com.spotify.helios.master.HostMatcher.java Source code

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Here is the source code for com.spotify.helios.master.HostMatcher.java

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/*
 * Copyright (c) 2016 Spotify AB.
 *
 * 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.spotify.helios.master;

import static com.google.common.base.Preconditions.checkNotNull;
import static java.util.Collections.emptyList;

import com.spotify.helios.common.descriptors.DeploymentGroup;
import com.spotify.helios.common.descriptors.HostSelector;
import com.spotify.helios.rollingupdate.AlphaNumericComparator;

import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.Lists;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.util.Collections;
import java.util.List;
import java.util.Locale;
import java.util.Map;

/**
 * Filters hosts based on their labels according to a List of HostSelectors.
 */
public class HostMatcher {

    private static final Logger log = LoggerFactory.getLogger(HostMatcher.class);

    private final Map<String, Map<String, String>> hostsAndLabels;

    public HostMatcher(final Map<String, Map<String, String>> hostsAndLabels) {
        this.hostsAndLabels = ImmutableMap.copyOf(checkNotNull(hostsAndLabels, "hostsAndLabels"));
    }

    public List<String> getMatchingHosts(final DeploymentGroup deploymentGroup) {
        final List<HostSelector> selectors = deploymentGroup.getHostSelectors();
        if (selectors == null || selectors.isEmpty()) {
            log.error("skipping deployment group with no host selectors: " + deploymentGroup.getName());
            return emptyList();
        }

        return getMatchingHosts(selectors);
    }

    public List<String> getMatchingHosts(final List<HostSelector> selectors) {

        final List<String> matchingHosts = Lists.newArrayList();

        for (final Map.Entry<String, Map<String, String>> entry : hostsAndLabels.entrySet()) {
            final String host = entry.getKey();
            final Map<String, String> hostLabels = entry.getValue();

            // every hostSelector in the group has to have a match in this host.
            // a match meaning the host has a label for that key and the value matches
            final boolean match = selectors.stream()
                    .allMatch(selector -> hostLabels.containsKey(selector.getLabel())
                            && selector.matches(hostLabels.get(selector.getLabel())));

            if (match) {
                matchingHosts.add(host);
            }
        }

        Collections.sort(matchingHosts, new AlphaNumericComparator(Locale.ENGLISH));
        return ImmutableList.copyOf(matchingHosts);
    }
}