PR comments

bwoebi · bwoebi · commit bca1af94e1d0 · 2026-04-02T16:59:13.000+02:00
Signed-off-by: Bob Weinand &lt;bob.weinand@datadoghq.com&gt;
diff --git a/datadog-ipc-macros/src/lib.rs b/datadog-ipc-macros/src/lib.rs
@@ -275,7 +275,7 @@ fn gen_serve_fn(
                     #[cfg(target_os = "linux")]
                     {
                         __pending_acks += 1;
-                        if #force_flush || __pending_acks >= 20 {
+                        if #force_flush || __pending_acks >= datadog_ipc::ACK_BUFFER_SIZE {
                             datadog_ipc::send_acks_async(&async_fd, __pending_acks).await;
                             __pending_acks = 0;
                         }
diff --git a/datadog-ipc/src/lib.rs b/datadog-ipc/src/lib.rs
@@ -19,6 +19,10 @@ pub mod codec;
 pub use client::IpcClientConn;
 #[cfg(target_os = "linux")]
 pub use platform::send_acks_async;
+
+/// Maximum number of 1-byte acks buffered per connection before a forced flush.
+/// Must match the `MAX_BATCH` limit inside `send_acks_async`.
+pub const ACK_BUFFER_SIZE: u32 = 20;
 pub use platform::{
     max_message_size, AsyncConn, PeerCredentials, SeqpacketConn, SeqpacketListener,
     HANDLE_SUFFIX_SIZE,
diff --git a/datadog-ipc/src/platform/unix/sockets/mod.rs b/datadog-ipc/src/platform/unix/sockets/mod.rs
@@ -515,7 +515,7 @@ pub async fn send_raw_async(fd: &AsyncConn, data: &[u8]) -> io::Result<()> {
 /// waiting for all outstanding ones at the next blocking call.
 #[cfg(target_os = "linux")]
 pub async fn send_acks_async(fd: &AsyncConn, count: u32) {
-    const MAX_BATCH: usize = 20;
+    const MAX_BATCH: usize = crate::ACK_BUFFER_SIZE as usize;
     let count = (count as usize).min(MAX_BATCH);
     if count == 0 {
         return;
diff --git a/datadog-sidecar/src/service/sidecar_server.rs b/datadog-sidecar/src/service/sidecar_server.rs
@@ -448,7 +448,9 @@ impl SidecarInterface for ConnectionSidecarHandler {
             };
             let mut telemetry_guard = telemetry_mutex.lock_or_panic();
             let Some(telemetry) = telemetry_guard.as_mut() else {
-                return; // extremely rare: stopped again between the two get_or_create calls
+                // Extremely rare: the client was stopped between the two get_or_create calls.
+                warn!("enqueue_actions: telemetry client stopped during retry for instance {instance_id:?}; dropping actions");
+                return;
             };
 
             // Auto-register any metrics known to this connection but not yet registered

Original file line number	Diff line number	Diff line change
`@@ -275,7 +275,7 @@ fn gen_serve_fn(`
`275`	`275`	`#[cfg(target_os = "linux")]`
`276`	`276`	`{`
`277`	`277`	`__pending_acks += 1;`
`278`		`- if #force_flush \|\| __pending_acks >= 20 {`
	`278`	`+ if #force_flush \|\| __pending_acks >= datadog_ipc::ACK_BUFFER_SIZE {`
`279`	`279`	`datadog_ipc::send_acks_async(&async_fd, __pending_acks).await;`
`280`	`280`	`__pending_acks = 0;`
`281`	`281`	`}`