/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.
 */
package org.apache.hadoop.hbase.wal;

import static com.codahale.metrics.MetricRegistry.name;

import com.codahale.metrics.ConsoleReporter;
import com.codahale.metrics.Histogram;
import com.codahale.metrics.Meter;
import com.codahale.metrics.MetricFilter;
import com.codahale.metrics.MetricRegistry;
import io.opentelemetry.api.trace.Span;
import io.opentelemetry.context.Scope;
import java.io.IOException;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.NavigableMap;
import java.util.Random;
import java.util.Set;
import java.util.TreeMap;
import java.util.concurrent.ThreadLocalRandom;
import java.util.concurrent.TimeUnit;
import java.util.stream.IntStream;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.conf.Configured;
import org.apache.hadoop.fs.FileStatus;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.hbase.HBaseConfiguration;
import org.apache.hadoop.hbase.HBaseTestingUtil;
import org.apache.hadoop.hbase.HConstants;
import org.apache.hadoop.hbase.MockRegionServerServices;
import org.apache.hadoop.hbase.TableName;
import org.apache.hadoop.hbase.client.ColumnFamilyDescriptorBuilder;
import org.apache.hadoop.hbase.client.Put;
import org.apache.hadoop.hbase.client.RegionInfo;
import org.apache.hadoop.hbase.client.RegionInfoBuilder;
import org.apache.hadoop.hbase.client.TableDescriptor;
import org.apache.hadoop.hbase.client.TableDescriptorBuilder;
import org.apache.hadoop.hbase.io.crypto.KeyProviderForTesting;
import org.apache.hadoop.hbase.regionserver.HRegion;
import org.apache.hadoop.hbase.regionserver.LogRoller;
import org.apache.hadoop.hbase.regionserver.MemStoreLAB;
import org.apache.hadoop.hbase.regionserver.MultiVersionConcurrencyControl;
import org.apache.hadoop.hbase.regionserver.wal.WALActionsListener;
import org.apache.hadoop.hbase.trace.TraceUtil;
import org.apache.hadoop.hbase.util.Bytes;
import org.apache.hadoop.hbase.util.CommonFSUtils;
import org.apache.hadoop.hbase.util.EnvironmentEdgeManager;
import org.apache.hadoop.hbase.util.Threads;
import org.apache.hadoop.util.Tool;
import org.apache.hadoop.util.ToolRunner;
import org.apache.yetus.audience.InterfaceAudience;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

// imports for things that haven't moved from regionserver.wal yet.

/**
 * This class runs performance benchmarks for {@link WAL}. See usage for this tool by running:
 * <code>$ hbase org.apache.hadoop.hbase.wal.WALPerformanceEvaluation -h</code>
 */
@InterfaceAudience.Private
public final class WALPerformanceEvaluation extends Configured implements Tool {
  private static final Logger LOG = LoggerFactory.getLogger(WALPerformanceEvaluation.class);

  private final MetricRegistry metrics = new MetricRegistry();
  private final Meter syncMeter =
    metrics.meter(name(WALPerformanceEvaluation.class, "syncMeter", "syncs"));

  private final Histogram syncHistogram =
    metrics.histogram(name(WALPerformanceEvaluation.class, "syncHistogram", "nanos-between-syncs"));
  private final Histogram syncCountHistogram =
    metrics.histogram(name(WALPerformanceEvaluation.class, "syncCountHistogram", "countPerSync"));
  private final Meter appendMeter =
    metrics.meter(name(WALPerformanceEvaluation.class, "appendMeter", "bytes"));
  private final Histogram latencyHistogram =
    metrics.histogram(name(WALPerformanceEvaluation.class, "latencyHistogram", "nanos"));

  private final MultiVersionConcurrencyControl mvcc = new MultiVersionConcurrencyControl();

  private HBaseTestingUtil TEST_UTIL;

  static final String TABLE_NAME = "WALPerformanceEvaluation";
  static final String QUALIFIER_PREFIX = "q";
  static final String FAMILY_PREFIX = "cf";

  private int numQualifiers = 1;
  private int valueSize = 512;
  private int keySize = 16;

  @Override
  public void setConf(Configuration conf) {
    super.setConf(conf);
  }

  /**
   * Perform WAL.append() of Put object, for the number of iterations requested. Keys and Vaues are
   * generated randomly, the number of column families, qualifiers and key/value size is tunable by
   * the user.
   */
  class WALPutBenchmark implements Runnable {
    private final long numIterations;
    private final int numFamilies;
    private final boolean noSync;
    private final HRegion region;
    private final int syncInterval;
    private final NavigableMap<byte[], Integer> scopes;

    WALPutBenchmark(final HRegion region, final TableDescriptor htd, final long numIterations,
      final boolean noSync, final int syncInterval) {
      this.numIterations = numIterations;
      this.noSync = noSync;
      this.syncInterval = syncInterval;
      this.numFamilies = htd.getColumnFamilyCount();
      this.region = region;
      scopes = new TreeMap<>(Bytes.BYTES_COMPARATOR);
      for (byte[] fam : htd.getColumnFamilyNames()) {
        scopes.put(fam, 0);
      }
    }

    @Override
    public void run() {
      byte[] key = new byte[keySize];
      byte[] value = new byte[valueSize];
      WAL wal = region.getWAL();
      Span threadSpan = TraceUtil.getGlobalTracer()
        .spanBuilder("WALPerfEval." + Thread.currentThread().getName()).startSpan();
      try (Scope threadScope = threadSpan.makeCurrent()) {
        int lastSync = 0;
        for (int i = 0; i < numIterations; ++i) {
          assert Span.current() == threadSpan : "Span leak detected.";
          Span loopSpan = TraceUtil.getGlobalTracer().spanBuilder("runLoopIter" + i).startSpan();
          try (Scope loopScope = loopSpan.makeCurrent()) {
            long now = System.nanoTime();
            Put put = setupPut(ThreadLocalRandom.current(), key, value, numFamilies);
            WALEdit walEdit = new WALEdit();
            walEdit.add(put.getFamilyCellMap());
            RegionInfo hri = region.getRegionInfo();
            final WALKeyImpl logkey =
              new WALKeyImpl(hri.getEncodedNameAsBytes(), hri.getTable(), now, mvcc, scopes);
            wal.appendData(hri, logkey, walEdit);
            if (!this.noSync) {
              if (++lastSync >= this.syncInterval) {
                wal.sync();
                lastSync = 0;
              }
            }
            latencyHistogram.update(System.nanoTime() - now);
          } finally {
            loopSpan.end();
          }
        }
      } catch (Exception e) {
        LOG.error(getClass().getSimpleName() + " Thread failed", e);
      } finally {
        threadSpan.end();
      }
    }
  }

  @Override
  public int run(String[] args) throws Exception {
    Path rootRegionDir = null;
    int numThreads = 1;
    long numIterations = 1000000;
    int numFamilies = 1;
    int syncInterval = 0;
    boolean noSync = false;
    boolean verify = false;
    boolean verbose = false;
    boolean cleanup = true;
    boolean noclosefs = false;
    long roll = Long.MAX_VALUE;
    boolean compress = false;
    String cipher = null;
    int numRegions = 1;
    // Process command line args
    for (int i = 0; i < args.length; i++) {
      String cmd = args[i];
      try {
        if (cmd.equals("-threads")) {
          numThreads = Integer.parseInt(args[++i]);
        } else if (cmd.equals("-iterations")) {
          numIterations = Long.parseLong(args[++i]);
        } else if (cmd.equals("-path")) {
          rootRegionDir = new Path(args[++i]);
        } else if (cmd.equals("-families")) {
          numFamilies = Integer.parseInt(args[++i]);
        } else if (cmd.equals("-qualifiers")) {
          numQualifiers = Integer.parseInt(args[++i]);
        } else if (cmd.equals("-keySize")) {
          keySize = Integer.parseInt(args[++i]);
        } else if (cmd.equals("-valueSize")) {
          valueSize = Integer.parseInt(args[++i]);
        } else if (cmd.equals("-syncInterval")) {
          syncInterval = Integer.parseInt(args[++i]);
        } else if (cmd.equals("-nosync")) {
          noSync = true;
        } else if (cmd.equals("-verify")) {
          verify = true;
        } else if (cmd.equals("-verbose")) {
          verbose = true;
        } else if (cmd.equals("-nocleanup")) {
          cleanup = false;
        } else if (cmd.equals("-noclosefs")) {
          noclosefs = true;
        } else if (cmd.equals("-roll")) {
          roll = Long.parseLong(args[++i]);
        } else if (cmd.equals("-compress")) {
          compress = true;
        } else if (cmd.equals("-encryption")) {
          cipher = args[++i];
        } else if (cmd.equals("-regions")) {
          numRegions = Integer.parseInt(args[++i]);
        } else if (cmd.equals("-traceFreq")) {
          // keep it here for compatible
          System.err.println("-traceFreq is not supported any more");
        } else if (cmd.equals("-h")) {
          printUsageAndExit();
        } else if (cmd.equals("--help")) {
          printUsageAndExit();
        } else {
          System.err.println("UNEXPECTED: " + cmd);
          printUsageAndExit();
        }
      } catch (Exception e) {
        printUsageAndExit();
      }
    }

    if (compress) {
      Configuration conf = getConf();
      conf.setBoolean(HConstants.ENABLE_WAL_COMPRESSION, true);
    }

    if (cipher != null) {
      // Set up WAL for encryption
      Configuration conf = getConf();
      conf.set(HConstants.CRYPTO_KEYPROVIDER_CONF_KEY, KeyProviderForTesting.class.getName());
      conf.set(HConstants.CRYPTO_MASTERKEY_NAME_CONF_KEY, "hbase");
      conf.setBoolean(HConstants.ENABLE_WAL_ENCRYPTION, true);
      conf.set(HConstants.CRYPTO_WAL_ALGORITHM_CONF_KEY, cipher);
    }

    if (numThreads < numRegions) {
      LOG.warn("Number of threads is less than the number of regions; some regions will sit idle.");
    }

    // Internal config. goes off number of threads; if more threads than handlers, stuff breaks.
    // In regionserver, number of handlers == number of threads.
    getConf().setInt(HConstants.REGION_SERVER_HANDLER_COUNT, numThreads);
    // We do not need memstore here, so disable memstore lab, otherwise we need to initialize
    // ChunkCreator
    getConf().setBoolean(MemStoreLAB.USEMSLAB_KEY, false);

    if (rootRegionDir == null) {
      TEST_UTIL = new HBaseTestingUtil(getConf());
      rootRegionDir = TEST_UTIL.getDataTestDirOnTestFS("WALPerformanceEvaluation");
    }
    // Run WAL Performance Evaluation
    // First set the fs from configs. In case we are on hadoop1
    CommonFSUtils.setFsDefault(getConf(), CommonFSUtils.getRootDir(getConf()));
    FileSystem fs = FileSystem.get(getConf());
    LOG.info("FileSystem={}, rootDir={}", fs, rootRegionDir);
    Span span = TraceUtil.getGlobalTracer().spanBuilder("WALPerfEval").startSpan();
    try (Scope scope = span.makeCurrent()) {
      rootRegionDir = rootRegionDir.makeQualified(fs.getUri(), fs.getWorkingDirectory());
      cleanRegionRootDir(fs, rootRegionDir);
      CommonFSUtils.setRootDir(getConf(), rootRegionDir);
      final WALFactory wals = new WALFactory(getConf(), "wals");
      final HRegion[] regions = new HRegion[numRegions];
      final Runnable[] benchmarks = new Runnable[numRegions];
      final MockRegionServerServices mockServices = new MockRegionServerServices(getConf());
      final LogRoller roller = new LogRoller(mockServices);
      Threads.setDaemonThreadRunning(roller, "WALPerfEval.logRoller");

      try {
        for (int i = 0; i < numRegions; i++) {
          // Initialize Table Descriptor
          // a table per desired region means we can avoid carving up the key space
          final TableDescriptor htd = createHTableDescriptor(i, numFamilies);
          regions[i] = openRegion(fs, rootRegionDir, htd, wals, roll, roller);
          benchmarks[i] = new WALPutBenchmark(regions[i], htd, numIterations, noSync, syncInterval);
        }
        ConsoleReporter reporter = ConsoleReporter.forRegistry(metrics).outputTo(System.out)
          .convertRatesTo(TimeUnit.SECONDS).filter(MetricFilter.ALL).build();
        reporter.start(30, TimeUnit.SECONDS);

        long putTime = runBenchmark(benchmarks, numThreads);
        logBenchmarkResult("Summary: threads=" + numThreads + ", iterations=" + numIterations
          + ", syncInterval=" + syncInterval, numIterations * numThreads, putTime);

        for (int i = 0; i < numRegions; i++) {
          if (regions[i] != null) {
            closeRegion(regions[i]);
            regions[i] = null;
          }
        }
        if (verify) {
          LOG.info("verifying written log entries.");
          Path dir = new Path(CommonFSUtils.getRootDir(getConf()),
            AbstractFSWALProvider.getWALDirectoryName("wals"));
          long editCount = 0;
          FileStatus[] fsss = fs.listStatus(dir);
          if (fsss.length == 0) throw new IllegalStateException("No WAL found");
          for (FileStatus fss : fsss) {
            Path p = fss.getPath();
            if (!fs.exists(p)) throw new IllegalStateException(p.toString());
            editCount += verify(wals, p, verbose);
          }
          long expected = numIterations * numThreads;
          if (editCount != expected) {
            throw new IllegalStateException("Counted=" + editCount + ", expected=" + expected);
          }
        }
      } finally {
        mockServices.stop("test clean up.");
        for (int i = 0; i < numRegions; i++) {
          if (regions[i] != null) {
            closeRegion(regions[i]);
          }
        }
        if (null != roller) {
          LOG.info("shutting down log roller.");
          roller.close();
        }
        wals.shutdown();
        // Remove the root dir for this test region
        if (cleanup) cleanRegionRootDir(fs, rootRegionDir);
      }
    } finally {
      span.end();
      // We may be called inside a test that wants to keep on using the fs.
      if (!noclosefs) {
        fs.close();
      }
    }

    return 0;
  }

  private static TableDescriptor createHTableDescriptor(final int regionNum,
    final int numFamilies) {
    TableDescriptorBuilder builder =
      TableDescriptorBuilder.newBuilder(TableName.valueOf(TABLE_NAME + ":" + regionNum));
    IntStream.range(0, numFamilies)
      .mapToObj(i -> ColumnFamilyDescriptorBuilder.of(FAMILY_PREFIX + i))
      .forEachOrdered(builder::setColumnFamily);
    return builder.build();
  }

  /**
   * Verify the content of the WAL file. Verify that the file has expected number of edits.
   * @param wals may not be null
   * @return Count of edits.
   */
  private long verify(final WALFactory wals, final Path wal, final boolean verbose)
    throws IOException {
    WALStreamReader reader = wals.createStreamReader(wal.getFileSystem(getConf()), wal);
    long count = 0;
    Map<String, Long> sequenceIds = new HashMap<>();
    try {
      while (true) {
        WAL.Entry e = reader.next();
        if (e == null) {
          LOG.debug("Read count=" + count + " from " + wal);
          break;
        }
        count++;
        long seqid = e.getKey().getSequenceId();
        if (sequenceIds.containsKey(Bytes.toString(e.getKey().getEncodedRegionName()))) {
          // sequenceIds should be increasing for every regions
          if (sequenceIds.get(Bytes.toString(e.getKey().getEncodedRegionName())) >= seqid) {
            throw new IllegalStateException("wal = " + wal.getName() + ", " + "previous seqid = "
              + sequenceIds.get(Bytes.toString(e.getKey().getEncodedRegionName()))
              + ", current seqid = " + seqid);
          }
        }
        // update the sequence Id.
        sequenceIds.put(Bytes.toString(e.getKey().getEncodedRegionName()), seqid);
        if (verbose) LOG.info("seqid=" + seqid);
      }
    } finally {
      reader.close();
    }
    return count;
  }

  private static void logBenchmarkResult(String testName, long numTests, long totalTime) {
    float tsec = totalTime / 1000.0f;
    LOG.info(String.format("%s took %.3fs %.3fops/s", testName, tsec, numTests / tsec));

  }

  private void printUsageAndExit() {
    System.err.printf("Usage: hbase %s [options]\n", getClass().getName());
    System.err.println(" where [options] are:");
    System.err.println("  -h|-help         Show this help and exit.");
    System.err.println("  -threads <N>     Number of threads writing on the WAL.");
    System.err.println("  -regions <N>     Number of regions to open in the WAL. Default: 1");
    System.err.println("  -iterations <N>  Number of iterations per thread.");
    System.err.println("  -path <PATH>     Path where region's root directory is created.");
    System.err.println("  -families <N>    Number of column families to write.");
    System.err.println("  -qualifiers <N>  Number of qualifiers to write.");
    System.err.println("  -keySize <N>     Row key size in byte.");
    System.err.println("  -valueSize <N>   Row/Col value size in byte.");
    System.err.println("  -nocleanup       Do NOT remove test data when done.");
    System.err.println("  -noclosefs       Do NOT close the filesystem when done.");
    System.err.println("  -nosync          Append without syncing");
    System.err.println(
      "  -syncInterval <N> Append N edits and then sync. " + "Default=0, i.e. sync every edit.");
    System.err.println("  -verify          Verify edits written in sequence");
    System.err
      .println("  -verbose         Output extra info; " + "e.g. all edit seq ids when verifying");
    System.err.println("  -roll <N>        Roll the way every N appends");
    System.err.println("  -encryption <A>  Encrypt the WAL with algorithm A, e.g. AES");
    System.err.println("  -traceFreq <N>   Rate of trace sampling. Default: 1.0, "
      + "only respected when tracing is enabled, ie -Dhbase.trace.spanreceiver.classes=...");
    System.err.println("");
    System.err.println("Examples:");
    System.err.println("");
    System.err.println(" To run 100 threads on hdfs with log rolling every 10k edits and "
      + "verification afterward do:");
    System.err.println(" $ hbase org.apache.hadoop.hbase.wal." + "WALPerformanceEvaluation \\");
    System.err.println("    -conf ./core-site.xml -path hdfs://example.org:7000/tmp "
      + "-threads 100 -roll 10000 -verify");
    System.exit(1);
  }

  private final Set<WAL> walsListenedTo = new HashSet<>();

  private HRegion openRegion(final FileSystem fs, final Path dir, final TableDescriptor htd,
    final WALFactory wals, final long whenToRoll, final LogRoller roller) throws IOException {
    // Initialize HRegion
    RegionInfo regionInfo = RegionInfoBuilder.newBuilder(htd.getTableName()).build();
    // Initialize WAL
    final WAL wal = wals.getWAL(regionInfo);
    // If we haven't already, attach a listener to this wal to handle rolls and metrics.
    if (walsListenedTo.add(wal)) {
      roller.addWAL(wal);
      wal.registerWALActionsListener(new WALActionsListener() {
        private int appends = 0;

        @Override
        public void visitLogEntryBeforeWrite(RegionInfo info, WALKey logKey, WALEdit logEdit) {
          this.appends++;
          if (this.appends % whenToRoll == 0) {
            LOG.info("Rolling after " + appends + " edits");
            // We used to do explicit call to rollWriter but changed it to a request
            // to avoid dead lock (there are less threads going on in this class than
            // in the regionserver -- regionserver does not have the issue).
            AbstractFSWALProvider.requestLogRoll(wal);
          }
        }

        @Override
        public void postSync(final long timeInNanos, final int handlerSyncs) {
          syncMeter.mark();
          syncHistogram.update(timeInNanos);
          syncCountHistogram.update(handlerSyncs);
        }

        @Override
        public void postAppend(final long size, final long elapsedTime, final WALKey logkey,
          final WALEdit logEdit) {
          appendMeter.mark(size);
        }
      });
    }

    return HRegion.createHRegion(regionInfo, dir, getConf(), htd, wal);
  }

  private void closeRegion(final HRegion region) throws IOException {
    if (region != null) {
      region.close();
      WAL wal = region.getWAL();
      if (wal != null) {
        wal.shutdown();
      }
    }
  }

  private void cleanRegionRootDir(final FileSystem fs, final Path dir) throws IOException {
    if (fs.exists(dir)) {
      fs.delete(dir, true);
    }
  }

  private Put setupPut(Random rand, byte[] key, byte[] value, final int numFamilies) {
    rand.nextBytes(key);
    Put put = new Put(key);
    for (int cf = 0; cf < numFamilies; ++cf) {
      for (int q = 0; q < numQualifiers; ++q) {
        rand.nextBytes(value);
        put.addColumn(Bytes.toBytes(FAMILY_PREFIX + cf), Bytes.toBytes(QUALIFIER_PREFIX + q),
          value);
      }
    }
    return put;
  }

  private long runBenchmark(Runnable[] runnable, final int numThreads) throws InterruptedException {
    Thread[] threads = new Thread[numThreads];
    long startTime = EnvironmentEdgeManager.currentTime();
    for (int i = 0; i < numThreads; ++i) {
      threads[i] =
        new Thread(runnable[i % runnable.length], "t" + i + ",r" + (i % runnable.length));
      threads[i].start();
    }
    for (Thread t : threads)
      t.join();
    long endTime = EnvironmentEdgeManager.currentTime();
    return (endTime - startTime);
  }

  /**
   * The guts of the {@link #main} method. Call this method to avoid the {@link #main(String[])}
   * System.exit.
   */
  static int innerMain(final Configuration c, final String[] args) throws Exception {
    return ToolRunner.run(c, new WALPerformanceEvaluation(), args);
  }

  public static void main(String[] args) throws Exception {
    System.exit(innerMain(HBaseConfiguration.create(), args));
  }
}