opendaylight/md-sal/sal-netconf-connector/src/main/java/org/opendaylight/controller/sal/connect/netconf/NetconfDevice.java

   1 /*
   2  * Copyright (c) 2014 Cisco Systems, Inc. and others.  All rights reserved.
   3  *
   4  * This program and the accompanying materials are made available under the
   5  * terms of the Eclipse Public License v1.0 which accompanies this distribution,
   6  * and is available at http://www.eclipse.org/legal/epl-v10.html
   7  */
   8 package org.opendaylight.controller.sal.connect.netconf;
   9
  10 import com.google.common.annotations.VisibleForTesting;
  11 import com.google.common.base.Function;
  12 import com.google.common.base.Optional;
  13 import com.google.common.base.Preconditions;
  14 import com.google.common.collect.Collections2;
  15 import com.google.common.collect.Lists;
  16 import com.google.common.collect.Sets;
  17 import com.google.common.util.concurrent.CheckedFuture;
  18 import com.google.common.util.concurrent.FutureCallback;
  19 import com.google.common.util.concurrent.Futures;
  20 import com.google.common.util.concurrent.ListenableFuture;
  21 import com.google.common.util.concurrent.ListeningExecutorService;
  22 import com.google.common.util.concurrent.MoreExecutors;
  23 import java.util.Collection;
  24 import java.util.HashSet;
  25 import java.util.LinkedList;
  26 import java.util.List;
  27 import java.util.Set;
  28 import java.util.concurrent.Callable;
  29 import java.util.concurrent.ExecutorService;
  30 import org.opendaylight.controller.md.sal.dom.api.DOMRpcException;
  31 import org.opendaylight.controller.md.sal.dom.api.DOMRpcResult;
  32 import org.opendaylight.controller.md.sal.dom.api.DOMRpcService;
  33 import org.opendaylight.controller.netconf.api.NetconfMessage;
  34 import org.opendaylight.controller.sal.connect.api.MessageTransformer;
  35 import org.opendaylight.controller.sal.connect.api.RemoteDevice;
  36 import org.opendaylight.controller.sal.connect.api.RemoteDeviceCommunicator;
  37 import org.opendaylight.controller.sal.connect.api.RemoteDeviceHandler;
  38 import org.opendaylight.controller.sal.connect.netconf.listener.NetconfDeviceCapabilities;
  39 import org.opendaylight.controller.sal.connect.netconf.listener.NetconfDeviceCommunicator;
  40 import org.opendaylight.controller.sal.connect.netconf.listener.NetconfSessionPreferences;
  41 import org.opendaylight.controller.sal.connect.netconf.sal.NetconfDeviceRpc;
  42 import org.opendaylight.controller.sal.connect.netconf.schema.NetconfRemoteSchemaYangSourceProvider;
  43 import org.opendaylight.controller.sal.connect.netconf.schema.mapping.NetconfMessageTransformer;
  44 import org.opendaylight.controller.sal.connect.netconf.util.NetconfMessageTransformUtil;
  45 import org.opendaylight.controller.sal.connect.util.RemoteDeviceId;
  46 import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.netconf.monitoring.extension.rev131210.$YangModuleInfoImpl;
  47 import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.netconf.notifications.rev120206.NetconfCapabilityChange;
  48 import org.opendaylight.yang.gen.v1.urn.opendaylight.netconf.node.topology.rev150114.netconf.node.fields.unavailable.capabilities.UnavailableCapability;
  49 import org.opendaylight.yangtools.sal.binding.generator.impl.ModuleInfoBackedContext;
  50 import org.opendaylight.yangtools.yang.common.QName;
  51 import org.opendaylight.yangtools.yang.data.api.schema.NormalizedNode;
  52 import org.opendaylight.yangtools.yang.model.api.SchemaContext;
  53 import org.opendaylight.yangtools.yang.model.repo.api.MissingSchemaSourceException;
  54 import org.opendaylight.yangtools.yang.model.repo.api.SchemaContextFactory;
  55 import org.opendaylight.yangtools.yang.model.repo.api.SchemaResolutionException;
  56 import org.opendaylight.yangtools.yang.model.repo.api.SchemaSourceRepresentation;
  57 import org.opendaylight.yangtools.yang.model.repo.api.SourceIdentifier;
  58 import org.opendaylight.yangtools.yang.model.repo.api.YangTextSchemaSource;
  59 import org.opendaylight.yangtools.yang.model.repo.spi.PotentialSchemaSource;
  60 import org.opendaylight.yangtools.yang.model.repo.spi.SchemaSourceRegistration;
  61 import org.opendaylight.yangtools.yang.model.repo.spi.SchemaSourceRegistry;
  62 import org.slf4j.Logger;
  63 import org.slf4j.LoggerFactory;
  64
  65 /**
  66  *  This is a mediator between NetconfDeviceCommunicator and NetconfDeviceSalFacade
  67  */
  68 public final class NetconfDevice implements RemoteDevice<NetconfSessionPreferences, NetconfMessage, NetconfDeviceCommunicator> {
  69
  70     private static final Logger logger = LoggerFactory.getLogger(NetconfDevice.class);
  71
  72     /**
  73      * Initial schema context contains schemas for netconf monitoring and netconf notifications
  74      */
  75     public static final SchemaContext INIT_SCHEMA_CTX;
  76
  77     static {
  78         try {
  79             final ModuleInfoBackedContext moduleInfoBackedContext = ModuleInfoBackedContext.create();
  80             moduleInfoBackedContext.addModuleInfos(
  81                     Lists.newArrayList(
  82                             $YangModuleInfoImpl.getInstance(),
  83                             org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.netconf.notification._1._0.rev080714.$YangModuleInfoImpl.getInstance(),
  84                             org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.netconf.base._1._0.rev110601.$YangModuleInfoImpl.getInstance()));
  85             INIT_SCHEMA_CTX = moduleInfoBackedContext.tryToCreateSchemaContext().get();
  86         } catch (final RuntimeException e) {
  87             logger.error("Unable to prepare schema context for netconf initialization", e);
  88             throw new ExceptionInInitializerError(e);
  89         }
  90     }
  91
  92     public static final Function<QName, SourceIdentifier> QNAME_TO_SOURCE_ID_FUNCTION = new Function<QName, SourceIdentifier>() {
  93         @Override
  94         public SourceIdentifier apply(final QName input) {
  95             return new SourceIdentifier(input.getLocalName(), Optional.fromNullable(input.getFormattedRevision()));
  96         }
  97     };
  98
  99     private final RemoteDeviceId id;
 100     private final boolean reconnectOnSchemasChange;
 101
 102     private final SchemaContextFactory schemaContextFactory;
 103     private final RemoteDeviceHandler<NetconfSessionPreferences> salFacade;
 104     private final ListeningExecutorService processingExecutor;
 105     private final SchemaSourceRegistry schemaRegistry;
 106     private final NetconfStateSchemas.NetconfStateSchemasResolver stateSchemasResolver;
 107     private final NotificationHandler notificationHandler;
 108     private final List<SchemaSourceRegistration<? extends SchemaSourceRepresentation>> sourceRegistrations = Lists.newArrayList();
 109
 110     // Message transformer is constructed once the schemas are available
 111     private MessageTransformer<NetconfMessage> messageTransformer;
 112
 113     public NetconfDevice(final SchemaResourcesDTO schemaResourcesDTO, final RemoteDeviceId id, final RemoteDeviceHandler<NetconfSessionPreferences> salFacade,
 114                          final ExecutorService globalProcessingExecutor) {
 115         this(schemaResourcesDTO, id, salFacade, globalProcessingExecutor, false);
 116     }
 117
 118     /**
 119      * Create rpc implementation capable of handling RPC for monitoring and notifications even before the schemas of remote device are downloaded
 120      */
 121     static NetconfDeviceRpc getRpcForInitialization(final NetconfDeviceCommunicator listener) {
 122         return new NetconfDeviceRpc(INIT_SCHEMA_CTX, listener, new NetconfMessageTransformer(INIT_SCHEMA_CTX));
 123     }
 124
 125
 126     // FIXME reduce parameters
 127     public NetconfDevice(final SchemaResourcesDTO schemaResourcesDTO, final RemoteDeviceId id, final RemoteDeviceHandler<NetconfSessionPreferences> salFacade,
 128                          final ExecutorService globalProcessingExecutor, final boolean reconnectOnSchemasChange) {
 129         this.id = id;
 130         this.reconnectOnSchemasChange = reconnectOnSchemasChange;
 131         this.schemaRegistry = schemaResourcesDTO.getSchemaRegistry();
 132         this.schemaContextFactory = schemaResourcesDTO.getSchemaContextFactory();
 133         this.salFacade = salFacade;
 134         this.stateSchemasResolver = schemaResourcesDTO.getStateSchemasResolver();
 135         this.processingExecutor = MoreExecutors.listeningDecorator(globalProcessingExecutor);
 136         this.notificationHandler = new NotificationHandler(salFacade, id);
 137     }
 138
 139     @Override
 140     public void onRemoteSessionUp(final NetconfSessionPreferences remoteSessionCapabilities,
 141                                   final NetconfDeviceCommunicator listener) {
 142         // SchemaContext setup has to be performed in a dedicated thread since
 143         // we are in a netty thread in this method
 144         // Yang models are being downloaded in this method and it would cause a
 145         // deadlock if we used the netty thread
 146         // http://netty.io/wiki/thread-model.html
 147         logger.debug("{}: Session to remote device established with {}", id, remoteSessionCapabilities);
 148
 149         final NetconfDeviceRpc initRpc = getRpcForInitialization(listener);
 150         final DeviceSourcesResolver task = new DeviceSourcesResolver(remoteSessionCapabilities, id, stateSchemasResolver, initRpc);
 151         final ListenableFuture<DeviceSources> sourceResolverFuture = processingExecutor.submit(task);
 152
 153         if(shouldListenOnSchemaChange(remoteSessionCapabilities)) {
 154            registerToBaseNetconfStream(initRpc, listener);
 155         }
 156
 157         final FutureCallback<DeviceSources> resolvedSourceCallback = new FutureCallback<DeviceSources>() {
 158             @Override
 159             public void onSuccess(final DeviceSources result) {
 160                 addProvidedSourcesToSchemaRegistry(initRpc, result);
 161                 setUpSchema(result);
 162             }
 163
 164             private void setUpSchema(final DeviceSources result) {
 165                 processingExecutor.submit(new RecursiveSchemaSetup(result, remoteSessionCapabilities, listener));
 166             }
 167
 168             @Override
 169             public void onFailure(final Throwable t) {
 170                 logger.warn("{}: Unexpected error resolving device sources: {}", id, t);
 171                 handleSalInitializationFailure(t, listener);
 172             }
 173         };
 174
 175         Futures.addCallback(sourceResolverFuture, resolvedSourceCallback);
 176     }
 177
 178     private void registerToBaseNetconfStream(final NetconfDeviceRpc deviceRpc, final NetconfDeviceCommunicator listener) {
 179        // TODO check whether the model describing create subscription is present in schema
 180         // Perhaps add a default schema context to support create-subscription if the model was not provided (same as what we do for base netconf operations in transformer)
 181        final CheckedFuture<DOMRpcResult, DOMRpcException> rpcResultListenableFuture =
 182                 deviceRpc.invokeRpc(NetconfMessageTransformUtil.toPath(NetconfMessageTransformUtil.CREATE_SUBSCRIPTION_RPC_QNAME), NetconfMessageTransformUtil.CREATE_SUBSCRIPTION_RPC_CONTENT);
 183
 184         final NotificationHandler.NotificationFilter filter = new NotificationHandler.NotificationFilter() {
 185             @Override
 186             public Optional<NormalizedNode<?, ?>> filterNotification(final NormalizedNode<?, ?> notification) {
 187                 if (isCapabilityChanged(notification)) {
 188                     logger.info("{}: Schemas change detected, reconnecting", id);
 189                     // Only disconnect is enough, the reconnecting nature of the connector will take care of reconnecting
 190                     listener.disconnect();
 191                     return Optional.absent();
 192                 }
 193                 return Optional.<NormalizedNode<?, ?>>of(notification);
 194             }
 195
 196             private boolean isCapabilityChanged(final NormalizedNode<?, ?> notification) {
 197                 return notification.getNodeType().equals(NetconfCapabilityChange.QNAME);
 198             }
 199         };
 200
 201         Futures.addCallback(rpcResultListenableFuture, new FutureCallback<DOMRpcResult>() {
 202             @Override
 203             public void onSuccess(final DOMRpcResult domRpcResult) {
 204                 notificationHandler.addNotificationFilter(filter);
 205             }
 206
 207             @Override
 208             public void onFailure(final Throwable t) {
 209                 logger.warn("Unable to subscribe to base notification stream. Schemas will not be reloaded on the fly", t);
 210             }
 211         });
 212     }
 213
 214     private boolean shouldListenOnSchemaChange(final NetconfSessionPreferences remoteSessionCapabilities) {
 215         return remoteSessionCapabilities.isNotificationsSupported() && reconnectOnSchemasChange;
 216     }
 217
 218     @VisibleForTesting
 219     void handleSalInitializationSuccess(final SchemaContext result, final NetconfSessionPreferences remoteSessionCapabilities, final DOMRpcService deviceRpc) {
 220         messageTransformer = new NetconfMessageTransformer(result);
 221
 222         updateTransformer(messageTransformer);
 223         // salFacade.onDeviceConnected has to be called before the notification handler is initialized
 224         salFacade.onDeviceConnected(result, remoteSessionCapabilities, deviceRpc);
 225         notificationHandler.onRemoteSchemaUp(messageTransformer);
 226
 227         logger.info("{}: Netconf connector initialized successfully", id);
 228     }
 229
 230     private void handleSalInitializationFailure(final Throwable t, final RemoteDeviceCommunicator<NetconfMessage> listener) {
 231         logger.error("{}: Initialization in sal failed, disconnecting from device", id, t);
 232         listener.close();
 233         onRemoteSessionDown();
 234         resetMessageTransformer();
 235     }
 236
 237     /**
 238      * Set the transformer to null as is in initial state
 239      */
 240     private void resetMessageTransformer() {
 241         updateTransformer(null);
 242     }
 243
 244     private void updateTransformer(final MessageTransformer<NetconfMessage> transformer) {
 245         messageTransformer = transformer;
 246     }
 247
 248     private void addProvidedSourcesToSchemaRegistry(final NetconfDeviceRpc deviceRpc, final DeviceSources deviceSources) {
 249         final NetconfRemoteSchemaYangSourceProvider yangProvider = new NetconfRemoteSchemaYangSourceProvider(id, deviceRpc);
 250         for (final SourceIdentifier sourceId : deviceSources.getProvidedSources()) {
 251             sourceRegistrations.add(schemaRegistry.registerSchemaSource(yangProvider,
 252                     PotentialSchemaSource.create(sourceId, YangTextSchemaSource.class, PotentialSchemaSource.Costs.REMOTE_IO.getValue())));
 253         }
 254     }
 255
 256     @Override
 257     public void onRemoteSessionDown() {
 258         notificationHandler.onRemoteSchemaDown();
 259
 260         salFacade.onDeviceDisconnected();
 261         for (final SchemaSourceRegistration<? extends SchemaSourceRepresentation> sourceRegistration : sourceRegistrations) {
 262             sourceRegistration.close();
 263         }
 264         resetMessageTransformer();
 265     }
 266
 267     @Override
 268     public void onRemoteSessionFailed(final Throwable throwable) {
 269         salFacade.onDeviceFailed(throwable);
 270     }
 271
 272     @Override
 273     public void onNotification(final NetconfMessage notification) {
 274         notificationHandler.handleNotification(notification);
 275     }
 276
 277     /**
 278      * Just a transfer object containing schema related dependencies. Injected in constructor.
 279      */
 280     public static class SchemaResourcesDTO {
 281         private final SchemaSourceRegistry schemaRegistry;
 282         private final SchemaContextFactory schemaContextFactory;
 283         private final NetconfStateSchemas.NetconfStateSchemasResolver stateSchemasResolver;
 284
 285         public SchemaResourcesDTO(final SchemaSourceRegistry schemaRegistry, final SchemaContextFactory schemaContextFactory, final NetconfStateSchemas.NetconfStateSchemasResolver stateSchemasResolver) {
 286             this.schemaRegistry = Preconditions.checkNotNull(schemaRegistry);
 287             this.schemaContextFactory = Preconditions.checkNotNull(schemaContextFactory);
 288             this.stateSchemasResolver = Preconditions.checkNotNull(stateSchemasResolver);
 289         }
 290
 291         public SchemaSourceRegistry getSchemaRegistry() {
 292             return schemaRegistry;
 293         }
 294
 295         public SchemaContextFactory getSchemaContextFactory() {
 296             return schemaContextFactory;
 297         }
 298
 299         public NetconfStateSchemas.NetconfStateSchemasResolver getStateSchemasResolver() {
 300             return stateSchemasResolver;
 301         }
 302     }
 303
 304     /**
 305      * Schema building callable.
 306      */
 307     private static class DeviceSourcesResolver implements Callable<DeviceSources> {
 308
 309         private final NetconfDeviceRpc deviceRpc;
 310         private final NetconfSessionPreferences remoteSessionCapabilities;
 311         private final RemoteDeviceId id;
 312         private final NetconfStateSchemas.NetconfStateSchemasResolver stateSchemasResolver;
 313
 314         DeviceSourcesResolver(final NetconfDeviceRpc deviceRpc, final NetconfSessionPreferences remoteSessionCapabilities,
 315                                      final RemoteDeviceId id, final NetconfStateSchemas.NetconfStateSchemasResolver stateSchemasResolver) {
 316             this.deviceRpc = deviceRpc;
 317             this.remoteSessionCapabilities = remoteSessionCapabilities;
 318             this.id = id;
 319             this.stateSchemasResolver = stateSchemasResolver;
 320         }
 321
 322         public DeviceSourcesResolver(final NetconfSessionPreferences remoteSessionCapabilities, final RemoteDeviceId id, final NetconfStateSchemas.NetconfStateSchemasResolver stateSchemasResolver, final NetconfDeviceRpc rpcForMonitoring) {
 323             this(rpcForMonitoring, remoteSessionCapabilities, id, stateSchemasResolver);
 324         }
 325
 326         @Override
 327         public DeviceSources call() throws Exception {
 328
 329             final Set<SourceIdentifier> requiredSources = Sets.newHashSet(Collections2.transform(
 330                     remoteSessionCapabilities.getModuleBasedCaps(), QNAME_TO_SOURCE_ID_FUNCTION));
 331
 332             // If monitoring is not supported, we will still attempt to create schema, sources might be already provided
 333             final NetconfStateSchemas availableSchemas = stateSchemasResolver.resolve(deviceRpc, remoteSessionCapabilities, id);
 334             logger.debug("{}: Schemas exposed by ietf-netconf-monitoring: {}", id, availableSchemas.getAvailableYangSchemasQNames());
 335
 336             final Set<SourceIdentifier> providedSources = Sets.newHashSet(Collections2.transform(
 337                     availableSchemas.getAvailableYangSchemasQNames(), QNAME_TO_SOURCE_ID_FUNCTION));
 338
 339             final Set<SourceIdentifier> requiredSourcesNotProvided = Sets.difference(requiredSources, providedSources);
 340
 341             if (!requiredSourcesNotProvided.isEmpty()) {
 342                 logger.warn("{}: Netconf device does not provide all yang models reported in hello message capabilities, required but not provided: {}",
 343                         id, requiredSourcesNotProvided);
 344                 logger.warn("{}: Attempting to build schema context from required sources", id);
 345             }
 346
 347
 348             // Here all the sources reported in netconf monitoring are merged with those reported in hello.
 349             // It is necessary to perform this since submodules are not mentioned in hello but still required.
 350             // This clashes with the option of a user to specify supported yang models manually in configuration for netconf-connector
 351             // and as a result one is not able to fully override yang models of a device. It is only possible to add additional models.
 352             final Set<SourceIdentifier> providedSourcesNotRequired = Sets.difference(providedSources, requiredSources);
 353             if (!providedSourcesNotRequired.isEmpty()) {
 354                 logger.warn("{}: Netconf device provides additional yang models not reported in hello message capabilities: {}",
 355                         id, providedSourcesNotRequired);
 356                 logger.warn("{}: Adding provided but not required sources as required to prevent failures", id);
 357                 logger.debug("{}: Netconf device reported in hello: {}", id, requiredSources);
 358                 requiredSources.addAll(providedSourcesNotRequired);
 359             }
 360
 361             return new DeviceSources(requiredSources, providedSources);
 362         }
 363     }
 364
 365     /**
 366      * Contains RequiredSources - sources from capabilities.
 367      */
 368     private static final class DeviceSources {
 369         private final Collection<SourceIdentifier> requiredSources;
 370         private final Collection<SourceIdentifier> providedSources;
 371
 372         public DeviceSources(final Collection<SourceIdentifier> requiredSources, final Collection<SourceIdentifier> providedSources) {
 373             this.requiredSources = requiredSources;
 374             this.providedSources = providedSources;
 375         }
 376
 377         public Collection<SourceIdentifier> getRequiredSources() {
 378             return requiredSources;
 379         }
 380
 381         public Collection<SourceIdentifier> getProvidedSources() {
 382             return providedSources;
 383         }
 384
 385     }
 386
 387     /**
 388      * Schema builder that tries to build schema context from provided sources or biggest subset of it.
 389      */
 390     private final class RecursiveSchemaSetup implements Runnable {
 391         private final DeviceSources deviceSources;
 392         private final NetconfSessionPreferences remoteSessionCapabilities;
 393         private final RemoteDeviceCommunicator<NetconfMessage> listener;
 394         private final NetconfDeviceCapabilities capabilities;
 395
 396         public RecursiveSchemaSetup(final DeviceSources deviceSources, final NetconfSessionPreferences remoteSessionCapabilities, final RemoteDeviceCommunicator<NetconfMessage> listener) {
 397             this.deviceSources = deviceSources;
 398             this.remoteSessionCapabilities = remoteSessionCapabilities;
 399             this.listener = listener;
 400             this.capabilities = remoteSessionCapabilities.getNetconfDeviceCapabilities();
 401         }
 402
 403         @Override
 404         public void run() {
 405             setUpSchema(deviceSources.getRequiredSources());
 406         }
 407
 408         /**
 409          * Recursively build schema context, in case of success or final failure notify device
 410          */
 411         // FIXME reimplement without recursion
 412         private void setUpSchema(final Collection<SourceIdentifier> requiredSources) {
 413             logger.trace("{}: Trying to build schema context from {}", id, requiredSources);
 414
 415             // If no more sources, fail
 416             if(requiredSources.isEmpty()) {
 417                 final IllegalStateException cause = new IllegalStateException(id + ": No more sources for schema context");
 418                 handleSalInitializationFailure(cause, listener);
 419                 salFacade.onDeviceFailed(cause);
 420                 return;
 421             }
 422
 423             final CheckedFuture<SchemaContext, SchemaResolutionException> schemaBuilderFuture = schemaContextFactory.createSchemaContext(requiredSources);
 424
 425             final FutureCallback<SchemaContext> RecursiveSchemaBuilderCallback = new FutureCallback<SchemaContext>() {
 426
 427                 @Override
 428                 public void onSuccess(final SchemaContext result) {
 429                     logger.debug("{}: Schema context built successfully from {}", id, requiredSources);
 430                     final Collection<QName> filteredQNames = Sets.difference(remoteSessionCapabilities.getModuleBasedCaps(), capabilities.getUnresolvedCapabilites().keySet());
 431                     capabilities.addCapabilities(filteredQNames);
 432                     capabilities.addNonModuleBasedCapabilities(remoteSessionCapabilities.getNonModuleCaps());
 433                     handleSalInitializationSuccess(result, remoteSessionCapabilities, getDeviceSpecificRpc(result));
 434                 }
 435
 436                 @Override
 437                 public void onFailure(final Throwable t) {
 438                     // In case source missing, try without it
 439                     if (t instanceof MissingSchemaSourceException) {
 440                         final SourceIdentifier missingSource = ((MissingSchemaSourceException) t).getSourceId();
 441                         logger.warn("{}: Unable to build schema context, missing source {}, will reattempt without it", id, missingSource);
 442                         capabilities.addUnresolvedCapabilities(getQNameFromSourceIdentifiers(Sets.newHashSet(missingSource)), UnavailableCapability.FailureReason.MissingSource);
 443                         setUpSchema(stripMissingSource(requiredSources, missingSource));
 444
 445                     // In case resolution error, try only with resolved sources
 446                     } else if (t instanceof SchemaResolutionException) {
 447                         // TODO check for infinite loop
 448                         final SchemaResolutionException resolutionException = (SchemaResolutionException) t;
 449                         final Set<SourceIdentifier> unresolvedSources = resolutionException.getUnsatisfiedImports().keySet();
 450                         capabilities.addUnresolvedCapabilities(getQNameFromSourceIdentifiers(unresolvedSources), UnavailableCapability.FailureReason.UnableToResolve);
 451                         logger.warn("{}: Unable to build schema context, unsatisfied imports {}, will reattempt with resolved only", id, resolutionException.getUnsatisfiedImports());
 452                         setUpSchema(resolutionException.getResolvedSources());
 453                     // unknown error, fail
 454                     } else {
 455                         handleSalInitializationFailure(t, listener);
 456                     }
 457                 }
 458             };
 459
 460             Futures.addCallback(schemaBuilderFuture, RecursiveSchemaBuilderCallback);
 461         }
 462
 463         private NetconfDeviceRpc getDeviceSpecificRpc(final SchemaContext result) {
 464             return new NetconfDeviceRpc(result, listener, new NetconfMessageTransformer(result));
 465         }
 466
 467         private Collection<SourceIdentifier> stripMissingSource(final Collection<SourceIdentifier> requiredSources, final SourceIdentifier sIdToRemove) {
 468             final LinkedList<SourceIdentifier> sourceIdentifiers = Lists.newLinkedList(requiredSources);
 469             final boolean removed = sourceIdentifiers.remove(sIdToRemove);
 470             Preconditions.checkState(removed, "{}: Trying to remove {} from {} failed", id, sIdToRemove, requiredSources);
 471             return sourceIdentifiers;
 472         }
 473
 474         private Collection<QName> getQNameFromSourceIdentifiers(final Collection<SourceIdentifier> identifiers) {
 475             final Collection<QName> qNames = new HashSet<>();
 476             for (final SourceIdentifier source : identifiers) {
 477                 final Optional<QName> qname = getQNameFromSourceIdentifier(source);
 478                 if (qname.isPresent()) {
 479                     qNames.add(qname.get());
 480                 }
 481             }
 482             if (qNames.isEmpty()) {
 483                 logger.debug("Unable to map any source identfiers to a capability reported by device : " + identifiers);
 484             }
 485             return qNames;
 486         }
 487
 488         private Optional<QName> getQNameFromSourceIdentifier(final SourceIdentifier identifier) {
 489             for (final QName qname : remoteSessionCapabilities.getModuleBasedCaps()) {
 490                 if (qname.getLocalName().equals(identifier.getName())
 491                         && qname.getFormattedRevision().equals(identifier.getRevision())) {
 492                     return Optional.of(qname);
 493                 }
 494             }
 495             throw new IllegalArgumentException("Unable to map identifier to a devices reported capability: " + identifier);
 496         }
 497     }
 498 }