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 static java.util.Objects.requireNonNull;
  11
  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.FluentFuture;
  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.ArrayList;
  24 import java.util.Collection;
  25 import java.util.Collections;
  26 import java.util.LinkedList;
  27 import java.util.List;
  28 import java.util.Optional;
  29 import java.util.Set;
  30 import java.util.concurrent.Callable;
  31 import java.util.concurrent.ExecutionException;
  32 import java.util.stream.Collectors;
  33 import javax.annotation.Nonnull;
  34 import javax.annotation.concurrent.GuardedBy;
  35 import org.opendaylight.mdsal.dom.api.DOMNotification;
  36 import org.opendaylight.mdsal.dom.api.DOMRpcResult;
  37 import org.opendaylight.mdsal.dom.api.DOMRpcService;
  38 import org.opendaylight.netconf.api.NetconfMessage;
  39 import org.opendaylight.netconf.sal.connect.api.DeviceActionFactory;
  40 import org.opendaylight.netconf.sal.connect.api.MessageTransformer;
  41 import org.opendaylight.netconf.sal.connect.api.NetconfDeviceSchemas;
  42 import org.opendaylight.netconf.sal.connect.api.NetconfDeviceSchemasResolver;
  43 import org.opendaylight.netconf.sal.connect.api.RemoteDevice;
  44 import org.opendaylight.netconf.sal.connect.api.RemoteDeviceCommunicator;
  45 import org.opendaylight.netconf.sal.connect.api.RemoteDeviceHandler;
  46 import org.opendaylight.netconf.sal.connect.netconf.listener.NetconfDeviceCapabilities;
  47 import org.opendaylight.netconf.sal.connect.netconf.listener.NetconfDeviceCommunicator;
  48 import org.opendaylight.netconf.sal.connect.netconf.listener.NetconfSessionPreferences;
  49 import org.opendaylight.netconf.sal.connect.netconf.sal.NetconfDeviceRpc;
  50 import org.opendaylight.netconf.sal.connect.netconf.schema.NetconfRemoteSchemaYangSourceProvider;
  51 import org.opendaylight.netconf.sal.connect.netconf.schema.YangLibrarySchemaYangSourceProvider;
  52 import org.opendaylight.netconf.sal.connect.netconf.schema.mapping.BaseSchema;
  53 import org.opendaylight.netconf.sal.connect.netconf.schema.mapping.NetconfMessageTransformer;
  54 import org.opendaylight.netconf.sal.connect.netconf.util.NetconfMessageTransformUtil;
  55 import org.opendaylight.netconf.sal.connect.util.RemoteDeviceId;
  56 import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.netconf.notifications.rev120206.NetconfCapabilityChange;
  57 import org.opendaylight.yang.gen.v1.urn.opendaylight.netconf.node.topology.rev150114.netconf.node.connection.status.available.capabilities.AvailableCapabilityBuilder;
  58 import org.opendaylight.yang.gen.v1.urn.opendaylight.netconf.node.topology.rev150114.netconf.node.connection.status.unavailable.capabilities.UnavailableCapability;
  59 import org.opendaylight.yangtools.yang.common.QName;
  60 import org.opendaylight.yangtools.yang.model.api.SchemaContext;
  61 import org.opendaylight.yangtools.yang.model.repo.api.MissingSchemaSourceException;
  62 import org.opendaylight.yangtools.yang.model.repo.api.RevisionSourceIdentifier;
  63 import org.opendaylight.yangtools.yang.model.repo.api.SchemaContextFactory;
  64 import org.opendaylight.yangtools.yang.model.repo.api.SchemaRepository;
  65 import org.opendaylight.yangtools.yang.model.repo.api.SchemaResolutionException;
  66 import org.opendaylight.yangtools.yang.model.repo.api.SchemaSourceRepresentation;
  67 import org.opendaylight.yangtools.yang.model.repo.api.SourceIdentifier;
  68 import org.opendaylight.yangtools.yang.model.repo.api.YangTextSchemaSource;
  69 import org.opendaylight.yangtools.yang.model.repo.spi.PotentialSchemaSource;
  70 import org.opendaylight.yangtools.yang.model.repo.spi.SchemaSourceProvider;
  71 import org.opendaylight.yangtools.yang.model.repo.spi.SchemaSourceRegistration;
  72 import org.opendaylight.yangtools.yang.model.repo.spi.SchemaSourceRegistry;
  73 import org.slf4j.Logger;
  74 import org.slf4j.LoggerFactory;
  75
  76 /**
  77  *  This is a mediator between NetconfDeviceCommunicator and NetconfDeviceSalFacade.
  78  */
  79 public class NetconfDevice
  80         implements RemoteDevice<NetconfSessionPreferences, NetconfMessage, NetconfDeviceCommunicator> {
  81
  82     private static final Logger LOG = LoggerFactory.getLogger(NetconfDevice.class);
  83
  84     protected final RemoteDeviceId id;
  85     protected final SchemaContextFactory schemaContextFactory;
  86     protected final SchemaSourceRegistry schemaRegistry;
  87     protected final SchemaRepository schemaRepository;
  88
  89     protected final List<SchemaSourceRegistration<? extends SchemaSourceRepresentation>> sourceRegistrations =
  90             new ArrayList<>();
  91
  92     private final RemoteDeviceHandler<NetconfSessionPreferences> salFacade;
  93     private final ListeningExecutorService processingExecutor;
  94     private final DeviceActionFactory deviceActionFactory;
  95     private final NetconfDeviceSchemasResolver stateSchemasResolver;
  96     private final NotificationHandler notificationHandler;
  97     private final boolean reconnectOnSchemasChange;
  98
  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 ListeningExecutorService globalProcessingExecutor,
 122                          final boolean reconnectOnSchemasChange) {
 123         this(schemaResourcesDTO, id, salFacade, globalProcessingExecutor, reconnectOnSchemasChange, null);
 124     }
 125
 126     public NetconfDevice(final SchemaResourcesDTO schemaResourcesDTO, final RemoteDeviceId id,
 127             final RemoteDeviceHandler<NetconfSessionPreferences> salFacade,
 128             final ListeningExecutorService globalProcessingExecutor, final boolean reconnectOnSchemasChange,
 129             final DeviceActionFactory deviceActionFactory) {
 130         this.id = id;
 131         this.reconnectOnSchemasChange = reconnectOnSchemasChange;
 132         this.deviceActionFactory = deviceActionFactory;
 133         this.schemaRegistry = schemaResourcesDTO.getSchemaRegistry();
 134         this.schemaRepository = schemaResourcesDTO.getSchemaRepository();
 135         this.schemaContextFactory = schemaResourcesDTO.getSchemaContextFactory();
 136         this.salFacade = salFacade;
 137         this.stateSchemasResolver = schemaResourcesDTO.getStateSchemasResolver();
 138         this.processingExecutor = requireNonNull(globalProcessingExecutor);
 139         this.notificationHandler = new NotificationHandler(salFacade, id);
 140     }
 141
 142     @Override
 143     public void onRemoteSessionUp(final NetconfSessionPreferences remoteSessionCapabilities,
 144                                   final NetconfDeviceCommunicator listener) {
 145         // SchemaContext setup has to be performed in a dedicated thread since
 146         // we are in a netty thread in this method
 147         // Yang models are being downloaded in this method and it would cause a
 148         // deadlock if we used the netty thread
 149         // http://netty.io/wiki/thread-model.html
 150         setConnected(true);
 151         LOG.debug("{}: Session to remote device established with {}", id, remoteSessionCapabilities);
 152
 153         final NetconfDeviceRpc initRpc =
 154                 getRpcForInitialization(listener, remoteSessionCapabilities.isNotificationsSupported());
 155         final DeviceSourcesResolver task =
 156                 new DeviceSourcesResolver(remoteSessionCapabilities, id, stateSchemasResolver, initRpc);
 157         final ListenableFuture<DeviceSources> sourceResolverFuture = processingExecutor.submit(task);
 158
 159         if (shouldListenOnSchemaChange(remoteSessionCapabilities)) {
 160             registerToBaseNetconfStream(initRpc, listener);
 161         }
 162
 163         final FutureCallback<DeviceSources> resolvedSourceCallback = new FutureCallback<DeviceSources>() {
 164             @Override
 165             public void onSuccess(@Nonnull final DeviceSources result) {
 166                 addProvidedSourcesToSchemaRegistry(result);
 167                 setUpSchema(result);
 168             }
 169
 170             private void setUpSchema(final DeviceSources result) {
 171                 processingExecutor.submit(new SchemaSetup(result, remoteSessionCapabilities, listener));
 172             }
 173
 174             @Override
 175             public void onFailure(final Throwable throwable) {
 176                 LOG.warn("{}: Unexpected error resolving device sources", id, throwable);
 177                 handleSalInitializationFailure(throwable, listener);
 178             }
 179         };
 180
 181         Futures.addCallback(sourceResolverFuture, resolvedSourceCallback, MoreExecutors.directExecutor());
 182     }
 183
 184     private void registerToBaseNetconfStream(final NetconfDeviceRpc deviceRpc,
 185                                              final NetconfDeviceCommunicator listener) {
 186         // TODO check whether the model describing create subscription is present in schema
 187         // Perhaps add a default schema context to support create-subscription if the model was not provided
 188         // (same as what we do for base netconf operations in transformer)
 189         final FluentFuture<DOMRpcResult> rpcResultListenableFuture = deviceRpc.invokeRpc(
 190                 NetconfMessageTransformUtil.toPath(NetconfMessageTransformUtil.CREATE_SUBSCRIPTION_RPC_QNAME),
 191                 NetconfMessageTransformUtil.CREATE_SUBSCRIPTION_RPC_CONTENT);
 192
 193         final NotificationHandler.NotificationFilter filter = new NotificationHandler.NotificationFilter() {
 194             @Override
 195             public Optional<DOMNotification> filterNotification(final DOMNotification notification) {
 196                 if (isCapabilityChanged(notification)) {
 197                     LOG.info("{}: Schemas change detected, reconnecting", id);
 198                     // Only disconnect is enough,
 199                     // the reconnecting nature of the connector will take care of reconnecting
 200                     listener.disconnect();
 201                     return Optional.empty();
 202                 }
 203                 return Optional.of(notification);
 204             }
 205
 206             private boolean isCapabilityChanged(final DOMNotification notification) {
 207                 return notification.getBody().getNodeType().equals(NetconfCapabilityChange.QNAME);
 208             }
 209         };
 210
 211         Futures.addCallback(rpcResultListenableFuture, new FutureCallback<DOMRpcResult>() {
 212             @Override
 213             public void onSuccess(final DOMRpcResult domRpcResult) {
 214                 notificationHandler.addNotificationFilter(filter);
 215             }
 216
 217             @Override
 218             public void onFailure(final Throwable throwable) {
 219                 LOG.warn("Unable to subscribe to base notification stream. Schemas will not be reloaded on the fly",
 220                         throwable);
 221             }
 222         }, MoreExecutors.directExecutor());
 223     }
 224
 225     private boolean shouldListenOnSchemaChange(final NetconfSessionPreferences remoteSessionCapabilities) {
 226         return remoteSessionCapabilities.isNotificationsSupported() && reconnectOnSchemasChange;
 227     }
 228
 229     private synchronized void handleSalInitializationSuccess(final SchemaContext result,
 230                                         final NetconfSessionPreferences remoteSessionCapabilities,
 231                                         final DOMRpcService deviceRpc,
 232                                         final RemoteDeviceCommunicator<NetconfMessage> listener) {
 233         //NetconfDevice.SchemaSetup can complete after NetconfDeviceCommunicator was closed. In that case do nothing,
 234         //since salFacade.onDeviceDisconnected was already called.
 235         if (connected) {
 236             final BaseSchema baseSchema =
 237                 remoteSessionCapabilities.isNotificationsSupported()
 238                         ? BaseSchema.BASE_NETCONF_CTX_WITH_NOTIFICATIONS : BaseSchema.BASE_NETCONF_CTX;
 239             this.messageTransformer = new NetconfMessageTransformer(result, true, baseSchema);
 240
 241             updateTransformer(this.messageTransformer);
 242             // salFacade.onDeviceConnected has to be called before the notification handler is initialized
 243             this.salFacade.onDeviceConnected(result, remoteSessionCapabilities, deviceRpc,
 244                     this.deviceActionFactory == null ? null : this.deviceActionFactory.createDeviceAction(
 245                             this.messageTransformer, listener, result));
 246             this.notificationHandler.onRemoteSchemaUp(this.messageTransformer);
 247
 248             LOG.info("{}: Netconf connector initialized successfully", id);
 249         } else {
 250             LOG.warn("{}: Device communicator was closed before schema setup finished.", id);
 251         }
 252     }
 253
 254     private void handleSalInitializationFailure(final Throwable throwable,
 255                                                 final RemoteDeviceCommunicator<NetconfMessage> listener) {
 256         LOG.error("{}: Initialization in sal failed, disconnecting from device", id, throwable);
 257         listener.close();
 258         onRemoteSessionDown();
 259         resetMessageTransformer();
 260     }
 261
 262     /**
 263      * Set the transformer to null as is in initial state.
 264      */
 265     private void resetMessageTransformer() {
 266         updateTransformer(null);
 267     }
 268
 269     private synchronized void updateTransformer(final MessageTransformer<NetconfMessage> transformer) {
 270         messageTransformer = transformer;
 271     }
 272
 273     private synchronized void setConnected(final boolean connected) {
 274         this.connected = connected;
 275     }
 276
 277     private void addProvidedSourcesToSchemaRegistry(final DeviceSources deviceSources) {
 278         final SchemaSourceProvider<YangTextSchemaSource> yangProvider = deviceSources.getSourceProvider();
 279         for (final SourceIdentifier sourceId : deviceSources.getProvidedSources()) {
 280             sourceRegistrations.add(schemaRegistry.registerSchemaSource(yangProvider,
 281                     PotentialSchemaSource.create(
 282                             sourceId, YangTextSchemaSource.class, PotentialSchemaSource.Costs.REMOTE_IO.getValue())));
 283         }
 284     }
 285
 286     @Override
 287     public void onRemoteSessionDown() {
 288         setConnected(false);
 289         notificationHandler.onRemoteSchemaDown();
 290
 291         salFacade.onDeviceDisconnected();
 292         for (final SchemaSourceRegistration<? extends SchemaSourceRepresentation> sourceRegistration
 293                 : sourceRegistrations) {
 294             sourceRegistration.close();
 295         }
 296         resetMessageTransformer();
 297     }
 298
 299     @Override
 300     public void onRemoteSessionFailed(final Throwable throwable) {
 301         setConnected(false);
 302         salFacade.onDeviceFailed(throwable);
 303     }
 304
 305     @Override
 306     public void onNotification(final NetconfMessage notification) {
 307         notificationHandler.handleNotification(notification);
 308     }
 309
 310     /**
 311      * Just a transfer object containing schema related dependencies. Injected in constructor.
 312      */
 313     public static class SchemaResourcesDTO {
 314         private final SchemaSourceRegistry schemaRegistry;
 315         private final SchemaRepository schemaRepository;
 316         private final SchemaContextFactory schemaContextFactory;
 317         private final NetconfDeviceSchemasResolver stateSchemasResolver;
 318
 319         public SchemaResourcesDTO(final SchemaSourceRegistry schemaRegistry,
 320                                   final SchemaRepository schemaRepository,
 321                                   final SchemaContextFactory schemaContextFactory,
 322                                   final NetconfDeviceSchemasResolver deviceSchemasResolver) {
 323             this.schemaRegistry = Preconditions.checkNotNull(schemaRegistry);
 324             this.schemaRepository = Preconditions.checkNotNull(schemaRepository);
 325             this.schemaContextFactory = Preconditions.checkNotNull(schemaContextFactory);
 326             this.stateSchemasResolver = Preconditions.checkNotNull(deviceSchemasResolver);
 327         }
 328
 329         public SchemaSourceRegistry getSchemaRegistry() {
 330             return schemaRegistry;
 331         }
 332
 333         public SchemaRepository getSchemaRepository() {
 334             return schemaRepository;
 335         }
 336
 337         public SchemaContextFactory getSchemaContextFactory() {
 338             return schemaContextFactory;
 339         }
 340
 341         public NetconfDeviceSchemasResolver getStateSchemasResolver() {
 342             return stateSchemasResolver;
 343         }
 344     }
 345
 346     /**
 347      * Schema building callable.
 348      */
 349     private static class DeviceSourcesResolver implements Callable<DeviceSources> {
 350
 351         private final NetconfDeviceRpc deviceRpc;
 352         private final NetconfSessionPreferences remoteSessionCapabilities;
 353         private final RemoteDeviceId id;
 354         private final NetconfDeviceSchemasResolver stateSchemasResolver;
 355
 356         DeviceSourcesResolver(final NetconfDeviceRpc deviceRpc,
 357                               final NetconfSessionPreferences remoteSessionCapabilities,
 358                               final RemoteDeviceId id, final NetconfDeviceSchemasResolver stateSchemasResolver) {
 359             this.deviceRpc = deviceRpc;
 360             this.remoteSessionCapabilities = remoteSessionCapabilities;
 361             this.id = id;
 362             this.stateSchemasResolver = stateSchemasResolver;
 363         }
 364
 365         DeviceSourcesResolver(final NetconfSessionPreferences remoteSessionCapabilities, final RemoteDeviceId id,
 366                                      final NetconfDeviceSchemasResolver stateSchemasResolver,
 367                                      final NetconfDeviceRpc rpcForMonitoring) {
 368             this(rpcForMonitoring, remoteSessionCapabilities, id, stateSchemasResolver);
 369         }
 370
 371         @Override
 372         public DeviceSources call() {
 373             final NetconfDeviceSchemas availableSchemas =
 374                     stateSchemasResolver.resolve(deviceRpc, remoteSessionCapabilities, id);
 375             LOG.debug("{}: Schemas exposed by ietf-netconf-monitoring: {}", id,
 376                     availableSchemas.getAvailableYangSchemasQNames());
 377
 378             final Set<QName> requiredSources = Sets.newHashSet(remoteSessionCapabilities.getModuleBasedCaps());
 379             final Set<QName> providedSources = availableSchemas.getAvailableYangSchemasQNames();
 380
 381             final Set<QName> requiredSourcesNotProvided = Sets.difference(requiredSources, providedSources);
 382             if (!requiredSourcesNotProvided.isEmpty()) {
 383                 LOG.warn("{}: Netconf device does not provide all yang models reported in hello message capabilities,"
 384                         + " required but not provided: {}", id, requiredSourcesNotProvided);
 385                 LOG.warn("{}: Attempting to build schema context from required sources", id);
 386             }
 387
 388             // Here all the sources reported in netconf monitoring are merged with those reported in hello.
 389             // It is necessary to perform this since submodules are not mentioned in hello but still required.
 390             // This clashes with the option of a user to specify supported yang models manually in configuration
 391             // for netconf-connector and as a result one is not able to fully override yang models of a device.
 392             // It is only possible to add additional models.
 393             final Set<QName> providedSourcesNotRequired = Sets.difference(providedSources, requiredSources);
 394             if (!providedSourcesNotRequired.isEmpty()) {
 395                 LOG.warn("{}: Netconf device provides additional yang models not reported in "
 396                         + "hello message capabilities: {}", id, providedSourcesNotRequired);
 397                 LOG.warn("{}: Adding provided but not required sources as required to prevent failures", id);
 398                 LOG.debug("{}: Netconf device reported in hello: {}", id, requiredSources);
 399                 requiredSources.addAll(providedSourcesNotRequired);
 400             }
 401
 402             final SchemaSourceProvider<YangTextSchemaSource> sourceProvider;
 403             if (availableSchemas instanceof LibraryModulesSchemas) {
 404                 sourceProvider = new YangLibrarySchemaYangSourceProvider(id,
 405                         ((LibraryModulesSchemas) availableSchemas).getAvailableModels());
 406             } else {
 407                 sourceProvider = new NetconfRemoteSchemaYangSourceProvider(id, deviceRpc);
 408             }
 409
 410             return new DeviceSources(requiredSources, providedSources, sourceProvider);
 411         }
 412     }
 413
 414     /**
 415      * Contains RequiredSources - sources from capabilities.
 416      */
 417     private static final class DeviceSources {
 418         private final Set<QName> requiredSources;
 419         private final Set<QName> providedSources;
 420         private final SchemaSourceProvider<YangTextSchemaSource> sourceProvider;
 421
 422         DeviceSources(final Set<QName> requiredSources, final Set<QName> providedSources,
 423                              final SchemaSourceProvider<YangTextSchemaSource> sourceProvider) {
 424             this.requiredSources = requiredSources;
 425             this.providedSources = providedSources;
 426             this.sourceProvider = sourceProvider;
 427         }
 428
 429         public Set<QName> getRequiredSourcesQName() {
 430             return requiredSources;
 431         }
 432
 433         public Set<QName> getProvidedSourcesQName() {
 434             return providedSources;
 435         }
 436
 437         public Collection<SourceIdentifier> getRequiredSources() {
 438             return Collections2.transform(requiredSources, DeviceSources::toSourceId);
 439         }
 440
 441         public Collection<SourceIdentifier> getProvidedSources() {
 442             return Collections2.transform(providedSources, DeviceSources::toSourceId);
 443         }
 444
 445         public SchemaSourceProvider<YangTextSchemaSource> getSourceProvider() {
 446             return sourceProvider;
 447         }
 448
 449         private static SourceIdentifier toSourceId(final QName input) {
 450             return RevisionSourceIdentifier.create(input.getLocalName(), input.getRevision());
 451         }
 452     }
 453
 454     /**
 455      * Schema builder that tries to build schema context from provided sources or biggest subset of it.
 456      */
 457     private final class SchemaSetup implements Runnable {
 458         private final DeviceSources deviceSources;
 459         private final NetconfSessionPreferences remoteSessionCapabilities;
 460         private final RemoteDeviceCommunicator<NetconfMessage> listener;
 461         private final NetconfDeviceCapabilities capabilities;
 462
 463         SchemaSetup(final DeviceSources deviceSources, final NetconfSessionPreferences remoteSessionCapabilities,
 464                            final RemoteDeviceCommunicator<NetconfMessage> listener) {
 465             this.deviceSources = deviceSources;
 466             this.remoteSessionCapabilities = remoteSessionCapabilities;
 467             this.listener = listener;
 468             this.capabilities = remoteSessionCapabilities.getNetconfDeviceCapabilities();
 469         }
 470
 471         @Override
 472         public void run() {
 473
 474             final Collection<SourceIdentifier> requiredSources = deviceSources.getRequiredSources();
 475             final Collection<SourceIdentifier> missingSources = filterMissingSources(requiredSources);
 476
 477             capabilities.addUnresolvedCapabilities(getQNameFromSourceIdentifiers(missingSources),
 478                     UnavailableCapability.FailureReason.MissingSource);
 479
 480             requiredSources.removeAll(missingSources);
 481             setUpSchema(requiredSources);
 482         }
 483
 484         private Collection<SourceIdentifier> filterMissingSources(final Collection<SourceIdentifier> requiredSources) {
 485             return requiredSources.parallelStream().filter(sourceIdentifier -> {
 486                 try {
 487                     schemaRepository.getSchemaSource(sourceIdentifier, YangTextSchemaSource.class).get();
 488                     return false;
 489                 } catch (InterruptedException | ExecutionException e) {
 490                     return true;
 491                 }
 492             }).collect(Collectors.toList());
 493         }
 494
 495         /**
 496          * Build schema context, in case of success or final failure notify device.
 497          *
 498          * @param requiredSources required sources
 499          */
 500         @SuppressWarnings("checkstyle:IllegalCatch")
 501         private void setUpSchema(Collection<SourceIdentifier> requiredSources) {
 502             while (!requiredSources.isEmpty()) {
 503                 LOG.trace("{}: Trying to build schema context from {}", id, requiredSources);
 504                 try {
 505                     final ListenableFuture<SchemaContext> schemaBuilderFuture = schemaContextFactory
 506                             .createSchemaContext(requiredSources);
 507                     final SchemaContext result = schemaBuilderFuture.get();
 508                     LOG.debug("{}: Schema context built successfully from {}", id, requiredSources);
 509                     final Collection<QName> filteredQNames = Sets.difference(deviceSources.getRequiredSourcesQName(),
 510                             capabilities.getUnresolvedCapabilites().keySet());
 511                     capabilities.addCapabilities(filteredQNames.stream().map(entry -> new AvailableCapabilityBuilder()
 512                             .setCapability(entry.toString()).setCapabilityOrigin(
 513                                     remoteSessionCapabilities.getModuleBasedCapsOrigin().get(entry)).build())
 514                             .collect(Collectors.toList()));
 515
 516                     capabilities.addNonModuleBasedCapabilities(remoteSessionCapabilities
 517                             .getNonModuleCaps().stream().map(entry -> new AvailableCapabilityBuilder()
 518                                     .setCapability(entry).setCapabilityOrigin(
 519                                             remoteSessionCapabilities.getNonModuleBasedCapsOrigin().get(entry)).build())
 520                             .collect(Collectors.toList()));
 521
 522                     handleSalInitializationSuccess(result, remoteSessionCapabilities, getDeviceSpecificRpc(result),
 523                             listener);
 524                     return;
 525                 } catch (final ExecutionException e) {
 526                     // schemaBuilderFuture.checkedGet() throws only SchemaResolutionException
 527                     // that might be wrapping a MissingSchemaSourceException so we need to look
 528                     // at the cause of the exception to make sure we don't misinterpret it.
 529                     final Throwable cause = e.getCause();
 530
 531                     if (cause instanceof MissingSchemaSourceException) {
 532                         requiredSources = handleMissingSchemaSourceException(
 533                                 requiredSources, (MissingSchemaSourceException) cause);
 534                         continue;
 535                     }
 536                     if (cause instanceof SchemaResolutionException) {
 537                         requiredSources = handleSchemaResolutionException(requiredSources,
 538                             (SchemaResolutionException) cause);
 539                     } else {
 540                         handleSalInitializationFailure(e, listener);
 541                         return;
 542                     }
 543                 } catch (final Exception e) {
 544                     // unknown error, fail
 545                     handleSalInitializationFailure(e, listener);
 546                     return;
 547                 }
 548             }
 549             // No more sources, fail
 550             final IllegalStateException cause = new IllegalStateException(id + ": No more sources for schema context");
 551             handleSalInitializationFailure(cause, listener);
 552             salFacade.onDeviceFailed(cause);
 553         }
 554
 555         private Collection<SourceIdentifier> handleMissingSchemaSourceException(
 556                 final Collection<SourceIdentifier> requiredSources, final MissingSchemaSourceException exception) {
 557             // In case source missing, try without it
 558             final SourceIdentifier missingSource = exception.getSourceId();
 559             LOG.warn("{}: Unable to build schema context, missing source {}, will reattempt without it",
 560                 id, missingSource);
 561             LOG.debug("{}: Unable to build schema context, missing source {}, will reattempt without it",
 562                 id, missingSource, exception);
 563             final Collection<QName> qNameOfMissingSource =
 564                 getQNameFromSourceIdentifiers(Sets.newHashSet(missingSource));
 565             if (!qNameOfMissingSource.isEmpty()) {
 566                 capabilities.addUnresolvedCapabilities(
 567                         qNameOfMissingSource, UnavailableCapability.FailureReason.MissingSource);
 568             }
 569             return stripUnavailableSource(requiredSources, missingSource);
 570         }
 571
 572         private Collection<SourceIdentifier> handleSchemaResolutionException(
 573             final Collection<SourceIdentifier> requiredSources, final SchemaResolutionException resolutionException) {
 574             // In case resolution error, try only with resolved sources
 575             // There are two options why schema resolution exception occurred : unsatisfied imports or flawed model
 576             // FIXME Do we really have assurance that these two cases cannot happen at once?
 577             if (resolutionException.getFailedSource() != null) {
 578                 // flawed model - exclude it
 579                 final SourceIdentifier failedSourceId = resolutionException.getFailedSource();
 580                 LOG.warn("{}: Unable to build schema context, failed to resolve source {}, will reattempt without it",
 581                     id, failedSourceId);
 582                 LOG.warn("{}: Unable to build schema context, failed to resolve source {}, will reattempt without it",
 583                     id, failedSourceId, resolutionException);
 584                 capabilities.addUnresolvedCapabilities(
 585                         getQNameFromSourceIdentifiers(Collections.singleton(failedSourceId)),
 586                         UnavailableCapability.FailureReason.UnableToResolve);
 587                 return stripUnavailableSource(requiredSources, resolutionException.getFailedSource());
 588             }
 589             // unsatisfied imports
 590             final Set<SourceIdentifier> unresolvedSources = resolutionException.getUnsatisfiedImports().keySet();
 591             capabilities.addUnresolvedCapabilities(getQNameFromSourceIdentifiers(unresolvedSources),
 592                 UnavailableCapability.FailureReason.UnableToResolve);
 593             LOG.warn("{}: Unable to build schema context, unsatisfied imports {}, will reattempt with resolved only",
 594                 id, resolutionException.getUnsatisfiedImports());
 595             LOG.debug("{}: Unable to build schema context, unsatisfied imports {}, will reattempt with resolved only",
 596                 id, resolutionException.getUnsatisfiedImports(), resolutionException);
 597             return resolutionException.getResolvedSources();
 598         }
 599
 600         protected NetconfDeviceRpc getDeviceSpecificRpc(final SchemaContext result) {
 601             return new NetconfDeviceRpc(result, listener, new NetconfMessageTransformer(result, true));
 602         }
 603
 604         private Collection<SourceIdentifier> stripUnavailableSource(final Collection<SourceIdentifier> requiredSources,
 605                                                                     final SourceIdentifier sourceIdToRemove) {
 606             final LinkedList<SourceIdentifier> sourceIdentifiers = Lists.newLinkedList(requiredSources);
 607             final boolean removed = sourceIdentifiers.remove(sourceIdToRemove);
 608             Preconditions.checkState(
 609                     removed, "{}: Trying to remove {} from {} failed", id, sourceIdToRemove, requiredSources);
 610             return sourceIdentifiers;
 611         }
 612
 613         private Collection<QName> getQNameFromSourceIdentifiers(final Collection<SourceIdentifier> identifiers) {
 614             final Collection<QName> qNames = Collections2.transform(identifiers, this::getQNameFromSourceIdentifier);
 615
 616             if (qNames.isEmpty()) {
 617                 LOG.debug("{}: Unable to map any source identifiers to a capability reported by device : {}", id,
 618                         identifiers);
 619             }
 620             return Collections2.filter(qNames, Predicates.notNull());
 621         }
 622
 623         private QName getQNameFromSourceIdentifier(final SourceIdentifier identifier) {
 624             // Required sources are all required and provided merged in DeviceSourcesResolver
 625             for (final QName qname : deviceSources.getRequiredSourcesQName()) {
 626                 if (!qname.getLocalName().equals(identifier.getName())) {
 627                     continue;
 628                 }
 629
 630                 if (identifier.getRevision().equals(qname.getRevision())) {
 631                     return qname;
 632                 }
 633             }
 634             LOG.warn("Unable to map identifier to a devices reported capability: {} Available: {}",identifier,
 635                     deviceSources.getRequiredSourcesQName());
 636             // return null since we cannot find the QName,
 637             // this capability will be removed from required sources and not reported as unresolved-capability
 638             return null;
 639         }
 640     }
 641 }