private Map<Long, TemplateInfo> listVolume(HostVO ssHost) {
    ListVolumeCommand cmd = new ListVolumeCommand(ssHost.getStorageUrl());
    Answer answer = _agentMgr.sendToSecStorage(ssHost, cmd);
    if (answer != null && answer.getResult()) {
      ListVolumeAnswer tanswer = (ListVolumeAnswer) answer;
      return tanswer.getTemplateInfo();
    } else {
      if (s_logger.isDebugEnabled()) {
        s_logger.debug("Can not list volumes for secondary storage host " + ssHost.getId());
      }
    }

    return null;
  }
  @Override
  @DB
  public boolean delete(TemplateProfile profile) {
    boolean success = true;

    VMTemplateVO template = profile.getTemplate();
    Long zoneId = profile.getZoneId();
    Long templateId = template.getId();

    String zoneName;
    List<HostVO> secondaryStorageHosts;
    if (!template.isCrossZones() && zoneId != null) {
      DataCenterVO zone = _dcDao.findById(zoneId);
      zoneName = zone.getName();
      secondaryStorageHosts = _ssvmMgr.listSecondaryStorageHostsInOneZone(zoneId);
    } else {
      zoneName = "(all zones)";
      secondaryStorageHosts = _ssvmMgr.listSecondaryStorageHostsInAllZones();
    }

    s_logger.debug(
        "Attempting to mark template host refs for template: "
            + template.getName()
            + " as destroyed in zone: "
            + zoneName);

    // Make sure the template is downloaded to all the necessary secondary storage hosts
    for (HostVO secondaryStorageHost : secondaryStorageHosts) {
      long hostId = secondaryStorageHost.getId();
      List<VMTemplateHostVO> templateHostVOs = _tmpltHostDao.listByHostTemplate(hostId, templateId);
      for (VMTemplateHostVO templateHostVO : templateHostVOs) {
        if (templateHostVO.getDownloadState() == Status.DOWNLOAD_IN_PROGRESS) {
          String errorMsg = "Please specify a template that is not currently being downloaded.";
          s_logger.debug(
              "Template: "
                  + template.getName()
                  + " is currently being downloaded to secondary storage host: "
                  + secondaryStorageHost.getName()
                  + "; cant' delete it.");
          throw new CloudRuntimeException(errorMsg);
        }
      }
    }

    Account account = _accountDao.findByIdIncludingRemoved(template.getAccountId());
    String eventType = "";

    if (template.getFormat().equals(ImageFormat.ISO)) {
      eventType = EventTypes.EVENT_ISO_DELETE;
    } else {
      eventType = EventTypes.EVENT_TEMPLATE_DELETE;
    }

    // Iterate through all necessary secondary storage hosts and mark the template on each host as
    // destroyed
    for (HostVO secondaryStorageHost : secondaryStorageHosts) {
      long hostId = secondaryStorageHost.getId();
      long sZoneId = secondaryStorageHost.getDataCenterId();
      List<VMTemplateHostVO> templateHostVOs = _tmpltHostDao.listByHostTemplate(hostId, templateId);
      for (VMTemplateHostVO templateHostVO : templateHostVOs) {
        VMTemplateHostVO lock = _tmpltHostDao.acquireInLockTable(templateHostVO.getId());
        try {
          if (lock == null) {
            s_logger.debug(
                "Failed to acquire lock when deleting templateHostVO with ID: "
                    + templateHostVO.getId());
            success = false;
            break;
          }
          UsageEventVO usageEvent =
              new UsageEventVO(eventType, account.getId(), sZoneId, templateId, null);
          _usageEventDao.persist(usageEvent);
          templateHostVO.setDestroyed(true);
          _tmpltHostDao.update(templateHostVO.getId(), templateHostVO);
          String installPath = templateHostVO.getInstallPath();
          if (installPath != null) {
            Answer answer =
                _agentMgr.sendToSecStorage(
                    secondaryStorageHost,
                    new DeleteTemplateCommand(secondaryStorageHost.getStorageUrl(), installPath));

            if (answer == null || !answer.getResult()) {
              s_logger.debug(
                  "Failed to delete "
                      + templateHostVO
                      + " due to "
                      + ((answer == null) ? "answer is null" : answer.getDetails()));
            } else {
              _tmpltHostDao.remove(templateHostVO.getId());
              s_logger.debug("Deleted template at: " + installPath);
            }
          } else {
            _tmpltHostDao.remove(templateHostVO.getId());
          }
          VMTemplateZoneVO templateZone = _tmpltZoneDao.findByZoneTemplate(sZoneId, templateId);

          if (templateZone != null) {
            _tmpltZoneDao.remove(templateZone.getId());
          }
        } finally {
          if (lock != null) {
            _tmpltHostDao.releaseFromLockTable(lock.getId());
          }
        }
      }

      if (!success) {
        break;
      }
    }

    s_logger.debug(
        "Successfully marked template host refs for template: "
            + template.getName()
            + " as destroyed in zone: "
            + zoneName);

    // If there are no more non-destroyed template host entries for this template, delete it
    if (success && (_tmpltHostDao.listByTemplateId(templateId).size() == 0)) {
      long accountId = template.getAccountId();

      VMTemplateVO lock = _tmpltDao.acquireInLockTable(templateId);

      try {
        if (lock == null) {
          s_logger.debug("Failed to acquire lock when deleting template with ID: " + templateId);
          success = false;
        } else if (_tmpltDao.remove(templateId)) {
          // Decrement the number of templates
          _resourceLimitMgr.decrementResourceCount(accountId, ResourceType.template);
        }

      } finally {
        if (lock != null) {
          _tmpltDao.releaseFromLockTable(lock.getId());
        }
      }

      s_logger.debug(
          "Removed template: "
              + template.getName()
              + " because all of its template host refs were marked as destroyed.");
    }

    return success;
  }
  @Override
  public void handleTemplateSync(HostVO ssHost) {
    if (ssHost == null) {
      s_logger.warn("Huh? ssHost is null");
      return;
    }
    long sserverId = ssHost.getId();
    long zoneId = ssHost.getDataCenterId();
    if (!(ssHost.getType() == Host.Type.SecondaryStorage
        || ssHost.getType() == Host.Type.LocalSecondaryStorage)) {
      s_logger.warn("Huh? Agent id " + sserverId + " is not secondary storage host");
      return;
    }

    Map<String, TemplateInfo> templateInfos = listTemplate(ssHost);
    if (templateInfos == null) {
      return;
    }

    Set<VMTemplateVO> toBeDownloaded = new HashSet<VMTemplateVO>();
    List<VMTemplateVO> allTemplates = _templateDao.listAllInZone(zoneId);
    List<VMTemplateVO> rtngTmplts = _templateDao.listAllSystemVMTemplates();
    List<VMTemplateVO> defaultBuiltin = _templateDao.listDefaultBuiltinTemplates();

    if (rtngTmplts != null) {
      for (VMTemplateVO rtngTmplt : rtngTmplts) {
        if (!allTemplates.contains(rtngTmplt)) {
          allTemplates.add(rtngTmplt);
        }
      }
    }

    if (defaultBuiltin != null) {
      for (VMTemplateVO builtinTmplt : defaultBuiltin) {
        if (!allTemplates.contains(builtinTmplt)) {
          allTemplates.add(builtinTmplt);
        }
      }
    }

    toBeDownloaded.addAll(allTemplates);

    for (VMTemplateVO tmplt : allTemplates) {
      String uniqueName = tmplt.getUniqueName();
      VMTemplateHostVO tmpltHost = _vmTemplateHostDao.findByHostTemplate(sserverId, tmplt.getId());
      if (templateInfos.containsKey(uniqueName)) {
        TemplateInfo tmpltInfo = templateInfos.remove(uniqueName);
        toBeDownloaded.remove(tmplt);
        if (tmpltHost != null) {
          s_logger.info(
              "Template Sync found " + tmplt.getName() + " already in the template host table");
          if (tmpltHost.getDownloadState() != Status.DOWNLOADED) {
            tmpltHost.setErrorString("");
          }
          if (tmpltInfo.isCorrupted()) {
            tmpltHost.setDownloadState(Status.DOWNLOAD_ERROR);
            String msg =
                "Template "
                    + tmplt.getName()
                    + ":"
                    + tmplt.getId()
                    + " is corrupted on secondary storage "
                    + tmpltHost.getId();
            tmpltHost.setErrorString(msg);
            s_logger.info("msg");
            if (tmplt.getUrl() == null) {
              msg =
                  "Private Template ("
                      + tmplt
                      + ") with install path "
                      + tmpltInfo.getInstallPath()
                      + "is corrupted, please check in secondary storage: "
                      + tmpltHost.getHostId();
              s_logger.warn(msg);
            } else {
              toBeDownloaded.add(tmplt);
            }

          } else {
            tmpltHost.setDownloadPercent(100);
            tmpltHost.setDownloadState(Status.DOWNLOADED);
            tmpltHost.setInstallPath(tmpltInfo.getInstallPath());
            tmpltHost.setSize(tmpltInfo.getSize());
            tmpltHost.setPhysicalSize(tmpltInfo.getPhysicalSize());
            tmpltHost.setLastUpdated(new Date());

            // Skipping limit checks for SYSTEM Account and for the templates created from volumes
            // or snapshots
            // which already got checked and incremented during createTemplate API call.
            if (tmpltInfo.getSize() > 0
                && tmplt.getAccountId() != Account.ACCOUNT_ID_SYSTEM
                && tmplt.getUrl() != null) {
              long accountId = tmplt.getAccountId();
              try {
                _resourceLimitMgr.checkResourceLimit(
                    _accountMgr.getAccount(accountId),
                    com.cloud.configuration.Resource.ResourceType.secondary_storage,
                    tmpltInfo.getSize() - UriUtils.getRemoteSize(tmplt.getUrl()));
              } catch (ResourceAllocationException e) {
                s_logger.warn(e.getMessage());
                _alertMgr.sendAlert(
                    _alertMgr.ALERT_TYPE_RESOURCE_LIMIT_EXCEEDED,
                    ssHost.getDataCenterId(),
                    null,
                    e.getMessage(),
                    e.getMessage());
              } finally {
                _resourceLimitMgr.recalculateResourceCount(
                    accountId,
                    _accountMgr.getAccount(accountId).getDomainId(),
                    com.cloud.configuration.Resource.ResourceType.secondary_storage.getOrdinal());
              }
            }
          }
          _vmTemplateHostDao.update(tmpltHost.getId(), tmpltHost);
        } else {
          tmpltHost =
              new VMTemplateHostVO(
                  sserverId,
                  tmplt.getId(),
                  new Date(),
                  100,
                  Status.DOWNLOADED,
                  null,
                  null,
                  null,
                  tmpltInfo.getInstallPath(),
                  tmplt.getUrl());
          tmpltHost.setSize(tmpltInfo.getSize());
          tmpltHost.setPhysicalSize(tmpltInfo.getPhysicalSize());
          _vmTemplateHostDao.persist(tmpltHost);
          VMTemplateZoneVO tmpltZoneVO =
              _vmTemplateZoneDao.findByZoneTemplate(zoneId, tmplt.getId());
          if (tmpltZoneVO == null) {
            tmpltZoneVO = new VMTemplateZoneVO(zoneId, tmplt.getId(), new Date());
            _vmTemplateZoneDao.persist(tmpltZoneVO);
          } else {
            tmpltZoneVO.setLastUpdated(new Date());
            _vmTemplateZoneDao.update(tmpltZoneVO.getId(), tmpltZoneVO);
          }
        }

        continue;
      }
      if (tmpltHost != null && tmpltHost.getDownloadState() != Status.DOWNLOADED) {
        s_logger.info(
            "Template Sync did not find "
                + tmplt.getName()
                + " ready on server "
                + sserverId
                + ", will request download to start/resume shortly");

      } else if (tmpltHost == null) {
        s_logger.info(
            "Template Sync did not find "
                + tmplt.getName()
                + " on the server "
                + sserverId
                + ", will request download shortly");
        VMTemplateHostVO templtHost =
            new VMTemplateHostVO(
                sserverId,
                tmplt.getId(),
                new Date(),
                0,
                Status.NOT_DOWNLOADED,
                null,
                null,
                null,
                null,
                tmplt.getUrl());
        _vmTemplateHostDao.persist(templtHost);
        VMTemplateZoneVO tmpltZoneVO = _vmTemplateZoneDao.findByZoneTemplate(zoneId, tmplt.getId());
        if (tmpltZoneVO == null) {
          tmpltZoneVO = new VMTemplateZoneVO(zoneId, tmplt.getId(), new Date());
          _vmTemplateZoneDao.persist(tmpltZoneVO);
        } else {
          tmpltZoneVO.setLastUpdated(new Date());
          _vmTemplateZoneDao.update(tmpltZoneVO.getId(), tmpltZoneVO);
        }
      }
    }

    if (toBeDownloaded.size() > 0) {
      /* Only download templates whose hypervirsor type is in the zone */
      List<HypervisorType> availHypers = _clusterDao.getAvailableHypervisorInZone(zoneId);
      if (availHypers.isEmpty()) {
        /*
         * This is for cloudzone, local secondary storage resource
         * started before cluster created
         */
        availHypers.add(HypervisorType.KVM);
      }
      /* Baremetal need not to download any template */
      availHypers.remove(HypervisorType.BareMetal);
      availHypers.add(HypervisorType.None); // bug 9809: resume ISO
      // download.
      for (VMTemplateVO tmplt : toBeDownloaded) {
        if (tmplt.getUrl() == null) { // If url is null we can't
          // initiate the download
          continue;
        }
        // if this is private template, and there is no record for this
        // template in this sHost, skip
        if (!tmplt.isPublicTemplate() && !tmplt.isFeatured()) {
          VMTemplateHostVO tmpltHost =
              _vmTemplateHostDao.findByHostTemplate(sserverId, tmplt.getId());
          if (tmpltHost == null) {
            continue;
          }
        }
        if (availHypers.contains(tmplt.getHypervisorType())) {
          if (_swiftMgr.isSwiftEnabled()) {
            if (_swiftMgr.isTemplateInstalled(tmplt.getId())) {
              continue;
            }
          }
          s_logger.debug(
              "Template " + tmplt.getName() + " needs to be downloaded to " + ssHost.getName());
          downloadTemplateToStorage(tmplt, ssHost);
        } else {
          s_logger.info(
              "Skipping download of template "
                  + tmplt.getName()
                  + " since we don't have any "
                  + tmplt.getHypervisorType()
                  + " hypervisors");
        }
      }
    }

    for (String uniqueName : templateInfos.keySet()) {
      TemplateInfo tInfo = templateInfos.get(uniqueName);
      List<UserVmVO> userVmUsingIso = _userVmDao.listByIsoId(tInfo.getId());
      // check if there is any Vm using this ISO.
      if (userVmUsingIso == null || userVmUsingIso.isEmpty()) {
        DeleteTemplateCommand dtCommand =
            new DeleteTemplateCommand(ssHost.getStorageUrl(), tInfo.getInstallPath());
        try {
          _agentMgr.sendToSecStorage(ssHost, dtCommand, null);
        } catch (AgentUnavailableException e) {
          String err =
              "Failed to delete "
                  + tInfo.getTemplateName()
                  + " on secondary storage "
                  + sserverId
                  + " which isn't in the database";
          s_logger.error(err);
          return;
        }

        String description =
            "Deleted template "
                + tInfo.getTemplateName()
                + " on secondary storage "
                + sserverId
                + " since it isn't in the database";
        s_logger.info(description);
      }
    }
  }
  @Override
  public void handleVolumeSync(HostVO ssHost) {
    if (ssHost == null) {
      s_logger.warn("Huh? ssHost is null");
      return;
    }
    long sserverId = ssHost.getId();
    if (!(ssHost.getType() == Host.Type.SecondaryStorage
        || ssHost.getType() == Host.Type.LocalSecondaryStorage)) {
      s_logger.warn("Huh? Agent id " + sserverId + " is not secondary storage host");
      return;
    }

    Map<Long, TemplateInfo> volumeInfos = listVolume(ssHost);
    if (volumeInfos == null) {
      return;
    }

    List<VolumeHostVO> dbVolumes = _volumeHostDao.listBySecStorage(sserverId);
    List<VolumeHostVO> toBeDownloaded = new ArrayList<VolumeHostVO>(dbVolumes);
    for (VolumeHostVO volumeHost : dbVolumes) {
      VolumeVO volume = _volumeDao.findById(volumeHost.getVolumeId());
      // Exists then don't download
      if (volumeInfos.containsKey(volume.getId())) {
        TemplateInfo volInfo = volumeInfos.remove(volume.getId());
        toBeDownloaded.remove(volumeHost);
        s_logger.info(
            "Volume Sync found " + volume.getUuid() + " already in the volume host table");
        if (volumeHost.getDownloadState() != Status.DOWNLOADED) {
          volumeHost.setErrorString("");
        }
        if (volInfo.isCorrupted()) {
          volumeHost.setDownloadState(Status.DOWNLOAD_ERROR);
          String msg = "Volume " + volume.getUuid() + " is corrupted on secondary storage ";
          volumeHost.setErrorString(msg);
          s_logger.info("msg");
          if (volumeHost.getDownloadUrl() == null) {
            msg =
                "Volume ("
                    + volume.getUuid()
                    + ") with install path "
                    + volInfo.getInstallPath()
                    + "is corrupted, please check in secondary storage: "
                    + volumeHost.getHostId();
            s_logger.warn(msg);
          } else {
            toBeDownloaded.add(volumeHost);
          }

        } else { // Put them in right status
          volumeHost.setDownloadPercent(100);
          volumeHost.setDownloadState(Status.DOWNLOADED);
          volumeHost.setInstallPath(volInfo.getInstallPath());
          volumeHost.setSize(volInfo.getSize());
          volumeHost.setPhysicalSize(volInfo.getPhysicalSize());
          volumeHost.setLastUpdated(new Date());
          _volumeHostDao.update(volumeHost.getId(), volumeHost);

          if (volume.getSize() == 0) {
            // Set volume size in volumes table
            volume.setSize(volInfo.getSize());
            _volumeDao.update(volumeHost.getVolumeId(), volume);
          }

          if (volInfo.getSize() > 0) {
            try {
              String url = _volumeHostDao.findByVolumeId(volume.getId()).getDownloadUrl();
              _resourceLimitMgr.checkResourceLimit(
                  _accountMgr.getAccount(volume.getAccountId()),
                  com.cloud.configuration.Resource.ResourceType.secondary_storage,
                  volInfo.getSize() - UriUtils.getRemoteSize(url));
            } catch (ResourceAllocationException e) {
              s_logger.warn(e.getMessage());
              _alertMgr.sendAlert(
                  _alertMgr.ALERT_TYPE_RESOURCE_LIMIT_EXCEEDED,
                  volume.getDataCenterId(),
                  volume.getPodId(),
                  e.getMessage(),
                  e.getMessage());
            } finally {
              _resourceLimitMgr.recalculateResourceCount(
                  volume.getAccountId(),
                  volume.getDomainId(),
                  com.cloud.configuration.Resource.ResourceType.secondary_storage.getOrdinal());
            }
          }
        }
        continue;
      }
      // Volume is not on secondary but we should download.
      if (volumeHost.getDownloadState() != Status.DOWNLOADED) {
        s_logger.info(
            "Volume Sync did not find "
                + volume.getName()
                + " ready on server "
                + sserverId
                + ", will request download to start/resume shortly");
        toBeDownloaded.add(volumeHost);
      }
    }

    // Download volumes which haven't been downloaded yet.
    if (toBeDownloaded.size() > 0) {
      for (VolumeHostVO volumeHost : toBeDownloaded) {
        if (volumeHost.getDownloadUrl() == null) { // If url is null we can't initiate the download
          continue;
        }
        s_logger.debug(
            "Volume "
                + volumeHost.getVolumeId()
                + " needs to be downloaded to "
                + ssHost.getName());
        downloadVolumeToStorage(
            _volumeDao.findById(volumeHost.getVolumeId()),
            ssHost,
            volumeHost.getDownloadUrl(),
            volumeHost.getChecksum(),
            volumeHost.getFormat());
      }
    }

    // Delete volumes which are not present on DB.
    for (Long uniqueName : volumeInfos.keySet()) {
      TemplateInfo vInfo = volumeInfos.get(uniqueName);
      DeleteVolumeCommand dtCommand =
          new DeleteVolumeCommand(ssHost.getStorageUrl(), vInfo.getInstallPath());
      try {
        _agentMgr.sendToSecStorage(ssHost, dtCommand, null);
      } catch (AgentUnavailableException e) {
        String err =
            "Failed to delete "
                + vInfo.getTemplateName()
                + " on secondary storage "
                + sserverId
                + " which isn't in the database";
        s_logger.error(err);
        return;
      }

      String description =
          "Deleted volume "
              + vInfo.getTemplateName()
              + " on secondary storage "
              + sserverId
              + " since it isn't in the database";
      s_logger.info(description);
    }
  }