plugins/netconf-client-mdsal/src/main/java/org/opendaylight/netconf/client/mdsal/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.client.mdsal;
   9
  10 import static com.google.common.base.Preconditions.checkState;
  11 import static java.util.Objects.requireNonNull;
  12 import static org.opendaylight.netconf.client.mdsal.impl.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.ImmutableMap;
  17 import com.google.common.collect.ImmutableSet;
  18 import com.google.common.collect.Sets;
  19 import com.google.common.util.concurrent.FutureCallback;
  20 import com.google.common.util.concurrent.Futures;
  21 import com.google.common.util.concurrent.ListenableFuture;
  22 import com.google.common.util.concurrent.MoreExecutors;
  23 import com.google.common.util.concurrent.SettableFuture;
  24 import java.io.Serial;
  25 import java.util.ArrayList;
  26 import java.util.Collection;
  27 import java.util.HashMap;
  28 import java.util.HashSet;
  29 import java.util.List;
  30 import java.util.Map;
  31 import java.util.Objects;
  32 import java.util.Set;
  33 import java.util.concurrent.CancellationException;
  34 import java.util.concurrent.ExecutionException;
  35 import java.util.concurrent.Executor;
  36 import java.util.stream.Collectors;
  37 import org.checkerframework.checker.lock.qual.GuardedBy;
  38 import org.eclipse.jdt.annotation.NonNull;
  39 import org.opendaylight.mdsal.dom.api.DOMRpcResult;
  40 import org.opendaylight.netconf.api.CapabilityURN;
  41 import org.opendaylight.netconf.api.messages.NetconfMessage;
  42 import org.opendaylight.netconf.client.mdsal.api.BaseNetconfSchemas;
  43 import org.opendaylight.netconf.client.mdsal.api.DeviceActionFactory;
  44 import org.opendaylight.netconf.client.mdsal.api.NetconfDeviceSchemasResolver;
  45 import org.opendaylight.netconf.client.mdsal.api.NetconfSessionPreferences;
  46 import org.opendaylight.netconf.client.mdsal.api.RemoteDevice;
  47 import org.opendaylight.netconf.client.mdsal.api.RemoteDeviceCommunicator;
  48 import org.opendaylight.netconf.client.mdsal.api.RemoteDeviceHandler;
  49 import org.opendaylight.netconf.client.mdsal.api.RemoteDeviceId;
  50 import org.opendaylight.netconf.client.mdsal.api.RemoteDeviceServices;
  51 import org.opendaylight.netconf.client.mdsal.api.RemoteDeviceServices.Rpcs;
  52 import org.opendaylight.netconf.client.mdsal.impl.BaseSchema;
  53 import org.opendaylight.netconf.client.mdsal.impl.NetconfMessageTransformUtil;
  54 import org.opendaylight.netconf.client.mdsal.impl.NetconfMessageTransformer;
  55 import org.opendaylight.netconf.client.mdsal.spi.NetconfDeviceRpc;
  56 import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.netconf.notifications.rev120206.NetconfCapabilityChange;
  57 import org.opendaylight.yang.gen.v1.urn.opendaylight.netconf.device.rev231025.connection.oper.available.capabilities.AvailableCapability;
  58 import org.opendaylight.yang.gen.v1.urn.opendaylight.netconf.device.rev231025.connection.oper.available.capabilities.AvailableCapabilityBuilder;
  59 import org.opendaylight.yang.gen.v1.urn.opendaylight.netconf.device.rev231025.connection.oper.unavailable.capabilities.UnavailableCapability;
  60 import org.opendaylight.yang.gen.v1.urn.opendaylight.netconf.device.rev231025.connection.oper.unavailable.capabilities.UnavailableCapability.FailureReason;
  61 import org.opendaylight.yangtools.concepts.Registration;
  62 import org.opendaylight.yangtools.rfc8528.model.api.SchemaMountConstants;
  63 import org.opendaylight.yangtools.yang.common.QName;
  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.MountPointContext;
  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.SchemaSourceRegistry;
  76 import org.slf4j.Logger;
  77 import org.slf4j.LoggerFactory;
  78
  79 /**
  80  *  This is a mediator between NetconfDeviceCommunicator and NetconfDeviceSalFacade.
  81  */
  82 public class NetconfDevice implements RemoteDevice<NetconfDeviceCommunicator> {
  83     private static final Logger LOG = LoggerFactory.getLogger(NetconfDevice.class);
  84
  85     private static final QName RFC8528_SCHEMA_MOUNTS_QNAME = QName.create(
  86         SchemaMountConstants.RFC8528_MODULE, "schema-mounts").intern();
  87     private static final YangInstanceIdentifier RFC8528_SCHEMA_MOUNTS = YangInstanceIdentifier.of(
  88         NodeIdentifier.create(RFC8528_SCHEMA_MOUNTS_QNAME));
  89
  90     protected final RemoteDeviceId id;
  91     protected final EffectiveModelContextFactory schemaContextFactory;
  92     protected final SchemaSourceRegistry schemaRegistry;
  93     protected final SchemaRepository schemaRepository;
  94
  95     protected final List<Registration> sourceRegistrations = new ArrayList<>();
  96
  97     private final RemoteDeviceHandler salFacade;
  98     private final Executor processingExecutor;
  99     private final DeviceActionFactory deviceActionFactory;
 100     private final NetconfDeviceSchemasResolver stateSchemasResolver;
 101     private final NotificationHandler notificationHandler;
 102     private final boolean reconnectOnSchemasChange;
 103     private final BaseNetconfSchemas baseSchemas;
 104
 105     @GuardedBy("this")
 106     private ListenableFuture<List<Object>> schemaFuturesList;
 107     @GuardedBy("this")
 108     private boolean connected = false;
 109
 110     public NetconfDevice(final SchemaResourcesDTO schemaResourcesDTO, final BaseNetconfSchemas baseSchemas,
 111             final RemoteDeviceId id, final RemoteDeviceHandler salFacade, final Executor globalProcessingExecutor,
 112             final boolean reconnectOnSchemasChange) {
 113         this(schemaResourcesDTO, baseSchemas, id, salFacade, globalProcessingExecutor, reconnectOnSchemasChange, null);
 114     }
 115
 116     public NetconfDevice(final SchemaResourcesDTO schemaResourcesDTO, final BaseNetconfSchemas baseSchemas,
 117             final RemoteDeviceId id, final RemoteDeviceHandler salFacade, final Executor globalProcessingExecutor,
 118             final boolean reconnectOnSchemasChange, final DeviceActionFactory deviceActionFactory) {
 119         this.baseSchemas = requireNonNull(baseSchemas);
 120         this.id = id;
 121         this.reconnectOnSchemasChange = reconnectOnSchemasChange;
 122         this.deviceActionFactory = deviceActionFactory;
 123         schemaRegistry = schemaResourcesDTO.getSchemaRegistry();
 124         schemaRepository = schemaResourcesDTO.getSchemaRepository();
 125         schemaContextFactory = schemaResourcesDTO.getSchemaContextFactory();
 126         this.salFacade = salFacade;
 127         stateSchemasResolver = schemaResourcesDTO.getStateSchemasResolver();
 128         processingExecutor = requireNonNull(globalProcessingExecutor);
 129         notificationHandler = new NotificationHandler(salFacade, id);
 130     }
 131
 132     @Override
 133     public synchronized void onRemoteSessionUp(final NetconfSessionPreferences remoteSessionCapabilities,
 134             final NetconfDeviceCommunicator listener) {
 135         // SchemaContext setup has to be performed in a dedicated thread since we are in a Netty thread in this method
 136         // YANG models are being downloaded in this method and it would cause a deadlock if we used the netty thread
 137         // https://netty.io/wiki/thread-model.html
 138         setConnected(true);
 139         LOG.debug("{}: Session to remote device established with {}", id, remoteSessionCapabilities);
 140
 141         final BaseSchema baseSchema = resolveBaseSchema(remoteSessionCapabilities.isNotificationsSupported());
 142         final NetconfDeviceRpc initRpc = new NetconfDeviceRpc(baseSchema.getEffectiveModelContext(), listener,
 143             new NetconfMessageTransformer(baseSchema.getMountPointContext(), false, baseSchema));
 144         final var sourceResolverFuture = Futures.submit(new DeviceSourcesResolver(id, baseSchema, initRpc,
 145                 remoteSessionCapabilities, stateSchemasResolver), processingExecutor);
 146
 147         if (shouldListenOnSchemaChange(remoteSessionCapabilities)) {
 148             registerToBaseNetconfStream(initRpc, listener);
 149         }
 150
 151         // Set up the EffectiveModelContext for the device
 152         final var futureSchema = Futures.transformAsync(sourceResolverFuture,
 153             deviceSources -> assembleSchemaContext(deviceSources, remoteSessionCapabilities), processingExecutor);
 154
 155         // Potentially acquire mount point list and interpret it
 156         final var netconfDeviceSchemaFuture = Futures.transformAsync(futureSchema,
 157             result -> Futures.transform(createMountPointContext(result.modelContext(), baseSchema, listener),
 158                 mount -> new NetconfDeviceSchema(result.capabilities(), mount), processingExecutor),
 159             processingExecutor);
 160         schemaFuturesList = Futures.allAsList(sourceResolverFuture, futureSchema, netconfDeviceSchemaFuture);
 161
 162         Futures.addCallback(netconfDeviceSchemaFuture, new FutureCallback<>() {
 163                 @Override
 164                 public void onSuccess(final NetconfDeviceSchema result) {
 165                     handleSalInitializationSuccess(listener, result, remoteSessionCapabilities,
 166                         getDeviceSpecificRpc(result.mountContext(), listener, baseSchema));
 167                 }
 168
 169                 @Override
 170                 public void onFailure(final Throwable cause) {
 171                     // The method onRemoteSessionDown was called while the EffectiveModelContext for the device
 172                     // was being processed.
 173                     if (cause instanceof CancellationException) {
 174                         LOG.warn("{}: Device communicator was tear down since the schema setup started", id);
 175                     } else {
 176                         handleSalInitializationFailure(listener, cause);
 177                     }
 178                 }
 179             }, 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 var rpcResultListenableFuture = deviceRpc.invokeRpc(
 188                 NetconfMessageTransformUtil.CREATE_SUBSCRIPTION_RPC_QNAME,
 189                 NetconfMessageTransformUtil.CREATE_SUBSCRIPTION_RPC_CONTENT);
 190
 191         Futures.addCallback(rpcResultListenableFuture, new FutureCallback<DOMRpcResult>() {
 192             @Override
 193             public void onSuccess(final DOMRpcResult domRpcResult) {
 194                 notificationHandler.addNotificationFilter(notification -> {
 195                     if (NetconfCapabilityChange.QNAME.equals(notification.getBody().name().getNodeType())) {
 196                         LOG.info("{}: Schemas change detected, reconnecting", id);
 197                         // Only disconnect is enough,
 198                         // the reconnecting nature of the connector will take care of reconnecting
 199                         listener.disconnect();
 200                         return false;
 201                     }
 202                     return true;
 203                 });
 204             }
 205
 206             @Override
 207             public void onFailure(final Throwable throwable) {
 208                 LOG.warn("Unable to subscribe to base notification stream. Schemas will not be reloaded on the fly",
 209                         throwable);
 210             }
 211         }, MoreExecutors.directExecutor());
 212     }
 213
 214     private boolean shouldListenOnSchemaChange(final NetconfSessionPreferences remoteSessionCapabilities) {
 215         return remoteSessionCapabilities.isNotificationsSupported() && reconnectOnSchemasChange;
 216     }
 217
 218     private synchronized void handleSalInitializationSuccess(final RemoteDeviceCommunicator listener,
 219             final NetconfDeviceSchema deviceSchema, final NetconfSessionPreferences remoteSessionCapabilities,
 220             final Rpcs deviceRpc) {
 221         // NetconfDevice.SchemaSetup can complete after NetconfDeviceCommunicator was closed. In that case do nothing,
 222         // since salFacade.onDeviceDisconnected was already called.
 223         if (!connected) {
 224             LOG.warn("{}: Device communicator was closed before schema setup finished.", id);
 225             return;
 226         }
 227
 228         final var messageTransformer = new NetconfMessageTransformer(deviceSchema.mountContext(), true,
 229             resolveBaseSchema(remoteSessionCapabilities.isNotificationsSupported()));
 230
 231         // Order is important here: salFacade has to see the device come up and then the notificationHandler can deliver
 232         // whatever notifications have been held back
 233         salFacade.onDeviceConnected(deviceSchema, remoteSessionCapabilities,
 234             new RemoteDeviceServices(deviceRpc, deviceActionFactory == null ? null
 235                 : deviceActionFactory.createDeviceAction(messageTransformer, listener)));
 236         notificationHandler.onRemoteSchemaUp(messageTransformer);
 237
 238         LOG.info("{}: Netconf connector initialized successfully", id);
 239     }
 240
 241     private void handleSalInitializationFailure(final RemoteDeviceCommunicator listener, final Throwable cause) {
 242         LOG.warn("{}: Unexpected error resolving device sources", id, cause);
 243         listener.close();
 244         cleanupInitialization();
 245         salFacade.onDeviceFailed(cause);
 246     }
 247
 248     private synchronized void cleanupInitialization() {
 249         connected = false;
 250         if (schemaFuturesList != null && !schemaFuturesList.isDone()) {
 251             if (!schemaFuturesList.cancel(true)) {
 252                 LOG.warn("The cleanup of Schema Futures for device {} was unsuccessful.", id);
 253             }
 254         }
 255         notificationHandler.onRemoteSchemaDown();
 256         sourceRegistrations.forEach(Registration::close);
 257         sourceRegistrations.clear();
 258     }
 259
 260     private synchronized void setConnected(final boolean connected) {
 261         this.connected = connected;
 262     }
 263
 264     private ListenableFuture<SchemaResult> assembleSchemaContext(final DeviceSources deviceSources,
 265             final NetconfSessionPreferences remoteSessionCapabilities) {
 266         LOG.debug("{}: Resolved device sources to {}", id, deviceSources);
 267
 268         sourceRegistrations.addAll(deviceSources.register(schemaRegistry));
 269
 270         return new SchemaSetup(deviceSources, remoteSessionCapabilities).startResolution();
 271     }
 272
 273     private ListenableFuture<@NonNull MountPointContext> createMountPointContext(
 274             final EffectiveModelContext schemaContext, final BaseSchema baseSchema,
 275             final NetconfDeviceCommunicator listener) {
 276         final MountPointContext emptyContext = MountPointContext.of(schemaContext);
 277         if (schemaContext.findModule(SchemaMountConstants.RFC8528_MODULE).isEmpty()) {
 278             return Futures.immediateFuture(emptyContext);
 279         }
 280
 281         // Create a temporary RPC invoker and acquire the mount point tree
 282         LOG.debug("{}: Acquiring available mount points", id);
 283         final NetconfDeviceRpc deviceRpc = new NetconfDeviceRpc(schemaContext, listener,
 284             new NetconfMessageTransformer(emptyContext, false, baseSchema));
 285
 286         return Futures.transform(deviceRpc.invokeRpc(NetconfMessageTransformUtil.NETCONF_GET_QNAME,
 287             Builders.containerBuilder().withNodeIdentifier(NETCONF_GET_NODEID)
 288                 .withChild(NetconfMessageTransformUtil.toFilterStructure(RFC8528_SCHEMA_MOUNTS, schemaContext))
 289                 .build()), rpcResult -> processSchemaMounts(rpcResult, emptyContext), MoreExecutors.directExecutor());
 290     }
 291
 292     private MountPointContext processSchemaMounts(final DOMRpcResult rpcResult, final MountPointContext emptyContext) {
 293         final var errors = rpcResult.errors();
 294         if (!errors.isEmpty()) {
 295             LOG.warn("{}: Schema-mounts acquisition resulted in errors {}", id, errors);
 296         }
 297         final var schemaMounts = rpcResult.value();
 298         if (schemaMounts == null) {
 299             LOG.debug("{}: device does not define any schema mounts", id);
 300             return emptyContext;
 301         }
 302
 303         return DeviceMountPointContext.create(emptyContext, schemaMounts);
 304     }
 305
 306     @Override
 307     public void onRemoteSessionDown() {
 308         cleanupInitialization();
 309         salFacade.onDeviceDisconnected();
 310     }
 311
 312     @Override
 313     public void onNotification(final NetconfMessage notification) {
 314         notificationHandler.handleNotification(notification);
 315     }
 316
 317     private BaseSchema resolveBaseSchema(final boolean notificationSupport) {
 318         return notificationSupport ? baseSchemas.baseSchemaWithNotifications() : baseSchemas.baseSchema();
 319     }
 320
 321     protected NetconfDeviceRpc getDeviceSpecificRpc(final MountPointContext result,
 322             final RemoteDeviceCommunicator listener, final BaseSchema schema) {
 323         return new NetconfDeviceRpc(result.getEffectiveModelContext(), listener,
 324             new NetconfMessageTransformer(result, true, schema));
 325     }
 326
 327     /**
 328      * Just a transfer object containing schema related dependencies. Injected in constructor.
 329      */
 330     public static class SchemaResourcesDTO {
 331         private final SchemaSourceRegistry schemaRegistry;
 332         private final SchemaRepository schemaRepository;
 333         private final EffectiveModelContextFactory schemaContextFactory;
 334         private final NetconfDeviceSchemasResolver stateSchemasResolver;
 335
 336         public SchemaResourcesDTO(final SchemaSourceRegistry schemaRegistry,
 337                                   final SchemaRepository schemaRepository,
 338                                   final EffectiveModelContextFactory schemaContextFactory,
 339                                   final NetconfDeviceSchemasResolver deviceSchemasResolver) {
 340             this.schemaRegistry = requireNonNull(schemaRegistry);
 341             this.schemaRepository = requireNonNull(schemaRepository);
 342             this.schemaContextFactory = requireNonNull(schemaContextFactory);
 343             stateSchemasResolver = requireNonNull(deviceSchemasResolver);
 344         }
 345
 346         public SchemaSourceRegistry getSchemaRegistry() {
 347             return schemaRegistry;
 348         }
 349
 350         public SchemaRepository getSchemaRepository() {
 351             return schemaRepository;
 352         }
 353
 354         public EffectiveModelContextFactory getSchemaContextFactory() {
 355             return schemaContextFactory;
 356         }
 357
 358         public NetconfDeviceSchemasResolver getStateSchemasResolver() {
 359             return stateSchemasResolver;
 360         }
 361     }
 362
 363     /**
 364      * A dedicated exception to indicate when we fail to setup an {@link EffectiveModelContext}.
 365      */
 366     public static final class EmptySchemaContextException extends Exception {
 367         @Serial
 368         private static final long serialVersionUID = 1L;
 369
 370         public EmptySchemaContextException(final String message) {
 371             super(message);
 372         }
 373     }
 374
 375     /**
 376      * {@link NetconfDeviceCapabilities} and {@link EffectiveModelContext}.
 377      */
 378     private record SchemaResult(
 379         @NonNull NetconfDeviceCapabilities capabilities,
 380         @NonNull EffectiveModelContext modelContext) {
 381
 382         SchemaResult {
 383             requireNonNull(capabilities);
 384             requireNonNull(modelContext);
 385         }
 386     }
 387
 388     /**
 389      * Schema builder that tries to build schema context from provided sources or biggest subset of it.
 390      */
 391     private final class SchemaSetup implements FutureCallback<EffectiveModelContext> {
 392         private final SettableFuture<SchemaResult> resultFuture = SettableFuture.create();
 393
 394         private final Set<AvailableCapability> nonModuleBasedCapabilities = new HashSet<>();
 395         private final Map<QName, FailureReason> unresolvedCapabilites = new HashMap<>();
 396         private final Set<AvailableCapability> resolvedCapabilities = new HashSet<>();
 397
 398         private final DeviceSources deviceSources;
 399         private final NetconfSessionPreferences remoteSessionCapabilities;
 400
 401         private Collection<SourceIdentifier> requiredSources;
 402
 403         SchemaSetup(final DeviceSources deviceSources, final NetconfSessionPreferences remoteSessionCapabilities) {
 404             this.deviceSources = deviceSources;
 405             this.remoteSessionCapabilities = remoteSessionCapabilities;
 406
 407             // If device supports notifications and does not contain necessary modules, add them automatically
 408             if (remoteSessionCapabilities.containsNonModuleCapability(CapabilityURN.NOTIFICATION)) {
 409                 // FIXME: mutable collection modification!
 410                 deviceSources.getRequiredSourcesQName().addAll(List.of(
 411                     org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.netconf.notification._1._0.rev080714
 412                         .$YangModuleInfoImpl.getInstance().getName(),
 413                     org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.yang.types.rev130715
 414                         .$YangModuleInfoImpl.getInstance().getName())
 415                 );
 416             }
 417
 418             requiredSources = deviceSources.getRequiredSources();
 419             final Collection<SourceIdentifier> missingSources = filterMissingSources(requiredSources);
 420
 421             addUnresolvedCapabilities(getQNameFromSourceIdentifiers(missingSources),
 422                 UnavailableCapability.FailureReason.MissingSource);
 423             requiredSources.removeAll(missingSources);
 424         }
 425
 426         ListenableFuture<SchemaResult> startResolution() {
 427             trySetupSchema();
 428             return resultFuture;
 429         }
 430
 431         @Override
 432         public void onSuccess(final EffectiveModelContext result) {
 433             LOG.debug("{}: Schema context built successfully from {}", id, requiredSources);
 434
 435             final Collection<QName> filteredQNames = Sets.difference(deviceSources.getRequiredSourcesQName(),
 436                     unresolvedCapabilites.keySet());
 437             resolvedCapabilities.addAll(filteredQNames.stream()
 438                 .map(capability -> new AvailableCapabilityBuilder()
 439                     .setCapability(capability.toString())
 440                     .setCapabilityOrigin(remoteSessionCapabilities.capabilityOrigin(capability))
 441                     .build())
 442                 .collect(Collectors.toList()));
 443
 444             nonModuleBasedCapabilities.addAll(remoteSessionCapabilities.nonModuleCaps().keySet().stream()
 445                 .map(capability -> new AvailableCapabilityBuilder()
 446                     .setCapability(capability)
 447                     .setCapabilityOrigin(remoteSessionCapabilities.capabilityOrigin(capability))
 448                     .build())
 449                 .collect(Collectors.toList()));
 450
 451
 452             resultFuture.set(new SchemaResult(new NetconfDeviceCapabilities(ImmutableMap.copyOf(unresolvedCapabilites),
 453                 ImmutableSet.copyOf(resolvedCapabilities), ImmutableSet.copyOf(nonModuleBasedCapabilities)), result));
 454         }
 455
 456         @Override
 457         public void onFailure(final Throwable cause) {
 458             // schemaBuilderFuture.checkedGet() throws only SchemaResolutionException
 459             // that might be wrapping a MissingSchemaSourceException so we need to look
 460             // at the cause of the exception to make sure we don't misinterpret it.
 461             if (cause instanceof MissingSchemaSourceException) {
 462                 requiredSources = handleMissingSchemaSourceException((MissingSchemaSourceException) cause);
 463             } else if (cause instanceof SchemaResolutionException) {
 464                 requiredSources = handleSchemaResolutionException((SchemaResolutionException) cause);
 465             } else {
 466                 LOG.debug("Unhandled failure", cause);
 467                 resultFuture.setException(cause);
 468                 // No more trying...
 469                 return;
 470             }
 471
 472             trySetupSchema();
 473         }
 474
 475         private void trySetupSchema() {
 476             if (!requiredSources.isEmpty()) {
 477                 // Initiate async resolution, drive it back based on the result
 478                 LOG.trace("{}: Trying to build schema context from {}", id, requiredSources);
 479                 Futures.addCallback(schemaContextFactory.createEffectiveModelContext(requiredSources), this,
 480                     MoreExecutors.directExecutor());
 481             } else {
 482                 LOG.debug("{}: no more sources for schema context", id);
 483                 resultFuture.setException(new EmptySchemaContextException(id + ": No more sources for schema context"));
 484             }
 485         }
 486
 487         private List<SourceIdentifier> filterMissingSources(final Collection<SourceIdentifier> origSources) {
 488             return origSources.parallelStream().filter(sourceIdentifier -> {
 489                 try {
 490                     schemaRepository.getSchemaSource(sourceIdentifier, YangTextSchemaSource.class).get();
 491                     return false;
 492                 } catch (InterruptedException | ExecutionException e) {
 493                     return true;
 494                 }
 495             }).collect(Collectors.toList());
 496         }
 497
 498         private void addUnresolvedCapabilities(final Collection<QName> capabilities, final FailureReason reason) {
 499             for (QName s : capabilities) {
 500                 unresolvedCapabilites.put(s, reason);
 501             }
 502         }
 503
 504         private List<SourceIdentifier> handleMissingSchemaSourceException(
 505                 final MissingSchemaSourceException exception) {
 506             // In case source missing, try without it
 507             final SourceIdentifier missingSource = exception.getSourceId();
 508             LOG.warn("{}: Unable to build schema context, missing source {}, will reattempt without it",
 509                 id, missingSource);
 510             LOG.debug("{}: Unable to build schema context, missing source {}, will reattempt without it",
 511                 id, missingSource, exception);
 512             final var qNameOfMissingSource = getQNameFromSourceIdentifiers(Sets.newHashSet(missingSource));
 513             if (!qNameOfMissingSource.isEmpty()) {
 514                 addUnresolvedCapabilities(qNameOfMissingSource, UnavailableCapability.FailureReason.MissingSource);
 515             }
 516             return stripUnavailableSource(missingSource);
 517         }
 518
 519         private Collection<SourceIdentifier> handleSchemaResolutionException(
 520                 final SchemaResolutionException resolutionException) {
 521             // In case resolution error, try only with resolved sources
 522             // There are two options why schema resolution exception occurred : unsatisfied imports or flawed model
 523             // FIXME Do we really have assurance that these two cases cannot happen at once?
 524             if (resolutionException.getFailedSource() != null) {
 525                 // flawed model - exclude it
 526                 final SourceIdentifier failedSourceId = resolutionException.getFailedSource();
 527                 LOG.warn("{}: Unable to build schema context, failed to resolve source {}, will reattempt without it",
 528                     id, failedSourceId);
 529                 LOG.warn("{}: Unable to build schema context, failed to resolve source {}, will reattempt without it",
 530                     id, failedSourceId, resolutionException);
 531                 addUnresolvedCapabilities(getQNameFromSourceIdentifiers(List.of(failedSourceId)),
 532                         UnavailableCapability.FailureReason.UnableToResolve);
 533                 return stripUnavailableSource(resolutionException.getFailedSource());
 534             }
 535             // unsatisfied imports
 536             addUnresolvedCapabilities(
 537                 getQNameFromSourceIdentifiers(resolutionException.getUnsatisfiedImports().keySet()),
 538                 UnavailableCapability.FailureReason.UnableToResolve);
 539             LOG.warn("{}: Unable to build schema context, unsatisfied imports {}, will reattempt with resolved only",
 540                 id, resolutionException.getUnsatisfiedImports());
 541             LOG.debug("{}: Unable to build schema context, unsatisfied imports {}, will reattempt with resolved only",
 542                 id, resolutionException.getUnsatisfiedImports(), resolutionException);
 543             return resolutionException.getResolvedSources();
 544         }
 545
 546         private List<SourceIdentifier> stripUnavailableSource(final SourceIdentifier sourceIdToRemove) {
 547             final var tmp = new ArrayList<>(requiredSources);
 548             checkState(tmp.remove(sourceIdToRemove), "%s: Trying to remove %s from %s failed", id, sourceIdToRemove,
 549                 requiredSources);
 550             return tmp;
 551         }
 552
 553         private Collection<QName> getQNameFromSourceIdentifiers(final Collection<SourceIdentifier> identifiers) {
 554             final Collection<QName> qNames = Collections2.transform(identifiers, this::getQNameFromSourceIdentifier);
 555
 556             if (qNames.isEmpty()) {
 557                 LOG.debug("{}: Unable to map any source identifiers to a capability reported by device : {}", id,
 558                         identifiers);
 559             }
 560             return Collections2.filter(qNames, Predicates.notNull());
 561         }
 562
 563         private QName getQNameFromSourceIdentifier(final SourceIdentifier identifier) {
 564             // Required sources are all required and provided merged in DeviceSourcesResolver
 565             for (final QName qname : deviceSources.getRequiredSourcesQName()) {
 566                 if (!qname.getLocalName().equals(identifier.name().getLocalName())) {
 567                     continue;
 568                 }
 569
 570                 if (Objects.equals(identifier.revision(), qname.getRevision().orElse(null))) {
 571                     return qname;
 572                 }
 573             }
 574             LOG.warn("Unable to map identifier to a devices reported capability: {} Available: {}",identifier,
 575                     deviceSources.getRequiredSourcesQName());
 576             // return null since we cannot find the QName,
 577             // this capability will be removed from required sources and not reported as unresolved-capability
 578             return null;
 579         }
 580     }
 581 }