io.druid.server.router.CoordinatorRuleManager.java Source code

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Here is the source code for io.druid.server.router.CoordinatorRuleManager.java

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/*
 * Druid - a distributed column store.
 * Copyright 2012 - 2015 Metamarkets Group 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 io.druid.server.router;

import com.fasterxml.jackson.core.type.TypeReference;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.google.common.base.Charsets;
import com.google.common.base.Supplier;
import com.google.common.collect.Lists;
import com.google.inject.Inject;
import com.metamx.common.concurrent.ScheduledExecutors;
import com.metamx.common.lifecycle.LifecycleStart;
import com.metamx.common.lifecycle.LifecycleStop;
import com.metamx.common.logger.Logger;
import com.metamx.http.client.HttpClient;
import com.metamx.http.client.Request;
import com.metamx.http.client.response.FullResponseHandler;
import com.metamx.http.client.response.FullResponseHolder;
import io.druid.client.selector.Server;
import io.druid.concurrent.Execs;
import io.druid.curator.discovery.ServerDiscoverySelector;
import io.druid.guice.ManageLifecycle;
import io.druid.guice.annotations.Global;
import io.druid.guice.annotations.Json;
import io.druid.server.coordinator.rules.Rule;
import org.jboss.netty.handler.codec.http.HttpMethod;
import org.jboss.netty.handler.codec.http.HttpResponseStatus;
import org.joda.time.Duration;

import java.net.URI;
import java.net.URISyntaxException;
import java.net.URL;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.atomic.AtomicReference;

/**
 */
@ManageLifecycle
public class CoordinatorRuleManager {
    private static final Logger log = new Logger(CoordinatorRuleManager.class);

    private final HttpClient httpClient;
    private final ObjectMapper jsonMapper;
    private final Supplier<TieredBrokerConfig> config;
    private final ServerDiscoverySelector selector;

    private final FullResponseHandler responseHandler;
    private final AtomicReference<ConcurrentHashMap<String, List<Rule>>> rules;

    private volatile ScheduledExecutorService exec;

    private final Object lock = new Object();

    private volatile boolean started = false;

    @Inject
    public CoordinatorRuleManager(@Global HttpClient httpClient, @Json ObjectMapper jsonMapper,
            Supplier<TieredBrokerConfig> config, ServerDiscoverySelector selector) {
        this.httpClient = httpClient;
        this.jsonMapper = jsonMapper;
        this.config = config;
        this.selector = selector;

        this.responseHandler = new FullResponseHandler(Charsets.UTF_8);
        this.rules = new AtomicReference<>(new ConcurrentHashMap<String, List<Rule>>());
    }

    @LifecycleStart
    public void start() {
        synchronized (lock) {
            if (started) {
                return;
            }

            this.exec = Execs.scheduledSingleThreaded("CoordinatorRuleManager-Exec--%d");

            ScheduledExecutors.scheduleWithFixedDelay(exec, new Duration(0),
                    config.get().getPollPeriod().toStandardDuration(), new Runnable() {
                        @Override
                        public void run() {
                            poll();
                        }
                    });

            started = true;
        }
    }

    @LifecycleStop
    public void stop() {
        synchronized (lock) {
            if (!started) {
                return;
            }

            rules.set(new ConcurrentHashMap<String, List<Rule>>());

            started = false;
            exec.shutdownNow();
            exec = null;
        }
    }

    public boolean isStarted() {
        return started;
    }

    @SuppressWarnings("unchecked")
    public void poll() {
        try {
            String url = getRuleURL();
            if (url == null) {
                return;
            }

            FullResponseHolder response = httpClient.go(new Request(HttpMethod.GET, new URL(url)), responseHandler)
                    .get();

            if (response.getStatus().equals(HttpResponseStatus.FOUND)) {
                url = response.getResponse().headers().get("Location");
                log.info("Redirecting rule request to [%s]", url);
                response = httpClient.go(new Request(HttpMethod.GET, new URL(url)), responseHandler).get();
            }

            ConcurrentHashMap<String, List<Rule>> newRules = new ConcurrentHashMap<>(
                    (Map<String, List<Rule>>) jsonMapper.readValue(response.getContent(),
                            new TypeReference<Map<String, List<Rule>>>() {
                            }));

            log.info("Got [%,d] rules", newRules.keySet().size());

            rules.set(newRules);
        } catch (Exception e) {
            log.error(e, "Exception while polling for rules");
        }
    }

    public List<Rule> getRulesWithDefault(final String dataSource) {
        List<Rule> retVal = Lists.newArrayList();
        Map<String, List<Rule>> theRules = rules.get();
        if (theRules.get(dataSource) != null) {
            retVal.addAll(theRules.get(dataSource));
        }
        if (theRules.get(config.get().getDefaultRule()) != null) {
            retVal.addAll(theRules.get(config.get().getDefaultRule()));
        }
        return retVal;
    }

    private String getRuleURL() throws URISyntaxException {
        Server server = selector.pick();

        if (server == null) {
            log.error("No instances found for [%s]!", config.get().getCoordinatorServiceName());
            return null;
        }

        return new URI(server.getScheme(), null, server.getAddress(), server.getPort(),
                config.get().getRulesEndpoint(), null, null).toString();
    }
}