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