MetricsGenerator.java

/**
 * Copyright 2016 Yahoo Inc.
 *
 * 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.
 */
package com.yahoo.pulsar.broker.stats;

import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import java.util.Map;

import com.google.common.collect.Maps;
import com.yahoo.pulsar.broker.PulsarService;
import com.yahoo.pulsar.broker.stats.metrics.JvmMetrics;
import com.yahoo.pulsar.broker.stats.metrics.ManagedLedgerCacheMetrics;
import com.yahoo.pulsar.broker.stats.metrics.ManagedLedgerMetrics;
import com.yahoo.pulsar.common.stats.Metrics;

public class MetricsGenerator {
    private final PulsarService pulsar;

    private final JvmMetrics jvmMetrics;

    public MetricsGenerator(PulsarService pulsar) {
        this.pulsar = pulsar;
        this.jvmMetrics = new JvmMetrics(pulsar);
    }

    public Collection<Metrics> generate() {
        return merge(collect());
    }

    private List<Metrics> collect() {
        List<Metrics> metricsCollection = new ArrayList<Metrics>();

        // add the collectors here
        metricsCollection.addAll(jvmMetrics.generate());
        metricsCollection.addAll(new ManagedLedgerCacheMetrics(pulsar).generate());
        metricsCollection.addAll(new ManagedLedgerMetrics(pulsar).generate());
        metricsCollection.addAll(pulsar.getBrokerService().getDestinationMetrics());
        metricsCollection.addAll(pulsar.getLoadManager().get().getLoadBalancingMetrics());

        return metricsCollection;
    }

    private Collection<Metrics> merge(List<Metrics> metricsCollection) {

        // map by dimension map -> metrics
        // since dimension map is unique
        Map<Map<String, String>, Metrics> mergedMetrics = Maps.newHashMap();

        for (Metrics metrics : metricsCollection) {
            Map<String, String> dimensionKey = metrics.getDimensions();

            if (!mergedMetrics.containsKey(dimensionKey)) {
                // create new one
                mergedMetrics.put(dimensionKey, metrics);
            } else {
                // merge all metrics to existing metrics as dimensions match
                mergedMetrics.get(dimensionKey).putAll(metrics.getMetrics());
            }
        }

        return mergedMetrics.values();
    }
}