main.cc

/* Copyright (c) 2016-2018 Stanford University
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR(S) DISCLAIM ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL AUTHORS BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

 /**
  * This file demonstrates the usage of the NanoLog API through the
  * implementation of simple benchmarking application that reports the
  * average latency and throughput of the NanoLog system.
  */
#include <chrono>

// Required to use the NanoLog system
#include "NanoLog.h"

// Optional: Import the NanoLog log levels into the current namespace; this
// allows the log levels (DEBUG, NOTICE, WARNING, ERROR) to be used without
// using the NanoLog namespace (i.e. NanoLog::DEBUG).
using namespace NanoLog::LogLevels;

int main(int argc, char** argv) {
    // Number of messages to log repeatedly and take the average latency
    const uint64_t RECORDS = 1000;

    std::chrono::high_resolution_clock::time_point start, stop;
    double time_span;

    // Optional: Set the output location for the NanoLog system. By default
    // the log will be output to ./compressedLog
    NanoLog::setLogFile("/tmp/logFile");

    // Optional optimization: pre-allocates thread-local data structures
    // needed by NanoLog. This can be invoked once per new
    // thread that will use the NanoLog system.
    NanoLog::preallocate();

    // Optional: Set the minimum LogLevel that log messages must have to be
    // persisted. Valid from least to greatest values are
    // DEBUG, NOTICE, WARNING, ERROR
    NanoLog::setLogLevel(NOTICE);

    NANO_LOG(DEBUG, "This message wont be logged since it is lower "
                        "than the current log level.");

    // Log levels can be named explicitly if one does not import the LogLevels
    // namespace with 'using'
    NANO_LOG(NanoLog::DEBUG, "Another message.");

    start = std::chrono::high_resolution_clock::now();
    for (int i = 0; i < RECORDS; ++i) {
        NANO_LOG(NOTICE, "Simple log message with 0 parameters");
    }
    stop = std::chrono::high_resolution_clock::now();

    time_span = std::chrono::duration_cast<std::chrono::duration<double>>(
                                                        stop - start).count();
    printf("The total time spent invoking NANO_LOG with no parameters %lu "
            "times took %0.2lf seconds (%0.2lf ns/message average)\r\n",
            RECORDS, time_span, (time_span/RECORDS)*1e9);

    start = std::chrono::high_resolution_clock::now();
    // Flush all pending log messages to disk
    NanoLog::sync();
    stop = std::chrono::high_resolution_clock::now();

    time_span = std::chrono::duration_cast<std::chrono::duration<double>>(
                                                        stop - start).count();
    printf("Flushing the log statements to disk took an additional "
                "%0.2lf secs\r\n", time_span);

    // Prints various statistics gathered by the NanoLog system to stdout
    printf("%s", NanoLog::getStats().c_str());
    NanoLog::printConfig();
}