/*
* Copyright (c) 2015 Spotify AB.
*
* 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 com.spotify.heroic.aggregation;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableMap;
import com.spotify.heroic.common.DateRange;
import com.spotify.heroic.metric.ShardedResultGroup;
import java.util.List;
import lombok.Data;
@Data
public class DistributedAggregationCombiner implements AggregationCombiner {
private final AggregationInstance reducer;
private final DateRange range;
private final BucketStrategy bucketStrategy;
private final long cadence;
/**
* Create a combiner from a global aggregation.
* <p>
* Notice that the cadence is taken from the root aggregation, since the reducer might
* lose it.
*
* @param root
* @param range
* @return
*/
public static DistributedAggregationCombiner create(
final AggregationInstance root, final DateRange range, final BucketStrategy bucketStrategy
) {
return new DistributedAggregationCombiner(root.reducer(), range, bucketStrategy,
root.cadence());
}
@Override
public List<ShardedResultGroup> combine(
final List<List<ShardedResultGroup>> all
) {
final AggregationSession session =
reducer.session(range, RetainQuotaWatcher.NO_QUOTA, bucketStrategy);
/* iterate through all groups and setup, and feed a reducer session for every group */
for (List<ShardedResultGroup> groups : all) {
for (final ShardedResultGroup g : groups) {
g.getMetrics().updateAggregation(session, g.getKey(), g.getSeries());
}
}
/* build results from every reducer group into a final result */
final ImmutableList.Builder<ShardedResultGroup> groups = ImmutableList.builder();
final AggregationResult result = session.result();
for (final AggregationOutput out : result.getResult()) {
groups.add(new ShardedResultGroup(ImmutableMap.of(), out.getKey(), out.getSeries(),
out.getMetrics(), cadence));
}
return groups.build();
}
}