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.LinkedList;
  25 import java.util.List;
  26 import java.util.Set;
  27 import java.util.concurrent.Callable;
  28 import java.util.concurrent.ExecutorService;
  29 import org.opendaylight.controller.md.sal.dom.api.DOMNotification;
  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.model.api.SchemaContext;
  52 import org.opendaylight.yangtools.yang.model.repo.api.MissingSchemaSourceException;
  53 import org.opendaylight.yangtools.yang.model.repo.api.SchemaContextFactory;
  54 import org.opendaylight.yangtools.yang.model.repo.api.SchemaResolutionException;
  55 import org.opendaylight.yangtools.yang.model.repo.api.SchemaSourceRepresentation;
  56 import org.opendaylight.yangtools.yang.model.repo.api.SourceIdentifier;
  57 import org.opendaylight.yangtools.yang.model.repo.api.YangTextSchemaSource;
  58 import org.opendaylight.yangtools.yang.model.repo.spi.PotentialSchemaSource;
  59 import org.opendaylight.yangtools.yang.model.repo.spi.SchemaSourceRegistration;
  60 import org.opendaylight.yangtools.yang.model.repo.spi.SchemaSourceRegistry;
  61 import org.slf4j.Logger;
  62 import org.slf4j.LoggerFactory;
  63
  64 /**
  65  *  This is a mediator between NetconfDeviceCommunicator and NetconfDeviceSalFacade
  66  */
  67 public final class NetconfDevice implements RemoteDevice<NetconfSessionPreferences, NetconfMessage, NetconfDeviceCommunicator> {
  68
  69     private static final Logger logger = LoggerFactory.getLogger(NetconfDevice.class);
  70
  71     /**
  72      * Initial schema context contains schemas for netconf monitoring and netconf notifications
  73      */
  74     public static final SchemaContext INIT_SCHEMA_CTX;
  75
  76     static {
  77         try {
  78             final ModuleInfoBackedContext moduleInfoBackedContext = ModuleInfoBackedContext.create();
  79             moduleInfoBackedContext.addModuleInfos(
  80                     Lists.newArrayList(
  81                             $YangModuleInfoImpl.getInstance(),
  82                             org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.netconf.notification._1._0.rev080714.$YangModuleInfoImpl.getInstance(),
  83                             org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.netconf.base._1._0.rev110601.$YangModuleInfoImpl.getInstance()));
  84             INIT_SCHEMA_CTX = moduleInfoBackedContext.tryToCreateSchemaContext().get();
  85         } catch (final RuntimeException e) {
  86             logger.error("Unable to prepare schema context for netconf initialization", e);
  87             throw new ExceptionInInitializerError(e);
  88         }
  89     }
  90
  91     public static final Function<QName, SourceIdentifier> QNAME_TO_SOURCE_ID_FUNCTION = new Function<QName, SourceIdentifier>() {
  92         @Override
  93         public SourceIdentifier apply(final QName input) {
  94             return new SourceIdentifier(input.getLocalName(), Optional.fromNullable(input.getFormattedRevision()));
  95         }
  96     };
  97
  98     private final RemoteDeviceId id;
  99     private final boolean reconnectOnSchemasChange;
 100
 101     private final SchemaContextFactory schemaContextFactory;
 102     private final RemoteDeviceHandler<NetconfSessionPreferences> salFacade;
 103     private final ListeningExecutorService processingExecutor;
 104     private final SchemaSourceRegistry schemaRegistry;
 105     private final NetconfStateSchemas.NetconfStateSchemasResolver stateSchemasResolver;
 106     private final NotificationHandler notificationHandler;
 107     private final List<SchemaSourceRegistration<? extends SchemaSourceRepresentation>> sourceRegistrations = Lists.newArrayList();
 108
 109     // Message transformer is constructed once the schemas are available
 110     private MessageTransformer<NetconfMessage> messageTransformer;
 111
 112     public NetconfDevice(final SchemaResourcesDTO schemaResourcesDTO, final RemoteDeviceId id, final RemoteDeviceHandler<NetconfSessionPreferences> salFacade,
 113                          final ExecutorService globalProcessingExecutor) {
 114         this(schemaResourcesDTO, id, salFacade, globalProcessingExecutor, false);
 115     }
 116
 117     /**
 118      * Create rpc implementation capable of handling RPC for monitoring and notifications even before the schemas of remote device are downloaded
 119      */
 120     static NetconfDeviceRpc getRpcForInitialization(final NetconfDeviceCommunicator listener) {
 121         return new NetconfDeviceRpc(INIT_SCHEMA_CTX, listener, new NetconfMessageTransformer(INIT_SCHEMA_CTX, false));
 122     }
 123
 124
 125     // FIXME reduce parameters
 126     public NetconfDevice(final SchemaResourcesDTO schemaResourcesDTO, final RemoteDeviceId id, final RemoteDeviceHandler<NetconfSessionPreferences> salFacade,
 127                          final ExecutorService globalProcessingExecutor, final boolean reconnectOnSchemasChange) {
 128         this.id = id;
 129         this.reconnectOnSchemasChange = reconnectOnSchemasChange;
 130         this.schemaRegistry = schemaResourcesDTO.getSchemaRegistry();
 131         this.schemaContextFactory = schemaResourcesDTO.getSchemaContextFactory();
 132         this.salFacade = salFacade;
 133         this.stateSchemasResolver = schemaResourcesDTO.getStateSchemasResolver();
 134         this.processingExecutor = MoreExecutors.listeningDecorator(globalProcessingExecutor);
 135         this.notificationHandler = new NotificationHandler(salFacade, id);
 136     }
 137
 138     @Override
 139     public void onRemoteSessionUp(final NetconfSessionPreferences remoteSessionCapabilities,
 140                                   final NetconfDeviceCommunicator listener) {
 141         // SchemaContext setup has to be performed in a dedicated thread since
 142         // we are in a netty thread in this method
 143         // Yang models are being downloaded in this method and it would cause a
 144         // deadlock if we used the netty thread
 145         // http://netty.io/wiki/thread-model.html
 146         logger.debug("{}: Session to remote device established with {}", id, remoteSessionCapabilities);
 147
 148         final NetconfDeviceRpc initRpc = getRpcForInitialization(listener);
 149         final DeviceSourcesResolver task = new DeviceSourcesResolver(remoteSessionCapabilities, id, stateSchemasResolver, initRpc);
 150         final ListenableFuture<DeviceSources> sourceResolverFuture = processingExecutor.submit(task);
 151
 152         if(shouldListenOnSchemaChange(remoteSessionCapabilities)) {
 153            registerToBaseNetconfStream(initRpc, listener);
 154         }
 155
 156         final FutureCallback<DeviceSources> resolvedSourceCallback = new FutureCallback<DeviceSources>() {
 157             @Override
 158             public void onSuccess(final DeviceSources result) {
 159                 addProvidedSourcesToSchemaRegistry(initRpc, result);
 160                 setUpSchema(result);
 161             }
 162
 163             private void setUpSchema(final DeviceSources result) {
 164                 processingExecutor.submit(new RecursiveSchemaSetup(result, remoteSessionCapabilities, listener));
 165             }
 166
 167             @Override
 168             public void onFailure(final Throwable t) {
 169                 logger.warn("{}: Unexpected error resolving device sources: {}", id, t);
 170                 handleSalInitializationFailure(t, listener);
 171             }
 172         };
 173
 174         Futures.addCallback(sourceResolverFuture, resolvedSourceCallback);
 175     }
 176
 177     private void registerToBaseNetconfStream(final NetconfDeviceRpc deviceRpc, final NetconfDeviceCommunicator listener) {
 178        // TODO check whether the model describing create subscription is present in schema
 179         // 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)
 180        final CheckedFuture<DOMRpcResult, DOMRpcException> rpcResultListenableFuture =
 181                 deviceRpc.invokeRpc(NetconfMessageTransformUtil.toPath(NetconfMessageTransformUtil.CREATE_SUBSCRIPTION_RPC_QNAME), NetconfMessageTransformUtil.CREATE_SUBSCRIPTION_RPC_CONTENT);
 182
 183         final NotificationHandler.NotificationFilter filter = new NotificationHandler.NotificationFilter() {
 184             @Override
 185             public Optional<DOMNotification> filterNotification(final DOMNotification notification) {
 186                 if (isCapabilityChanged(notification)) {
 187                     logger.info("{}: Schemas change detected, reconnecting", id);
 188                     // Only disconnect is enough, the reconnecting nature of the connector will take care of reconnecting
 189                     listener.disconnect();
 190                     return Optional.absent();
 191                 }
 192                 return Optional.of(notification);
 193             }
 194
 195             private boolean isCapabilityChanged(final DOMNotification notification) {
 196                 return notification.getBody().getNodeType().equals(NetconfCapabilityChange.QNAME);
 197             }
 198         };
 199
 200         Futures.addCallback(rpcResultListenableFuture, new FutureCallback<DOMRpcResult>() {
 201             @Override
 202             public void onSuccess(final DOMRpcResult domRpcResult) {
 203                 notificationHandler.addNotificationFilter(filter);
 204             }
 205
 206             @Override
 207             public void onFailure(final Throwable t) {
 208                 logger.warn("Unable to subscribe to base notification stream. Schemas will not be reloaded on the fly", t);
 209             }
 210         });
 211     }
 212
 213     private boolean shouldListenOnSchemaChange(final NetconfSessionPreferences remoteSessionCapabilities) {
 214         return remoteSessionCapabilities.isNotificationsSupported() && reconnectOnSchemasChange;
 215     }
 216
 217     @VisibleForTesting
 218     void handleSalInitializationSuccess(final SchemaContext result, final NetconfSessionPreferences remoteSessionCapabilities, final DOMRpcService deviceRpc) {
 219         messageTransformer = new NetconfMessageTransformer(result, true);
 220
 221         updateTransformer(messageTransformer);
 222         // salFacade.onDeviceConnected has to be called before the notification handler is initialized
 223         salFacade.onDeviceConnected(result, remoteSessionCapabilities, deviceRpc);
 224         notificationHandler.onRemoteSchemaUp(messageTransformer);
 225
 226         logger.info("{}: Netconf connector initialized successfully", id);
 227     }
 228
 229     private void handleSalInitializationFailure(final Throwable t, final RemoteDeviceCommunicator<NetconfMessage> listener) {
 230         logger.error("{}: Initialization in sal failed, disconnecting from device", id, t);
 231         listener.close();
 232         onRemoteSessionDown();
 233         resetMessageTransformer();
 234     }
 235
 236     /**
 237      * Set the transformer to null as is in initial state
 238      */
 239     private void resetMessageTransformer() {
 240         updateTransformer(null);
 241     }
 242
 243     private void updateTransformer(final MessageTransformer<NetconfMessage> transformer) {
 244         messageTransformer = transformer;
 245     }
 246
 247     private void addProvidedSourcesToSchemaRegistry(final NetconfDeviceRpc deviceRpc, final DeviceSources deviceSources) {
 248         final NetconfRemoteSchemaYangSourceProvider yangProvider = new NetconfRemoteSchemaYangSourceProvider(id, deviceRpc);
 249         for (final SourceIdentifier sourceId : deviceSources.getProvidedSources()) {
 250             sourceRegistrations.add(schemaRegistry.registerSchemaSource(yangProvider,
 251                     PotentialSchemaSource.create(sourceId, YangTextSchemaSource.class, PotentialSchemaSource.Costs.REMOTE_IO.getValue())));
 252         }
 253     }
 254
 255     @Override
 256     public void onRemoteSessionDown() {
 257         notificationHandler.onRemoteSchemaDown();
 258
 259         salFacade.onDeviceDisconnected();
 260         for (final SchemaSourceRegistration<? extends SchemaSourceRepresentation> sourceRegistration : sourceRegistrations) {
 261             sourceRegistration.close();
 262         }
 263         resetMessageTransformer();
 264     }
 265
 266     @Override
 267     public void onRemoteSessionFailed(final Throwable throwable) {
 268         salFacade.onDeviceFailed(throwable);
 269     }
 270
 271     @Override
 272     public void onNotification(final NetconfMessage notification) {
 273         notificationHandler.handleNotification(notification);
 274     }
 275
 276     /**
 277      * Just a transfer object containing schema related dependencies. Injected in constructor.
 278      */
 279     public static class SchemaResourcesDTO {
 280         private final SchemaSourceRegistry schemaRegistry;
 281         private final SchemaContextFactory schemaContextFactory;
 282         private final NetconfStateSchemas.NetconfStateSchemasResolver stateSchemasResolver;
 283
 284         public SchemaResourcesDTO(final SchemaSourceRegistry schemaRegistry, final SchemaContextFactory schemaContextFactory, final NetconfStateSchemas.NetconfStateSchemasResolver stateSchemasResolver) {
 285             this.schemaRegistry = Preconditions.checkNotNull(schemaRegistry);
 286             this.schemaContextFactory = Preconditions.checkNotNull(schemaContextFactory);
 287             this.stateSchemasResolver = Preconditions.checkNotNull(stateSchemasResolver);
 288         }
 289
 290         public SchemaSourceRegistry getSchemaRegistry() {
 291             return schemaRegistry;
 292         }
 293
 294         public SchemaContextFactory getSchemaContextFactory() {
 295             return schemaContextFactory;
 296         }
 297
 298         public NetconfStateSchemas.NetconfStateSchemasResolver getStateSchemasResolver() {
 299             return stateSchemasResolver;
 300         }
 301     }
 302
 303     /**
 304      * Schema building callable.
 305      */
 306     private static class DeviceSourcesResolver implements Callable<DeviceSources> {
 307
 308         private final NetconfDeviceRpc deviceRpc;
 309         private final NetconfSessionPreferences remoteSessionCapabilities;
 310         private final RemoteDeviceId id;
 311         private final NetconfStateSchemas.NetconfStateSchemasResolver stateSchemasResolver;
 312
 313         DeviceSourcesResolver(final NetconfDeviceRpc deviceRpc, final NetconfSessionPreferences remoteSessionCapabilities,
 314                                      final RemoteDeviceId id, final NetconfStateSchemas.NetconfStateSchemasResolver stateSchemasResolver) {
 315             this.deviceRpc = deviceRpc;
 316             this.remoteSessionCapabilities = remoteSessionCapabilities;
 317             this.id = id;
 318             this.stateSchemasResolver = stateSchemasResolver;
 319         }
 320
 321         public DeviceSourcesResolver(final NetconfSessionPreferences remoteSessionCapabilities, final RemoteDeviceId id, final NetconfStateSchemas.NetconfStateSchemasResolver stateSchemasResolver, final NetconfDeviceRpc rpcForMonitoring) {
 322             this(rpcForMonitoring, remoteSessionCapabilities, id, stateSchemasResolver);
 323         }
 324
 325         @Override
 326         public DeviceSources call() throws Exception {
 327             final NetconfStateSchemas availableSchemas = stateSchemasResolver.resolve(deviceRpc, remoteSessionCapabilities, id);
 328             logger.debug("{}: Schemas exposed by ietf-netconf-monitoring: {}", id, availableSchemas.getAvailableYangSchemasQNames());
 329
 330             final Set<QName> requiredSources = Sets.newHashSet(remoteSessionCapabilities.getModuleBasedCaps());
 331             final Set<QName> providedSources = availableSchemas.getAvailableYangSchemasQNames();
 332
 333             final Set<QName> requiredSourcesNotProvided = Sets.difference(requiredSources, providedSources);
 334             if (!requiredSourcesNotProvided.isEmpty()) {
 335                 logger.warn("{}: Netconf device does not provide all yang models reported in hello message capabilities, required but not provided: {}",
 336                         id, requiredSourcesNotProvided);
 337                 logger.warn("{}: Attempting to build schema context from required sources", id);
 338             }
 339
 340             // Here all the sources reported in netconf monitoring are merged with those reported in hello.
 341             // It is necessary to perform this since submodules are not mentioned in hello but still required.
 342             // This clashes with the option of a user to specify supported yang models manually in configuration for netconf-connector
 343             // and as a result one is not able to fully override yang models of a device. It is only possible to add additional models.
 344             final Set<QName> providedSourcesNotRequired = Sets.difference(providedSources, requiredSources);
 345             if (!providedSourcesNotRequired.isEmpty()) {
 346                 logger.warn("{}: Netconf device provides additional yang models not reported in hello message capabilities: {}",
 347                         id, providedSourcesNotRequired);
 348                 logger.warn("{}: Adding provided but not required sources as required to prevent failures", id);
 349                 logger.debug("{}: Netconf device reported in hello: {}", id, requiredSources);
 350                 requiredSources.addAll(providedSourcesNotRequired);
 351             }
 352
 353             return new DeviceSources(requiredSources, providedSources);
 354         }
 355     }
 356
 357     /**
 358      * Contains RequiredSources - sources from capabilities.
 359      */
 360     private static final class DeviceSources {
 361         private final Set<QName> requiredSources;
 362         private final Set<QName> providedSources;
 363
 364         public DeviceSources(final Set<QName> requiredSources, final Set<QName> providedSources) {
 365             this.requiredSources = requiredSources;
 366             this.providedSources = providedSources;
 367         }
 368
 369         public Set<QName> getRequiredSourcesQName() {
 370             return requiredSources;
 371         }
 372
 373         public Set<QName> getProvidedSourcesQName() {
 374             return providedSources;
 375         }
 376
 377         public Collection<SourceIdentifier> getRequiredSources() {
 378             return Collections2.transform(requiredSources, QNAME_TO_SOURCE_ID_FUNCTION);
 379         }
 380
 381         public Collection<SourceIdentifier> getProvidedSources() {
 382             return Collections2.transform(providedSources, QNAME_TO_SOURCE_ID_FUNCTION);
 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(deviceSources.getProvidedSourcesQName(), 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, true));
 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 = Collections2.transform(identifiers, new Function<SourceIdentifier, QName>() {
 476                 @Override
 477                 public QName apply(final SourceIdentifier sourceIdentifier) {
 478                     return getQNameFromSourceIdentifier(sourceIdentifier);
 479                 }
 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 QName getQNameFromSourceIdentifier(final SourceIdentifier identifier) {
 489             // Required sources are all required and provided merged in DeviceSourcesResolver
 490             for (final QName qname : deviceSources.getRequiredSourcesQName()) {
 491                 if(qname.getLocalName().equals(identifier.getName()) == false) {
 492                     continue;
 493                 }
 494
 495                 if(identifier.getRevision().equals(SourceIdentifier.NOT_PRESENT_FORMATTED_REVISION) &&
 496                         qname.getRevision() == null) {
 497                     return qname;
 498                 }
 499
 500                 if (qname.getFormattedRevision().equals(identifier.getRevision())) {
 501                     return qname;
 502                 }
 503             }
 504             throw new IllegalArgumentException("Unable to map identifier to a devices reported capability: " + identifier + " Available: " + deviceSources.getRequiredSourcesQName());
 505         }
 506     }
 507 }