From 9f9015a35b591043ebaf6e306f967ffc62cd07f5 Mon Sep 17 00:00:00 2001
From: tv <tv@krebsco.de>
Date: Thu, 5 Nov 2026 03:37:48 +0100
Subject: measure sync envelopes

---
 src/swarm/sync.rs | 10 ++++++++++
 1 file changed, 10 insertions(+)

(limited to 'src/swarm/sync.rs')

diff --git a/src/swarm/sync.rs b/src/swarm/sync.rs
index 6c67e57..ed4c4da 100644
--- a/src/swarm/sync.rs
+++ b/src/swarm/sync.rs
@@ -238,6 +238,13 @@ async fn deliver_sync_to_peer(state: &AppState, peer: &str) -> Result<()> {
                 let Some(body) = body else {
                     return (session, Ok(None));
                 };
+                // What the envelope adds to an Automerge message (`swarm::stats`), and of
+                // that, the swarm ID and the epoch (msgpack: 36 bytes the epoch).
+                let inner = match &body {
+                    transport::SyncBody::Message(payload) => Some(payload.0.len()),
+                    transport::SyncBody::Delta(_) => None,
+                };
+                let ids = rmp_serde::encode::to_vec(&swarm_id).map_or(0, |id| id.len()) + 36;
                 let envelope = transport::SyncEnvelope {
                     swarm_id,
                     epoch,
@@ -251,6 +258,9 @@ async fn deliver_sync_to_peer(state: &AppState, peer: &str) -> Result<()> {
                 let encoded = transport
                     .encode(&peer_owned, &ParsedMessage::Sync(envelope))
                     .map(Some);
+                if let (Ok(Some(encoded)), Some(inner)) = (&encoded, inner) {
+                    stats.sync_framing(encoded.payload_len.saturating_sub(inner), ids);
+                }
                 (session, encoded)
             },
         )
-- 
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