content: // 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 com.cloud.storage.download;
  
  import java.util.Collections;
  import java.util.Date;
  import java.util.HashMap;
  import java.util.List;
  import java.util.Map;
  import java.util.Timer;
  
  import javax.inject.Inject;
  
  import org.apache.cloudstack.engine.subsystem.api.storage.DataObject;
  import org.apache.cloudstack.engine.subsystem.api.storage.DataStore;
  import org.apache.cloudstack.engine.subsystem.api.storage.DataStoreManager;
  import org.apache.cloudstack.engine.subsystem.api.storage.EndPoint;
  import org.apache.cloudstack.engine.subsystem.api.storage.TemplateService;
  import org.apache.cloudstack.engine.subsystem.api.storage.VolumeService;
  import org.apache.cloudstack.engine.subsystem.api.storage.ZoneScope;
  import org.apache.cloudstack.framework.async.AsyncCompletionCallback;
  import org.apache.cloudstack.managed.context.ManagedContextTimerTask;
  import org.apache.cloudstack.storage.command.DownloadCommand;
  import org.apache.cloudstack.storage.command.DownloadCommand.ResourceType;
  import org.apache.cloudstack.storage.command.DownloadProgressCommand;
  import org.apache.cloudstack.storage.command.DownloadProgressCommand.RequestType;
  import org.apache.cloudstack.utils.cache.LazyCache;
  import org.apache.logging.log4j.Level;
  import org.apache.logging.log4j.LogManager;
  import org.apache.logging.log4j.Logger;
  
  import com.cloud.agent.Listener;
  import com.cloud.agent.api.AgentControlAnswer;
  import com.cloud.agent.api.AgentControlCommand;
  import com.cloud.agent.api.Answer;
  import com.cloud.agent.api.Command;
  import com.cloud.agent.api.StartupCommand;
  import com.cloud.agent.api.StartupRoutingCommand;
  import com.cloud.agent.api.StartupSecondaryStorageCommand;
  import com.cloud.agent.api.storage.DownloadAnswer;
  import com.cloud.agent.api.to.DataObjectType;
  import com.cloud.exception.ConnectionException;
  import com.cloud.host.Host;
  import com.cloud.hypervisor.Hypervisor;
  import com.cloud.resource.ResourceManager;
  import com.cloud.storage.VMTemplateStorageResourceAssoc.Status;
  import com.cloud.storage.download.DownloadState.DownloadEvent;
  import com.cloud.storage.upload.UploadListener;
  import com.cloud.utils.exception.CloudRuntimeException;
  
  /**
   * Monitor progress of template download to a single storage server
   *
   */
  public class DownloadListener implements Listener {
  
      private static final class StatusTask extends ManagedContextTimerTask {
          private final DownloadListener dl;
          private final RequestType reqType;
  
          public StatusTask(DownloadListener dl, RequestType req) {
              reqType = req;
              this.dl = dl;
          }
  
          @Override
          protected void runInContext() {
              dl.sendCommand(reqType);
  
          }
      }
  
      private static final class TimeoutTask extends ManagedContextTimerTask {
          private final DownloadListener dl;
  
          public TimeoutTask(DownloadListener dl) {
              this.dl = dl;
          }
  
          @Override
          protected void runInContext() {
              dl.checkProgress();
          }
      }
  
      protected Logger logger = LogManager.getLogger(getClass());
      public static final int SMALL_DELAY = 100;
      public static final long STATUS_POLL_INTERVAL = 10000L;
      public static final long DOWNLOAD_TIMEOUT = 5 * STATUS_POLL_INTERVAL;
  
      public static final String DOWNLOADED = Status.DOWNLOADED.toString();
      public static final String NOT_DOWNLOADED = Status.NOT_DOWNLOADED.toString();
      public static final String DOWNLOAD_ERROR = Status.DOWNLOAD_ERROR.toString();
      public static final String DOWNLOAD_IN_PROGRESS = Status.DOWNLOAD_IN_PROGRESS.toString();
      public static final String DOWNLOAD_ABANDONED = Status.ABANDONED.toString();
  
      private EndPoint _ssAgent;
  
      private DataObject object;
  
      private boolean _downloadActive = true;
      private final DownloadMonitorImpl _downloadMonitor;
  
      private DownloadState _currState;
  
      private DownloadCommand _cmd;
  
      private Timer _timer;
  
      private StatusTask _statusTask;
      private TimeoutTask _timeoutTask;
      private Date _lastUpdated = new Date();
      private String jobId;
  
      private final Map<String, DownloadState> _stateMap = new HashMap<String, DownloadState>();
      private AsyncCompletionCallback<DownloadAnswer> _callback;
  
      @Inject
      private ResourceManager _resourceMgr;
      @Inject
      private TemplateService _imageSrv;
      @Inject
      private DataStoreManager _storeMgr;
      @Inject
      private VolumeService _volumeSrv;
  
      private LazyCache<Long, List<Hypervisor.HypervisorType>> zoneHypervisorsCache;
  
      private List<Hypervisor.HypervisorType> listAvailHypervisorInZone(long zoneId) {
          if (_resourceMgr == null) {
              return Collections.emptyList();
          }
          return _resourceMgr.listAvailHypervisorInZone(zoneId);
      }
  
      protected void initZoneHypervisorsCache() {
          zoneHypervisorsCache =
                  new LazyCache<>(32, 30, this::listAvailHypervisorInZone);
      }
  
      // TODO: this constructor should be the one used for template only, remove other template constructor later
      public DownloadListener(EndPoint ssAgent, DataStore store, DataObject object, Timer timer, DownloadMonitorImpl downloadMonitor, DownloadCommand cmd,
              AsyncCompletionCallback<DownloadAnswer> callback) {
          _ssAgent = ssAgent;
          this.object = object;
          _downloadMonitor = downloadMonitor;
          _cmd = cmd;
          initStateMachine();
          _currState = getState(Status.NOT_DOWNLOADED.toString());
          this._timer = timer;
          _timeoutTask = new TimeoutTask(this);
          this._timer.schedule(_timeoutTask, 3 * STATUS_POLL_INTERVAL);
          _callback = callback;
          DownloadAnswer answer = new DownloadAnswer("", Status.NOT_DOWNLOADED);
          callback(answer);
          initZoneHypervisorsCache();
      }
  
      public DownloadListener(DownloadMonitorImpl monitor) {
          _downloadMonitor = monitor;
          initZoneHypervisorsCache();
      }
  
      public AsyncCompletionCallback<DownloadAnswer> getCallback() {
          return _callback;
      }
  
      public void setCurrState(Status currState) {
          _currState = getState(currState.toString());
      }
  
      private void initStateMachine() {
          _stateMap.put(Status.NOT_DOWNLOADED.toString(), new NotDownloadedState(this));
          _stateMap.put(Status.DOWNLOADED.toString(), new DownloadCompleteState(this));
          _stateMap.put(Status.DOWNLOAD_ERROR.toString(), new DownloadErrorState(this));
          _stateMap.put(Status.DOWNLOAD_IN_PROGRESS.toString(), new DownloadInProgressState(this));
          _stateMap.put(Status.ABANDONED.toString(), new DownloadAbandonedState(this));
      }
  
      private DownloadState getState(String stateName) {
          return _stateMap.get(stateName);
      }
  
      public void sendCommand(RequestType reqType) {
          if (getJobId() != null) {
              if (logger.isTraceEnabled()) {
                  log("Sending progress command ", Level.TRACE);
              }
              try {
                  DownloadProgressCommand dcmd = new DownloadProgressCommand(getCommand(), getJobId(), reqType);
                  if (object.getType() == DataObjectType.VOLUME) {
                      dcmd.setResourceType(ResourceType.VOLUME);
                  } else if (object.getType() == DataObjectType.SNAPSHOT) {
                      dcmd.setResourceType(ResourceType.SNAPSHOT);
                  }
                  _ssAgent.sendMessageAsync(dcmd, new UploadListener.Callback(_ssAgent.getId(), this));
              } catch (Exception e) {
                  logger.debug("Send command failed", e);
                  setDisconnected();
              }
          }
  
      }
  
      public void checkProgress() {
          transition(DownloadEvent.TIMEOUT_CHECK, null);
      }
  
      public void setDisconnected() {
          transition(DownloadEvent.DISCONNECT, null);
      }
  
      public void logDisconnect() {
          logger.warn("Unable to monitor download progress of {} : uuid: {}({}) at host [id: {}, uuid: {}]",
                  object.getType(), object.getUuid(), object, _ssAgent.getId(), _ssAgent.getUuid());
      }
  
      public void log(String message, Level level) {
          logger.log(level, "{}, {}: {}({}) at host [id: {}, uuid: {}]",
                  message, object.getType(), object.getUuid(), object, _ssAgent.getId(), _ssAgent.getUuid());
      }
  
      @Override
      public boolean isRecurring() {
          return false;
      }
  
      @Override
      public boolean processAnswers(long agentId, long seq, Answer[] answers) {
          boolean processed = false;
          if (answers != null & answers.length > 0) {
              if (answers[0] instanceof DownloadAnswer) {
                  final DownloadAnswer answer = (DownloadAnswer)answers[0];
                  if (getJobId() == null) {
                      setJobId(answer.getJobId());
                  } else if (!getJobId().equalsIgnoreCase(answer.getJobId())) {
                      return false;//TODO
                  }
                  transition(DownloadEvent.DOWNLOAD_ANSWER, answer);
                  processed = true;
              }
          }
          return processed;
      }
  
      private synchronized void transition(DownloadEvent event, Object evtObj) {
          if (_currState == null) {
              return;
          }
          String prevName = _currState.getName();
          String nextState = _currState.handleEvent(event, evtObj);
          if (nextState != null) {
              _currState = getState(nextState);
              if (_currState != null) {
                  _currState.onEntry(prevName, event, evtObj);
              } else {
                  throw new CloudRuntimeException("Invalid next state: currState=" + prevName + ", evt=" + event + ", next=" + nextState);
              }
          } else {
              throw new CloudRuntimeException("Unhandled event transition: currState=" + prevName + ", evt=" + event);
          }
      }
  
      public void callback(DownloadAnswer answer) {
          if (_callback != null) {
              _callback.complete(answer);
          }
      }
  
      @Override
      public boolean processCommands(long agentId, long seq, Command[] req) {
          return false;
      }
  
      @Override
      public AgentControlAnswer processControlCommand(long agentId, AgentControlCommand cmd) {
          return null;
      }
  
      @Override
      public void processHostAdded(long hostId) {
      }
  
      @Override
      public void processConnect(Host agent, StartupCommand cmd, boolean forRebalance) throws ConnectionException {
          if (cmd instanceof StartupRoutingCommand) {
              List<Hypervisor.HypervisorType> hypervisors = zoneHypervisorsCache.get(agent.getDataCenterId());
              Hypervisor.HypervisorType hostHyper = agent.getHypervisorType();
              if (hypervisors.contains(hostHyper)) {
                  return;
              }
              _imageSrv.handleSysTemplateDownload(hostHyper, agent.getDataCenterId());
              // update template_zone_ref for cross-zone templates
              _imageSrv.associateCrosszoneTemplatesToZone(agent.getDataCenterId());
  
          }
          /* This can be removed
          else if ( cmd instanceof StartupStorageCommand) {
              StartupStorageCommand storage = (StartupStorageCommand)cmd;
              if( storage.getResourceType() == Storage.StorageResourceType.SECONDARY_STORAGE ||
                      storage.getResourceType() == Storage.StorageResourceType.LOCAL_SECONDARY_STORAGE  ) {
                  downloadMonitor.addSystemVMTemplatesToHost(agent, storage.getTemplateInfo());
                  downloadMonitor.handleTemplateSync(agent);
                  downloadMonitor.handleVolumeSync(agent);
              }
          }*/
          else if (cmd instanceof StartupSecondaryStorageCommand) {
              try{
                  List<DataStore> imageStores = _storeMgr.getImageStoresByScopeExcludingReadOnly(new ZoneScope(agent.getDataCenterId()));
                  for (DataStore store : imageStores) {
                      _volumeSrv.handleVolumeSync(store);
                      _imageSrv.handleTemplateSync(store);
                  }
              }catch (Exception e){
                  logger.error("Caught exception while doing template/volume sync ", e);
              }
          }
      }
  
      @Override
      public boolean processDisconnect(long agentId, com.cloud.host.Status state) {
          setDisconnected();
          return true;
      }
  
      @Override
      public void processHostAboutToBeRemoved(long hostId) {
      }
  
      @Override
      public void processHostRemoved(long hostId, long clusterId) {
      }
  
      public void setCommand(DownloadCommand cmd) {
          this._cmd = cmd;
      }
  
      public DownloadCommand getCommand() {
          return _cmd;
      }
  
      public void abandon() {
          transition(DownloadEvent.ABANDON_DOWNLOAD, null);
      }
  
      public void setJobId(String jobId) {
          this.jobId = jobId;
      }
  
      public String getJobId() {
          return jobId;
      }
  
      public void scheduleStatusCheck(RequestType request) {
          if (_statusTask != null)
              _statusTask.cancel();
  
          _statusTask = new StatusTask(this, request);
          _timer.schedule(_statusTask, STATUS_POLL_INTERVAL);
      }
  
      public void scheduleTimeoutTask(long delay) {
          if (_timeoutTask != null)
              _timeoutTask.cancel();
  
          _timeoutTask = new TimeoutTask(this);
          _timer.schedule(_timeoutTask, delay);
          if (logger.isDebugEnabled()) {
              log("Scheduling timeout at " + delay + " ms", Level.DEBUG);
          }
      }
  
      public void scheduleImmediateStatusCheck(RequestType request) {
          if (_statusTask != null)
              _statusTask.cancel();
          _statusTask = new StatusTask(this, request);
          _timer.schedule(_statusTask, SMALL_DELAY);
      }
  
      public boolean isDownloadActive() {
          return _downloadActive;
      }
  
      public void cancelStatusTask() {
          if (_statusTask != null)
              _statusTask.cancel();
      }
  
      public Date getLastUpdated() {
          return _lastUpdated;
      }
  
      public void setLastUpdated() {
          _lastUpdated = new Date();
      }
  
      public void setDownloadInactive(Status reason) {
          _downloadActive = false;
      }
  
      public void cancelTimeoutTask() {
          if (_timeoutTask != null)
              _timeoutTask.cancel();
      }
  
      public void logDownloadStart() {
      }
  
      @Override
      public boolean processTimeout(long agentId, long seq) {
          return true;
      }
  
      @Override
      public int getTimeout() {
          return -1;
      }
  }
  