From 87396c80a6651bca432619bf3ef710f9b82334a9 Mon Sep 17 00:00:00 2001
From: Yufeng Wang <yufengwang@google.com>
Date: Fri, 25 Oct 2024 21:20:23 -0700
Subject: [PATCH] Redirect the log to log file from console

---
 examples/fabric-sync/main.cpp | 55 +++++++++++++++++++++++++++++++++++
 1 file changed, 55 insertions(+)

diff --git a/examples/fabric-sync/main.cpp b/examples/fabric-sync/main.cpp
index 84c014dfcbf010..66541b32de91f9 100644
--- a/examples/fabric-sync/main.cpp
+++ b/examples/fabric-sync/main.cpp
@@ -20,14 +20,69 @@
 
 using namespace chip;
 
+namespace {
+
+constexpr char kFabricSyncLogFilePath[] = "/tmp/fabric_sync.log";
+
+// File pointer for the log file
+FILE * sLogFile = nullptr;
+
+void OpenLogFile(const char * filePath)
+{
+    sLogFile = fopen(filePath, "a");
+    if (sLogFile == nullptr)
+    {
+        perror("Failed to open log file");
+    }
+}
+
+void CloseLogFile()
+{
+    if (sLogFile != nullptr)
+    {
+        fclose(sLogFile);
+        sLogFile = nullptr;
+    }
+}
+
+void ENFORCE_FORMAT(3, 0) LoggingCallback(const char * module, uint8_t category, const char * msg, va_list args)
+{
+    if (sLogFile == nullptr)
+    {
+        return;
+    }
+
+    uint64_t timeMs       = System::SystemClock().GetMonotonicMilliseconds64().count();
+    uint64_t seconds      = timeMs / 1000;
+    uint64_t milliseconds = timeMs % 1000;
+
+    flockfile(sLogFile);
+
+    fprintf(sLogFile, "[%llu.%06llu] CHIP:%s: ", static_cast<unsigned long long>(seconds),
+            static_cast<unsigned long long>(milliseconds), module);
+    vfprintf(sLogFile, msg, args);
+    fprintf(sLogFile, "\n");
+    fflush(sLogFile);
+
+    funlockfile(sLogFile);
+}
+
+} // namespace
+
 void ApplicationInit()
 {
     ChipLogProgress(NotSpecified, "Fabric-Sync: ApplicationInit()");
+
+    OpenLogFile(kFabricSyncLogFilePath);
+
+    // Redirect logs to the custom logging callback
+    Logging::SetLogRedirectCallback(LoggingCallback);
 }
 
 void ApplicationShutdown()
 {
     ChipLogDetail(NotSpecified, "Fabric-Sync: ApplicationShutdown()");
+    CloseLogFile();
 }
 
 int main(int argc, char * argv[])