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.Collections;
  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 java.util.stream.Collectors;
  31 import org.opendaylight.controller.md.sal.dom.api.DOMNotification;
  32 import org.opendaylight.controller.md.sal.dom.api.DOMRpcException;
  33 import org.opendaylight.controller.md.sal.dom.api.DOMRpcResult;
  34 import org.opendaylight.controller.md.sal.dom.api.DOMRpcService;
  35 import org.opendaylight.netconf.api.NetconfMessage;
  36 import org.opendaylight.netconf.sal.connect.api.MessageTransformer;
  37 import org.opendaylight.netconf.sal.connect.api.NetconfDeviceSchemas;
  38 import org.opendaylight.netconf.sal.connect.api.NetconfDeviceSchemasResolver;
  39 import org.opendaylight.netconf.sal.connect.api.RemoteDevice;
  40 import org.opendaylight.netconf.sal.connect.api.RemoteDeviceCommunicator;
  41 import org.opendaylight.netconf.sal.connect.api.RemoteDeviceHandler;
  42 import org.opendaylight.netconf.sal.connect.netconf.listener.NetconfDeviceCapabilities;
  43 import org.opendaylight.netconf.sal.connect.netconf.listener.NetconfDeviceCommunicator;
  44 import org.opendaylight.netconf.sal.connect.netconf.listener.NetconfSessionPreferences;
  45 import org.opendaylight.netconf.sal.connect.netconf.sal.NetconfDeviceRpc;
  46 import org.opendaylight.netconf.sal.connect.netconf.schema.NetconfRemoteSchemaYangSourceProvider;
  47 import org.opendaylight.netconf.sal.connect.netconf.schema.YangLibrarySchemaYangSourceProvider;
  48 import org.opendaylight.netconf.sal.connect.netconf.schema.mapping.BaseSchema;
  49 import org.opendaylight.netconf.sal.connect.netconf.schema.mapping.NetconfMessageTransformer;
  50 import org.opendaylight.netconf.sal.connect.netconf.util.NetconfMessageTransformUtil;
  51 import org.opendaylight.netconf.sal.connect.util.RemoteDeviceId;
  52 import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.netconf.notifications.rev120206.NetconfCapabilityChange;
  53 import org.opendaylight.yang.gen.v1.urn.opendaylight.netconf.node.topology.rev150114.netconf.node.connection.status.available.capabilities.AvailableCapability;
  54 import org.opendaylight.yang.gen.v1.urn.opendaylight.netconf.node.topology.rev150114.netconf.node.connection.status.available.capabilities.AvailableCapabilityBuilder;
  55 import org.opendaylight.yang.gen.v1.urn.opendaylight.netconf.node.topology.rev150114.netconf.node.connection.status.unavailable.capabilities.UnavailableCapability;
  56 import org.opendaylight.yangtools.yang.common.QName;
  57 import org.opendaylight.yangtools.yang.model.api.SchemaContext;
  58 import org.opendaylight.yangtools.yang.model.repo.api.MissingSchemaSourceException;
  59 import org.opendaylight.yangtools.yang.model.repo.api.RevisionSourceIdentifier;
  60 import org.opendaylight.yangtools.yang.model.repo.api.SchemaContextFactory;
  61 import org.opendaylight.yangtools.yang.model.repo.api.SchemaRepository;
  62 import org.opendaylight.yangtools.yang.model.repo.api.SchemaResolutionException;
  63 import org.opendaylight.yangtools.yang.model.repo.api.SchemaSourceException;
  64 import org.opendaylight.yangtools.yang.model.repo.api.SchemaSourceRepresentation;
  65 import org.opendaylight.yangtools.yang.model.repo.api.SourceIdentifier;
  66 import org.opendaylight.yangtools.yang.model.repo.api.YangTextSchemaSource;
  67 import org.opendaylight.yangtools.yang.model.repo.spi.PotentialSchemaSource;
  68 import org.opendaylight.yangtools.yang.model.repo.spi.SchemaSourceProvider;
  69 import org.opendaylight.yangtools.yang.model.repo.spi.SchemaSourceRegistration;
  70 import org.opendaylight.yangtools.yang.model.repo.spi.SchemaSourceRegistry;
  71 import org.opendaylight.yangtools.yang.parser.util.ASTSchemaSource;
  72 import org.slf4j.Logger;
  73 import org.slf4j.LoggerFactory;
  74
  75 /**
  76  *  This is a mediator between NetconfDeviceCommunicator and NetconfDeviceSalFacade
  77  */
  78 public class NetconfDevice implements RemoteDevice<NetconfSessionPreferences, NetconfMessage, NetconfDeviceCommunicator> {
  79
  80     private static final Logger LOG = LoggerFactory.getLogger(NetconfDevice.class);
  81
  82     public static final Function<QName, SourceIdentifier> QNAME_TO_SOURCE_ID_FUNCTION =
  83             input -> RevisionSourceIdentifier.create(input.getLocalName(),
  84                 Optional.fromNullable(input.getFormattedRevision()));
  85
  86     protected final RemoteDeviceId id;
  87     private final boolean reconnectOnSchemasChange;
  88
  89     protected final SchemaContextFactory schemaContextFactory;
  90     private final RemoteDeviceHandler<NetconfSessionPreferences> salFacade;
  91     private final ListeningExecutorService processingExecutor;
  92     protected final SchemaSourceRegistry schemaRegistry;
  93     protected final SchemaRepository schemaRepository;
  94     private final NetconfDeviceSchemasResolver stateSchemasResolver;
  95     private final NotificationHandler notificationHandler;
  96     protected final List<SchemaSourceRegistration<? extends SchemaSourceRepresentation>> sourceRegistrations = Lists.newArrayList();
  97
  98     // Message transformer is constructed once the schemas are available
  99     private MessageTransformer<NetconfMessage> messageTransformer;
 100
 101     /**
 102      * Create rpc implementation capable of handling RPC for monitoring and notifications even before the schemas of remote device are downloaded
 103      */
 104     static NetconfDeviceRpc getRpcForInitialization(final NetconfDeviceCommunicator listener, final boolean notificationSupport) {
 105         final BaseSchema baseSchema = notificationSupport ?
 106                 BaseSchema.BASE_NETCONF_CTX_WITH_NOTIFICATIONS :
 107                 BaseSchema.BASE_NETCONF_CTX;
 108
 109         return new NetconfDeviceRpc(baseSchema.getSchemaContext(), listener, new NetconfMessageTransformer(baseSchema.getSchemaContext(), false, baseSchema));
 110     }
 111
 112     public NetconfDevice(final SchemaResourcesDTO schemaResourcesDTO, final RemoteDeviceId id, final RemoteDeviceHandler<NetconfSessionPreferences> salFacade,
 113                          final ExecutorService globalProcessingExecutor, final boolean reconnectOnSchemasChange) {
 114         this.id = id;
 115         this.reconnectOnSchemasChange = reconnectOnSchemasChange;
 116         this.schemaRegistry = schemaResourcesDTO.getSchemaRegistry();
 117         this.schemaRepository = schemaResourcesDTO.getSchemaRepository();
 118         this.schemaContextFactory = schemaResourcesDTO.getSchemaContextFactory();
 119         this.salFacade = salFacade;
 120         this.stateSchemasResolver = schemaResourcesDTO.getStateSchemasResolver();
 121         this.processingExecutor = MoreExecutors.listeningDecorator(globalProcessingExecutor);
 122         this.notificationHandler = new NotificationHandler(salFacade, id);
 123     }
 124
 125     @Override
 126     public void onRemoteSessionUp(final NetconfSessionPreferences remoteSessionCapabilities,
 127                                   final NetconfDeviceCommunicator listener) {
 128         // SchemaContext setup has to be performed in a dedicated thread since
 129         // we are in a netty thread in this method
 130         // Yang models are being downloaded in this method and it would cause a
 131         // deadlock if we used the netty thread
 132         // http://netty.io/wiki/thread-model.html
 133         LOG.debug("{}: Session to remote device established with {}", id, remoteSessionCapabilities);
 134
 135         final NetconfDeviceRpc initRpc = getRpcForInitialization(listener, remoteSessionCapabilities.isNotificationsSupported());
 136         final DeviceSourcesResolver task = new DeviceSourcesResolver(remoteSessionCapabilities, id, stateSchemasResolver, initRpc);
 137         final ListenableFuture<DeviceSources> sourceResolverFuture = processingExecutor.submit(task);
 138
 139         if (shouldListenOnSchemaChange(remoteSessionCapabilities)) {
 140             registerToBaseNetconfStream(initRpc, listener);
 141         }
 142
 143         final FutureCallback<DeviceSources> resolvedSourceCallback = new FutureCallback<DeviceSources>() {
 144             @Override
 145             public void onSuccess(final DeviceSources result) {
 146                 addProvidedSourcesToSchemaRegistry(result);
 147                 setUpSchema(result);
 148             }
 149
 150             private void setUpSchema(final DeviceSources result) {
 151                 processingExecutor.submit(new SchemaSetup(result, remoteSessionCapabilities, listener));
 152             }
 153
 154             @Override
 155             public void onFailure(final Throwable t) {
 156                 LOG.warn("{}: Unexpected error resolving device sources: {}", id, t);
 157                 handleSalInitializationFailure(t, listener);
 158             }
 159         };
 160
 161         Futures.addCallback(sourceResolverFuture, resolvedSourceCallback);
 162     }
 163
 164     private void registerToBaseNetconfStream(final NetconfDeviceRpc deviceRpc, final NetconfDeviceCommunicator listener) {
 165        // TODO check whether the model describing create subscription is present in schema
 166         // 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)
 167         final CheckedFuture<DOMRpcResult, DOMRpcException> rpcResultListenableFuture = deviceRpc.invokeRpc(
 168             NetconfMessageTransformUtil.toPath(NetconfMessageTransformUtil.CREATE_SUBSCRIPTION_RPC_QNAME),
 169             NetconfMessageTransformUtil.CREATE_SUBSCRIPTION_RPC_CONTENT);
 170
 171         final NotificationHandler.NotificationFilter filter = new NotificationHandler.NotificationFilter() {
 172             @Override
 173             public Optional<DOMNotification> filterNotification(final DOMNotification notification) {
 174                 if (isCapabilityChanged(notification)) {
 175                     LOG.info("{}: Schemas change detected, reconnecting", id);
 176                     // Only disconnect is enough, the reconnecting nature of the connector will take care of reconnecting
 177                     listener.disconnect();
 178                     return Optional.absent();
 179                 }
 180                 return Optional.of(notification);
 181             }
 182
 183             private boolean isCapabilityChanged(final DOMNotification notification) {
 184                 return notification.getBody().getNodeType().equals(NetconfCapabilityChange.QNAME);
 185             }
 186         };
 187
 188         Futures.addCallback(rpcResultListenableFuture, new FutureCallback<DOMRpcResult>() {
 189             @Override
 190             public void onSuccess(final DOMRpcResult domRpcResult) {
 191                 notificationHandler.addNotificationFilter(filter);
 192             }
 193
 194             @Override
 195             public void onFailure(final Throwable t) {
 196                 LOG.warn("Unable to subscribe to base notification stream. Schemas will not be reloaded on the fly", t);
 197             }
 198         });
 199     }
 200
 201     private boolean shouldListenOnSchemaChange(final NetconfSessionPreferences remoteSessionCapabilities) {
 202         return remoteSessionCapabilities.isNotificationsSupported() && reconnectOnSchemasChange;
 203     }
 204
 205     void handleSalInitializationSuccess(final SchemaContext result, final NetconfSessionPreferences remoteSessionCapabilities, final DOMRpcService deviceRpc) {
 206         final BaseSchema baseSchema =
 207                 remoteSessionCapabilities.isNotificationsSupported() ?
 208                 BaseSchema.BASE_NETCONF_CTX_WITH_NOTIFICATIONS :
 209                 BaseSchema.BASE_NETCONF_CTX;
 210         messageTransformer = new NetconfMessageTransformer(result, true, baseSchema);
 211
 212         updateTransformer(messageTransformer);
 213         // salFacade.onDeviceConnected has to be called before the notification handler is initialized
 214         salFacade.onDeviceConnected(result, remoteSessionCapabilities, deviceRpc);
 215         notificationHandler.onRemoteSchemaUp(messageTransformer);
 216
 217         LOG.info("{}: Netconf connector initialized successfully", id);
 218     }
 219
 220     void handleSalInitializationFailure(final Throwable t, final RemoteDeviceCommunicator<NetconfMessage> listener) {
 221         LOG.error("{}: Initialization in sal failed, disconnecting from device", id, t);
 222         listener.close();
 223         onRemoteSessionDown();
 224         resetMessageTransformer();
 225     }
 226
 227     /**
 228      * Set the transformer to null as is in initial state
 229      */
 230     private void resetMessageTransformer() {
 231         updateTransformer(null);
 232     }
 233
 234     private void updateTransformer(final MessageTransformer<NetconfMessage> transformer) {
 235         messageTransformer = transformer;
 236     }
 237
 238     private void addProvidedSourcesToSchemaRegistry(final DeviceSources deviceSources) {
 239         final SchemaSourceProvider<YangTextSchemaSource> yangProvider = deviceSources.getSourceProvider();
 240         for (final SourceIdentifier sourceId : deviceSources.getProvidedSources()) {
 241             sourceRegistrations.add(schemaRegistry.registerSchemaSource(yangProvider,
 242                     PotentialSchemaSource.create(sourceId, YangTextSchemaSource.class, PotentialSchemaSource.Costs.REMOTE_IO.getValue())));
 243         }
 244     }
 245
 246     @Override
 247     public void onRemoteSessionDown() {
 248         notificationHandler.onRemoteSchemaDown();
 249
 250         salFacade.onDeviceDisconnected();
 251         for (final SchemaSourceRegistration<? extends SchemaSourceRepresentation> sourceRegistration : sourceRegistrations) {
 252             sourceRegistration.close();
 253         }
 254         resetMessageTransformer();
 255     }
 256
 257     @Override
 258     public void onRemoteSessionFailed(final Throwable throwable) {
 259         salFacade.onDeviceFailed(throwable);
 260     }
 261
 262     @Override
 263     public void onNotification(final NetconfMessage notification) {
 264         notificationHandler.handleNotification(notification);
 265     }
 266
 267     /**
 268      * Just a transfer object containing schema related dependencies. Injected in constructor.
 269      */
 270     public static class SchemaResourcesDTO {
 271         private final SchemaSourceRegistry schemaRegistry;
 272         private final SchemaRepository schemaRepository;
 273         private final SchemaContextFactory schemaContextFactory;
 274         private final NetconfDeviceSchemasResolver stateSchemasResolver;
 275
 276         public SchemaResourcesDTO(final SchemaSourceRegistry schemaRegistry,
 277                                   final SchemaRepository schemaRepository,
 278                                   final SchemaContextFactory schemaContextFactory,
 279                                   final NetconfDeviceSchemasResolver deviceSchemasResolver) {
 280             this.schemaRegistry = Preconditions.checkNotNull(schemaRegistry);
 281             this.schemaRepository = Preconditions.checkNotNull(schemaRepository);
 282             this.schemaContextFactory = Preconditions.checkNotNull(schemaContextFactory);
 283             this.stateSchemasResolver = Preconditions.checkNotNull(deviceSchemasResolver);
 284         }
 285
 286         public SchemaSourceRegistry getSchemaRegistry() {
 287             return schemaRegistry;
 288         }
 289
 290         public SchemaRepository getSchemaRepository() {
 291             return schemaRepository;
 292         }
 293
 294         public SchemaContextFactory getSchemaContextFactory() {
 295             return schemaContextFactory;
 296         }
 297
 298         public NetconfDeviceSchemasResolver 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 NetconfDeviceSchemasResolver stateSchemasResolver;
 312
 313         DeviceSourcesResolver(final NetconfDeviceRpc deviceRpc, final NetconfSessionPreferences remoteSessionCapabilities,
 314                                      final RemoteDeviceId id, final NetconfDeviceSchemasResolver 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 NetconfDeviceSchemasResolver stateSchemasResolver, final NetconfDeviceRpc rpcForMonitoring) {
 322             this(rpcForMonitoring, remoteSessionCapabilities, id, stateSchemasResolver);
 323         }
 324
 325         @Override
 326         public DeviceSources call() throws Exception {
 327             final NetconfDeviceSchemas availableSchemas = stateSchemasResolver.resolve(deviceRpc, remoteSessionCapabilities, id);
 328             LOG.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                 LOG.warn("{}: Netconf device does not provide all yang models reported in hello message capabilities, required but not provided: {}",
 336                         id, requiredSourcesNotProvided);
 337                 LOG.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                 LOG.warn("{}: Netconf device provides additional yang models not reported in hello message capabilities: {}",
 347                         id, providedSourcesNotRequired);
 348                 LOG.warn("{}: Adding provided but not required sources as required to prevent failures", id);
 349                 LOG.debug("{}: Netconf device reported in hello: {}", id, requiredSources);
 350                 requiredSources.addAll(providedSourcesNotRequired);
 351             }
 352
 353             final SchemaSourceProvider<YangTextSchemaSource> sourceProvider;
 354             if(availableSchemas instanceof LibraryModulesSchemas) {
 355                 sourceProvider = new YangLibrarySchemaYangSourceProvider(id,
 356                         ((LibraryModulesSchemas) availableSchemas).getAvailableModels());
 357             } else {
 358                 sourceProvider = new NetconfRemoteSchemaYangSourceProvider(id, deviceRpc);
 359             }
 360
 361             return new DeviceSources(requiredSources, providedSources, sourceProvider);
 362         }
 363     }
 364
 365     /**
 366      * Contains RequiredSources - sources from capabilities.
 367      */
 368     private static final class DeviceSources {
 369         private final Set<QName> requiredSources;
 370         private final Set<QName> providedSources;
 371         private final SchemaSourceProvider<YangTextSchemaSource> sourceProvider;
 372
 373         public DeviceSources(final Set<QName> requiredSources, final Set<QName> providedSources,
 374                              final SchemaSourceProvider<YangTextSchemaSource> sourceProvider) {
 375             this.requiredSources = requiredSources;
 376             this.providedSources = providedSources;
 377             this.sourceProvider = sourceProvider;
 378         }
 379
 380         public Set<QName> getRequiredSourcesQName() {
 381             return requiredSources;
 382         }
 383
 384         public Set<QName> getProvidedSourcesQName() {
 385             return providedSources;
 386         }
 387
 388         public Collection<SourceIdentifier> getRequiredSources() {
 389             return Collections2.transform(requiredSources, QNAME_TO_SOURCE_ID_FUNCTION);
 390         }
 391
 392         public Collection<SourceIdentifier> getProvidedSources() {
 393             return Collections2.transform(providedSources, QNAME_TO_SOURCE_ID_FUNCTION);
 394         }
 395
 396         public SchemaSourceProvider<YangTextSchemaSource> getSourceProvider() {
 397             return sourceProvider;
 398         }
 399     }
 400
 401     /**
 402      * Schema builder that tries to build schema context from provided sources or biggest subset of it.
 403      */
 404     private final class SchemaSetup implements Runnable {
 405         private final DeviceSources deviceSources;
 406         private final NetconfSessionPreferences remoteSessionCapabilities;
 407         private final RemoteDeviceCommunicator<NetconfMessage> listener;
 408         private final NetconfDeviceCapabilities capabilities;
 409
 410         public SchemaSetup(final DeviceSources deviceSources, final NetconfSessionPreferences remoteSessionCapabilities, final RemoteDeviceCommunicator<NetconfMessage> listener) {
 411             this.deviceSources = deviceSources;
 412             this.remoteSessionCapabilities = remoteSessionCapabilities;
 413             this.listener = listener;
 414             this.capabilities = remoteSessionCapabilities.getNetconfDeviceCapabilities();
 415         }
 416
 417         @Override
 418         public void run() {
 419
 420             final Collection<SourceIdentifier> requiredSources = deviceSources.getRequiredSources();
 421             final Collection<SourceIdentifier> missingSources = filterMissingSources(requiredSources);
 422
 423             capabilities.addUnresolvedCapabilities(getQNameFromSourceIdentifiers(missingSources),
 424                     UnavailableCapability.FailureReason.MissingSource);
 425
 426             requiredSources.removeAll(missingSources);
 427             setUpSchema(requiredSources);
 428         }
 429
 430         private Collection<SourceIdentifier> filterMissingSources(final Collection<SourceIdentifier> requiredSources) {
 431
 432             return requiredSources.parallelStream().filter(sourceIdentifier -> {
 433                     boolean remove = false;
 434                     try {
 435                         schemaRepository.getSchemaSource(sourceIdentifier, ASTSchemaSource.class).checkedGet();
 436                     } catch (SchemaSourceException e) {
 437                         remove = true;
 438                     }
 439                     return remove;
 440                 }).collect(Collectors.toList());
 441         }
 442
 443         /**
 444          * Build schema context, in case of success or final failure notify device
 445          */
 446         private void setUpSchema(Collection<SourceIdentifier> requiredSources) {
 447             while (!requiredSources.isEmpty()) {
 448                 LOG.trace("{}: Trying to build schema context from {}", id, requiredSources);
 449                 try {
 450                     final CheckedFuture<SchemaContext, SchemaResolutionException> schemaBuilderFuture = schemaContextFactory.createSchemaContext(requiredSources);
 451                     final SchemaContext result = schemaBuilderFuture.checkedGet();
 452                     LOG.debug("{}: Schema context built successfully from {}", id, requiredSources);
 453                     final Collection<QName> filteredQNames = Sets.difference(deviceSources.getRequiredSourcesQName(), capabilities.getUnresolvedCapabilites().keySet());
 454                     capabilities.addCapabilities(filteredQNames.stream().map(entry -> new AvailableCapabilityBuilder()
 455                             .setCapability(entry.toString()).setCapabilityOrigin(remoteSessionCapabilities.getModuleBasedCapsOrigin().get(entry)).build())
 456                             .collect(Collectors.toList()));
 457
 458                     capabilities.addNonModuleBasedCapabilities(remoteSessionCapabilities.getNonModuleCaps().stream().map(entry -> new AvailableCapabilityBuilder()
 459                             .setCapability(entry).setCapabilityOrigin(AvailableCapability.CapabilityOrigin.DeviceAdvertised).build())
 460                             .collect(Collectors.toList()));
 461
 462                     handleSalInitializationSuccess(result, remoteSessionCapabilities, getDeviceSpecificRpc(result));
 463                     return;
 464                 } catch (final Throwable t) {
 465                     if (t instanceof MissingSchemaSourceException){
 466                         requiredSources = handleMissingSchemaSourceException(requiredSources, (MissingSchemaSourceException) t);
 467                     } else if (t instanceof SchemaResolutionException) {
 468                         // schemaBuilderFuture.checkedGet() throws only SchemaResolutionException
 469                         // that might be wrapping a MissingSchemaSourceException so we need to look
 470                         // at the cause of the exception to make sure we don't misinterpret it.
 471                         if (t.getCause() instanceof MissingSchemaSourceException) {
 472                             requiredSources = handleMissingSchemaSourceException(requiredSources, (MissingSchemaSourceException) t.getCause());
 473                             continue;
 474                         }
 475                         requiredSources = handleSchemaResolutionException(requiredSources, (SchemaResolutionException) t);
 476                     } else {
 477                         // unknown error, fail
 478                         handleSalInitializationFailure(t, listener);
 479                         return;
 480                     }
 481                 }
 482             }
 483             // No more sources, fail
 484             final IllegalStateException cause = new IllegalStateException(id + ": No more sources for schema context");
 485             handleSalInitializationFailure(cause, listener);
 486             salFacade.onDeviceFailed(cause);
 487         }
 488
 489         private Collection<SourceIdentifier> handleMissingSchemaSourceException(final Collection<SourceIdentifier> requiredSources, final MissingSchemaSourceException t) {
 490             // In case source missing, try without it
 491             final SourceIdentifier missingSource = t.getSourceId();
 492             LOG.warn("{}: Unable to build schema context, missing source {}, will reattempt without it", id, missingSource);
 493             LOG.debug("{}: Unable to build schema context, missing source {}, will reattempt without it", t);
 494             final Collection<QName> qNameOfMissingSource = getQNameFromSourceIdentifiers(Sets.newHashSet(missingSource));
 495             if (!qNameOfMissingSource.isEmpty()) {
 496                 capabilities.addUnresolvedCapabilities(qNameOfMissingSource, UnavailableCapability.FailureReason.MissingSource);
 497             }
 498             return stripUnavailableSource(requiredSources, missingSource);
 499         }
 500
 501         private Collection<SourceIdentifier> handleSchemaResolutionException(final Collection<SourceIdentifier> requiredSources, final SchemaResolutionException resolutionException) {
 502             // In case resolution error, try only with resolved sources
 503             // There are two options why schema resolution exception occurred : unsatisfied imports or flawed model
 504             // FIXME Do we really have assurance that these two cases cannot happen at once?
 505             if (resolutionException.getFailedSource() != null) {
 506                 // flawed model - exclude it
 507                 final SourceIdentifier failedSourceId = resolutionException.getFailedSource();
 508                 LOG.warn("{}: Unable to build schema context, failed to resolve source {}, will reattempt without it", id, failedSourceId);
 509                 LOG.warn("{}: Unable to build schema context, failed to resolve source {}, will reattempt without it", id, resolutionException);
 510                 capabilities.addUnresolvedCapabilities(getQNameFromSourceIdentifiers(Collections.singleton(failedSourceId)),
 511                         UnavailableCapability.FailureReason.UnableToResolve);
 512                 return stripUnavailableSource(requiredSources, resolutionException.getFailedSource());
 513             }
 514             // unsatisfied imports
 515             final Set<SourceIdentifier> unresolvedSources = resolutionException.getUnsatisfiedImports().keySet();
 516             capabilities.addUnresolvedCapabilities(getQNameFromSourceIdentifiers(unresolvedSources), UnavailableCapability.FailureReason.UnableToResolve);
 517             LOG.warn("{}: Unable to build schema context, unsatisfied imports {}, will reattempt with resolved only", id, resolutionException.getUnsatisfiedImports());
 518             LOG.debug("{}: Unable to build schema context, unsatisfied imports {}, will reattempt with resolved only", resolutionException);
 519             return resolutionException.getResolvedSources();
 520         }
 521
 522         protected NetconfDeviceRpc getDeviceSpecificRpc(final SchemaContext result) {
 523             return new NetconfDeviceRpc(result, listener, new NetconfMessageTransformer(result, true));
 524         }
 525
 526         private Collection<SourceIdentifier> stripUnavailableSource(final Collection<SourceIdentifier> requiredSources, final SourceIdentifier sIdToRemove) {
 527             final LinkedList<SourceIdentifier> sourceIdentifiers = Lists.newLinkedList(requiredSources);
 528             final boolean removed = sourceIdentifiers.remove(sIdToRemove);
 529             Preconditions.checkState(removed, "{}: Trying to remove {} from {} failed", id, sIdToRemove, requiredSources);
 530             return sourceIdentifiers;
 531         }
 532
 533         private Collection<QName> getQNameFromSourceIdentifiers(final Collection<SourceIdentifier> identifiers) {
 534             final Collection<QName> qNames = Collections2.transform(identifiers, this::getQNameFromSourceIdentifier);
 535
 536             if (qNames.isEmpty()) {
 537                 LOG.debug("{}: Unable to map any source identifiers to a capability reported by device : {}", id, identifiers);
 538             }
 539             return Collections2.filter(qNames, Predicates.notNull());
 540         }
 541
 542         private QName getQNameFromSourceIdentifier(final SourceIdentifier identifier) {
 543             // Required sources are all required and provided merged in DeviceSourcesResolver
 544             for (final QName qname : deviceSources.getRequiredSourcesQName()) {
 545                 if (!qname.getLocalName().equals(identifier.getName())) {
 546                     continue;
 547                 }
 548
 549                 final String rev = getNullableRev(identifier);
 550                 if (rev == null) {
 551                     if (qname.getRevision() == null) {
 552                         return qname;
 553                     }
 554                 } else if (qname.getFormattedRevision().equals(rev)) {
 555                     return qname;
 556                 }
 557             }
 558             LOG.warn("Unable to map identifier to a devices reported capability: {} Available: {}",identifier, deviceSources.getRequiredSourcesQName());
 559             // return null since we cannot find the QName, this capability will be removed from required sources and not reported as unresolved-capability
 560             return null;
 561         }
 562
 563         private String getNullableRev(final SourceIdentifier identifier) {
 564             final String rev = identifier.getRevision();
 565             return rev == null || SourceIdentifier.NOT_PRESENT_FORMATTED_REVISION.equals(rev) ? null : rev;
 566         }
 567     }
 568 }