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 import static org.opendaylight.netconf.sal.connect.netconf.util.NetconfMessageTransformUtil.NETCONF_GET_NODEID;
  13
  14 import com.google.common.base.Predicates;
  15 import com.google.common.collect.Collections2;
  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 com.google.common.util.concurrent.SettableFuture;
  23 import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
  24 import io.netty.util.concurrent.EventExecutor;
  25 import java.util.ArrayList;
  26 import java.util.Collection;
  27 import java.util.Collections;
  28 import java.util.LinkedList;
  29 import java.util.List;
  30 import java.util.Optional;
  31 import java.util.Set;
  32 import java.util.concurrent.ExecutionException;
  33 import java.util.concurrent.TimeUnit;
  34 import java.util.stream.Collectors;
  35 import org.checkerframework.checker.lock.qual.GuardedBy;
  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.NetconfDeviceSchemasResolver;
  42 import org.opendaylight.netconf.sal.connect.api.RemoteDevice;
  43 import org.opendaylight.netconf.sal.connect.api.RemoteDeviceCommunicator;
  44 import org.opendaylight.netconf.sal.connect.api.RemoteDeviceHandler;
  45 import org.opendaylight.netconf.sal.connect.netconf.listener.NetconfDeviceCapabilities;
  46 import org.opendaylight.netconf.sal.connect.netconf.listener.NetconfDeviceCommunicator;
  47 import org.opendaylight.netconf.sal.connect.netconf.listener.NetconfSessionPreferences;
  48 import org.opendaylight.netconf.sal.connect.netconf.sal.NetconfDeviceRpc;
  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.optional.rev190614.NetconfNodeAugmentedOptional;
  55 import org.opendaylight.yang.gen.v1.urn.opendaylight.netconf.node.topology.rev150114.NetconfNode;
  56 import org.opendaylight.yang.gen.v1.urn.opendaylight.netconf.node.topology.rev150114.netconf.node.connection.status.available.capabilities.AvailableCapabilityBuilder;
  57 import org.opendaylight.yang.gen.v1.urn.opendaylight.netconf.node.topology.rev150114.netconf.node.connection.status.unavailable.capabilities.UnavailableCapability;
  58 import org.opendaylight.yangtools.rcf8528.data.util.EmptyMountPointContext;
  59 import org.opendaylight.yangtools.rfc8528.data.api.MountPointContext;
  60 import org.opendaylight.yangtools.rfc8528.model.api.SchemaMountConstants;
  61 import org.opendaylight.yangtools.yang.common.QName;
  62 import org.opendaylight.yangtools.yang.common.RpcError;
  63 import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier;
  64 import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier.NodeIdentifier;
  65 import org.opendaylight.yangtools.yang.data.api.schema.ContainerNode;
  66 import org.opendaylight.yangtools.yang.data.api.schema.NormalizedNode;
  67 import org.opendaylight.yangtools.yang.data.impl.schema.Builders;
  68 import org.opendaylight.yangtools.yang.model.api.EffectiveModelContext;
  69 import org.opendaylight.yangtools.yang.model.repo.api.EffectiveModelContextFactory;
  70 import org.opendaylight.yangtools.yang.model.repo.api.MissingSchemaSourceException;
  71 import org.opendaylight.yangtools.yang.model.repo.api.SchemaRepository;
  72 import org.opendaylight.yangtools.yang.model.repo.api.SchemaResolutionException;
  73 import org.opendaylight.yangtools.yang.model.repo.api.SourceIdentifier;
  74 import org.opendaylight.yangtools.yang.model.repo.api.YangTextSchemaSource;
  75 import org.opendaylight.yangtools.yang.model.repo.spi.PotentialSchemaSource;
  76 import org.opendaylight.yangtools.yang.model.repo.spi.SchemaSourceProvider;
  77 import org.opendaylight.yangtools.yang.model.repo.spi.SchemaSourceRegistration;
  78 import org.opendaylight.yangtools.yang.model.repo.spi.SchemaSourceRegistry;
  79 import org.slf4j.Logger;
  80 import org.slf4j.LoggerFactory;
  81
  82 /**
  83  *  This is a mediator between NetconfDeviceCommunicator and NetconfDeviceSalFacade.
  84  */
  85 public class NetconfDevice
  86         implements RemoteDevice<NetconfSessionPreferences, NetconfMessage, NetconfDeviceCommunicator> {
  87
  88     @SuppressFBWarnings(value = "SLF4J_LOGGER_SHOULD_BE_PRIVATE",
  89             justification = "Needed for common logging of related classes")
  90     static final Logger LOG = LoggerFactory.getLogger(NetconfDevice.class);
  91
  92     private static final QName RFC8528_SCHEMA_MOUNTS_QNAME = QName.create(
  93         SchemaMountConstants.RFC8528_MODULE, "schema-mounts").intern();
  94     private static final YangInstanceIdentifier RFC8528_SCHEMA_MOUNTS = YangInstanceIdentifier.create(
  95         NodeIdentifier.create(RFC8528_SCHEMA_MOUNTS_QNAME));
  96
  97     protected final RemoteDeviceId id;
  98     protected final EffectiveModelContextFactory schemaContextFactory;
  99     protected final SchemaSourceRegistry schemaRegistry;
 100     protected final SchemaRepository schemaRepository;
 101
 102     protected final List<SchemaSourceRegistration<?>> sourceRegistrations = new ArrayList<>();
 103
 104     private final RemoteDeviceHandler<NetconfSessionPreferences> salFacade;
 105     private final ListeningExecutorService processingExecutor;
 106     private final DeviceActionFactory deviceActionFactory;
 107     private final NetconfDeviceSchemasResolver stateSchemasResolver;
 108     private final NotificationHandler notificationHandler;
 109     private final boolean reconnectOnSchemasChange;
 110     private final NetconfNode node;
 111     private final EventExecutor eventExecutor;
 112     private final NetconfNodeAugmentedOptional nodeOptional;
 113
 114     @GuardedBy("this")
 115     private boolean connected = false;
 116
 117     // Message transformer is constructed once the schemas are available
 118     private MessageTransformer<NetconfMessage> messageTransformer;
 119
 120     public NetconfDevice(final SchemaResourcesDTO schemaResourcesDTO, final RemoteDeviceId id,
 121                          final RemoteDeviceHandler<NetconfSessionPreferences> salFacade,
 122                          final ListeningExecutorService globalProcessingExecutor,
 123                          final boolean reconnectOnSchemasChange) {
 124         this(schemaResourcesDTO, id, salFacade, globalProcessingExecutor, reconnectOnSchemasChange, null, null, null,
 125                 null);
 126     }
 127
 128     public NetconfDevice(final SchemaResourcesDTO schemaResourcesDTO, final RemoteDeviceId id,
 129             final RemoteDeviceHandler<NetconfSessionPreferences> salFacade,
 130             final ListeningExecutorService globalProcessingExecutor, final boolean reconnectOnSchemasChange,
 131             final DeviceActionFactory deviceActionFactory, final NetconfNode node, final EventExecutor eventExecutor,
 132             final NetconfNodeAugmentedOptional nodeOptional) {
 133         this.id = id;
 134         this.reconnectOnSchemasChange = reconnectOnSchemasChange;
 135         this.deviceActionFactory = deviceActionFactory;
 136         this.node = node;
 137         this.eventExecutor = eventExecutor;
 138         this.nodeOptional = nodeOptional;
 139         this.schemaRegistry = schemaResourcesDTO.getSchemaRegistry();
 140         this.schemaRepository = schemaResourcesDTO.getSchemaRepository();
 141         this.schemaContextFactory = schemaResourcesDTO.getSchemaContextFactory();
 142         this.salFacade = salFacade;
 143         this.stateSchemasResolver = schemaResourcesDTO.getStateSchemasResolver();
 144         this.processingExecutor = requireNonNull(globalProcessingExecutor);
 145         this.notificationHandler = new NotificationHandler(salFacade, id);
 146     }
 147
 148     @Override
 149     public void onRemoteSessionUp(final NetconfSessionPreferences remoteSessionCapabilities,
 150                                   final NetconfDeviceCommunicator listener) {
 151         // SchemaContext setup has to be performed in a dedicated thread since
 152         // we are in a netty thread in this method
 153         // Yang models are being downloaded in this method and it would cause a
 154         // deadlock if we used the netty thread
 155         // http://netty.io/wiki/thread-model.html
 156         setConnected(true);
 157         LOG.debug("{}: Session to remote device established with {}", id, remoteSessionCapabilities);
 158
 159         final BaseSchema baseSchema = resolveBaseSchema(remoteSessionCapabilities.isNotificationsSupported());
 160         final NetconfDeviceRpc initRpc = new NetconfDeviceRpc(baseSchema.getSchemaContext(), listener,
 161             new NetconfMessageTransformer(baseSchema.getMountPointContext(), false, baseSchema));
 162         final ListenableFuture<DeviceSources> sourceResolverFuture = processingExecutor.submit(
 163             new DeviceSourcesResolver(id, baseSchema, initRpc, remoteSessionCapabilities, stateSchemasResolver));
 164
 165         if (shouldListenOnSchemaChange(remoteSessionCapabilities)) {
 166             registerToBaseNetconfStream(initRpc, listener);
 167         }
 168
 169         // Set up the SchemaContext for the device
 170         final ListenableFuture<EffectiveModelContext> futureSchema = Futures.transformAsync(sourceResolverFuture,
 171             deviceSources -> assembleSchemaContext(deviceSources, remoteSessionCapabilities), processingExecutor);
 172
 173         // Potentially acquire mount point list and interpret it
 174         final ListenableFuture<MountPointContext> futureContext = Futures.transformAsync(futureSchema,
 175             schemaContext -> createMountPointContext(schemaContext, baseSchema, listener), processingExecutor);
 176
 177         Futures.addCallback(futureContext, new FutureCallback<MountPointContext>() {
 178             @Override
 179             public void onSuccess(final MountPointContext result) {
 180                 handleSalInitializationSuccess(result, remoteSessionCapabilities,
 181                     getDeviceSpecificRpc(result, listener), listener);
 182             }
 183
 184             @Override
 185             public void onFailure(final Throwable cause) {
 186                 LOG.warn("{}: Unexpected error resolving device sources", id, cause);
 187
 188                 // No more sources, fail or try to reconnect
 189                 if (cause instanceof EmptySchemaContextException) {
 190                     if (nodeOptional != null && nodeOptional.getIgnoreMissingSchemaSources().isAllowed()) {
 191                         eventExecutor.schedule(() -> {
 192                             LOG.warn("Reconnection is allowed! This can lead to unexpected errors at runtime.");
 193                             LOG.warn("{} : No more sources for schema context.", id);
 194                             LOG.info("{} : Try to remount device.", id);
 195                             onRemoteSessionDown();
 196                             salFacade.onDeviceReconnected(remoteSessionCapabilities, node);
 197                         }, nodeOptional.getIgnoreMissingSchemaSources().getReconnectTime().toJava(),
 198                             TimeUnit.MILLISECONDS);
 199                         return;
 200                     }
 201                 }
 202
 203                 handleSalInitializationFailure(cause, listener);
 204                 salFacade.onDeviceFailed(cause);
 205             }
 206         }, MoreExecutors.directExecutor());
 207     }
 208
 209     private void registerToBaseNetconfStream(final NetconfDeviceRpc deviceRpc,
 210                                              final NetconfDeviceCommunicator listener) {
 211         // TODO check whether the model describing create subscription is present in schema
 212         // Perhaps add a default schema context to support create-subscription if the model was not provided
 213         // (same as what we do for base netconf operations in transformer)
 214         final ListenableFuture<DOMRpcResult> rpcResultListenableFuture = deviceRpc.invokeRpc(
 215                 NetconfMessageTransformUtil.CREATE_SUBSCRIPTION_RPC_PATH,
 216                 NetconfMessageTransformUtil.CREATE_SUBSCRIPTION_RPC_CONTENT);
 217
 218         Futures.addCallback(rpcResultListenableFuture, new FutureCallback<DOMRpcResult>() {
 219             @Override
 220             public void onSuccess(final DOMRpcResult domRpcResult) {
 221                 notificationHandler.addNotificationFilter(notification -> {
 222                     if (NetconfCapabilityChange.QNAME.equals(notification.getBody().getNodeType())) {
 223                         LOG.info("{}: Schemas change detected, reconnecting", id);
 224                         // Only disconnect is enough,
 225                         // the reconnecting nature of the connector will take care of reconnecting
 226                         listener.disconnect();
 227                         return Optional.empty();
 228                     }
 229                     return Optional.of(notification);
 230                 });
 231             }
 232
 233             @Override
 234             public void onFailure(final Throwable throwable) {
 235                 LOG.warn("Unable to subscribe to base notification stream. Schemas will not be reloaded on the fly",
 236                         throwable);
 237             }
 238         }, MoreExecutors.directExecutor());
 239     }
 240
 241     private boolean shouldListenOnSchemaChange(final NetconfSessionPreferences remoteSessionCapabilities) {
 242         return remoteSessionCapabilities.isNotificationsSupported() && reconnectOnSchemasChange;
 243     }
 244
 245     @SuppressFBWarnings(value = "UPM_UNCALLED_PRIVATE_METHOD",
 246             justification = "https://github.com/spotbugs/spotbugs/issues/811")
 247     private synchronized void handleSalInitializationSuccess(final MountPointContext result,
 248                                         final NetconfSessionPreferences remoteSessionCapabilities,
 249                                         final DOMRpcService deviceRpc,
 250                                         final RemoteDeviceCommunicator<NetconfMessage> listener) {
 251         //NetconfDevice.SchemaSetup can complete after NetconfDeviceCommunicator was closed. In that case do nothing,
 252         //since salFacade.onDeviceDisconnected was already called.
 253         if (connected) {
 254             final BaseSchema baseSchema =
 255                 remoteSessionCapabilities.isNotificationsSupported()
 256                         ? BaseSchema.BASE_NETCONF_CTX_WITH_NOTIFICATIONS : BaseSchema.BASE_NETCONF_CTX;
 257             this.messageTransformer = new NetconfMessageTransformer(result, true, baseSchema);
 258
 259             // salFacade.onDeviceConnected has to be called before the notification handler is initialized
 260             this.salFacade.onDeviceConnected(result, remoteSessionCapabilities, deviceRpc,
 261                     this.deviceActionFactory == null ? null : this.deviceActionFactory.createDeviceAction(
 262                             this.messageTransformer, listener, result.getSchemaContext()));
 263             this.notificationHandler.onRemoteSchemaUp(this.messageTransformer);
 264
 265             LOG.info("{}: Netconf connector initialized successfully", id);
 266         } else {
 267             LOG.warn("{}: Device communicator was closed before schema setup finished.", id);
 268         }
 269     }
 270
 271     @SuppressFBWarnings(value = "UPM_UNCALLED_PRIVATE_METHOD",
 272             justification = "https://github.com/spotbugs/spotbugs/issues/811")
 273     private void handleSalInitializationFailure(final Throwable throwable,
 274                                                 final RemoteDeviceCommunicator<NetconfMessage> listener) {
 275         LOG.error("{}: Initialization in sal failed, disconnecting from device", id, throwable);
 276         listener.close();
 277         onRemoteSessionDown();
 278         resetMessageTransformer();
 279     }
 280
 281     /**
 282      * Set the transformer to null as is in initial state.
 283      */
 284     private void resetMessageTransformer() {
 285         updateTransformer(null);
 286     }
 287
 288     private synchronized void updateTransformer(final MessageTransformer<NetconfMessage> transformer) {
 289         messageTransformer = transformer;
 290     }
 291
 292     private synchronized void setConnected(final boolean connected) {
 293         this.connected = connected;
 294     }
 295
 296     @SuppressFBWarnings(value = "UPM_UNCALLED_PRIVATE_METHOD",
 297             justification = "https://github.com/spotbugs/spotbugs/issues/811")
 298     private ListenableFuture<EffectiveModelContext> assembleSchemaContext(final DeviceSources deviceSources,
 299             final NetconfSessionPreferences remoteSessionCapabilities) {
 300         LOG.debug("{}: Resolved device sources to {}", id, deviceSources);
 301         final SchemaSourceProvider<YangTextSchemaSource> yangProvider = deviceSources.getSourceProvider();
 302         for (final SourceIdentifier sourceId : deviceSources.getProvidedSources()) {
 303             sourceRegistrations.add(schemaRegistry.registerSchemaSource(yangProvider,
 304                 PotentialSchemaSource.create(sourceId, YangTextSchemaSource.class,
 305                     PotentialSchemaSource.Costs.REMOTE_IO.getValue())));
 306         }
 307
 308         return new SchemaSetup(deviceSources, remoteSessionCapabilities).startResolution();
 309     }
 310
 311     private ListenableFuture<MountPointContext> createMountPointContext(final EffectiveModelContext schemaContext,
 312             final BaseSchema baseSchema, final NetconfDeviceCommunicator listener) {
 313         final MountPointContext emptyContext = new EmptyMountPointContext(schemaContext);
 314         if (!schemaContext.findModule(SchemaMountConstants.RFC8528_MODULE).isPresent()) {
 315             return Futures.immediateFuture(emptyContext);
 316         }
 317
 318         // Create a temporary RPC invoker and acquire the mount point tree
 319         LOG.debug("{}: Acquiring available mount points", id);
 320         final NetconfDeviceRpc deviceRpc = new NetconfDeviceRpc(schemaContext, listener,
 321             new NetconfMessageTransformer(emptyContext, false, baseSchema));
 322
 323         return Futures.transform(deviceRpc.invokeRpc(NetconfMessageTransformUtil.NETCONF_GET_PATH,
 324             Builders.containerBuilder().withNodeIdentifier(NETCONF_GET_NODEID)
 325                 .withChild(NetconfMessageTransformUtil.toFilterStructure(RFC8528_SCHEMA_MOUNTS, schemaContext))
 326                 .build()), rpcResult -> processSchemaMounts(rpcResult, emptyContext), MoreExecutors.directExecutor());
 327     }
 328
 329     private MountPointContext processSchemaMounts(final DOMRpcResult rpcResult, final MountPointContext emptyContext) {
 330         final Collection<? extends RpcError> errors = rpcResult.getErrors();
 331         if (!errors.isEmpty()) {
 332             LOG.warn("{}: Schema-mounts acquisition resulted in errors {}", id, errors);
 333         }
 334         final NormalizedNode<?, ?> schemaMounts = rpcResult.getResult();
 335         if (schemaMounts == null) {
 336             LOG.debug("{}: device does not define any schema mounts", id);
 337             return emptyContext;
 338         }
 339         if (!(schemaMounts instanceof ContainerNode)) {
 340             LOG.warn("{}: ignoring non-container schema mounts {}", id, schemaMounts);
 341             return emptyContext;
 342         }
 343
 344         return DeviceMountPointContext.create(emptyContext, (ContainerNode) schemaMounts);
 345     }
 346
 347     @Override
 348     public void onRemoteSessionDown() {
 349         setConnected(false);
 350         notificationHandler.onRemoteSchemaDown();
 351
 352         salFacade.onDeviceDisconnected();
 353         sourceRegistrations.forEach(SchemaSourceRegistration::close);
 354         sourceRegistrations.clear();
 355         resetMessageTransformer();
 356     }
 357
 358     @Override
 359     public void onRemoteSessionFailed(final Throwable throwable) {
 360         setConnected(false);
 361         salFacade.onDeviceFailed(throwable);
 362     }
 363
 364     @Override
 365     public void onNotification(final NetconfMessage notification) {
 366         notificationHandler.handleNotification(notification);
 367     }
 368
 369     private static BaseSchema resolveBaseSchema(final boolean notificationSupport) {
 370         return notificationSupport ? BaseSchema.BASE_NETCONF_CTX_WITH_NOTIFICATIONS : BaseSchema.BASE_NETCONF_CTX;
 371     }
 372
 373     protected NetconfDeviceRpc getDeviceSpecificRpc(final MountPointContext result,
 374             final RemoteDeviceCommunicator<NetconfMessage> listener) {
 375         return new NetconfDeviceRpc(result.getSchemaContext(), listener, new NetconfMessageTransformer(result, true));
 376     }
 377
 378     /**
 379      * Just a transfer object containing schema related dependencies. Injected in constructor.
 380      */
 381     public static class SchemaResourcesDTO {
 382         private final SchemaSourceRegistry schemaRegistry;
 383         private final SchemaRepository schemaRepository;
 384         private final EffectiveModelContextFactory schemaContextFactory;
 385         private final NetconfDeviceSchemasResolver stateSchemasResolver;
 386
 387         public SchemaResourcesDTO(final SchemaSourceRegistry schemaRegistry,
 388                                   final SchemaRepository schemaRepository,
 389                                   final EffectiveModelContextFactory schemaContextFactory,
 390                                   final NetconfDeviceSchemasResolver deviceSchemasResolver) {
 391             this.schemaRegistry = requireNonNull(schemaRegistry);
 392             this.schemaRepository = requireNonNull(schemaRepository);
 393             this.schemaContextFactory = requireNonNull(schemaContextFactory);
 394             this.stateSchemasResolver = requireNonNull(deviceSchemasResolver);
 395         }
 396
 397         public SchemaSourceRegistry getSchemaRegistry() {
 398             return schemaRegistry;
 399         }
 400
 401         public SchemaRepository getSchemaRepository() {
 402             return schemaRepository;
 403         }
 404
 405         public EffectiveModelContextFactory getSchemaContextFactory() {
 406             return schemaContextFactory;
 407         }
 408
 409         public NetconfDeviceSchemasResolver getStateSchemasResolver() {
 410             return stateSchemasResolver;
 411         }
 412     }
 413
 414     /**
 415      * A dedicated exception to indicate when we fail to setup a SchemaContext.
 416      *
 417      * @author Robert Varga
 418      */
 419     private static final class EmptySchemaContextException extends Exception {
 420         private static final long serialVersionUID = 1L;
 421
 422         EmptySchemaContextException(final String message) {
 423             super(message);
 424         }
 425     }
 426
 427     /**
 428      * Schema builder that tries to build schema context from provided sources or biggest subset of it.
 429      */
 430     private final class SchemaSetup implements FutureCallback<EffectiveModelContext> {
 431         private final SettableFuture<EffectiveModelContext> resultFuture = SettableFuture.create();
 432
 433         private final DeviceSources deviceSources;
 434         private final NetconfSessionPreferences remoteSessionCapabilities;
 435         private final NetconfDeviceCapabilities capabilities;
 436
 437         private Collection<SourceIdentifier> requiredSources;
 438
 439         SchemaSetup(final DeviceSources deviceSources, final NetconfSessionPreferences remoteSessionCapabilities) {
 440             this.deviceSources = deviceSources;
 441             this.remoteSessionCapabilities = remoteSessionCapabilities;
 442             this.capabilities = remoteSessionCapabilities.getNetconfDeviceCapabilities();
 443
 444             requiredSources = deviceSources.getRequiredSources();
 445             final Collection<SourceIdentifier> missingSources = filterMissingSources(requiredSources);
 446
 447             capabilities.addUnresolvedCapabilities(getQNameFromSourceIdentifiers(missingSources),
 448                     UnavailableCapability.FailureReason.MissingSource);
 449             requiredSources.removeAll(missingSources);
 450         }
 451
 452         ListenableFuture<EffectiveModelContext> startResolution() {
 453             trySetupSchema();
 454             return resultFuture;
 455         }
 456
 457         @Override
 458         public void onSuccess(final EffectiveModelContext result) {
 459             LOG.debug("{}: Schema context built successfully from {}", id, requiredSources);
 460
 461             final Collection<QName> filteredQNames = Sets.difference(deviceSources.getRequiredSourcesQName(),
 462                     capabilities.getUnresolvedCapabilites().keySet());
 463             capabilities.addCapabilities(filteredQNames.stream().map(entry -> new AvailableCapabilityBuilder()
 464                     .setCapability(entry.toString()).setCapabilityOrigin(
 465                             remoteSessionCapabilities.getModuleBasedCapsOrigin().get(entry)).build())
 466                     .collect(Collectors.toList()));
 467
 468             capabilities.addNonModuleBasedCapabilities(remoteSessionCapabilities
 469                     .getNonModuleCaps().stream().map(entry -> new AvailableCapabilityBuilder()
 470                             .setCapability(entry).setCapabilityOrigin(
 471                                     remoteSessionCapabilities.getNonModuleBasedCapsOrigin().get(entry)).build())
 472                     .collect(Collectors.toList()));
 473
 474             resultFuture.set(result);
 475         }
 476
 477         @Override
 478         public void onFailure(final Throwable cause) {
 479             // schemaBuilderFuture.checkedGet() throws only SchemaResolutionException
 480             // that might be wrapping a MissingSchemaSourceException so we need to look
 481             // at the cause of the exception to make sure we don't misinterpret it.
 482             if (cause instanceof MissingSchemaSourceException) {
 483                 requiredSources = handleMissingSchemaSourceException((MissingSchemaSourceException) cause);
 484             } else if (cause instanceof SchemaResolutionException) {
 485                 requiredSources = handleSchemaResolutionException((SchemaResolutionException) cause);
 486             } else {
 487                 LOG.debug("Unhandled failure", cause);
 488                 resultFuture.setException(cause);
 489                 // No more trying...
 490                 return;
 491             }
 492
 493             trySetupSchema();
 494         }
 495
 496         private void trySetupSchema() {
 497             if (!requiredSources.isEmpty()) {
 498                 // Initiate async resolution, drive it back based on the result
 499                 LOG.trace("{}: Trying to build schema context from {}", id, requiredSources);
 500                 Futures.addCallback(schemaContextFactory.createEffectiveModelContext(requiredSources), this,
 501                     MoreExecutors.directExecutor());
 502             } else {
 503                 LOG.debug("{}: no more sources for schema context", id);
 504                 resultFuture.setException(new EmptySchemaContextException(id + ": No more sources for schema context"));
 505             }
 506         }
 507
 508         private Collection<SourceIdentifier> filterMissingSources(final Collection<SourceIdentifier> origSources) {
 509             return origSources.parallelStream().filter(sourceIdentifier -> {
 510                 try {
 511                     schemaRepository.getSchemaSource(sourceIdentifier, YangTextSchemaSource.class).get();
 512                     return false;
 513                 } catch (InterruptedException | ExecutionException e) {
 514                     return true;
 515                 }
 516             }).collect(Collectors.toList());
 517         }
 518
 519         private Collection<SourceIdentifier> handleMissingSchemaSourceException(
 520                 final MissingSchemaSourceException exception) {
 521             // In case source missing, try without it
 522             final SourceIdentifier missingSource = exception.getSourceId();
 523             LOG.warn("{}: Unable to build schema context, missing source {}, will reattempt without it",
 524                 id, missingSource);
 525             LOG.debug("{}: Unable to build schema context, missing source {}, will reattempt without it",
 526                 id, missingSource, exception);
 527             final Collection<QName> qNameOfMissingSource =
 528                 getQNameFromSourceIdentifiers(Sets.newHashSet(missingSource));
 529             if (!qNameOfMissingSource.isEmpty()) {
 530                 capabilities.addUnresolvedCapabilities(
 531                         qNameOfMissingSource, UnavailableCapability.FailureReason.MissingSource);
 532             }
 533             return stripUnavailableSource(missingSource);
 534         }
 535
 536         private Collection<SourceIdentifier> handleSchemaResolutionException(
 537                 final SchemaResolutionException resolutionException) {
 538             // In case resolution error, try only with resolved sources
 539             // There are two options why schema resolution exception occurred : unsatisfied imports or flawed model
 540             // FIXME Do we really have assurance that these two cases cannot happen at once?
 541             if (resolutionException.getFailedSource() != null) {
 542                 // flawed model - exclude it
 543                 final SourceIdentifier failedSourceId = resolutionException.getFailedSource();
 544                 LOG.warn("{}: Unable to build schema context, failed to resolve source {}, will reattempt without it",
 545                     id, failedSourceId);
 546                 LOG.warn("{}: Unable to build schema context, failed to resolve source {}, will reattempt without it",
 547                     id, failedSourceId, resolutionException);
 548                 capabilities.addUnresolvedCapabilities(
 549                         getQNameFromSourceIdentifiers(Collections.singleton(failedSourceId)),
 550                         UnavailableCapability.FailureReason.UnableToResolve);
 551                 return stripUnavailableSource(resolutionException.getFailedSource());
 552             }
 553             // unsatisfied imports
 554             final Set<SourceIdentifier> unresolvedSources = resolutionException.getUnsatisfiedImports().keySet();
 555             capabilities.addUnresolvedCapabilities(getQNameFromSourceIdentifiers(unresolvedSources),
 556                 UnavailableCapability.FailureReason.UnableToResolve);
 557             LOG.warn("{}: Unable to build schema context, unsatisfied imports {}, will reattempt with resolved only",
 558                 id, resolutionException.getUnsatisfiedImports());
 559             LOG.debug("{}: Unable to build schema context, unsatisfied imports {}, will reattempt with resolved only",
 560                 id, resolutionException.getUnsatisfiedImports(), resolutionException);
 561             return resolutionException.getResolvedSources();
 562         }
 563
 564         private Collection<SourceIdentifier> stripUnavailableSource(final SourceIdentifier sourceIdToRemove) {
 565             final LinkedList<SourceIdentifier> sourceIdentifiers = new LinkedList<>(requiredSources);
 566             checkState(sourceIdentifiers.remove(sourceIdToRemove),
 567                     "%s: Trying to remove %s from %s failed", id, sourceIdToRemove, requiredSources);
 568             return sourceIdentifiers;
 569         }
 570
 571         private Collection<QName> getQNameFromSourceIdentifiers(final Collection<SourceIdentifier> identifiers) {
 572             final Collection<QName> qNames = Collections2.transform(identifiers, this::getQNameFromSourceIdentifier);
 573
 574             if (qNames.isEmpty()) {
 575                 LOG.debug("{}: Unable to map any source identifiers to a capability reported by device : {}", id,
 576                         identifiers);
 577             }
 578             return Collections2.filter(qNames, Predicates.notNull());
 579         }
 580
 581         private QName getQNameFromSourceIdentifier(final SourceIdentifier identifier) {
 582             // Required sources are all required and provided merged in DeviceSourcesResolver
 583             for (final QName qname : deviceSources.getRequiredSourcesQName()) {
 584                 if (!qname.getLocalName().equals(identifier.getName())) {
 585                     continue;
 586                 }
 587
 588                 if (identifier.getRevision().equals(qname.getRevision())) {
 589                     return qname;
 590                 }
 591             }
 592             LOG.warn("Unable to map identifier to a devices reported capability: {} Available: {}",identifier,
 593                     deviceSources.getRequiredSourcesQName());
 594             // return null since we cannot find the QName,
 595             // this capability will be removed from required sources and not reported as unresolved-capability
 596             return null;
 597         }
 598     }
 599 }