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.BaseNetconfSchemas;
  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.optional.rev190614.NetconfNodeAugmentedOptional;
  56 import org.opendaylight.yang.gen.v1.urn.opendaylight.netconf.node.topology.rev150114.NetconfNode;
  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.rcf8528.data.util.EmptyMountPointContext;
  60 import org.opendaylight.yangtools.rfc8528.data.api.MountPointContext;
  61 import org.opendaylight.yangtools.rfc8528.model.api.SchemaMountConstants;
  62 import org.opendaylight.yangtools.yang.common.QName;
  63 import org.opendaylight.yangtools.yang.common.RpcError;
  64 import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier;
  65 import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier.NodeIdentifier;
  66 import org.opendaylight.yangtools.yang.data.api.schema.ContainerNode;
  67 import org.opendaylight.yangtools.yang.data.api.schema.NormalizedNode;
  68 import org.opendaylight.yangtools.yang.data.impl.schema.Builders;
  69 import org.opendaylight.yangtools.yang.model.api.EffectiveModelContext;
  70 import org.opendaylight.yangtools.yang.model.repo.api.EffectiveModelContextFactory;
  71 import org.opendaylight.yangtools.yang.model.repo.api.MissingSchemaSourceException;
  72 import org.opendaylight.yangtools.yang.model.repo.api.SchemaRepository;
  73 import org.opendaylight.yangtools.yang.model.repo.api.SchemaResolutionException;
  74 import org.opendaylight.yangtools.yang.model.repo.api.SourceIdentifier;
  75 import org.opendaylight.yangtools.yang.model.repo.api.YangTextSchemaSource;
  76 import org.opendaylight.yangtools.yang.model.repo.spi.PotentialSchemaSource;
  77 import org.opendaylight.yangtools.yang.model.repo.spi.SchemaSourceProvider;
  78 import org.opendaylight.yangtools.yang.model.repo.spi.SchemaSourceRegistration;
  79 import org.opendaylight.yangtools.yang.model.repo.spi.SchemaSourceRegistry;
  80 import org.slf4j.Logger;
  81 import org.slf4j.LoggerFactory;
  82
  83 /**
  84  *  This is a mediator between NetconfDeviceCommunicator and NetconfDeviceSalFacade.
  85  */
  86 public class NetconfDevice
  87         implements RemoteDevice<NetconfSessionPreferences, NetconfMessage, NetconfDeviceCommunicator> {
  88
  89     @SuppressFBWarnings(value = "SLF4J_LOGGER_SHOULD_BE_PRIVATE",
  90             justification = "Needed for common logging of related classes")
  91     static final Logger LOG = LoggerFactory.getLogger(NetconfDevice.class);
  92
  93     private static final QName RFC8528_SCHEMA_MOUNTS_QNAME = QName.create(
  94         SchemaMountConstants.RFC8528_MODULE, "schema-mounts").intern();
  95     private static final YangInstanceIdentifier RFC8528_SCHEMA_MOUNTS = YangInstanceIdentifier.create(
  96         NodeIdentifier.create(RFC8528_SCHEMA_MOUNTS_QNAME));
  97
  98     protected final RemoteDeviceId id;
  99     protected final EffectiveModelContextFactory schemaContextFactory;
 100     protected final SchemaSourceRegistry schemaRegistry;
 101     protected final SchemaRepository schemaRepository;
 102
 103     protected final List<SchemaSourceRegistration<?>> sourceRegistrations = new ArrayList<>();
 104
 105     private final RemoteDeviceHandler<NetconfSessionPreferences> salFacade;
 106     private final ListeningExecutorService processingExecutor;
 107     private final DeviceActionFactory deviceActionFactory;
 108     private final NetconfDeviceSchemasResolver stateSchemasResolver;
 109     private final NotificationHandler notificationHandler;
 110     private final boolean reconnectOnSchemasChange;
 111     private final BaseNetconfSchemas baseSchemas;
 112     private final NetconfNode node;
 113     private final EventExecutor eventExecutor;
 114     private final NetconfNodeAugmentedOptional nodeOptional;
 115
 116     @GuardedBy("this")
 117     private boolean connected = false;
 118
 119     // Message transformer is constructed once the schemas are available
 120     private MessageTransformer<NetconfMessage> messageTransformer;
 121
 122     public NetconfDevice(final SchemaResourcesDTO schemaResourcesDTO, final BaseNetconfSchemas baseSchemas,
 123             final RemoteDeviceId id, final RemoteDeviceHandler<NetconfSessionPreferences> salFacade,
 124             final ListeningExecutorService globalProcessingExecutor, final boolean reconnectOnSchemasChange) {
 125         this(schemaResourcesDTO, baseSchemas, id, salFacade, globalProcessingExecutor, reconnectOnSchemasChange, null,
 126             null, null, null);
 127     }
 128
 129     public NetconfDevice(final SchemaResourcesDTO schemaResourcesDTO, final BaseNetconfSchemas baseSchemas,
 130             final RemoteDeviceId id, final RemoteDeviceHandler<NetconfSessionPreferences> salFacade,
 131             final ListeningExecutorService globalProcessingExecutor, final boolean reconnectOnSchemasChange,
 132             final DeviceActionFactory deviceActionFactory, final NetconfNode node, final EventExecutor eventExecutor,
 133             final NetconfNodeAugmentedOptional nodeOptional) {
 134         this.baseSchemas = requireNonNull(baseSchemas);
 135         this.id = id;
 136         this.reconnectOnSchemasChange = reconnectOnSchemasChange;
 137         this.deviceActionFactory = deviceActionFactory;
 138         this.node = node;
 139         this.eventExecutor = eventExecutor;
 140         this.nodeOptional = nodeOptional;
 141         this.schemaRegistry = schemaResourcesDTO.getSchemaRegistry();
 142         this.schemaRepository = schemaResourcesDTO.getSchemaRepository();
 143         this.schemaContextFactory = schemaResourcesDTO.getSchemaContextFactory();
 144         this.salFacade = salFacade;
 145         this.stateSchemasResolver = schemaResourcesDTO.getStateSchemasResolver();
 146         this.processingExecutor = requireNonNull(globalProcessingExecutor);
 147         this.notificationHandler = new NotificationHandler(salFacade, id);
 148     }
 149
 150     @Override
 151     public void onRemoteSessionUp(final NetconfSessionPreferences remoteSessionCapabilities,
 152                                   final NetconfDeviceCommunicator listener) {
 153         // SchemaContext setup has to be performed in a dedicated thread since
 154         // we are in a netty thread in this method
 155         // Yang models are being downloaded in this method and it would cause a
 156         // deadlock if we used the netty thread
 157         // http://netty.io/wiki/thread-model.html
 158         setConnected(true);
 159         LOG.debug("{}: Session to remote device established with {}", id, remoteSessionCapabilities);
 160
 161         final BaseSchema baseSchema = resolveBaseSchema(remoteSessionCapabilities.isNotificationsSupported());
 162         final NetconfDeviceRpc initRpc = new NetconfDeviceRpc(baseSchema.getSchemaContext(), listener,
 163             new NetconfMessageTransformer(baseSchema.getMountPointContext(), false, baseSchema));
 164         final ListenableFuture<DeviceSources> sourceResolverFuture = processingExecutor.submit(
 165             new DeviceSourcesResolver(id, baseSchema, initRpc, remoteSessionCapabilities, stateSchemasResolver));
 166
 167         if (shouldListenOnSchemaChange(remoteSessionCapabilities)) {
 168             registerToBaseNetconfStream(initRpc, listener);
 169         }
 170
 171         // Set up the SchemaContext for the device
 172         final ListenableFuture<EffectiveModelContext> futureSchema = Futures.transformAsync(sourceResolverFuture,
 173             deviceSources -> assembleSchemaContext(deviceSources, remoteSessionCapabilities), processingExecutor);
 174
 175         // Potentially acquire mount point list and interpret it
 176         final ListenableFuture<MountPointContext> futureContext = Futures.transformAsync(futureSchema,
 177             schemaContext -> createMountPointContext(schemaContext, baseSchema, listener), processingExecutor);
 178
 179         Futures.addCallback(futureContext, new FutureCallback<MountPointContext>() {
 180             @Override
 181             public void onSuccess(final MountPointContext result) {
 182                 handleSalInitializationSuccess(result, remoteSessionCapabilities,
 183                     getDeviceSpecificRpc(result, listener), listener);
 184             }
 185
 186             @Override
 187             public void onFailure(final Throwable cause) {
 188                 LOG.warn("{}: Unexpected error resolving device sources", id, cause);
 189
 190                 // No more sources, fail or try to reconnect
 191                 if (cause instanceof EmptySchemaContextException) {
 192                     if (nodeOptional != null && nodeOptional.getIgnoreMissingSchemaSources().isAllowed()) {
 193                         eventExecutor.schedule(() -> {
 194                             LOG.warn("Reconnection is allowed! This can lead to unexpected errors at runtime.");
 195                             LOG.warn("{} : No more sources for schema context.", id);
 196                             LOG.info("{} : Try to remount device.", id);
 197                             onRemoteSessionDown();
 198                             salFacade.onDeviceReconnected(remoteSessionCapabilities, node);
 199                         }, nodeOptional.getIgnoreMissingSchemaSources().getReconnectTime().toJava(),
 200                             TimeUnit.MILLISECONDS);
 201                         return;
 202                     }
 203                 }
 204
 205                 handleSalInitializationFailure(cause, listener);
 206                 salFacade.onDeviceFailed(cause);
 207             }
 208         }, MoreExecutors.directExecutor());
 209     }
 210
 211     private void registerToBaseNetconfStream(final NetconfDeviceRpc deviceRpc,
 212                                              final NetconfDeviceCommunicator listener) {
 213         // TODO check whether the model describing create subscription is present in schema
 214         // Perhaps add a default schema context to support create-subscription if the model was not provided
 215         // (same as what we do for base netconf operations in transformer)
 216         final ListenableFuture<DOMRpcResult> rpcResultListenableFuture = deviceRpc.invokeRpc(
 217                 NetconfMessageTransformUtil.CREATE_SUBSCRIPTION_RPC_PATH,
 218                 NetconfMessageTransformUtil.CREATE_SUBSCRIPTION_RPC_CONTENT);
 219
 220         Futures.addCallback(rpcResultListenableFuture, new FutureCallback<DOMRpcResult>() {
 221             @Override
 222             public void onSuccess(final DOMRpcResult domRpcResult) {
 223                 notificationHandler.addNotificationFilter(notification -> {
 224                     if (NetconfCapabilityChange.QNAME.equals(notification.getBody().getNodeType())) {
 225                         LOG.info("{}: Schemas change detected, reconnecting", id);
 226                         // Only disconnect is enough,
 227                         // the reconnecting nature of the connector will take care of reconnecting
 228                         listener.disconnect();
 229                         return Optional.empty();
 230                     }
 231                     return Optional.of(notification);
 232                 });
 233             }
 234
 235             @Override
 236             public void onFailure(final Throwable throwable) {
 237                 LOG.warn("Unable to subscribe to base notification stream. Schemas will not be reloaded on the fly",
 238                         throwable);
 239             }
 240         }, MoreExecutors.directExecutor());
 241     }
 242
 243     private boolean shouldListenOnSchemaChange(final NetconfSessionPreferences remoteSessionCapabilities) {
 244         return remoteSessionCapabilities.isNotificationsSupported() && reconnectOnSchemasChange;
 245     }
 246
 247     @SuppressFBWarnings(value = "UPM_UNCALLED_PRIVATE_METHOD",
 248             justification = "https://github.com/spotbugs/spotbugs/issues/811")
 249     private synchronized void handleSalInitializationSuccess(final MountPointContext result,
 250                                         final NetconfSessionPreferences remoteSessionCapabilities,
 251                                         final DOMRpcService deviceRpc,
 252                                         final RemoteDeviceCommunicator<NetconfMessage> listener) {
 253         //NetconfDevice.SchemaSetup can complete after NetconfDeviceCommunicator was closed. In that case do nothing,
 254         //since salFacade.onDeviceDisconnected was already called.
 255         if (connected) {
 256             this.messageTransformer = new NetconfMessageTransformer(result, true,
 257                 resolveBaseSchema(remoteSessionCapabilities.isNotificationsSupported()));
 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 BaseSchema resolveBaseSchema(final boolean notificationSupport) {
 370         return notificationSupport ? baseSchemas.getBaseSchemaWithNotifications() : baseSchemas.getBaseSchema();
 371     }
 372
 373     protected NetconfDeviceRpc getDeviceSpecificRpc(final MountPointContext result,
 374             final RemoteDeviceCommunicator<NetconfMessage> listener) {
 375         return new NetconfDeviceRpc(result.getSchemaContext(), listener,
 376             new NetconfMessageTransformer(result, true, baseSchemas.getBaseSchema()));
 377     }
 378
 379     /**
 380      * Just a transfer object containing schema related dependencies. Injected in constructor.
 381      */
 382     public static class SchemaResourcesDTO {
 383         private final SchemaSourceRegistry schemaRegistry;
 384         private final SchemaRepository schemaRepository;
 385         private final EffectiveModelContextFactory schemaContextFactory;
 386         private final NetconfDeviceSchemasResolver stateSchemasResolver;
 387
 388         public SchemaResourcesDTO(final SchemaSourceRegistry schemaRegistry,
 389                                   final SchemaRepository schemaRepository,
 390                                   final EffectiveModelContextFactory schemaContextFactory,
 391                                   final NetconfDeviceSchemasResolver deviceSchemasResolver) {
 392             this.schemaRegistry = requireNonNull(schemaRegistry);
 393             this.schemaRepository = requireNonNull(schemaRepository);
 394             this.schemaContextFactory = requireNonNull(schemaContextFactory);
 395             this.stateSchemasResolver = requireNonNull(deviceSchemasResolver);
 396         }
 397
 398         public SchemaSourceRegistry getSchemaRegistry() {
 399             return schemaRegistry;
 400         }
 401
 402         public SchemaRepository getSchemaRepository() {
 403             return schemaRepository;
 404         }
 405
 406         public EffectiveModelContextFactory getSchemaContextFactory() {
 407             return schemaContextFactory;
 408         }
 409
 410         public NetconfDeviceSchemasResolver getStateSchemasResolver() {
 411             return stateSchemasResolver;
 412         }
 413     }
 414
 415     /**
 416      * A dedicated exception to indicate when we fail to setup a SchemaContext.
 417      *
 418      * @author Robert Varga
 419      */
 420     private static final class EmptySchemaContextException extends Exception {
 421         private static final long serialVersionUID = 1L;
 422
 423         EmptySchemaContextException(final String message) {
 424             super(message);
 425         }
 426     }
 427
 428     /**
 429      * Schema builder that tries to build schema context from provided sources or biggest subset of it.
 430      */
 431     private final class SchemaSetup implements FutureCallback<EffectiveModelContext> {
 432         private final SettableFuture<EffectiveModelContext> resultFuture = SettableFuture.create();
 433
 434         private final DeviceSources deviceSources;
 435         private final NetconfSessionPreferences remoteSessionCapabilities;
 436         private final NetconfDeviceCapabilities capabilities;
 437
 438         private Collection<SourceIdentifier> requiredSources;
 439
 440         SchemaSetup(final DeviceSources deviceSources, final NetconfSessionPreferences remoteSessionCapabilities) {
 441             this.deviceSources = deviceSources;
 442             this.remoteSessionCapabilities = remoteSessionCapabilities;
 443             this.capabilities = remoteSessionCapabilities.getNetconfDeviceCapabilities();
 444
 445             requiredSources = deviceSources.getRequiredSources();
 446             final Collection<SourceIdentifier> missingSources = filterMissingSources(requiredSources);
 447
 448             capabilities.addUnresolvedCapabilities(getQNameFromSourceIdentifiers(missingSources),
 449                     UnavailableCapability.FailureReason.MissingSource);
 450             requiredSources.removeAll(missingSources);
 451         }
 452
 453         ListenableFuture<EffectiveModelContext> startResolution() {
 454             trySetupSchema();
 455             return resultFuture;
 456         }
 457
 458         @Override
 459         public void onSuccess(final EffectiveModelContext result) {
 460             LOG.debug("{}: Schema context built successfully from {}", id, requiredSources);
 461
 462             final Collection<QName> filteredQNames = Sets.difference(deviceSources.getRequiredSourcesQName(),
 463                     capabilities.getUnresolvedCapabilites().keySet());
 464             capabilities.addCapabilities(filteredQNames.stream().map(entry -> new AvailableCapabilityBuilder()
 465                     .setCapability(entry.toString()).setCapabilityOrigin(
 466                             remoteSessionCapabilities.getModuleBasedCapsOrigin().get(entry)).build())
 467                     .collect(Collectors.toList()));
 468
 469             capabilities.addNonModuleBasedCapabilities(remoteSessionCapabilities
 470                     .getNonModuleCaps().stream().map(entry -> new AvailableCapabilityBuilder()
 471                             .setCapability(entry).setCapabilityOrigin(
 472                                     remoteSessionCapabilities.getNonModuleBasedCapsOrigin().get(entry)).build())
 473                     .collect(Collectors.toList()));
 474
 475             resultFuture.set(result);
 476         }
 477
 478         @Override
 479         public void onFailure(final Throwable cause) {
 480             // schemaBuilderFuture.checkedGet() throws only SchemaResolutionException
 481             // that might be wrapping a MissingSchemaSourceException so we need to look
 482             // at the cause of the exception to make sure we don't misinterpret it.
 483             if (cause instanceof MissingSchemaSourceException) {
 484                 requiredSources = handleMissingSchemaSourceException((MissingSchemaSourceException) cause);
 485             } else if (cause instanceof SchemaResolutionException) {
 486                 requiredSources = handleSchemaResolutionException((SchemaResolutionException) cause);
 487             } else {
 488                 LOG.debug("Unhandled failure", cause);
 489                 resultFuture.setException(cause);
 490                 // No more trying...
 491                 return;
 492             }
 493
 494             trySetupSchema();
 495         }
 496
 497         private void trySetupSchema() {
 498             if (!requiredSources.isEmpty()) {
 499                 // Initiate async resolution, drive it back based on the result
 500                 LOG.trace("{}: Trying to build schema context from {}", id, requiredSources);
 501                 Futures.addCallback(schemaContextFactory.createEffectiveModelContext(requiredSources), this,
 502                     MoreExecutors.directExecutor());
 503             } else {
 504                 LOG.debug("{}: no more sources for schema context", id);
 505                 resultFuture.setException(new EmptySchemaContextException(id + ": No more sources for schema context"));
 506             }
 507         }
 508
 509         private Collection<SourceIdentifier> filterMissingSources(final Collection<SourceIdentifier> origSources) {
 510             return origSources.parallelStream().filter(sourceIdentifier -> {
 511                 try {
 512                     schemaRepository.getSchemaSource(sourceIdentifier, YangTextSchemaSource.class).get();
 513                     return false;
 514                 } catch (InterruptedException | ExecutionException e) {
 515                     return true;
 516                 }
 517             }).collect(Collectors.toList());
 518         }
 519
 520         private Collection<SourceIdentifier> handleMissingSchemaSourceException(
 521                 final MissingSchemaSourceException exception) {
 522             // In case source missing, try without it
 523             final SourceIdentifier missingSource = exception.getSourceId();
 524             LOG.warn("{}: Unable to build schema context, missing source {}, will reattempt without it",
 525                 id, missingSource);
 526             LOG.debug("{}: Unable to build schema context, missing source {}, will reattempt without it",
 527                 id, missingSource, exception);
 528             final Collection<QName> qNameOfMissingSource =
 529                 getQNameFromSourceIdentifiers(Sets.newHashSet(missingSource));
 530             if (!qNameOfMissingSource.isEmpty()) {
 531                 capabilities.addUnresolvedCapabilities(
 532                         qNameOfMissingSource, UnavailableCapability.FailureReason.MissingSource);
 533             }
 534             return stripUnavailableSource(missingSource);
 535         }
 536
 537         private Collection<SourceIdentifier> handleSchemaResolutionException(
 538                 final SchemaResolutionException resolutionException) {
 539             // In case resolution error, try only with resolved sources
 540             // There are two options why schema resolution exception occurred : unsatisfied imports or flawed model
 541             // FIXME Do we really have assurance that these two cases cannot happen at once?
 542             if (resolutionException.getFailedSource() != null) {
 543                 // flawed model - exclude it
 544                 final SourceIdentifier failedSourceId = resolutionException.getFailedSource();
 545                 LOG.warn("{}: Unable to build schema context, failed to resolve source {}, will reattempt without it",
 546                     id, failedSourceId);
 547                 LOG.warn("{}: Unable to build schema context, failed to resolve source {}, will reattempt without it",
 548                     id, failedSourceId, resolutionException);
 549                 capabilities.addUnresolvedCapabilities(
 550                         getQNameFromSourceIdentifiers(Collections.singleton(failedSourceId)),
 551                         UnavailableCapability.FailureReason.UnableToResolve);
 552                 return stripUnavailableSource(resolutionException.getFailedSource());
 553             }
 554             // unsatisfied imports
 555             final Set<SourceIdentifier> unresolvedSources = resolutionException.getUnsatisfiedImports().keySet();
 556             capabilities.addUnresolvedCapabilities(getQNameFromSourceIdentifiers(unresolvedSources),
 557                 UnavailableCapability.FailureReason.UnableToResolve);
 558             LOG.warn("{}: Unable to build schema context, unsatisfied imports {}, will reattempt with resolved only",
 559                 id, resolutionException.getUnsatisfiedImports());
 560             LOG.debug("{}: Unable to build schema context, unsatisfied imports {}, will reattempt with resolved only",
 561                 id, resolutionException.getUnsatisfiedImports(), resolutionException);
 562             return resolutionException.getResolvedSources();
 563         }
 564
 565         private Collection<SourceIdentifier> stripUnavailableSource(final SourceIdentifier sourceIdToRemove) {
 566             final LinkedList<SourceIdentifier> sourceIdentifiers = new LinkedList<>(requiredSources);
 567             checkState(sourceIdentifiers.remove(sourceIdToRemove),
 568                     "%s: Trying to remove %s from %s failed", id, sourceIdToRemove, requiredSources);
 569             return sourceIdentifiers;
 570         }
 571
 572         private Collection<QName> getQNameFromSourceIdentifiers(final Collection<SourceIdentifier> identifiers) {
 573             final Collection<QName> qNames = Collections2.transform(identifiers, this::getQNameFromSourceIdentifier);
 574
 575             if (qNames.isEmpty()) {
 576                 LOG.debug("{}: Unable to map any source identifiers to a capability reported by device : {}", id,
 577                         identifiers);
 578             }
 579             return Collections2.filter(qNames, Predicates.notNull());
 580         }
 581
 582         private QName getQNameFromSourceIdentifier(final SourceIdentifier identifier) {
 583             // Required sources are all required and provided merged in DeviceSourcesResolver
 584             for (final QName qname : deviceSources.getRequiredSourcesQName()) {
 585                 if (!qname.getLocalName().equals(identifier.getName())) {
 586                     continue;
 587                 }
 588
 589                 if (identifier.getRevision().equals(qname.getRevision())) {
 590                     return qname;
 591                 }
 592             }
 593             LOG.warn("Unable to map identifier to a devices reported capability: {} Available: {}",identifier,
 594                     deviceSources.getRequiredSourcesQName());
 595             // return null since we cannot find the QName,
 596             // this capability will be removed from required sources and not reported as unresolved-capability
 597             return null;
 598         }
 599     }
 600 }