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.alarmcallbacks; import com.fasterxml.jackson.core.JsonProcessingException; import com.fasterxml.jackson.databind.ObjectMapper; import com.google.common.collect.Maps; import com.squareup.okhttp.MediaType; import com.squareup.okhttp.OkHttpClient; import com.squareup.okhttp.Request; import com.squareup.okhttp.RequestBody; import com.squareup.okhttp.Response; import org.graylog2.plugin.alarms.AlertCondition; import org.graylog2.plugin.alarms.callbacks.AlarmCallback; import org.graylog2.plugin.alarms.callbacks.AlarmCallbackConfigurationException; import org.graylog2.plugin.alarms.callbacks.AlarmCallbackException; import org.graylog2.plugin.configuration.Configuration; import org.graylog2.plugin.configuration.ConfigurationException; import org.graylog2.plugin.configuration.ConfigurationRequest; import org.graylog2.plugin.configuration.fields.ConfigurationField; import org.graylog2.plugin.configuration.fields.TextField; import org.graylog2.plugin.streams.Stream; import javax.inject.Inject; import java.io.IOException; import java.net.MalformedURLException; import java.net.URL; import java.util.Map; import static com.google.common.base.Strings.isNullOrEmpty; import static javax.ws.rs.core.MediaType.APPLICATION_JSON; public class HTTPAlarmCallback implements AlarmCallback { private static final String CK_URL = "url"; private static final MediaType CONTENT_TYPE = MediaType.parse(APPLICATION_JSON); private final OkHttpClient httpClient; private final ObjectMapper objectMapper; private Configuration configuration; @Inject public HTTPAlarmCallback(final OkHttpClient httpClient, final ObjectMapper objectMapper) { this.httpClient = httpClient; this.objectMapper = objectMapper; } @Override public void initialize(final Configuration config) throws AlarmCallbackConfigurationException { this.configuration = config; } @Override public void call(final Stream stream, final AlertCondition.CheckResult result) throws AlarmCallbackException { final Map<String, Object> event = Maps.newHashMap(); event.put("stream", stream); event.put("check_result", result); final Response r; try { final byte[] body = objectMapper.writeValueAsBytes(event); final URL url = new URL(configuration.getString(CK_URL)); final Request request = new Request.Builder().url(url).post(RequestBody.create(CONTENT_TYPE, body)) .build(); r = httpClient.newCall(request).execute(); } catch (JsonProcessingException e) { throw new AlarmCallbackException("Unable to serialize alarm", e); } catch (MalformedURLException e) { throw new AlarmCallbackException("Malformed URL", e); } catch (IOException e) { throw new AlarmCallbackException(e.getMessage(), e); } if (!r.isSuccessful()) { throw new AlarmCallbackException("Expected successful HTTP response [2xx] but got [" + r.code() + "]."); } } @Override public ConfigurationRequest getRequestedConfiguration() { final ConfigurationRequest configurationRequest = new ConfigurationRequest(); configurationRequest.addField(new TextField(CK_URL, "URL", "https://example.org/alerts", "The URL to POST to when an alert is triggered", ConfigurationField.Optional.NOT_OPTIONAL)); return configurationRequest; } @Override public String getName() { return "HTTP Alarm Callback"; } @Override public Map<String, Object> getAttributes() { return configuration.getSource(); } @Override public void checkConfiguration() throws ConfigurationException { if (isNullOrEmpty(configuration.getString(CK_URL))) { throw new ConfigurationException("URL parameter is missing!"); } try { new URL(configuration.getString(CK_URL)); } catch (MalformedURLException e) { throw new ConfigurationException("Malformed URL", e); } } }