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 com.google.common.base.Preconditions.checkState;
  11 import static java.util.Objects.requireNonNull;
  12
  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.FutureCallback;
  18 import com.google.common.util.concurrent.Futures;
  19 import com.google.common.util.concurrent.ListenableFuture;
  20 import com.google.common.util.concurrent.ListeningExecutorService;
  21 import com.google.common.util.concurrent.MoreExecutors;
  22 import java.util.ArrayList;
  23 import java.util.Collection;
  24 import java.util.Collections;
  25 import java.util.LinkedList;
  26 import java.util.List;
  27 import java.util.Optional;
  28 import java.util.Set;
  29 import java.util.concurrent.Callable;
  30 import java.util.concurrent.ExecutionException;
  31 import java.util.stream.Collectors;
  32 import org.checkerframework.checker.lock.qual.GuardedBy;
  33 import org.opendaylight.mdsal.dom.api.DOMNotification;
  34 import org.opendaylight.mdsal.dom.api.DOMRpcResult;
  35 import org.opendaylight.mdsal.dom.api.DOMRpcService;
  36 import org.opendaylight.netconf.api.NetconfMessage;
  37 import org.opendaylight.netconf.sal.connect.api.DeviceActionFactory;
  38 import org.opendaylight.netconf.sal.connect.api.MessageTransformer;
  39 import org.opendaylight.netconf.sal.connect.api.NetconfDeviceSchemas;
  40 import org.opendaylight.netconf.sal.connect.api.NetconfDeviceSchemasResolver;
  41 import org.opendaylight.netconf.sal.connect.api.RemoteDevice;
  42 import org.opendaylight.netconf.sal.connect.api.RemoteDeviceCommunicator;
  43 import org.opendaylight.netconf.sal.connect.api.RemoteDeviceHandler;
  44 import org.opendaylight.netconf.sal.connect.netconf.listener.NetconfDeviceCapabilities;
  45 import org.opendaylight.netconf.sal.connect.netconf.listener.NetconfDeviceCommunicator;
  46 import org.opendaylight.netconf.sal.connect.netconf.listener.NetconfSessionPreferences;
  47 import org.opendaylight.netconf.sal.connect.netconf.sal.NetconfDeviceRpc;
  48 import org.opendaylight.netconf.sal.connect.netconf.schema.NetconfRemoteSchemaYangSourceProvider;
  49 import org.opendaylight.netconf.sal.connect.netconf.schema.YangLibrarySchemaYangSourceProvider;
  50 import org.opendaylight.netconf.sal.connect.netconf.schema.mapping.BaseSchema;
  51 import org.opendaylight.netconf.sal.connect.netconf.schema.mapping.NetconfMessageTransformer;
  52 import org.opendaylight.netconf.sal.connect.netconf.util.NetconfMessageTransformUtil;
  53 import org.opendaylight.netconf.sal.connect.util.RemoteDeviceId;
  54 import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.netconf.notifications.rev120206.NetconfCapabilityChange;
  55 import org.opendaylight.yang.gen.v1.urn.opendaylight.netconf.node.topology.rev150114.netconf.node.connection.status.available.capabilities.AvailableCapabilityBuilder;
  56 import org.opendaylight.yang.gen.v1.urn.opendaylight.netconf.node.topology.rev150114.netconf.node.connection.status.unavailable.capabilities.UnavailableCapability;
  57 import org.opendaylight.yangtools.yang.common.QName;
  58 import org.opendaylight.yangtools.yang.model.api.SchemaContext;
  59 import org.opendaylight.yangtools.yang.model.repo.api.MissingSchemaSourceException;
  60 import org.opendaylight.yangtools.yang.model.repo.api.RevisionSourceIdentifier;
  61 import org.opendaylight.yangtools.yang.model.repo.api.SchemaContextFactory;
  62 import org.opendaylight.yangtools.yang.model.repo.api.SchemaRepository;
  63 import org.opendaylight.yangtools.yang.model.repo.api.SchemaResolutionException;
  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.slf4j.Logger;
  72 import org.slf4j.LoggerFactory;
  73
  74 /**
  75  *  This is a mediator between NetconfDeviceCommunicator and NetconfDeviceSalFacade.
  76  */
  77 public class NetconfDevice
  78         implements RemoteDevice<NetconfSessionPreferences, NetconfMessage, NetconfDeviceCommunicator> {
  79
  80     private static final Logger LOG = LoggerFactory.getLogger(NetconfDevice.class);
  81
  82     protected final RemoteDeviceId id;
  83     protected final SchemaContextFactory schemaContextFactory;
  84     protected final SchemaSourceRegistry schemaRegistry;
  85     protected final SchemaRepository schemaRepository;
  86
  87     protected final List<SchemaSourceRegistration<? extends SchemaSourceRepresentation>> sourceRegistrations =
  88             new ArrayList<>();
  89
  90     private final RemoteDeviceHandler<NetconfSessionPreferences> salFacade;
  91     private final ListeningExecutorService processingExecutor;
  92     private final DeviceActionFactory deviceActionFactory;
  93     private final NetconfDeviceSchemasResolver stateSchemasResolver;
  94     private final NotificationHandler notificationHandler;
  95     private final boolean reconnectOnSchemasChange;
  96
  97     @GuardedBy("this")
  98     private boolean connected = false;
  99
 100     // Message transformer is constructed once the schemas are available
 101     private MessageTransformer<NetconfMessage> messageTransformer;
 102
 103     /**
 104      * Create rpc implementation capable of handling RPC for monitoring and notifications
 105      * even before the schemas of remote device are downloaded.
 106      */
 107     static NetconfDeviceRpc getRpcForInitialization(final NetconfDeviceCommunicator listener,
 108                                                     final boolean notificationSupport) {
 109         final BaseSchema baseSchema = notificationSupport
 110                 ? BaseSchema.BASE_NETCONF_CTX_WITH_NOTIFICATIONS
 111                 : BaseSchema.BASE_NETCONF_CTX;
 112
 113         return new NetconfDeviceRpc(baseSchema.getSchemaContext(), listener,
 114                 new NetconfMessageTransformer(baseSchema.getSchemaContext(), false, baseSchema));
 115     }
 116
 117     public NetconfDevice(final SchemaResourcesDTO schemaResourcesDTO, final RemoteDeviceId id,
 118                          final RemoteDeviceHandler<NetconfSessionPreferences> salFacade,
 119                          final ListeningExecutorService globalProcessingExecutor,
 120                          final boolean reconnectOnSchemasChange) {
 121         this(schemaResourcesDTO, id, salFacade, globalProcessingExecutor, reconnectOnSchemasChange, null);
 122     }
 123
 124     public NetconfDevice(final SchemaResourcesDTO schemaResourcesDTO, final RemoteDeviceId id,
 125             final RemoteDeviceHandler<NetconfSessionPreferences> salFacade,
 126             final ListeningExecutorService globalProcessingExecutor, final boolean reconnectOnSchemasChange,
 127             final DeviceActionFactory deviceActionFactory) {
 128         this.id = id;
 129         this.reconnectOnSchemasChange = reconnectOnSchemasChange;
 130         this.deviceActionFactory = deviceActionFactory;
 131         this.schemaRegistry = schemaResourcesDTO.getSchemaRegistry();
 132         this.schemaRepository = schemaResourcesDTO.getSchemaRepository();
 133         this.schemaContextFactory = schemaResourcesDTO.getSchemaContextFactory();
 134         this.salFacade = salFacade;
 135         this.stateSchemasResolver = schemaResourcesDTO.getStateSchemasResolver();
 136         this.processingExecutor = requireNonNull(globalProcessingExecutor);
 137         this.notificationHandler = new NotificationHandler(salFacade, id);
 138     }
 139
 140     @Override
 141     public void onRemoteSessionUp(final NetconfSessionPreferences remoteSessionCapabilities,
 142                                   final NetconfDeviceCommunicator listener) {
 143         // SchemaContext setup has to be performed in a dedicated thread since
 144         // we are in a netty thread in this method
 145         // Yang models are being downloaded in this method and it would cause a
 146         // deadlock if we used the netty thread
 147         // http://netty.io/wiki/thread-model.html
 148         setConnected(true);
 149         LOG.debug("{}: Session to remote device established with {}", id, remoteSessionCapabilities);
 150
 151         final NetconfDeviceRpc initRpc =
 152                 getRpcForInitialization(listener, remoteSessionCapabilities.isNotificationsSupported());
 153         final DeviceSourcesResolver task =
 154                 new DeviceSourcesResolver(remoteSessionCapabilities, id, stateSchemasResolver, initRpc);
 155         final ListenableFuture<DeviceSources> sourceResolverFuture = processingExecutor.submit(task);
 156
 157         if (shouldListenOnSchemaChange(remoteSessionCapabilities)) {
 158             registerToBaseNetconfStream(initRpc, listener);
 159         }
 160
 161         final FutureCallback<DeviceSources> resolvedSourceCallback = new FutureCallback<DeviceSources>() {
 162             @Override
 163             public void onSuccess(final DeviceSources result) {
 164                 addProvidedSourcesToSchemaRegistry(result);
 165                 setUpSchema(result);
 166             }
 167
 168             private void setUpSchema(final DeviceSources result) {
 169                 processingExecutor.submit(new SchemaSetup(result, remoteSessionCapabilities, listener));
 170             }
 171
 172             @Override
 173             public void onFailure(final Throwable throwable) {
 174                 LOG.warn("{}: Unexpected error resolving device sources", id, throwable);
 175                 handleSalInitializationFailure(throwable, listener);
 176             }
 177         };
 178
 179         Futures.addCallback(sourceResolverFuture, resolvedSourceCallback, MoreExecutors.directExecutor());
 180     }
 181
 182     private void registerToBaseNetconfStream(final NetconfDeviceRpc deviceRpc,
 183                                              final NetconfDeviceCommunicator listener) {
 184         // TODO check whether the model describing create subscription is present in schema
 185         // Perhaps add a default schema context to support create-subscription if the model was not provided
 186         // (same as what we do for base netconf operations in transformer)
 187         final ListenableFuture<DOMRpcResult> rpcResultListenableFuture = deviceRpc.invokeRpc(
 188                 NetconfMessageTransformUtil.toPath(NetconfMessageTransformUtil.CREATE_SUBSCRIPTION_RPC_QNAME),
 189                 NetconfMessageTransformUtil.CREATE_SUBSCRIPTION_RPC_CONTENT);
 190
 191         final NotificationHandler.NotificationFilter filter = new NotificationHandler.NotificationFilter() {
 192             @Override
 193             public Optional<DOMNotification> filterNotification(final DOMNotification notification) {
 194                 if (isCapabilityChanged(notification)) {
 195                     LOG.info("{}: Schemas change detected, reconnecting", id);
 196                     // Only disconnect is enough,
 197                     // the reconnecting nature of the connector will take care of reconnecting
 198                     listener.disconnect();
 199                     return Optional.empty();
 200                 }
 201                 return Optional.of(notification);
 202             }
 203
 204             private boolean isCapabilityChanged(final DOMNotification notification) {
 205                 return notification.getBody().getNodeType().equals(NetconfCapabilityChange.QNAME);
 206             }
 207         };
 208
 209         Futures.addCallback(rpcResultListenableFuture, new FutureCallback<DOMRpcResult>() {
 210             @Override
 211             public void onSuccess(final DOMRpcResult domRpcResult) {
 212                 notificationHandler.addNotificationFilter(filter);
 213             }
 214
 215             @Override
 216             public void onFailure(final Throwable throwable) {
 217                 LOG.warn("Unable to subscribe to base notification stream. Schemas will not be reloaded on the fly",
 218                         throwable);
 219             }
 220         }, MoreExecutors.directExecutor());
 221     }
 222
 223     private boolean shouldListenOnSchemaChange(final NetconfSessionPreferences remoteSessionCapabilities) {
 224         return remoteSessionCapabilities.isNotificationsSupported() && reconnectOnSchemasChange;
 225     }
 226
 227     private synchronized void handleSalInitializationSuccess(final SchemaContext result,
 228                                         final NetconfSessionPreferences remoteSessionCapabilities,
 229                                         final DOMRpcService deviceRpc,
 230                                         final RemoteDeviceCommunicator<NetconfMessage> listener) {
 231         //NetconfDevice.SchemaSetup can complete after NetconfDeviceCommunicator was closed. In that case do nothing,
 232         //since salFacade.onDeviceDisconnected was already called.
 233         if (connected) {
 234             final BaseSchema baseSchema =
 235                 remoteSessionCapabilities.isNotificationsSupported()
 236                         ? BaseSchema.BASE_NETCONF_CTX_WITH_NOTIFICATIONS : BaseSchema.BASE_NETCONF_CTX;
 237             this.messageTransformer = new NetconfMessageTransformer(result, true, baseSchema);
 238
 239             updateTransformer(this.messageTransformer);
 240             // salFacade.onDeviceConnected has to be called before the notification handler is initialized
 241             this.salFacade.onDeviceConnected(result, remoteSessionCapabilities, deviceRpc,
 242                     this.deviceActionFactory == null ? null : this.deviceActionFactory.createDeviceAction(
 243                             this.messageTransformer, listener, result));
 244             this.notificationHandler.onRemoteSchemaUp(this.messageTransformer);
 245
 246             LOG.info("{}: Netconf connector initialized successfully", id);
 247         } else {
 248             LOG.warn("{}: Device communicator was closed before schema setup finished.", id);
 249         }
 250     }
 251
 252     private void handleSalInitializationFailure(final Throwable throwable,
 253                                                 final RemoteDeviceCommunicator<NetconfMessage> listener) {
 254         LOG.error("{}: Initialization in sal failed, disconnecting from device", id, throwable);
 255         listener.close();
 256         onRemoteSessionDown();
 257         resetMessageTransformer();
 258     }
 259
 260     /**
 261      * Set the transformer to null as is in initial state.
 262      */
 263     private void resetMessageTransformer() {
 264         updateTransformer(null);
 265     }
 266
 267     private synchronized void updateTransformer(final MessageTransformer<NetconfMessage> transformer) {
 268         messageTransformer = transformer;
 269     }
 270
 271     private synchronized void setConnected(final boolean connected) {
 272         this.connected = connected;
 273     }
 274
 275     private void addProvidedSourcesToSchemaRegistry(final DeviceSources deviceSources) {
 276         final SchemaSourceProvider<YangTextSchemaSource> yangProvider = deviceSources.getSourceProvider();
 277         for (final SourceIdentifier sourceId : deviceSources.getProvidedSources()) {
 278             sourceRegistrations.add(schemaRegistry.registerSchemaSource(yangProvider,
 279                     PotentialSchemaSource.create(
 280                             sourceId, YangTextSchemaSource.class, PotentialSchemaSource.Costs.REMOTE_IO.getValue())));
 281         }
 282     }
 283
 284     @Override
 285     public void onRemoteSessionDown() {
 286         setConnected(false);
 287         notificationHandler.onRemoteSchemaDown();
 288
 289         salFacade.onDeviceDisconnected();
 290         for (final SchemaSourceRegistration<? extends SchemaSourceRepresentation> sourceRegistration
 291                 : sourceRegistrations) {
 292             sourceRegistration.close();
 293         }
 294         resetMessageTransformer();
 295     }
 296
 297     @Override
 298     public void onRemoteSessionFailed(final Throwable throwable) {
 299         setConnected(false);
 300         salFacade.onDeviceFailed(throwable);
 301     }
 302
 303     @Override
 304     public void onNotification(final NetconfMessage notification) {
 305         notificationHandler.handleNotification(notification);
 306     }
 307
 308     /**
 309      * Just a transfer object containing schema related dependencies. Injected in constructor.
 310      */
 311     public static class SchemaResourcesDTO {
 312         private final SchemaSourceRegistry schemaRegistry;
 313         private final SchemaRepository schemaRepository;
 314         private final SchemaContextFactory schemaContextFactory;
 315         private final NetconfDeviceSchemasResolver stateSchemasResolver;
 316
 317         public SchemaResourcesDTO(final SchemaSourceRegistry schemaRegistry,
 318                                   final SchemaRepository schemaRepository,
 319                                   final SchemaContextFactory schemaContextFactory,
 320                                   final NetconfDeviceSchemasResolver deviceSchemasResolver) {
 321             this.schemaRegistry = requireNonNull(schemaRegistry);
 322             this.schemaRepository = requireNonNull(schemaRepository);
 323             this.schemaContextFactory = requireNonNull(schemaContextFactory);
 324             this.stateSchemasResolver = requireNonNull(deviceSchemasResolver);
 325         }
 326
 327         public SchemaSourceRegistry getSchemaRegistry() {
 328             return schemaRegistry;
 329         }
 330
 331         public SchemaRepository getSchemaRepository() {
 332             return schemaRepository;
 333         }
 334
 335         public SchemaContextFactory getSchemaContextFactory() {
 336             return schemaContextFactory;
 337         }
 338
 339         public NetconfDeviceSchemasResolver getStateSchemasResolver() {
 340             return stateSchemasResolver;
 341         }
 342     }
 343
 344     /**
 345      * Schema building callable.
 346      */
 347     private static class DeviceSourcesResolver implements Callable<DeviceSources> {
 348
 349         private final NetconfDeviceRpc deviceRpc;
 350         private final NetconfSessionPreferences remoteSessionCapabilities;
 351         private final RemoteDeviceId id;
 352         private final NetconfDeviceSchemasResolver stateSchemasResolver;
 353
 354         DeviceSourcesResolver(final NetconfDeviceRpc deviceRpc,
 355                               final NetconfSessionPreferences remoteSessionCapabilities,
 356                               final RemoteDeviceId id, final NetconfDeviceSchemasResolver stateSchemasResolver) {
 357             this.deviceRpc = deviceRpc;
 358             this.remoteSessionCapabilities = remoteSessionCapabilities;
 359             this.id = id;
 360             this.stateSchemasResolver = stateSchemasResolver;
 361         }
 362
 363         DeviceSourcesResolver(final NetconfSessionPreferences remoteSessionCapabilities, final RemoteDeviceId id,
 364                                      final NetconfDeviceSchemasResolver stateSchemasResolver,
 365                                      final NetconfDeviceRpc rpcForMonitoring) {
 366             this(rpcForMonitoring, remoteSessionCapabilities, id, stateSchemasResolver);
 367         }
 368
 369         @Override
 370         public DeviceSources call() {
 371             final NetconfDeviceSchemas availableSchemas =
 372                     stateSchemasResolver.resolve(deviceRpc, remoteSessionCapabilities, id);
 373             LOG.debug("{}: Schemas exposed by ietf-netconf-monitoring: {}", id,
 374                     availableSchemas.getAvailableYangSchemasQNames());
 375
 376             final Set<QName> requiredSources = Sets.newHashSet(remoteSessionCapabilities.getModuleBasedCaps());
 377             final Set<QName> providedSources = availableSchemas.getAvailableYangSchemasQNames();
 378
 379             final Set<QName> requiredSourcesNotProvided = Sets.difference(requiredSources, providedSources);
 380             if (!requiredSourcesNotProvided.isEmpty()) {
 381                 LOG.warn("{}: Netconf device does not provide all yang models reported in hello message capabilities,"
 382                         + " required but not provided: {}", id, requiredSourcesNotProvided);
 383                 LOG.warn("{}: Attempting to build schema context from required sources", id);
 384             }
 385
 386             // Here all the sources reported in netconf monitoring are merged with those reported in hello.
 387             // It is necessary to perform this since submodules are not mentioned in hello but still required.
 388             // This clashes with the option of a user to specify supported yang models manually in configuration
 389             // for netconf-connector and as a result one is not able to fully override yang models of a device.
 390             // It is only possible to add additional models.
 391             final Set<QName> providedSourcesNotRequired = Sets.difference(providedSources, requiredSources);
 392             if (!providedSourcesNotRequired.isEmpty()) {
 393                 LOG.warn("{}: Netconf device provides additional yang models not reported in "
 394                         + "hello message capabilities: {}", id, providedSourcesNotRequired);
 395                 LOG.warn("{}: Adding provided but not required sources as required to prevent failures", id);
 396                 LOG.debug("{}: Netconf device reported in hello: {}", id, requiredSources);
 397                 requiredSources.addAll(providedSourcesNotRequired);
 398             }
 399
 400             final SchemaSourceProvider<YangTextSchemaSource> sourceProvider;
 401             if (availableSchemas instanceof LibraryModulesSchemas) {
 402                 sourceProvider = new YangLibrarySchemaYangSourceProvider(id,
 403                         ((LibraryModulesSchemas) availableSchemas).getAvailableModels());
 404             } else {
 405                 sourceProvider = new NetconfRemoteSchemaYangSourceProvider(id, deviceRpc);
 406             }
 407
 408             return new DeviceSources(requiredSources, providedSources, sourceProvider);
 409         }
 410     }
 411
 412     /**
 413      * Contains RequiredSources - sources from capabilities.
 414      */
 415     private static final class DeviceSources {
 416         private final Set<QName> requiredSources;
 417         private final Set<QName> providedSources;
 418         private final SchemaSourceProvider<YangTextSchemaSource> sourceProvider;
 419
 420         DeviceSources(final Set<QName> requiredSources, final Set<QName> providedSources,
 421                              final SchemaSourceProvider<YangTextSchemaSource> sourceProvider) {
 422             this.requiredSources = requiredSources;
 423             this.providedSources = providedSources;
 424             this.sourceProvider = sourceProvider;
 425         }
 426
 427         public Set<QName> getRequiredSourcesQName() {
 428             return requiredSources;
 429         }
 430
 431         public Set<QName> getProvidedSourcesQName() {
 432             return providedSources;
 433         }
 434
 435         public Collection<SourceIdentifier> getRequiredSources() {
 436             return Collections2.transform(requiredSources, DeviceSources::toSourceId);
 437         }
 438
 439         public Collection<SourceIdentifier> getProvidedSources() {
 440             return Collections2.transform(providedSources, DeviceSources::toSourceId);
 441         }
 442
 443         public SchemaSourceProvider<YangTextSchemaSource> getSourceProvider() {
 444             return sourceProvider;
 445         }
 446
 447         private static SourceIdentifier toSourceId(final QName input) {
 448             return RevisionSourceIdentifier.create(input.getLocalName(), input.getRevision());
 449         }
 450     }
 451
 452     /**
 453      * Schema builder that tries to build schema context from provided sources or biggest subset of it.
 454      */
 455     private final class SchemaSetup implements Runnable {
 456         private final DeviceSources deviceSources;
 457         private final NetconfSessionPreferences remoteSessionCapabilities;
 458         private final RemoteDeviceCommunicator<NetconfMessage> listener;
 459         private final NetconfDeviceCapabilities capabilities;
 460
 461         SchemaSetup(final DeviceSources deviceSources, final NetconfSessionPreferences remoteSessionCapabilities,
 462                            final RemoteDeviceCommunicator<NetconfMessage> listener) {
 463             this.deviceSources = deviceSources;
 464             this.remoteSessionCapabilities = remoteSessionCapabilities;
 465             this.listener = listener;
 466             this.capabilities = remoteSessionCapabilities.getNetconfDeviceCapabilities();
 467         }
 468
 469         @Override
 470         public void run() {
 471
 472             final Collection<SourceIdentifier> requiredSources = deviceSources.getRequiredSources();
 473             final Collection<SourceIdentifier> missingSources = filterMissingSources(requiredSources);
 474
 475             capabilities.addUnresolvedCapabilities(getQNameFromSourceIdentifiers(missingSources),
 476                     UnavailableCapability.FailureReason.MissingSource);
 477
 478             requiredSources.removeAll(missingSources);
 479             setUpSchema(requiredSources);
 480         }
 481
 482         private Collection<SourceIdentifier> filterMissingSources(final Collection<SourceIdentifier> requiredSources) {
 483             return requiredSources.parallelStream().filter(sourceIdentifier -> {
 484                 try {
 485                     schemaRepository.getSchemaSource(sourceIdentifier, YangTextSchemaSource.class).get();
 486                     return false;
 487                 } catch (InterruptedException | ExecutionException e) {
 488                     return true;
 489                 }
 490             }).collect(Collectors.toList());
 491         }
 492
 493         /**
 494          * Build schema context, in case of success or final failure notify device.
 495          *
 496          * @param requiredSources required sources
 497          */
 498         @SuppressWarnings("checkstyle:IllegalCatch")
 499         private void setUpSchema(Collection<SourceIdentifier> requiredSources) {
 500             while (!requiredSources.isEmpty()) {
 501                 LOG.trace("{}: Trying to build schema context from {}", id, requiredSources);
 502                 try {
 503                     final ListenableFuture<SchemaContext> schemaBuilderFuture = schemaContextFactory
 504                             .createSchemaContext(requiredSources);
 505                     final SchemaContext result = schemaBuilderFuture.get();
 506                     LOG.debug("{}: Schema context built successfully from {}", id, requiredSources);
 507                     final Collection<QName> filteredQNames = Sets.difference(deviceSources.getRequiredSourcesQName(),
 508                             capabilities.getUnresolvedCapabilites().keySet());
 509                     capabilities.addCapabilities(filteredQNames.stream().map(entry -> new AvailableCapabilityBuilder()
 510                             .setCapability(entry.toString()).setCapabilityOrigin(
 511                                     remoteSessionCapabilities.getModuleBasedCapsOrigin().get(entry)).build())
 512                             .collect(Collectors.toList()));
 513
 514                     capabilities.addNonModuleBasedCapabilities(remoteSessionCapabilities
 515                             .getNonModuleCaps().stream().map(entry -> new AvailableCapabilityBuilder()
 516                                     .setCapability(entry).setCapabilityOrigin(
 517                                             remoteSessionCapabilities.getNonModuleBasedCapsOrigin().get(entry)).build())
 518                             .collect(Collectors.toList()));
 519
 520                     handleSalInitializationSuccess(result, remoteSessionCapabilities, getDeviceSpecificRpc(result),
 521                             listener);
 522                     return;
 523                 } catch (final ExecutionException e) {
 524                     // schemaBuilderFuture.checkedGet() throws only SchemaResolutionException
 525                     // that might be wrapping a MissingSchemaSourceException so we need to look
 526                     // at the cause of the exception to make sure we don't misinterpret it.
 527                     final Throwable cause = e.getCause();
 528
 529                     if (cause instanceof MissingSchemaSourceException) {
 530                         requiredSources = handleMissingSchemaSourceException(
 531                                 requiredSources, (MissingSchemaSourceException) cause);
 532                         continue;
 533                     }
 534                     if (cause instanceof SchemaResolutionException) {
 535                         requiredSources = handleSchemaResolutionException(requiredSources,
 536                             (SchemaResolutionException) cause);
 537                     } else {
 538                         handleSalInitializationFailure(e, listener);
 539                         return;
 540                     }
 541                 } catch (final Exception e) {
 542                     // unknown error, fail
 543                     handleSalInitializationFailure(e, listener);
 544                     return;
 545                 }
 546             }
 547             // No more sources, fail
 548             final IllegalStateException cause = new IllegalStateException(id + ": No more sources for schema context");
 549             handleSalInitializationFailure(cause, listener);
 550             salFacade.onDeviceFailed(cause);
 551         }
 552
 553         private Collection<SourceIdentifier> handleMissingSchemaSourceException(
 554                 final Collection<SourceIdentifier> requiredSources, final MissingSchemaSourceException exception) {
 555             // In case source missing, try without it
 556             final SourceIdentifier missingSource = exception.getSourceId();
 557             LOG.warn("{}: Unable to build schema context, missing source {}, will reattempt without it",
 558                 id, missingSource);
 559             LOG.debug("{}: Unable to build schema context, missing source {}, will reattempt without it",
 560                 id, missingSource, exception);
 561             final Collection<QName> qNameOfMissingSource =
 562                 getQNameFromSourceIdentifiers(Sets.newHashSet(missingSource));
 563             if (!qNameOfMissingSource.isEmpty()) {
 564                 capabilities.addUnresolvedCapabilities(
 565                         qNameOfMissingSource, UnavailableCapability.FailureReason.MissingSource);
 566             }
 567             return stripUnavailableSource(requiredSources, missingSource);
 568         }
 569
 570         private Collection<SourceIdentifier> handleSchemaResolutionException(
 571             final Collection<SourceIdentifier> requiredSources, final SchemaResolutionException resolutionException) {
 572             // In case resolution error, try only with resolved sources
 573             // There are two options why schema resolution exception occurred : unsatisfied imports or flawed model
 574             // FIXME Do we really have assurance that these two cases cannot happen at once?
 575             if (resolutionException.getFailedSource() != null) {
 576                 // flawed model - exclude it
 577                 final SourceIdentifier failedSourceId = resolutionException.getFailedSource();
 578                 LOG.warn("{}: Unable to build schema context, failed to resolve source {}, will reattempt without it",
 579                     id, failedSourceId);
 580                 LOG.warn("{}: Unable to build schema context, failed to resolve source {}, will reattempt without it",
 581                     id, failedSourceId, resolutionException);
 582                 capabilities.addUnresolvedCapabilities(
 583                         getQNameFromSourceIdentifiers(Collections.singleton(failedSourceId)),
 584                         UnavailableCapability.FailureReason.UnableToResolve);
 585                 return stripUnavailableSource(requiredSources, resolutionException.getFailedSource());
 586             }
 587             // unsatisfied imports
 588             final Set<SourceIdentifier> unresolvedSources = resolutionException.getUnsatisfiedImports().keySet();
 589             capabilities.addUnresolvedCapabilities(getQNameFromSourceIdentifiers(unresolvedSources),
 590                 UnavailableCapability.FailureReason.UnableToResolve);
 591             LOG.warn("{}: Unable to build schema context, unsatisfied imports {}, will reattempt with resolved only",
 592                 id, resolutionException.getUnsatisfiedImports());
 593             LOG.debug("{}: Unable to build schema context, unsatisfied imports {}, will reattempt with resolved only",
 594                 id, resolutionException.getUnsatisfiedImports(), resolutionException);
 595             return resolutionException.getResolvedSources();
 596         }
 597
 598         protected NetconfDeviceRpc getDeviceSpecificRpc(final SchemaContext result) {
 599             return new NetconfDeviceRpc(result, listener, new NetconfMessageTransformer(result, true));
 600         }
 601
 602         private Collection<SourceIdentifier> stripUnavailableSource(final Collection<SourceIdentifier> requiredSources,
 603                                                                     final SourceIdentifier sourceIdToRemove) {
 604             final LinkedList<SourceIdentifier> sourceIdentifiers = Lists.newLinkedList(requiredSources);
 605             checkState(sourceIdentifiers.remove(sourceIdToRemove),
 606                     "%s: Trying to remove %s from %s failed", id, sourceIdToRemove, requiredSources);
 607             return sourceIdentifiers;
 608         }
 609
 610         private Collection<QName> getQNameFromSourceIdentifiers(final Collection<SourceIdentifier> identifiers) {
 611             final Collection<QName> qNames = Collections2.transform(identifiers, this::getQNameFromSourceIdentifier);
 612
 613             if (qNames.isEmpty()) {
 614                 LOG.debug("{}: Unable to map any source identifiers to a capability reported by device : {}", id,
 615                         identifiers);
 616             }
 617             return Collections2.filter(qNames, Predicates.notNull());
 618         }
 619
 620         private QName getQNameFromSourceIdentifier(final SourceIdentifier identifier) {
 621             // Required sources are all required and provided merged in DeviceSourcesResolver
 622             for (final QName qname : deviceSources.getRequiredSourcesQName()) {
 623                 if (!qname.getLocalName().equals(identifier.getName())) {
 624                     continue;
 625                 }
 626
 627                 if (identifier.getRevision().equals(qname.getRevision())) {
 628                     return qname;
 629                 }
 630             }
 631             LOG.warn("Unable to map identifier to a devices reported capability: {} Available: {}",identifier,
 632                     deviceSources.getRequiredSourcesQName());
 633             // return null since we cannot find the QName,
 634             // this capability will be removed from required sources and not reported as unresolved-capability
 635             return null;
 636         }
 637     }
 638 }