From 1a65284a3f31cc2a4d1f321e6e61e50cddb0c6d8 Mon Sep 17 00:00:00 2001
From: Masaori Koshiba <masaori@apache.org>
Date: Tue, 7 Apr 2026 13:32:13 +0900
Subject: [PATCH] Flush logs before shutdown

---
 include/proxy/logging/Log.h          |  2 ++
 src/proxy/logging/Log.cc             | 25 +++++++++++++++++++------
 src/traffic_server/traffic_server.cc |  8 ++++++++
 3 files changed, 29 insertions(+), 6 deletions(-)

diff --git a/include/proxy/logging/Log.h b/include/proxy/logging/Log.h
index ef7df731c0d..480d17b30b4 100644
--- a/include/proxy/logging/Log.h
+++ b/include/proxy/logging/Log.h
@@ -173,6 +173,8 @@ class Log
   static int va_error(const char *format, va_list ap);
   static int error(const char *format, ...) TS_PRINTFLIKE(1, 2);
 
+  static void flush_all_objects();
+
   // public data members
   static LogObject *error_log;
   /** The latest fully initialized LogConfig.
diff --git a/src/proxy/logging/Log.cc b/src/proxy/logging/Log.cc
index 1f0e15bf903..3462bfaefb0 100644
--- a/src/proxy/logging/Log.cc
+++ b/src/proxy/logging/Log.cc
@@ -1325,6 +1325,14 @@ Log::va_error(const char *format, va_list ap)
   return ret_val;
 }
 
+void
+Log::flush_all_objects()
+{
+  if (config) {
+    config->log_object_manager.flush_all_objects();
+  }
+}
+
 /*-------------------------------------------------------------------------
   Log::preproc_thread_main
 
@@ -1343,9 +1351,6 @@ Log::preproc_thread_main(void *args)
   Log::preproc_notify[idx].lock();
 
   while (true) {
-    if (TSSystemState::is_event_system_shut_down()) {
-      return nullptr;
-    }
     LogConfig *current = static_cast<LogConfig *>(configProcessor.get(log_configid));
 
     if (likely(current)) {
@@ -1360,6 +1365,13 @@ Log::preproc_thread_main(void *args)
       configProcessor.release(log_configid, current);
     }
 
+    // Drain any remaining buffers before exiting on shutdown.
+    if (TSSystemState::is_event_system_shut_down()) {
+      // Signal flush thread to drain data we just pushed.
+      Log::flush_notify->signal();
+      return nullptr;
+    }
+
     // wait for more work; a spurious wake-up is ok since we'll just
     // check the queue and find there is nothing to do, then wait
     // again.
@@ -1384,9 +1396,6 @@ Log::flush_thread_main(void * /* args ATS_UNUSED */)
   Log::flush_notify->lock();
 
   while (true) {
-    if (TSSystemState::is_event_system_shut_down()) {
-      return nullptr;
-    }
     fdata = static_cast<LogFlushData *>(ink_atomiclist_popall(flush_data_list));
 
     // invert the list
@@ -1478,6 +1487,10 @@ Log::flush_thread_main(void * /* args ATS_UNUSED */)
     // check the queue and find there is nothing to do, then wait
     // again.
     //
+    if (TSSystemState::is_event_system_shut_down()) {
+      return nullptr;
+    }
+
     Log::flush_notify->wait();
   }
 
diff --git a/src/traffic_server/traffic_server.cc b/src/traffic_server/traffic_server.cc
index 10945ecf246..6790de6892d 100644
--- a/src/traffic_server/traffic_server.cc
+++ b/src/traffic_server/traffic_server.cc
@@ -287,7 +287,15 @@ struct AutoStopCont : public Continuation {
       jsonrpcServer->stop_thread();
     }
 
+    // Push buffered log entries into the preproc queue before shutdown.
+    Log::flush_all_objects();
+
     TSSystemState::shut_down_event_system();
+
+    // Wake preproc threads to drain remaining log buffers before exit.
+    for (int i = 0; i < Log::preproc_threads; i++) {
+      Log::preproc_notify[i].signal();
+    }
     delete this;
     return EVENT_CONT;
   }