io.druid.indexing.common.actions.RemoteTaskActionClient.java Source code

Introduction

Here is the source code for io.druid.indexing.common.actions.RemoteTaskActionClient.java

Source

/*
 * 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.indexing.common.actions;

import com.fasterxml.jackson.core.type.TypeReference;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.google.common.base.Charsets;
import com.google.common.base.Throwables;
import com.metamx.common.ISE;
import com.metamx.common.logger.Logger;
import com.metamx.http.client.HttpClient;
import com.metamx.http.client.Request;
import com.metamx.http.client.response.StatusResponseHandler;
import com.metamx.http.client.response.StatusResponseHolder;
import io.druid.client.selector.Server;
import io.druid.curator.discovery.ServerDiscoverySelector;
import io.druid.indexing.common.RetryPolicy;
import io.druid.indexing.common.RetryPolicyFactory;
import io.druid.indexing.common.task.Task;
import org.jboss.netty.channel.ChannelException;
import org.jboss.netty.handler.codec.http.HttpMethod;
import org.joda.time.Duration;

import javax.ws.rs.core.MediaType;
import java.io.IOException;
import java.net.URI;
import java.net.URISyntaxException;
import java.util.Map;
import java.util.Random;

public class RemoteTaskActionClient implements TaskActionClient {
    private final Task task;
    private final HttpClient httpClient;
    private final ServerDiscoverySelector selector;
    private final RetryPolicyFactory retryPolicyFactory;
    private final ObjectMapper jsonMapper;
    private final Random random = new Random();

    private static final Logger log = new Logger(RemoteTaskActionClient.class);

    public RemoteTaskActionClient(Task task, HttpClient httpClient, ServerDiscoverySelector selector,
            RetryPolicyFactory retryPolicyFactory, ObjectMapper jsonMapper) {
        this.task = task;
        this.httpClient = httpClient;
        this.selector = selector;
        this.retryPolicyFactory = retryPolicyFactory;
        this.jsonMapper = jsonMapper;
    }

    @Override
    public <RetType> RetType submit(TaskAction<RetType> taskAction) throws IOException {
        log.info("Performing action for task[%s]: %s", task.getId(), taskAction);

        byte[] dataToSend = jsonMapper.writeValueAsBytes(new TaskActionHolder(task, taskAction));

        final RetryPolicy retryPolicy = retryPolicyFactory.makeRetryPolicy();

        while (true) {
            try {
                final Server server;
                final URI serviceUri;
                try {
                    server = getServiceInstance();
                    serviceUri = makeServiceUri(server);
                } catch (Exception e) {
                    // Want to retry, so throw an IOException.
                    throw new IOException("Failed to locate service uri", e);
                }

                final StatusResponseHolder response;

                log.info("Submitting action for task[%s] to overlord[%s]: %s", task.getId(), serviceUri,
                        taskAction);

                try {
                    response = httpClient.go(new Request(HttpMethod.POST, serviceUri.toURL()).setContent(
                            MediaType.APPLICATION_JSON, dataToSend), new StatusResponseHandler(Charsets.UTF_8))
                            .get();
                } catch (Exception e) {
                    Throwables.propagateIfInstanceOf(e.getCause(), IOException.class);
                    Throwables.propagateIfInstanceOf(e.getCause(), ChannelException.class);
                    throw Throwables.propagate(e);
                }

                if (response.getStatus().getCode() / 200 == 1) {
                    final Map<String, Object> responseDict = jsonMapper.readValue(response.getContent(),
                            new TypeReference<Map<String, Object>>() {
                            });
                    return jsonMapper.convertValue(responseDict.get("result"), taskAction.getReturnTypeReference());
                } else {
                    // Want to retry, so throw an IOException.
                    throw new IOException(String.format(
                            "Scary HTTP status returned: %s. Check your overlord[%s] logs for exceptions.",
                            response.getStatus(), server.getHost()));
                }
            } catch (IOException | ChannelException e) {
                log.warn(e, "Exception submitting action for task[%s]", task.getId());

                final Duration delay = retryPolicy.getAndIncrementRetryDelay();
                if (delay == null) {
                    throw e;
                } else {
                    try {
                        final long sleepTime = jitter(delay.getMillis());
                        log.info("Will try again in [%s].", new Duration(sleepTime).toString());
                        Thread.sleep(sleepTime);
                    } catch (InterruptedException e2) {
                        throw Throwables.propagate(e2);
                    }
                }
            }
        }
    }

    private long jitter(long input) {
        final double jitter = random.nextGaussian() * input / 4.0;
        long retval = input + (long) jitter;
        return retval < 0 ? 0 : retval;
    }

    private URI makeServiceUri(final Server instance) throws URISyntaxException {
        return new URI(instance.getScheme(), null, instance.getAddress(), instance.getPort(),
                "/druid/indexer/v1/action", null, null);
    }

    private Server getServiceInstance() {
        final Server instance = selector.pick();
        if (instance == null) {
            throw new ISE("Cannot find instance of indexer to talk to!");
        } else {
            return instance;
        }
    }
}