Hotfix for glog PR (ray-project#2734)

src/ray/util/logging.cc

@@ -114,10 +114,11 @@ void RayLog::ShutDownRayLog() {
 #endif
 }
 
-RayLog::RayLog(const char *file_name, int line_number, int severity) {
+RayLog::RayLog(const char *file_name, int line_number, int severity)
+    // glog does not have DEBUG level, we can handle it here.
+    : is_enabled_(severity >= severity_threshold_) {
 #ifdef RAY_USE_GLOG
-  // glog does not have DEBUG level, we can handle it here.
-  if (severity >= severity_threshold_) {
+  if (is_enabled_) {
     logging_provider_.reset(
         new google::LogMessage(file_name, line_number, GetMappedSeverity(severity)));
   }
@@ -129,12 +130,16 @@ RayLog::RayLog(const char *file_name, int line_number, int severity) {
 
 std::ostream &RayLog::Stream() {
 #ifdef RAY_USE_GLOG
+  // Before calling this function, user should check IsEnabled.
+  // When IsEnabled == false, logging_provider_ will be empty.
   return logging_provider_->stream();
 #else
   return logging_provider_->Stream();
 #endif
 }
 
+bool RayLog::IsEnabled() const { return is_enabled_; }
+
 RayLog::~RayLog() { logging_provider_.reset(); }
 
 }  // namespace ray

src/ray/util/logging.h

@@ -65,28 +65,32 @@ class RayLogBase {
  public:
   virtual ~RayLogBase(){};
 
+  virtual bool IsEnabled() const { return false; };
+
   template <typename T>
   RayLogBase &operator<<(const T &t) {
-    RAY_IGNORE_EXPR(t);
+    if (IsEnabled()) {
+      Stream() << t;
+    } else {
+      RAY_IGNORE_EXPR(t);
+    }
     return *this;
   }
+
+ protected:
+  virtual std::ostream &Stream() { return std::cerr; };
 };
 
 class RayLog : public RayLogBase {
  public:
   RayLog(const char *file_name, int line_number, int severity);
+
   virtual ~RayLog();
 
-  template <typename T>
-  RayLogBase &operator<<(const T &t) {
-    if (logging_provider_ == nullptr) {
-      // This means the logging level is lower than the threshold.
-      RAY_IGNORE_EXPR(t);
-    } else {
-      this->Stream() << t;
-    }
-    return *this;
-  }
+  /// Return whether or not logging is enabled.
+  ///
+  /// \return True if logging is enabled and false otherwise.
+  virtual bool IsEnabled() const;
 
   // The init function of ray log for a program which should be called only once.
   // If logDir is empty, the log won't output to file.
@@ -96,9 +100,13 @@ class RayLog : public RayLogBase {
   static void ShutDownRayLog();
 
  private:
-  std::ostream &Stream();
   std::unique_ptr<LoggingProvider> logging_provider_;
+  /// True if log messages should be logged and false if they should be ignored.
+  bool is_enabled_;
   static int severity_threshold_;
+
+ protected:
+  virtual std::ostream &Stream();
 };
 
 // This class make RAY_CHECK compilation pass to change the << operator to void.

src/ray/util/logging_test.cc

@@ -18,11 +18,17 @@ int64_t current_time_ms() {
 // This file just print some information using the logging macro.
 
 void PrintLog() {
-  RAY_LOG(DEBUG) << "This is the DEBUG message";
-  RAY_LOG(INFO) << "This is the INFO message";
-  RAY_LOG(WARNING) << "This is the WARNING message";
-  RAY_LOG(ERROR) << "This is the ERROR message";
-  RAY_CHECK(true) << "This is a RAY_CHECK message but it won't show up";
+  RAY_LOG(DEBUG) << "This is the"
+                 << " DEBUG"
+                 << " message";
+  RAY_LOG(INFO) << "This is the"
+                << " INFO message";
+  RAY_LOG(WARNING) << "This is the"
+                   << " WARNING message";
+  RAY_LOG(ERROR) << "This is the"
+                 << " ERROR message";
+  RAY_CHECK(true) << "This is a RAY_CHECK"
+                  << " message but it won't show up";
   // The following 2 lines should not run since it will cause program failure.
   // RAY_LOG(FATAL) << "This is the FATAL message";
   // RAY_CHECK(false) << "This is a RAY_CHECK message but it won't show up";
@@ -47,23 +53,26 @@ TEST(LogPerfTest, PerfTest) {
 
   int64_t start_time = current_time_ms();
   for (int i = 0; i < rounds; ++i) {
-    RAY_LOG(DEBUG) << "This is the RAY_DEBUG message";
+    RAY_LOG(DEBUG) << "This is the "
+                   << "RAY_DEBUG message";
   }
   int64_t elapsed = current_time_ms() - start_time;
   std::cout << "Testing DEBUG log for " << rounds << " rounds takes " << elapsed << " ms."
             << std::endl;
 
   start_time = current_time_ms();
   for (int i = 0; i < rounds; ++i) {
-    RAY_LOG(ERROR) << "This is the RAY_ERROR message";
+    RAY_LOG(ERROR) << "This is the "
+                   << "RAY_ERROR message";
   }
   elapsed = current_time_ms() - start_time;
   std::cout << "Testing RAY_ERROR log for " << rounds << " rounds takes " << elapsed
             << " ms." << std::endl;
 
   start_time = current_time_ms();
   for (int i = 0; i < rounds; ++i) {
-    RAY_CHECK(i >= 0) << "This is a RAY_CHECK message but it won't show up";
+    RAY_CHECK(i >= 0) << "This is a RAY_CHECK "
+                      << "message but it won't show up";
   }
   elapsed = current_time_ms() - start_time;
   std::cout << "Testing RAY_CHECK(true) for " << rounds << " rounds takes " << elapsed