content: /*
   * 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.beam.runners.spark.structuredstreaming.metrics;
  
  import static org.apache.beam.runners.core.metrics.MetricsContainerStepMap.asAttemptedOnlyMetricResults;
  import static org.apache.beam.vendor.guava.v32_1_2_jre.com.google.common.base.Predicates.not;
  
  import com.codahale.metrics.Gauge;
  import com.codahale.metrics.Metric;
  import com.codahale.metrics.MetricFilter;
  import java.util.HashMap;
  import java.util.Map;
  import java.util.stream.Collectors;
  import java.util.stream.Stream;
  import javax.annotation.Nullable;
  import org.apache.beam.runners.core.metrics.MetricsContainerStepMap;
  import org.apache.beam.sdk.metrics.DistributionResult;
  import org.apache.beam.sdk.metrics.GaugeResult;
  import org.apache.beam.sdk.metrics.MetricKey;
  import org.apache.beam.sdk.metrics.MetricName;
  import org.apache.beam.sdk.metrics.MetricQueryResults;
  import org.apache.beam.sdk.metrics.MetricResult;
  import org.apache.beam.sdk.metrics.MetricResults;
  import org.apache.beam.vendor.guava.v32_1_2_jre.com.google.common.annotations.VisibleForTesting;
  import org.apache.beam.vendor.guava.v32_1_2_jre.com.google.common.base.Strings;
  import org.apache.beam.vendor.guava.v32_1_2_jre.com.google.common.collect.Streams;
  
  /**
   * An adapter between the {@link MetricsContainerStepMap} and the Dropwizard {@link Metric}
   * interface.
   */
  class SparkBeamMetric extends BeamMetricSet {
  
    private static final String ILLEGAL_CHARACTERS = "[^A-Za-z0-9-]";
  
    private final MetricsAccumulator metrics;
  
    SparkBeamMetric(MetricsAccumulator metrics) {
      this.metrics = metrics;
    }
  
    @Override
    public Map<String, Gauge<Double>> getValue(String prefix, MetricFilter filter) {
      MetricResults metricResults = asAttemptedOnlyMetricResults(metrics.value());
      Map<String, Gauge<Double>> metrics = new HashMap<>();
      MetricQueryResults allMetrics = metricResults.allMetrics();
      for (MetricResult<Long> metricResult : allMetrics.getCounters()) {
        putFiltered(metrics, filter, renderName(prefix, metricResult), metricResult.getAttempted());
      }
      for (MetricResult<DistributionResult> metricResult : allMetrics.getDistributions()) {
        DistributionResult result = metricResult.getAttempted();
        String baseName = renderName(prefix, metricResult);
        putFiltered(metrics, filter, baseName + ".count", result.getCount());
        putFiltered(metrics, filter, baseName + ".sum", result.getSum());
        putFiltered(metrics, filter, baseName + ".min", result.getMin());
        putFiltered(metrics, filter, baseName + ".max", result.getMax());
        putFiltered(metrics, filter, baseName + ".mean", result.getMean());
      }
      for (MetricResult<GaugeResult> metricResult : allMetrics.getGauges()) {
        putFiltered(
            metrics,
            filter,
            renderName(prefix, metricResult),
            metricResult.getAttempted().getValue());
      }
      return metrics;
    }
  
    @VisibleForTesting
    @SuppressWarnings("nullness") // ok to have nullable elements on stream
    static String renderName(String prefix, MetricResult<?> metricResult) {
      MetricKey key = metricResult.getKey();
      MetricName name = key.metricName();
      String step = key.stepName();
      return Streams.concat(
              Stream.of(prefix), // prefix is not cleaned, should it be?
              Stream.of(stripSuffix(normalizePart(step))),
              Stream.of(name.getNamespace(), name.getName()).map(SparkBeamMetric::normalizePart))
          .filter(not(Strings::isNullOrEmpty))
          .collect(Collectors.joining("."));
    }
  
    private static @Nullable String normalizePart(@Nullable String str) {
      return str != null ? str.replaceAll(ILLEGAL_CHARACTERS, "_") : null;
    }
  
    private static @Nullable String stripSuffix(@Nullable String str) {
      return str != null && str.endsWith("_") ? str.substring(0, str.length() - 1) : str;
    }
  
    private void putFiltered(
        Map<String, Gauge<Double>> metrics, MetricFilter filter, String name, Number value) {
      Gauge<Double> metric = staticGauge(value);
      if (filter.matches(name, metric)) {
        metrics.put(name, metric);
      }
    }
  }
  