netdata · stelfrag · Dec 20, 2025 · Jan 12, 2026 · Jan 12, 2026 · Jan 13, 2026
@@ -1065,6 +1065,8 @@ set(LIBNETDATA_FILES
         src/libnetdata/log/nd_log-format-json.c
         src/libnetdata/log/nd_log-to-file.c
         src/libnetdata/log/nd_log-to-windows-events.c
+        src/libnetdata/log/nd_log-queue.c
+        src/libnetdata/log/nd_log-queue.h
         src/libnetdata/string/utf8.c
         src/libnetdata/spawn_server/log-forwarder.c
         src/libnetdata/spawn_server/log-forwarder.h

@@ -407,6 +407,10 @@ static void netdata_cleanup_and_exit(EXIT_REASON reason, bool abnormal, bool exi
     fprintf(stderr, "All done, exiting...\n");
 #endif
 
+    // Shutdown async logging queue, flushing any remaining messages
+    // This must be done late in shutdown to allow logging during cleanup
+    nd_log_shutdown();
+
     if(!exit_when_done) {
         curl_global_cleanup();
         return;

@@ -1,6 +1,7 @@
 // SPDX-License-Identifier: GPL-3.0-or-later
 
 #include "nd_log-internals.h"
+#include "nd_log-queue.h"
 
 // --------------------------------------------------------------------------------------------------------------------
 
@@ -271,13 +272,30 @@ void nd_log_initialize(void) {
 #if defined(HAVE_LIBBACKTRACE)
     stacktrace_init();
 #endif
+
+    // Initialize async logging queue
+    // This starts the background logger thread
+    nd_log_queue_init();
+}
+
+void nd_log_shutdown(void) {
+    // Shutdown async logging queue, flushing pending messages
+    nd_log_queue_shutdown();
 }
 
 void nd_log_reopen_log_files(bool log) {
     if(log)
         netdata_log_info("Reopening all log files.");
 
-    nd_log_initialize();
+    if (nd_log_queue_enabled()) {
+        // Async logging is active - use REOPEN opcode
+        // This is handled entirely in the logger thread, so no FILE* races
+        nd_log_queue_reopen();
+    } else {
+        // Async logging not active - reopen directly
+        for(size_t i = 0 ; i < _NDLS_MAX ; i++)
+            nd_log_open(&nd_log.sources[i], i);
+    }
 
     if(log)
         netdata_log_info("Log files re-opened.");
@@ -288,6 +306,10 @@ int nd_log_systemd_journal_fd(void) {
 }
 
 void nd_log_reopen_log_files_for_spawn_server(const char *name) {
+    // After fork, the logger thread doesn't exist. Disable async queue
+    // before anything else to prevent stale uv_async_send calls.
+    nd_log_queue_disown_after_fork();
+
     nd_log.fatal_hook_cb = NULL;
     nd_log.fatal_final_cb = NULL;
 

@@ -230,6 +230,7 @@ bool nd_logger_syslog(int priority, ND_LOG_FORMAT format, struct log_field *fiel
 
 bool nd_log_journal_systemd_init(void);
 bool nd_log_journal_direct_init(const char *path);
+void nd_logger_journal_format(BUFFER *wb, struct log_field *fields, size_t fields_max);
 bool nd_logger_journal_direct(struct log_field *fields, size_t fields_max);
 bool nd_logger_journal_libsystemd(struct log_field *fields, size_t fields_max);