code: /*
   * Licensed to the Apache Software Foundation (ASF) under one or more
   * contributor license agreements.  See the NOTICE file distributed with
   * this work for additional information regarding copyright ownership.
   * The ASF licenses this file to You 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 org.apache.skywalking.oap.server.core.alarm.provider.slack;
  
  import com.google.gson.Gson;
  import com.google.gson.JsonArray;
  import com.google.gson.JsonObject;
  import lombok.RequiredArgsConstructor;
  import lombok.extern.slf4j.Slf4j;
  import org.apache.skywalking.oap.server.core.alarm.AlarmMessage;
  import org.apache.skywalking.oap.server.core.alarm.HttpAlarmCallback;
  import org.apache.skywalking.oap.server.core.alarm.provider.AlarmRulesWatcher;
  
  import java.net.URI;
  import java.util.List;
  import java.util.Map;
  
  /**
   * Use SkyWalking alarm slack webhook API calls a remote endpoints.
   */
  @Slf4j
  @RequiredArgsConstructor
  public class SlackhookCallback extends HttpAlarmCallback {
      private static final Gson GSON = new Gson();
  
      private final AlarmRulesWatcher alarmRulesWatcher;
  
      @Override
      public void doAlarm(List<AlarmMessage> alarmMessages) throws Exception {
          if (alarmRulesWatcher.getSlackSettings() == null || alarmRulesWatcher.getSlackSettings().getWebhooks().isEmpty()) {
              return;
          }
  
          for (final var url : alarmRulesWatcher.getSlackSettings().getWebhooks()) {
              final var jsonObject = new JsonObject();
              final var jsonElements = new JsonArray();
              for (AlarmMessage item : alarmMessages) {
                  jsonElements.add(GSON.fromJson(
                          String.format(
                                  alarmRulesWatcher.getSlackSettings().getTextTemplate(), item.getAlarmMessage()
                          ), JsonObject.class));
              }
              jsonObject.add("blocks", jsonElements);
              final var body = GSON.toJson(jsonObject);
              post(URI.create(url), body, Map.of());
          }
      }
  }
  