncanpharvey

crates/datadog-serverless-compat/src/main.rs

@@ -46,7 +46,7 @@ const AGENT_HOST: &str = "0.0.0.0";
 
 #[tokio::main]
 pub async fn main() {
-    info!("Stats test - buffer length: 90, bucket duration: 10");
+    info!("Stats test - buffer length: configurable / default 90, bucket duration: 10");
 
     let log_level = env::var("DD_LOG_LEVEL")
         .map(|val| val.to_lowercase())

crates/datadog-trace-agent/src/config.rs

@@ -84,6 +84,8 @@ pub struct Config {
     pub stats_flush_interval: u64,
     /// how often to flush traces, in seconds
     pub trace_flush_interval: u64,
+    /// buffer length for span concentrator
+    pub stats_buffer_length: usize,
     pub trace_intake: Endpoint,
     pub trace_stats_intake: Endpoint,
     /// timeout for environment verification, in milliseconds
@@ -131,6 +133,11 @@ impl Config {
             Tags::new()
         };
 
+        let stats_buffer_length: usize = env::var("DD_STATS_BUFFER_LENGTH")
+            .ok()
+            .and_then(|val| val.parse::<usize>().ok())
+            .unwrap_or(90);
+
         #[allow(clippy::unwrap_used)]
         Ok(Config {
             app_name: Some(app_name),
@@ -157,6 +164,7 @@ impl Config {
                 .or_else(|_| env::var("HTTPS_PROXY"))
                 .ok(),
             tags,
+            stats_buffer_length,
         })
     }
 }

crates/datadog-trace-agent/src/stats_concentrator_service.rs

@@ -10,7 +10,6 @@ use tracing::error;
 
 const S_TO_NS: u64 = 1_000_000_000;
 const BUCKET_DURATION_NS: u64 = 10 * S_TO_NS; // 10 seconds
-const BUFFER_LENGTH: usize = 90;
 
 #[derive(Debug, thiserror::Error)]
 pub enum StatsError {
@@ -119,7 +118,7 @@ impl StatsConcentratorService {
             SystemTime::now(),
             vec![],
             vec![],
-            BUFFER_LENGTH,
+            config.stats_buffer_length,
         );
         let service: StatsConcentratorService = Self {
             concentrator,