add glog->folly log bridge

Summary: This class is intended to be useful when part of your project is using folly logging and part is using glog - simply install this bridge up-front and everything is routed to folly logging.

Reviewed By: simpkins

Differential Revision: D19952822

fbshipit-source-id: 898846fc7b647ddd93222f46c56450c1454dc738

folly/logging/BridgeFromGoogleLogging.cpp

+/*
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <folly/logging/BridgeFromGoogleLogging.h>
+
+#include <folly/logging/Logger.h>
+#include <folly/logging/xlog.h>
+
+namespace folly {
+namespace logging {
+
+namespace {
+constexpr folly::LogLevel asFollyLogLevel(::google::LogSeverity severity) {
+  switch (severity) {
+    case ::google::GLOG_FATAL:
+      return folly::LogLevel::FATAL;
+    case ::google::GLOG_ERROR:
+      return folly::LogLevel::ERR;
+    case ::google::GLOG_WARNING:
+      return folly::LogLevel::WARNING;
+    case ::google::GLOG_INFO:
+      return folly::LogLevel::INFO;
+    default:
+      return folly::LogLevel::INFO2;
+  }
+}
+} // namespace
+
+BridgeFromGoogleLogging::BridgeFromGoogleLogging() {
+  ::google::AddLogSink(this);
+}
+
+BridgeFromGoogleLogging::~BridgeFromGoogleLogging() noexcept {
+  ::google::RemoveLogSink(this);
+}
+
+void BridgeFromGoogleLogging::send(
+    ::google::LogSeverity severity,
+    const char* full_filename,
+    const char* base_filename,
+    int line,
+    const struct ::tm* pTime,
+    const char* message,
+    size_t message_len,
+    ::gflags::int32 usecs) {
+  struct ::tm time = *pTime;
+  folly::Logger const logger{full_filename};
+  auto follyLevel = asFollyLogLevel(severity);
+  if (logger.getCategory()->logCheck(follyLevel)) {
+    folly::LogMessage logMessage{
+        logger.getCategory(),
+        follyLevel,
+        std::chrono::system_clock::from_time_t(mktime(&time)) +
+            std::chrono::microseconds(usecs),
+        base_filename,
+        static_cast<unsigned>(line),
+        {},
+        std::string{message, message_len}};
+    logger.getCategory()->admitMessage(logMessage);
+  }
+}
+
+void BridgeFromGoogleLogging::send(
+    ::google::LogSeverity severity,
+    const char* full_filename,
+    const char* base_filename,
+    int line,
+    const struct ::tm* pTime,
+    const char* message,
+    size_t message_len) {
+  struct ::tm time = *pTime;
+  auto usecs = std::chrono::duration_cast<std::chrono::microseconds>(
+      std::chrono::system_clock::now() -
+      std::chrono::system_clock::from_time_t(mktime(&time)));
+  send(
+      severity,
+      full_filename,
+      base_filename,
+      line,
+      pTime,
+      message,
+      message_len,
+      usecs.count());
+}
+
+} // namespace logging
+} // namespace folly

folly/logging/BridgeFromGoogleLogging.h

+/*
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+#define GLOG_NO_ABBREVIATED_SEVERITIES
+
+#include <glog/logging.h>
+
+namespace folly {
+namespace logging {
+/* Class to bridge GLOG to folly logging.
+ *
+ * You only need one instance of this class in your program at a time. While
+ * it's in scope it will bridge all GLOG messages to the folly logging
+ * pipeline.
+ *
+ * You probably want this very early in `main` as:
+ *   folly::logging::BridgeFromGoogleLogging glogToXlogBridge{};
+ */
+struct BridgeFromGoogleLogging : ::google::LogSink {
+  BridgeFromGoogleLogging();
+  ~BridgeFromGoogleLogging() noexcept override;
+
+  void send(
+      ::google::LogSeverity severity,
+      const char* full_filename,
+      const char* base_filename,
+      int line,
+      const struct ::tm* pTime,
+      const char* message,
+      size_t message_len,
+      ::google::int32 usecs);
+
+  void send(
+      ::google::LogSeverity severity,
+      const char* full_filename,
+      const char* base_filename,
+      int line,
+      const struct ::tm* pTime,
+      const char* message,
+      size_t message_len) override;
+};
+} // namespace logging
+} // namespace folly

folly/logging/test/BridgeFromGoogleLoggingTest.cpp

+/*
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <folly/logging/xlog.h>
+
+#include <folly/logging/BridgeFromGoogleLogging.h>
+#include <folly/logging/LogConfigParser.h>
+#include <folly/logging/LogHandler.h>
+#include <folly/logging/LogMessage.h>
+#include <folly/logging/LoggerDB.h>
+#include <folly/logging/test/TestLogHandler.h>
+#include <folly/portability/GTest.h>
+#include <folly/test/TestUtils.h>
+
+using namespace folly;
+using std::make_shared;
+
+namespace {
+class BridgeFromGoogleLoggingTest : public testing::Test {
+ public:
+  BridgeFromGoogleLoggingTest() {
+    // Note that the XLOG* macros always use the main LoggerDB singleton.
+    // There is no way to get them to use a test LoggerDB during unit tests.
+    //
+    // In order to ensure that changes to the LoggerDB singleton do not persist
+    // across test functions we reset the configuration to a fixed state before
+    // each test starts.
+    auto config =
+        parseLogConfig(".=WARN:default; default=stream:stream=stderr");
+    LoggerDB::get().resetConfig(config);
+  }
+};
+} // namespace
+
+TEST_F(BridgeFromGoogleLoggingTest, bridge) {
+  auto handler = make_shared<TestLogHandler>();
+  logging::BridgeFromGoogleLogging test_bridge{};
+  LoggerDB::get().getCategory("")->addHandler(handler);
+  auto& messages = handler->getMessages();
+
+  // info messages are not enabled initially.
+  EXPECT_FALSE(XLOG_IS_ON(INFO));
+  EXPECT_TRUE(XLOG_IS_ON(ERR));
+  LOG(INFO) << "testing 1";
+  EXPECT_EQ(0, messages.size());
+  messages.clear();
+
+  // Increase the log level, then log a message.
+  LoggerDB::get().setLevel("", LogLevel::INFO);
+
+  LOG(INFO) << "testing: " << 1 << 2 << 3;
+  ASSERT_EQ(1, messages.size());
+  EXPECT_EQ("testing: 123", messages[0].first.getMessage());
+  EXPECT_TRUE(messages[0].first.getFileName().endsWith(
+      "BridgeFromGoogleLoggingTest.cpp"))
+      << "unexpected file name: " << messages[0].first.getFileName();
+  EXPECT_EQ(LogLevel::INFO, messages[0].first.getLevel());
+  messages.clear();
+}