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 javax.annotation.concurrent.GuardedBy;
  32 import org.opendaylight.controller.md.sal.dom.api.DOMNotification;
  33 import org.opendaylight.controller.md.sal.dom.api.DOMRpcException;
  34 import org.opendaylight.controller.md.sal.dom.api.DOMRpcResult;
  35 import org.opendaylight.controller.md.sal.dom.api.DOMRpcService;
  36 import org.opendaylight.netconf.api.NetconfMessage;
  37 import org.opendaylight.netconf.sal.connect.api.MessageTransformer;
  38 import org.opendaylight.netconf.sal.connect.api.NetconfDeviceSchemas;
  39 import org.opendaylight.netconf.sal.connect.api.NetconfDeviceSchemasResolver;
  40 import org.opendaylight.netconf.sal.connect.api.RemoteDevice;
  41 import org.opendaylight.netconf.sal.connect.api.RemoteDeviceCommunicator;
  42 import org.opendaylight.netconf.sal.connect.api.RemoteDeviceHandler;
  43 import org.opendaylight.netconf.sal.connect.netconf.listener.NetconfDeviceCapabilities;
  44 import org.opendaylight.netconf.sal.connect.netconf.listener.NetconfDeviceCommunicator;
  45 import org.opendaylight.netconf.sal.connect.netconf.listener.NetconfSessionPreferences;
  46 import org.opendaylight.netconf.sal.connect.netconf.sal.NetconfDeviceRpc;
  47 import org.opendaylight.netconf.sal.connect.netconf.schema.NetconfRemoteSchemaYangSourceProvider;
  48 import org.opendaylight.netconf.sal.connect.netconf.schema.YangLibrarySchemaYangSourceProvider;
  49 import org.opendaylight.netconf.sal.connect.netconf.schema.mapping.BaseSchema;
  50 import org.opendaylight.netconf.sal.connect.netconf.schema.mapping.NetconfMessageTransformer;
  51 import org.opendaylight.netconf.sal.connect.netconf.util.NetconfMessageTransformUtil;
  52 import org.opendaylight.netconf.sal.connect.util.RemoteDeviceId;
  53 import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.netconf.notifications.rev120206.NetconfCapabilityChange;
  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
  79         implements RemoteDevice<NetconfSessionPreferences, NetconfMessage, NetconfDeviceCommunicator> {
  80
  81     private static final Logger LOG = LoggerFactory.getLogger(NetconfDevice.class);
  82
  83     public static final Function<QName, SourceIdentifier> QNAME_TO_SOURCE_ID_FUNCTION =
  84         input -> RevisionSourceIdentifier.create(input.getLocalName(),
  85                     Optional.fromNullable(input.getFormattedRevision()));
  86
  87     protected final RemoteDeviceId id;
  88     private final boolean reconnectOnSchemasChange;
  89
  90     protected final SchemaContextFactory schemaContextFactory;
  91     private final RemoteDeviceHandler<NetconfSessionPreferences> salFacade;
  92     private final ListeningExecutorService processingExecutor;
  93     protected final SchemaSourceRegistry schemaRegistry;
  94     protected final SchemaRepository schemaRepository;
  95     private final NetconfDeviceSchemasResolver stateSchemasResolver;
  96     private final NotificationHandler notificationHandler;
  97     protected final List<SchemaSourceRegistration<? extends SchemaSourceRepresentation>> sourceRegistrations =
  98             Lists.newArrayList();
  99     @GuardedBy("this")
 100     private boolean connected = false;
 101
 102     // Message transformer is constructed once the schemas are available
 103     private MessageTransformer<NetconfMessage> messageTransformer;
 104
 105     /**
 106      * Create rpc implementation capable of handling RPC for monitoring and notifications
 107      * even before the schemas of remote device are downloaded.
 108      */
 109     static NetconfDeviceRpc getRpcForInitialization(final NetconfDeviceCommunicator listener,
 110                                                     final boolean notificationSupport) {
 111         final BaseSchema baseSchema = notificationSupport
 112                 ? BaseSchema.BASE_NETCONF_CTX_WITH_NOTIFICATIONS
 113                 : BaseSchema.BASE_NETCONF_CTX;
 114
 115         return new NetconfDeviceRpc(baseSchema.getSchemaContext(), listener,
 116                 new NetconfMessageTransformer(baseSchema.getSchemaContext(), false, baseSchema));
 117     }
 118
 119     public NetconfDevice(final SchemaResourcesDTO schemaResourcesDTO, final RemoteDeviceId id,
 120                          final RemoteDeviceHandler<NetconfSessionPreferences> salFacade,
 121                          final ExecutorService globalProcessingExecutor, final boolean reconnectOnSchemasChange) {
 122         this.id = id;
 123         this.reconnectOnSchemasChange = reconnectOnSchemasChange;
 124         this.schemaRegistry = schemaResourcesDTO.getSchemaRegistry();
 125         this.schemaRepository = schemaResourcesDTO.getSchemaRepository();
 126         this.schemaContextFactory = schemaResourcesDTO.getSchemaContextFactory();
 127         this.salFacade = salFacade;
 128         this.stateSchemasResolver = schemaResourcesDTO.getStateSchemasResolver();
 129         this.processingExecutor = MoreExecutors.listeningDecorator(globalProcessingExecutor);
 130         this.notificationHandler = new NotificationHandler(salFacade, id);
 131     }
 132
 133     @Override
 134     public void onRemoteSessionUp(final NetconfSessionPreferences remoteSessionCapabilities,
 135                                   final NetconfDeviceCommunicator listener) {
 136         // SchemaContext setup has to be performed in a dedicated thread since
 137         // we are in a netty thread in this method
 138         // Yang models are being downloaded in this method and it would cause a
 139         // deadlock if we used the netty thread
 140         // http://netty.io/wiki/thread-model.html
 141         setConnected(true);
 142         LOG.debug("{}: Session to remote device established with {}", id, remoteSessionCapabilities);
 143
 144         final NetconfDeviceRpc initRpc =
 145                 getRpcForInitialization(listener, remoteSessionCapabilities.isNotificationsSupported());
 146         final DeviceSourcesResolver task =
 147                 new DeviceSourcesResolver(remoteSessionCapabilities, id, stateSchemasResolver, initRpc);
 148         final ListenableFuture<DeviceSources> sourceResolverFuture = processingExecutor.submit(task);
 149
 150         if (shouldListenOnSchemaChange(remoteSessionCapabilities)) {
 151             registerToBaseNetconfStream(initRpc, listener);
 152         }
 153
 154         final FutureCallback<DeviceSources> resolvedSourceCallback = new FutureCallback<DeviceSources>() {
 155             @Override
 156             public void onSuccess(final DeviceSources result) {
 157                 addProvidedSourcesToSchemaRegistry(result);
 158                 setUpSchema(result);
 159             }
 160
 161             private void setUpSchema(final DeviceSources result) {
 162                 processingExecutor.submit(new SchemaSetup(result, remoteSessionCapabilities, listener));
 163             }
 164
 165             @Override
 166             public void onFailure(final Throwable throwable) {
 167                 LOG.warn("{}: Unexpected error resolving device sources: {}", id, throwable);
 168                 handleSalInitializationFailure(throwable, listener);
 169             }
 170         };
 171
 172         Futures.addCallback(sourceResolverFuture, resolvedSourceCallback);
 173     }
 174
 175     private void registerToBaseNetconfStream(final NetconfDeviceRpc deviceRpc,
 176                                              final NetconfDeviceCommunicator listener) {
 177         // TODO check whether the model describing create subscription is present in schema
 178         // Perhaps add a default schema context to support create-subscription if the model was not provided
 179         // (same as what we do for base netconf operations in transformer)
 180         final CheckedFuture<DOMRpcResult, DOMRpcException> rpcResultListenableFuture = deviceRpc.invokeRpc(
 181                 NetconfMessageTransformUtil.toPath(NetconfMessageTransformUtil.CREATE_SUBSCRIPTION_RPC_QNAME),
 182                 NetconfMessageTransformUtil.CREATE_SUBSCRIPTION_RPC_CONTENT);
 183
 184         final NotificationHandler.NotificationFilter filter = new NotificationHandler.NotificationFilter() {
 185             @Override
 186             public Optional<DOMNotification> filterNotification(final DOMNotification notification) {
 187                 if (isCapabilityChanged(notification)) {
 188                     LOG.info("{}: Schemas change detected, reconnecting", id);
 189                     // Only disconnect is enough,
 190                     // the reconnecting nature of the connector will take care of reconnecting
 191                     listener.disconnect();
 192                     return Optional.absent();
 193                 }
 194                 return Optional.of(notification);
 195             }
 196
 197             private boolean isCapabilityChanged(final DOMNotification notification) {
 198                 return notification.getBody().getNodeType().equals(NetconfCapabilityChange.QNAME);
 199             }
 200         };
 201
 202         Futures.addCallback(rpcResultListenableFuture, new FutureCallback<DOMRpcResult>() {
 203             @Override
 204             public void onSuccess(final DOMRpcResult domRpcResult) {
 205                 notificationHandler.addNotificationFilter(filter);
 206             }
 207
 208             @Override
 209             public void onFailure(final Throwable throwable) {
 210                 LOG.warn("Unable to subscribe to base notification stream. Schemas will not be reloaded on the fly",
 211                         throwable);
 212             }
 213         });
 214     }
 215
 216     private boolean shouldListenOnSchemaChange(final NetconfSessionPreferences remoteSessionCapabilities) {
 217         return remoteSessionCapabilities.isNotificationsSupported() && reconnectOnSchemasChange;
 218     }
 219
 220     private synchronized void handleSalInitializationSuccess(final SchemaContext result,
 221                                         final NetconfSessionPreferences remoteSessionCapabilities,
 222                                         final DOMRpcService deviceRpc) {
 223         //NetconfDevice.SchemaSetup can complete after NetconfDeviceCommunicator was closed. In that case do nothing,
 224         //since salFacade.onDeviceDisconnected was already called.
 225         if (connected) {
 226             final BaseSchema baseSchema =
 227                 remoteSessionCapabilities.isNotificationsSupported()
 228                         ? BaseSchema.BASE_NETCONF_CTX_WITH_NOTIFICATIONS : BaseSchema.BASE_NETCONF_CTX;
 229             messageTransformer = new NetconfMessageTransformer(result, true, baseSchema);
 230
 231             updateTransformer(messageTransformer);
 232             // salFacade.onDeviceConnected has to be called before the notification handler is initialized
 233             salFacade.onDeviceConnected(result, remoteSessionCapabilities, deviceRpc);
 234             notificationHandler.onRemoteSchemaUp(messageTransformer);
 235
 236             LOG.info("{}: Netconf connector initialized successfully", id);
 237         } else {
 238             LOG.warn("{}: Device communicator was closed before schema setup finished.", id);
 239         }
 240     }
 241
 242     private void handleSalInitializationFailure(final Throwable throwable,
 243                                                 final RemoteDeviceCommunicator<NetconfMessage> listener) {
 244         LOG.error("{}: Initialization in sal failed, disconnecting from device", id, throwable);
 245         listener.close();
 246         onRemoteSessionDown();
 247         resetMessageTransformer();
 248     }
 249
 250     /**
 251      * Set the transformer to null as is in initial state.
 252      */
 253     private void resetMessageTransformer() {
 254         updateTransformer(null);
 255     }
 256
 257     private void updateTransformer(final MessageTransformer<NetconfMessage> transformer) {
 258         messageTransformer = transformer;
 259     }
 260
 261     private synchronized void setConnected(final boolean connected) {
 262         this.connected = connected;
 263     }
 264
 265     private void addProvidedSourcesToSchemaRegistry(final DeviceSources deviceSources) {
 266         final SchemaSourceProvider<YangTextSchemaSource> yangProvider = deviceSources.getSourceProvider();
 267         for (final SourceIdentifier sourceId : deviceSources.getProvidedSources()) {
 268             sourceRegistrations.add(schemaRegistry.registerSchemaSource(yangProvider,
 269                     PotentialSchemaSource.create(
 270                             sourceId, YangTextSchemaSource.class, PotentialSchemaSource.Costs.REMOTE_IO.getValue())));
 271         }
 272     }
 273
 274     @Override
 275     public void onRemoteSessionDown() {
 276         setConnected(false);
 277         notificationHandler.onRemoteSchemaDown();
 278
 279         salFacade.onDeviceDisconnected();
 280         for (final SchemaSourceRegistration<? extends SchemaSourceRepresentation> sourceRegistration
 281                 : sourceRegistrations) {
 282             sourceRegistration.close();
 283         }
 284         resetMessageTransformer();
 285     }
 286
 287     @Override
 288     public void onRemoteSessionFailed(final Throwable throwable) {
 289         setConnected(false);
 290         salFacade.onDeviceFailed(throwable);
 291     }
 292
 293     @Override
 294     public void onNotification(final NetconfMessage notification) {
 295         notificationHandler.handleNotification(notification);
 296     }
 297
 298     /**
 299      * Just a transfer object containing schema related dependencies. Injected in constructor.
 300      */
 301     public static class SchemaResourcesDTO {
 302         private final SchemaSourceRegistry schemaRegistry;
 303         private final SchemaRepository schemaRepository;
 304         private final SchemaContextFactory schemaContextFactory;
 305         private final NetconfDeviceSchemasResolver stateSchemasResolver;
 306
 307         public SchemaResourcesDTO(final SchemaSourceRegistry schemaRegistry,
 308                                   final SchemaRepository schemaRepository,
 309                                   final SchemaContextFactory schemaContextFactory,
 310                                   final NetconfDeviceSchemasResolver deviceSchemasResolver) {
 311             this.schemaRegistry = Preconditions.checkNotNull(schemaRegistry);
 312             this.schemaRepository = Preconditions.checkNotNull(schemaRepository);
 313             this.schemaContextFactory = Preconditions.checkNotNull(schemaContextFactory);
 314             this.stateSchemasResolver = Preconditions.checkNotNull(deviceSchemasResolver);
 315         }
 316
 317         public SchemaSourceRegistry getSchemaRegistry() {
 318             return schemaRegistry;
 319         }
 320
 321         public SchemaRepository getSchemaRepository() {
 322             return schemaRepository;
 323         }
 324
 325         public SchemaContextFactory getSchemaContextFactory() {
 326             return schemaContextFactory;
 327         }
 328
 329         public NetconfDeviceSchemasResolver getStateSchemasResolver() {
 330             return stateSchemasResolver;
 331         }
 332     }
 333
 334     /**
 335      * Schema building callable.
 336      */
 337     private static class DeviceSourcesResolver implements Callable<DeviceSources> {
 338
 339         private final NetconfDeviceRpc deviceRpc;
 340         private final NetconfSessionPreferences remoteSessionCapabilities;
 341         private final RemoteDeviceId id;
 342         private final NetconfDeviceSchemasResolver stateSchemasResolver;
 343
 344         DeviceSourcesResolver(final NetconfDeviceRpc deviceRpc,
 345                               final NetconfSessionPreferences remoteSessionCapabilities,
 346                               final RemoteDeviceId id, final NetconfDeviceSchemasResolver stateSchemasResolver) {
 347             this.deviceRpc = deviceRpc;
 348             this.remoteSessionCapabilities = remoteSessionCapabilities;
 349             this.id = id;
 350             this.stateSchemasResolver = stateSchemasResolver;
 351         }
 352
 353         DeviceSourcesResolver(final NetconfSessionPreferences remoteSessionCapabilities, final RemoteDeviceId id,
 354                                      final NetconfDeviceSchemasResolver stateSchemasResolver,
 355                                      final NetconfDeviceRpc rpcForMonitoring) {
 356             this(rpcForMonitoring, remoteSessionCapabilities, id, stateSchemasResolver);
 357         }
 358
 359         @Override
 360         public DeviceSources call() throws Exception {
 361             final NetconfDeviceSchemas availableSchemas =
 362                     stateSchemasResolver.resolve(deviceRpc, remoteSessionCapabilities, id);
 363             LOG.debug("{}: Schemas exposed by ietf-netconf-monitoring: {}", id,
 364                     availableSchemas.getAvailableYangSchemasQNames());
 365
 366             final Set<QName> requiredSources = Sets.newHashSet(remoteSessionCapabilities.getModuleBasedCaps());
 367             final Set<QName> providedSources = availableSchemas.getAvailableYangSchemasQNames();
 368
 369             final Set<QName> requiredSourcesNotProvided = Sets.difference(requiredSources, providedSources);
 370             if (!requiredSourcesNotProvided.isEmpty()) {
 371                 LOG.warn("{}: Netconf device does not provide all yang models reported in hello message capabilities,"
 372                         + " required but not provided: {}", id, requiredSourcesNotProvided);
 373                 LOG.warn("{}: Attempting to build schema context from required sources", id);
 374             }
 375
 376             // Here all the sources reported in netconf monitoring are merged with those reported in hello.
 377             // It is necessary to perform this since submodules are not mentioned in hello but still required.
 378             // This clashes with the option of a user to specify supported yang models manually in configuration
 379             // for netconf-connector and as a result one is not able to fully override yang models of a device.
 380             // It is only possible to add additional models.
 381             final Set<QName> providedSourcesNotRequired = Sets.difference(providedSources, requiredSources);
 382             if (!providedSourcesNotRequired.isEmpty()) {
 383                 LOG.warn("{}: Netconf device provides additional yang models not reported in "
 384                         + "hello message capabilities: {}", id, providedSourcesNotRequired);
 385                 LOG.warn("{}: Adding provided but not required sources as required to prevent failures", id);
 386                 LOG.debug("{}: Netconf device reported in hello: {}", id, requiredSources);
 387                 requiredSources.addAll(providedSourcesNotRequired);
 388             }
 389
 390             final SchemaSourceProvider<YangTextSchemaSource> sourceProvider;
 391             if (availableSchemas instanceof LibraryModulesSchemas) {
 392                 sourceProvider = new YangLibrarySchemaYangSourceProvider(id,
 393                         ((LibraryModulesSchemas) availableSchemas).getAvailableModels());
 394             } else {
 395                 sourceProvider = new NetconfRemoteSchemaYangSourceProvider(id, deviceRpc);
 396             }
 397
 398             return new DeviceSources(requiredSources, providedSources, sourceProvider);
 399         }
 400     }
 401
 402     /**
 403      * Contains RequiredSources - sources from capabilities.
 404      */
 405     private static final class DeviceSources {
 406         private final Set<QName> requiredSources;
 407         private final Set<QName> providedSources;
 408         private final SchemaSourceProvider<YangTextSchemaSource> sourceProvider;
 409
 410         DeviceSources(final Set<QName> requiredSources, final Set<QName> providedSources,
 411                              final SchemaSourceProvider<YangTextSchemaSource> sourceProvider) {
 412             this.requiredSources = requiredSources;
 413             this.providedSources = providedSources;
 414             this.sourceProvider = sourceProvider;
 415         }
 416
 417         public Set<QName> getRequiredSourcesQName() {
 418             return requiredSources;
 419         }
 420
 421         public Set<QName> getProvidedSourcesQName() {
 422             return providedSources;
 423         }
 424
 425         public Collection<SourceIdentifier> getRequiredSources() {
 426             return Collections2.transform(requiredSources, QNAME_TO_SOURCE_ID_FUNCTION);
 427         }
 428
 429         public Collection<SourceIdentifier> getProvidedSources() {
 430             return Collections2.transform(providedSources, QNAME_TO_SOURCE_ID_FUNCTION);
 431         }
 432
 433         public SchemaSourceProvider<YangTextSchemaSource> getSourceProvider() {
 434             return sourceProvider;
 435         }
 436     }
 437
 438     /**
 439      * Schema builder that tries to build schema context from provided sources or biggest subset of it.
 440      */
 441     private final class SchemaSetup implements Runnable {
 442         private final DeviceSources deviceSources;
 443         private final NetconfSessionPreferences remoteSessionCapabilities;
 444         private final RemoteDeviceCommunicator<NetconfMessage> listener;
 445         private final NetconfDeviceCapabilities capabilities;
 446
 447         SchemaSetup(final DeviceSources deviceSources, final NetconfSessionPreferences remoteSessionCapabilities,
 448                            final RemoteDeviceCommunicator<NetconfMessage> listener) {
 449             this.deviceSources = deviceSources;
 450             this.remoteSessionCapabilities = remoteSessionCapabilities;
 451             this.listener = listener;
 452             this.capabilities = remoteSessionCapabilities.getNetconfDeviceCapabilities();
 453         }
 454
 455         @Override
 456         public void run() {
 457
 458             final Collection<SourceIdentifier> requiredSources = deviceSources.getRequiredSources();
 459             final Collection<SourceIdentifier> missingSources = filterMissingSources(requiredSources);
 460
 461             capabilities.addUnresolvedCapabilities(getQNameFromSourceIdentifiers(missingSources),
 462                     UnavailableCapability.FailureReason.MissingSource);
 463
 464             requiredSources.removeAll(missingSources);
 465             setUpSchema(requiredSources);
 466         }
 467
 468         private Collection<SourceIdentifier> filterMissingSources(final Collection<SourceIdentifier> requiredSources) {
 469
 470             return requiredSources.parallelStream().filter(sourceIdentifier -> {
 471                 boolean remove = false;
 472                 try {
 473                     schemaRepository.getSchemaSource(sourceIdentifier, ASTSchemaSource.class).checkedGet();
 474                 } catch (SchemaSourceException e) {
 475                     remove = true;
 476                 }
 477                 return remove;
 478             }).collect(Collectors.toList());
 479         }
 480
 481         /**
 482          * Build schema context, in case of success or final failure notify device.
 483          */
 484         @SuppressWarnings("checkstyle:IllegalCatch")
 485         private void setUpSchema(Collection<SourceIdentifier> requiredSources) {
 486             while (!requiredSources.isEmpty()) {
 487                 LOG.trace("{}: Trying to build schema context from {}", id, requiredSources);
 488                 try {
 489                     final CheckedFuture<SchemaContext, SchemaResolutionException> schemaBuilderFuture =
 490                             schemaContextFactory.createSchemaContext(requiredSources);
 491                     final SchemaContext result = schemaBuilderFuture.checkedGet();
 492                     LOG.debug("{}: Schema context built successfully from {}", id, requiredSources);
 493                     final Collection<QName> filteredQNames = Sets.difference(deviceSources.getRequiredSourcesQName(),
 494                             capabilities.getUnresolvedCapabilites().keySet());
 495                     capabilities.addCapabilities(filteredQNames.stream().map(entry -> new AvailableCapabilityBuilder()
 496                             .setCapability(entry.toString()).setCapabilityOrigin(
 497                                     remoteSessionCapabilities.getModuleBasedCapsOrigin().get(entry)).build())
 498                             .collect(Collectors.toList()));
 499
 500                     capabilities.addNonModuleBasedCapabilities(remoteSessionCapabilities
 501                             .getNonModuleCaps().stream().map(entry -> new AvailableCapabilityBuilder()
 502                             .setCapability(entry).setCapabilityOrigin(
 503                                             remoteSessionCapabilities.getNonModuleBasedCapsOrigin().get(entry)).build())
 504                             .collect(Collectors.toList()));
 505
 506                     handleSalInitializationSuccess(result, remoteSessionCapabilities, getDeviceSpecificRpc(result));
 507                     return;
 508                 } catch (final Throwable t) {
 509                     if (t instanceof MissingSchemaSourceException) {
 510                         requiredSources =
 511                                 handleMissingSchemaSourceException(requiredSources, (MissingSchemaSourceException) t);
 512                     } else if (t instanceof SchemaResolutionException) {
 513                         // schemaBuilderFuture.checkedGet() throws only SchemaResolutionException
 514                         // that might be wrapping a MissingSchemaSourceException so we need to look
 515                         // at the cause of the exception to make sure we don't misinterpret it.
 516                         if (t.getCause() instanceof MissingSchemaSourceException) {
 517                             requiredSources = handleMissingSchemaSourceException(
 518                                     requiredSources, (MissingSchemaSourceException) t.getCause());
 519                             continue;
 520                         }
 521                         requiredSources =
 522                                 handleSchemaResolutionException(requiredSources, (SchemaResolutionException) t);
 523                     } else {
 524                         // unknown error, fail
 525                         handleSalInitializationFailure(t, listener);
 526                         return;
 527                     }
 528                 }
 529             }
 530             // No more sources, fail
 531             final IllegalStateException cause = new IllegalStateException(id + ": No more sources for schema context");
 532             handleSalInitializationFailure(cause, listener);
 533             salFacade.onDeviceFailed(cause);
 534         }
 535
 536         private Collection<SourceIdentifier> handleMissingSchemaSourceException(
 537                 final Collection<SourceIdentifier> requiredSources, final MissingSchemaSourceException exception) {
 538             // In case source missing, try without it
 539             final SourceIdentifier missingSource = exception.getSourceId();
 540             LOG.warn("{}: Unable to build schema context, missing source {}, will reattempt without it", id,
 541                     missingSource);
 542             LOG.debug("{}: Unable to build schema context, missing source {}, will reattempt without it",
 543                     exception);
 544             final Collection<QName> qNameOfMissingSource =
 545                     getQNameFromSourceIdentifiers(Sets.newHashSet(missingSource));
 546             if (!qNameOfMissingSource.isEmpty()) {
 547                 capabilities.addUnresolvedCapabilities(
 548                         qNameOfMissingSource, UnavailableCapability.FailureReason.MissingSource);
 549             }
 550             return stripUnavailableSource(requiredSources, missingSource);
 551         }
 552
 553         private Collection<SourceIdentifier> handleSchemaResolutionException(
 554             final Collection<SourceIdentifier> requiredSources, final SchemaResolutionException resolutionException) {
 555             // In case resolution error, try only with resolved sources
 556             // There are two options why schema resolution exception occurred : unsatisfied imports or flawed model
 557             // FIXME Do we really have assurance that these two cases cannot happen at once?
 558             if (resolutionException.getFailedSource() != null) {
 559                 // flawed model - exclude it
 560                 final SourceIdentifier failedSourceId = resolutionException.getFailedSource();
 561                 LOG.warn("{}: Unable to build schema context, failed to resolve source {}, will reattempt without it",
 562                         id, failedSourceId);
 563                 LOG.warn("{}: Unable to build schema context, failed to resolve source {}, will reattempt without it",
 564                         id, resolutionException);
 565                 capabilities.addUnresolvedCapabilities(getQNameFromSourceIdentifiers(
 566                         Collections.singleton(failedSourceId)), UnavailableCapability.FailureReason.UnableToResolve);
 567                 return stripUnavailableSource(requiredSources, resolutionException.getFailedSource());
 568             }
 569             // unsatisfied imports
 570             final Set<SourceIdentifier> unresolvedSources = resolutionException.getUnsatisfiedImports().keySet();
 571             capabilities.addUnresolvedCapabilities(
 572                 getQNameFromSourceIdentifiers(unresolvedSources), UnavailableCapability.FailureReason.UnableToResolve);
 573             LOG.warn("{}: Unable to build schema context, unsatisfied imports {}, will reattempt with resolved only",
 574                     id, resolutionException.getUnsatisfiedImports());
 575             LOG.debug("{}: Unable to build schema context, unsatisfied imports {}, will reattempt with resolved only",
 576                     resolutionException);
 577             return resolutionException.getResolvedSources();
 578         }
 579
 580         protected NetconfDeviceRpc getDeviceSpecificRpc(final SchemaContext result) {
 581             return new NetconfDeviceRpc(result, listener, new NetconfMessageTransformer(result, true));
 582         }
 583
 584         private Collection<SourceIdentifier> stripUnavailableSource(final Collection<SourceIdentifier> requiredSources,
 585                                                                     final SourceIdentifier sourceIdToRemove) {
 586             final LinkedList<SourceIdentifier> sourceIdentifiers = Lists.newLinkedList(requiredSources);
 587             final boolean removed = sourceIdentifiers.remove(sourceIdToRemove);
 588             Preconditions.checkState(
 589                     removed, "{}: Trying to remove {} from {} failed", id, sourceIdToRemove, requiredSources);
 590             return sourceIdentifiers;
 591         }
 592
 593         private Collection<QName> getQNameFromSourceIdentifiers(final Collection<SourceIdentifier> identifiers) {
 594             final Collection<QName> qNames = Collections2.transform(identifiers, this::getQNameFromSourceIdentifier);
 595
 596             if (qNames.isEmpty()) {
 597                 LOG.debug("{}: Unable to map any source identifiers to a capability reported by device : {}", id,
 598                         identifiers);
 599             }
 600             return Collections2.filter(qNames, Predicates.notNull());
 601         }
 602
 603         private QName getQNameFromSourceIdentifier(final SourceIdentifier identifier) {
 604             // Required sources are all required and provided merged in DeviceSourcesResolver
 605             for (final QName qname : deviceSources.getRequiredSourcesQName()) {
 606                 if (!qname.getLocalName().equals(identifier.getName())) {
 607                     continue;
 608                 }
 609
 610                 final String rev = getNullableRev(identifier);
 611                 if (rev == null) {
 612                     if (qname.getRevision() == null) {
 613                         return qname;
 614                     }
 615                 } else if (qname.getFormattedRevision().equals(rev)) {
 616                     return qname;
 617                 }
 618             }
 619             LOG.warn("Unable to map identifier to a devices reported capability: {} Available: {}",identifier,
 620                     deviceSources.getRequiredSourcesQName());
 621             // return null since we cannot find the QName,
 622             // this capability will be removed from required sources and not reported as unresolved-capability
 623             return null;
 624         }
 625
 626         private String getNullableRev(final SourceIdentifier identifier) {
 627             final String rev = identifier.getRevision();
 628             return rev == null || SourceIdentifier.NOT_PRESENT_FORMATTED_REVISION.equals(rev) ? null : rev;
 629         }
 630     }
 631 }