Java tutorial
/** * This file is part of Graylog. * * Graylog is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * * Graylog is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with Graylog. If not, see <http://www.gnu.org/licenses/>. */ package org.graylog2.inputs.transports; import com.codahale.metrics.MetricSet; import com.google.common.annotations.VisibleForTesting; import com.google.common.collect.Maps; import com.google.common.eventbus.EventBus; import com.google.common.eventbus.Subscribe; import com.google.inject.assistedinject.Assisted; import com.google.inject.assistedinject.AssistedInject; import com.squareup.okhttp.Headers; import com.squareup.okhttp.OkHttpClient; import com.squareup.okhttp.Request; import com.squareup.okhttp.Response; import org.graylog2.plugin.ServerStatus; import org.graylog2.plugin.configuration.Configuration; import org.graylog2.plugin.configuration.ConfigurationRequest; import org.graylog2.plugin.configuration.fields.ConfigurationField; import org.graylog2.plugin.configuration.fields.DropdownField; import org.graylog2.plugin.configuration.fields.NumberField; import org.graylog2.plugin.configuration.fields.TextField; import org.graylog2.plugin.inputs.MessageInput; import org.graylog2.plugin.inputs.MisfireException; import org.graylog2.plugin.inputs.annotations.ConfigClass; import org.graylog2.plugin.inputs.annotations.FactoryClass; import org.graylog2.plugin.inputs.codecs.CodecAggregator; import org.graylog2.plugin.inputs.transports.ThrottleableTransport; import org.graylog2.plugin.inputs.transports.Transport; import org.graylog2.plugin.journal.RawMessage; import org.graylog2.plugin.lifecycles.Lifecycle; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import javax.inject.Named; import java.io.IOException; import java.net.InetSocketAddress; import java.net.MalformedURLException; import java.net.URL; import java.util.Collections; import java.util.Map; import java.util.concurrent.ScheduledExecutorService; import java.util.concurrent.ScheduledFuture; import java.util.concurrent.TimeUnit; import static com.google.common.base.Strings.isNullOrEmpty; public class HttpPollTransport extends ThrottleableTransport { private static final Logger LOG = LoggerFactory.getLogger(HttpPollTransport.class); private static final String CK_URL = "target_url"; private static final String CK_HEADERS = "headers"; private static final String CK_TIMEUNIT = "timeunit"; private static final String CK_INTERVAL = "interval"; private final Configuration configuration; private final EventBus serverEventBus; private final ServerStatus serverStatus; private final ScheduledExecutorService scheduler; private final OkHttpClient httpClient; private volatile boolean paused = true; private ScheduledFuture<?> scheduledFuture; @AssistedInject public HttpPollTransport(@Assisted Configuration configuration, EventBus serverEventBus, ServerStatus serverStatus, @Named("daemonScheduler") ScheduledExecutorService scheduler, OkHttpClient httpClient) { super(serverEventBus, configuration); this.configuration = configuration; this.serverEventBus = serverEventBus; this.serverStatus = serverStatus; this.scheduler = scheduler; this.httpClient = httpClient; } @VisibleForTesting static Map<String, String> parseHeaders(String headerString) { if (isNullOrEmpty(headerString)) { return Collections.emptyMap(); } final Map<String, String> headers = Maps.newHashMap(); for (String headerPart : headerString.trim().split(",")) { final String[] parts = headerPart.trim().split(":"); if (parts.length == 2) { headers.put(parts[0].trim(), parts[1].trim()); } } return headers; } @Subscribe public void lifecycleStateChange(Lifecycle lifecycle) { LOG.debug("Lifecycle changed to {}", lifecycle); switch (lifecycle) { case RUNNING: paused = false; break; default: paused = true; } } @Override public void setMessageAggregator(CodecAggregator aggregator) { // not supported } @Override public void doLaunch(final MessageInput input) throws MisfireException { serverStatus.awaitRunning(new Runnable() { @Override public void run() { lifecycleStateChange(Lifecycle.RUNNING); } }); // listen for lifecycle changes serverEventBus.register(this); final Map<String, String> headers = parseHeaders(configuration.getString(CK_HEADERS)); // figure out a reasonable remote address final String url = configuration.getString(CK_URL); final InetSocketAddress remoteAddress; InetSocketAddress remoteAddress1; try { final URL url1 = new URL(url); final int port = url1.getPort(); remoteAddress1 = new InetSocketAddress(url1.getHost(), port != -1 ? port : 80); } catch (MalformedURLException e) { remoteAddress1 = null; } remoteAddress = remoteAddress1; final Runnable task = new Runnable() { @Override public void run() { if (paused) { LOG.debug("Message processing paused, not polling HTTP resource {}.", url); return; } if (isThrottled()) { // this transport won't block, but we can simply skip this iteration LOG.debug("Not polling HTTP resource {} because we are throttled.", url); } final Request.Builder requestBuilder = new Request.Builder().get().url(url) .headers(Headers.of(headers)); try { final Response r = httpClient.newCall(requestBuilder.build()).execute(); if (!r.isSuccessful()) { throw new RuntimeException("Expected successful HTTP status code [2xx], got " + r.code()); } input.processRawMessage(new RawMessage(r.body().bytes(), remoteAddress)); } catch (IOException e) { LOG.error("Could not fetch HTTP resource at " + url, e); } } }; scheduledFuture = scheduler.scheduleAtFixedRate(task, 0, configuration.getInt(CK_INTERVAL), TimeUnit.valueOf(configuration.getString(CK_TIMEUNIT))); } @Override public void doStop() { serverEventBus.unregister(this); if (scheduledFuture != null) { scheduledFuture.cancel(true); } } @Override public MetricSet getMetricSet() { // TODO do we need any metrics here? return null; } @FactoryClass public interface Factory extends Transport.Factory<HttpPollTransport> { @Override HttpPollTransport create(Configuration configuration); @Override Config getConfig(); } @ConfigClass public static class Config extends ThrottleableTransport.Config { @Override public ConfigurationRequest getRequestedConfiguration() { final ConfigurationRequest r = super.getRequestedConfiguration(); r.addField(new TextField(CK_URL, "URI of JSON resource", "http://example.org/api", "HTTP resource returning JSON on GET", ConfigurationField.Optional.NOT_OPTIONAL)); r.addField(new TextField(CK_HEADERS, "Additional HTTP headers", "", "Add a comma separated list of additional HTTP headers. For example: Accept: application/json, X-Requester: Graylog2", ConfigurationField.Optional.OPTIONAL)); r.addField(new NumberField(CK_INTERVAL, "Interval", 1, "Time between every collector run. Select a time unit in the corresponding dropdown. Example: Run every 5 minutes.", ConfigurationField.Optional.NOT_OPTIONAL)); r.addField(new DropdownField(CK_TIMEUNIT, "Interval time unit", TimeUnit.MINUTES.toString(), DropdownField.ValueTemplates.timeUnits(), ConfigurationField.Optional.NOT_OPTIONAL)); return r; } } }