1 files changed, 193 insertions, 0 deletions
diff --git a/src/rocksdb/logging/env_logger.h b/src/rocksdb/logging/env_logger.h
new file mode 100644
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+++ b/src/rocksdb/logging/env_logger.h
@@ -0,0 +1,193 @@
+//  Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
+//  This source code is licensed under both the GPLv2 (found in the
+//  COPYING file in the root directory) and Apache 2.0 License
+//  (found in the LICENSE.Apache file in the root directory).
+//
+// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file. See the AUTHORS file for names of contributors.
+//
+// Logger implementation that uses custom Env object for logging.
+
+#pragma once
+
+#include <time.h>
+
+#include <atomic>
+#include <memory>
+
+#include "file/writable_file_writer.h"
+#include "monitoring/iostats_context_imp.h"
+#include "port/sys_time.h"
+#include "rocksdb/env.h"
+#include "rocksdb/file_system.h"
+#include "rocksdb/perf_level.h"
+#include "rocksdb/slice.h"
+#include "test_util/sync_point.h"
+#include "util/mutexlock.h"
+
+namespace ROCKSDB_NAMESPACE {
+
+class EnvLogger : public Logger {
+ public:
+  EnvLogger(std::unique_ptr<FSWritableFile>&& writable_file,
+            const std::string& fname, const EnvOptions& options, Env* env,
+            InfoLogLevel log_level = InfoLogLevel::ERROR_LEVEL)
+      : Logger(log_level),
+        env_(env),
+        clock_(env_->GetSystemClock().get()),
+        file_(std::move(writable_file), fname, options, clock_),
+        last_flush_micros_(0),
+        flush_pending_(false) {}
+
+  ~EnvLogger() {
+    if (!closed_) {
+      closed_ = true;
+      CloseHelper().PermitUncheckedError();
+    }
+  }
+
+ private:
+  // A guard to prepare file operations, such as mutex and skip
+  // I/O context.
+  class FileOpGuard {
+   public:
+    explicit FileOpGuard(EnvLogger& logger)
+        : logger_(logger), prev_perf_level_(GetPerfLevel()) {
+      // Preserve iostats not to pollute writes from user writes. We might
+      // need a better solution than this.
+      SetPerfLevel(PerfLevel::kDisable);
+      IOSTATS_SET_DISABLE(true);
+      logger.mutex_.Lock();
+    }
+    ~FileOpGuard() {
+      logger_.mutex_.Unlock();
+      IOSTATS_SET_DISABLE(false);
+      SetPerfLevel(prev_perf_level_);
+    }
+
+   private:
+    EnvLogger& logger_;
+    PerfLevel prev_perf_level_;
+  };
+
+  void FlushLocked() {
+    mutex_.AssertHeld();
+    if (flush_pending_) {
+      flush_pending_ = false;
+      file_.Flush().PermitUncheckedError();
+    }
+    last_flush_micros_ = clock_->NowMicros();
+  }
+
+  void Flush() override {
+    TEST_SYNC_POINT("EnvLogger::Flush:Begin1");
+    TEST_SYNC_POINT("EnvLogger::Flush:Begin2");
+
+    FileOpGuard guard(*this);
+    FlushLocked();
+  }
+
+  Status CloseImpl() override { return CloseHelper(); }
+
+  Status CloseHelper() {
+    FileOpGuard guard(*this);
+    const auto close_status = file_.Close();
+
+    if (close_status.ok()) {
+      return close_status;
+    }
+    return Status::IOError("Close of log file failed with error:" +
+                           (close_status.getState()
+                                ? std::string(close_status.getState())
+                                : std::string()));
+  }
+
+  using Logger::Logv;
+  void Logv(const char* format, va_list ap) override {
+    IOSTATS_TIMER_GUARD(logger_nanos);
+
+    const uint64_t thread_id = env_->GetThreadID();
+
+    // We try twice: the first time with a fixed-size stack allocated buffer,
+    // and the second time with a much larger dynamically allocated buffer.
+    char buffer[500];
+    for (int iter = 0; iter < 2; iter++) {
+      char* base;
+      int bufsize;
+      if (iter == 0) {
+        bufsize = sizeof(buffer);
+        base = buffer;
+      } else {
+        bufsize = 65536;
+        base = new char[bufsize];
+      }
+      char* p = base;
+      char* limit = base + bufsize;
+
+      port::TimeVal now_tv;
+      port::GetTimeOfDay(&now_tv, nullptr);
+      const time_t seconds = now_tv.tv_sec;
+      struct tm t;
+      port::LocalTimeR(&seconds, &t);
+      p += snprintf(p, limit - p, "%04d/%02d/%02d-%02d:%02d:%02d.%06d %llu ",
+                    t.tm_year + 1900, t.tm_mon + 1, t.tm_mday, t.tm_hour,
+                    t.tm_min, t.tm_sec, static_cast<int>(now_tv.tv_usec),
+                    static_cast<long long unsigned int>(thread_id));
+
+      // Print the message
+      if (p < limit) {
+        va_list backup_ap;
+        va_copy(backup_ap, ap);
+        p += vsnprintf(p, limit - p, format, backup_ap);
+        va_end(backup_ap);
+      }
+
+      // Truncate to available space if necessary
+      if (p >= limit) {
+        if (iter == 0) {
+          continue;  // Try again with larger buffer
+        } else {
+          p = limit - 1;
+        }
+      }
+
+      // Add newline if necessary
+      if (p == base || p[-1] != '\n') {
+        *p++ = '\n';
+      }
+
+      assert(p <= limit);
+      {
+        FileOpGuard guard(*this);
+        // We will ignore any error returned by Append().
+        file_.Append(Slice(base, p - base)).PermitUncheckedError();
+        flush_pending_ = true;
+        const uint64_t now_micros = clock_->NowMicros();
+        if (now_micros - last_flush_micros_ >= flush_every_seconds_ * 1000000) {
+          FlushLocked();
+        }
+      }
+      if (base != buffer) {
+        delete[] base;
+      }
+      break;
+    }
+  }
+
+  size_t GetLogFileSize() const override {
+    MutexLock l(&mutex_);
+    return file_.GetFileSize();
+  }
+
+ private:
+  Env* env_;
+  SystemClock* clock_;
+  WritableFileWriter file_;
+  mutable port::Mutex mutex_;  // Mutex to protect the shared variables below.
+  const static uint64_t flush_every_seconds_ = 5;
+  std::atomic_uint_fast64_t last_flush_micros_;
+  std::atomic<bool> flush_pending_;
+};
+
+}  // namespace ROCKSDB_NAMESPACE