From 1e2ca68fc764e8691498b0d4f0a624c16124bc84 Mon Sep 17 00:00:00 2001
From: Juergen Kunz <juergen@foss.global>
Date: Mon, 16 Mar 2026 13:01:32 +0000
Subject: [PATCH] fix(rustproxy-http): improve HTTP/2 proxy error logging with
 warning-level connection failures and debug error details

---
 changelog.md                                    |  6 ++++++
 rust/crates/rustproxy-http/src/proxy_service.rs | 15 ++++++++-------
 ts/00_commitinfo_data.ts                        |  2 +-
 3 files changed, 15 insertions(+), 8 deletions(-)

diff --git a/changelog.md b/changelog.md
index 3f388bd..0c96eda 100644
--- a/changelog.md
+++ b/changelog.md
@@ -1,5 +1,11 @@
 # Changelog
 
+## 2026-03-16 - 25.11.11 - fix(rustproxy-http)
+improve HTTP/2 proxy error logging with warning-level connection failures and debug error details
+
+- Adds debug-formatted error fields to HTTP/2 handshake, retry, fallback, and request failure logs
+- Promotes upstream HTTP/2 connection error logs from debug to warn to improve operational visibility
+
 ## 2026-03-16 - 25.11.10 - fix(rustproxy-http)
 validate pooled HTTP/2 connections asynchronously before reuse and evict stale senders
 
diff --git a/rust/crates/rustproxy-http/src/proxy_service.rs b/rust/crates/rustproxy-http/src/proxy_service.rs
index 656afc9..0629d27 100644
--- a/rust/crates/rustproxy-http/src/proxy_service.rs
+++ b/rust/crates/rustproxy-http/src/proxy_service.rs
@@ -990,7 +990,7 @@ impl HttpProxyService {
         ) = match tokio::time::timeout(self.connect_timeout, h2_builder.handshake(io)).await {
             Ok(Ok(h)) => h,
             Ok(Err(e)) => {
-                error!(backend = %backend_key, domain = %domain, error = %e, "Backend H2 handshake failed");
+                error!(backend = %backend_key, domain = %domain, error = %e, error_debug = ?e, "Backend H2 handshake failed");
                 self.metrics.backend_handshake_error(&backend_key);
                 return Ok(error_response(StatusCode::BAD_GATEWAY, "Backend H2 handshake failed"));
             }
@@ -1008,7 +1008,7 @@ impl HttpProxyService {
             let key = pool_key.clone();
             tokio::spawn(async move {
                 if let Err(e) = conn.await {
-                    debug!("HTTP/2 upstream connection error: {}", e);
+                    warn!("HTTP/2 upstream connection error: {} ({:?})", e, e);
                 }
                 pool.remove_h2(&key);
             });
@@ -1140,7 +1140,7 @@ impl HttpProxyService {
         ) = match tokio::time::timeout(self.connect_timeout, h2_builder.handshake(io)).await {
             Ok(Ok(h)) => h,
             Ok(Err(e)) => {
-                error!(backend = %backend_key, domain = %domain, error = %e, "H2 retry: handshake failed");
+                error!(backend = %backend_key, domain = %domain, error = %e, error_debug = ?e, "H2 retry: handshake failed");
                 self.metrics.backend_handshake_error(&backend_key);
                 self.metrics.backend_connection_closed(&backend_key);
                 return Ok(error_response(StatusCode::BAD_GATEWAY, "Backend H2 retry handshake failed"));
@@ -1159,7 +1159,7 @@ impl HttpProxyService {
             let key = pool_key.clone();
             tokio::spawn(async move {
                 if let Err(e) = conn.await {
-                    debug!("H2 retry: upstream connection error: {}", e);
+                    warn!("H2 retry: upstream connection error: {} ({:?})", e, e);
                 }
                 pool.remove_h2(&key);
             });
@@ -1288,7 +1288,7 @@ impl HttpProxyService {
                     let key = pool_key.clone();
                     tokio::spawn(async move {
                         if let Err(e) = conn.await {
-                            debug!("HTTP/2 upstream connection error: {}", e);
+                            warn!("HTTP/2 upstream connection error: {} ({:?})", e, e);
                         }
                         pool.remove_h2(&key);
                     });
@@ -1343,6 +1343,7 @@ impl HttpProxyService {
                             backend = %bk,
                             domain = %domain,
                             error = %e,
+                            error_debug = ?e,
                             "Auto-detect: H2 request failed, falling back to H1"
                         );
                         self.metrics.backend_h2_failure(&bk);
@@ -1600,11 +1601,11 @@ impl HttpProxyService {
                 // Evict the dead sender so subsequent requests get fresh connections
                 if let Some(key) = pool_key {
                     let bk = format!("{}:{}", key.host, key.port);
-                    error!(backend = %bk, domain = %domain, error = %e, "Backend H2 request failed");
+                    error!(backend = %bk, domain = %domain, error = %e, error_debug = ?e, "Backend H2 request failed");
                     self.metrics.backend_request_error(&bk);
                     self.connection_pool.remove_h2(key);
                 } else {
-                    error!(domain = %domain, error = %e, "Backend H2 request failed");
+                    error!(domain = %domain, error = %e, error_debug = ?e, "Backend H2 request failed");
                 }
                 return Ok(error_response(StatusCode::BAD_GATEWAY, "Backend H2 request failed"));
             }
diff --git a/ts/00_commitinfo_data.ts b/ts/00_commitinfo_data.ts
index 6a07a5e..6af2b3d 100644
--- a/ts/00_commitinfo_data.ts
+++ b/ts/00_commitinfo_data.ts
@@ -3,6 +3,6 @@
  */
 export const commitinfo = {
   name: '@push.rocks/smartproxy',
-  version: '25.11.10',
+  version: '25.11.11',
   description: 'A powerful proxy package with unified route-based configuration for high traffic management. Features include SSL/TLS support, flexible routing patterns, WebSocket handling, advanced security options, and automatic ACME certificate management.'
 }