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.ExecutionException;
  34 import java.util.concurrent.Executor;
  35 import java.util.stream.Collectors;
  36 import org.checkerframework.checker.lock.qual.GuardedBy;
  37 import org.eclipse.jdt.annotation.NonNull;
  38 import org.opendaylight.mdsal.dom.api.DOMRpcResult;
  39 import org.opendaylight.netconf.api.CapabilityURN;
  40 import org.opendaylight.netconf.api.NetconfMessage;
  41 import org.opendaylight.netconf.client.mdsal.api.BaseNetconfSchemas;
  42 import org.opendaylight.netconf.client.mdsal.api.DeviceActionFactory;
  43 import org.opendaylight.netconf.client.mdsal.api.NetconfDeviceSchemasResolver;
  44 import org.opendaylight.netconf.client.mdsal.api.NetconfSessionPreferences;
  45 import org.opendaylight.netconf.client.mdsal.api.RemoteDevice;
  46 import org.opendaylight.netconf.client.mdsal.api.RemoteDeviceCommunicator;
  47 import org.opendaylight.netconf.client.mdsal.api.RemoteDeviceHandler;
  48 import org.opendaylight.netconf.client.mdsal.api.RemoteDeviceId;
  49 import org.opendaylight.netconf.client.mdsal.api.RemoteDeviceServices;
  50 import org.opendaylight.netconf.client.mdsal.api.RemoteDeviceServices.Rpcs;
  51 import org.opendaylight.netconf.client.mdsal.impl.BaseSchema;
  52 import org.opendaylight.netconf.client.mdsal.impl.NetconfMessageTransformUtil;
  53 import org.opendaylight.netconf.client.mdsal.impl.NetconfMessageTransformer;
  54 import org.opendaylight.netconf.client.mdsal.spi.NetconfDeviceRpc;
  55 import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.netconf.notifications.rev120206.NetconfCapabilityChange;
  56 import org.opendaylight.yang.gen.v1.urn.opendaylight.netconf.device.rev230430.connection.oper.available.capabilities.AvailableCapability;
  57 import org.opendaylight.yang.gen.v1.urn.opendaylight.netconf.device.rev230430.connection.oper.available.capabilities.AvailableCapabilityBuilder;
  58 import org.opendaylight.yang.gen.v1.urn.opendaylight.netconf.device.rev230430.connection.oper.unavailable.capabilities.UnavailableCapability;
  59 import org.opendaylight.yang.gen.v1.urn.opendaylight.netconf.device.rev230430.connection.oper.unavailable.capabilities.UnavailableCapability.FailureReason;
  60 import org.opendaylight.yangtools.concepts.Registration;
  61 import org.opendaylight.yangtools.rfc8528.model.api.SchemaMountConstants;
  62 import org.opendaylight.yangtools.yang.common.QName;
  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.MountPointContext;
  66 import org.opendaylight.yangtools.yang.data.impl.schema.Builders;
  67 import org.opendaylight.yangtools.yang.model.api.EffectiveModelContext;
  68 import org.opendaylight.yangtools.yang.model.repo.api.EffectiveModelContextFactory;
  69 import org.opendaylight.yangtools.yang.model.repo.api.MissingSchemaSourceException;
  70 import org.opendaylight.yangtools.yang.model.repo.api.SchemaRepository;
  71 import org.opendaylight.yangtools.yang.model.repo.api.SchemaResolutionException;
  72 import org.opendaylight.yangtools.yang.model.repo.api.SourceIdentifier;
  73 import org.opendaylight.yangtools.yang.model.repo.api.YangTextSchemaSource;
  74 import org.opendaylight.yangtools.yang.model.repo.spi.SchemaSourceRegistry;
  75 import org.slf4j.Logger;
  76 import org.slf4j.LoggerFactory;
  77
  78 /**
  79  *  This is a mediator between NetconfDeviceCommunicator and NetconfDeviceSalFacade.
  80  */
  81 public class NetconfDevice implements RemoteDevice<NetconfDeviceCommunicator> {
  82     private static final Logger LOG = LoggerFactory.getLogger(NetconfDevice.class);
  83
  84     private static final QName RFC8528_SCHEMA_MOUNTS_QNAME = QName.create(
  85         SchemaMountConstants.RFC8528_MODULE, "schema-mounts").intern();
  86     private static final YangInstanceIdentifier RFC8528_SCHEMA_MOUNTS = YangInstanceIdentifier.of(
  87         NodeIdentifier.create(RFC8528_SCHEMA_MOUNTS_QNAME));
  88
  89     protected final RemoteDeviceId id;
  90     protected final EffectiveModelContextFactory schemaContextFactory;
  91     protected final SchemaSourceRegistry schemaRegistry;
  92     protected final SchemaRepository schemaRepository;
  93
  94     protected final List<Registration> sourceRegistrations = new ArrayList<>();
  95
  96     private final RemoteDeviceHandler salFacade;
  97     private final Executor processingExecutor;
  98     private final DeviceActionFactory deviceActionFactory;
  99     private final NetconfDeviceSchemasResolver stateSchemasResolver;
 100     private final NotificationHandler notificationHandler;
 101     private final boolean reconnectOnSchemasChange;
 102     private final BaseNetconfSchemas baseSchemas;
 103
 104     @GuardedBy("this")
 105     private boolean connected = false;
 106
 107     public NetconfDevice(final SchemaResourcesDTO schemaResourcesDTO, final BaseNetconfSchemas baseSchemas,
 108             final RemoteDeviceId id, final RemoteDeviceHandler salFacade, final Executor globalProcessingExecutor,
 109             final boolean reconnectOnSchemasChange) {
 110         this(schemaResourcesDTO, baseSchemas, id, salFacade, globalProcessingExecutor, reconnectOnSchemasChange, null);
 111     }
 112
 113     public NetconfDevice(final SchemaResourcesDTO schemaResourcesDTO, final BaseNetconfSchemas baseSchemas,
 114             final RemoteDeviceId id, final RemoteDeviceHandler salFacade, final Executor globalProcessingExecutor,
 115             final boolean reconnectOnSchemasChange, final DeviceActionFactory deviceActionFactory) {
 116         this.baseSchemas = requireNonNull(baseSchemas);
 117         this.id = id;
 118         this.reconnectOnSchemasChange = reconnectOnSchemasChange;
 119         this.deviceActionFactory = deviceActionFactory;
 120         schemaRegistry = schemaResourcesDTO.getSchemaRegistry();
 121         schemaRepository = schemaResourcesDTO.getSchemaRepository();
 122         schemaContextFactory = schemaResourcesDTO.getSchemaContextFactory();
 123         this.salFacade = salFacade;
 124         stateSchemasResolver = schemaResourcesDTO.getStateSchemasResolver();
 125         processingExecutor = requireNonNull(globalProcessingExecutor);
 126         notificationHandler = new NotificationHandler(salFacade, id);
 127     }
 128
 129     @Override
 130     public void onRemoteSessionUp(final NetconfSessionPreferences remoteSessionCapabilities,
 131                                   final NetconfDeviceCommunicator listener) {
 132         // SchemaContext setup has to be performed in a dedicated thread since we are in a Netty thread in this method
 133         // YANG models are being downloaded in this method and it would cause a deadlock if we used the netty thread
 134         // https://netty.io/wiki/thread-model.html
 135         setConnected(true);
 136         LOG.debug("{}: Session to remote device established with {}", id, remoteSessionCapabilities);
 137
 138         final BaseSchema baseSchema = resolveBaseSchema(remoteSessionCapabilities.isNotificationsSupported());
 139         final NetconfDeviceRpc initRpc = new NetconfDeviceRpc(baseSchema.getEffectiveModelContext(), listener,
 140             new NetconfMessageTransformer(baseSchema.getMountPointContext(), false, baseSchema));
 141         final ListenableFuture<DeviceSources> sourceResolverFuture = Futures.submit(
 142             new DeviceSourcesResolver(id, baseSchema, initRpc, remoteSessionCapabilities, stateSchemasResolver),
 143             processingExecutor);
 144
 145         if (shouldListenOnSchemaChange(remoteSessionCapabilities)) {
 146             registerToBaseNetconfStream(initRpc, listener);
 147         }
 148
 149         // Set up the EffectiveModelContext for the device
 150         final var futureSchema = Futures.transformAsync(sourceResolverFuture,
 151             deviceSources -> assembleSchemaContext(deviceSources, remoteSessionCapabilities), processingExecutor);
 152
 153         Futures.addCallback(
 154             // Potentially acquire mount point list and interpret it
 155             Futures.transformAsync(futureSchema,
 156                 result -> Futures.transform(createMountPointContext(result.modelContext(), baseSchema, listener),
 157                     mount -> new NetconfDeviceSchema(result.capabilities(), mount), processingExecutor),
 158                 processingExecutor),
 159             new FutureCallback<>() {
 160                 @Override
 161                 public void onSuccess(final NetconfDeviceSchema result) {
 162                     handleSalInitializationSuccess(listener, result, remoteSessionCapabilities,
 163                         getDeviceSpecificRpc(result.mountContext(), listener, baseSchema));
 164                 }
 165
 166                 @Override
 167                 public void onFailure(final Throwable cause) {
 168                     handleSalInitializationFailure(listener, cause);
 169                 }
 170             }, MoreExecutors.directExecutor());
 171     }
 172
 173     private void registerToBaseNetconfStream(final NetconfDeviceRpc deviceRpc,
 174                                              final NetconfDeviceCommunicator listener) {
 175         // TODO check whether the model describing create subscription is present in schema
 176         // Perhaps add a default schema context to support create-subscription if the model was not provided
 177         // (same as what we do for base netconf operations in transformer)
 178         final var rpcResultListenableFuture = deviceRpc.invokeRpc(
 179                 NetconfMessageTransformUtil.CREATE_SUBSCRIPTION_RPC_QNAME,
 180                 NetconfMessageTransformUtil.CREATE_SUBSCRIPTION_RPC_CONTENT);
 181
 182         Futures.addCallback(rpcResultListenableFuture, new FutureCallback<DOMRpcResult>() {
 183             @Override
 184             public void onSuccess(final DOMRpcResult domRpcResult) {
 185                 notificationHandler.addNotificationFilter(notification -> {
 186                     if (NetconfCapabilityChange.QNAME.equals(notification.getBody().name().getNodeType())) {
 187                         LOG.info("{}: Schemas change detected, reconnecting", id);
 188                         // Only disconnect is enough,
 189                         // the reconnecting nature of the connector will take care of reconnecting
 190                         listener.disconnect();
 191                         return false;
 192                     }
 193                     return true;
 194                 });
 195             }
 196
 197             @Override
 198             public void onFailure(final Throwable throwable) {
 199                 LOG.warn("Unable to subscribe to base notification stream. Schemas will not be reloaded on the fly",
 200                         throwable);
 201             }
 202         }, MoreExecutors.directExecutor());
 203     }
 204
 205     private boolean shouldListenOnSchemaChange(final NetconfSessionPreferences remoteSessionCapabilities) {
 206         return remoteSessionCapabilities.isNotificationsSupported() && reconnectOnSchemasChange;
 207     }
 208
 209     private synchronized void handleSalInitializationSuccess(final RemoteDeviceCommunicator listener,
 210             final NetconfDeviceSchema deviceSchema, final NetconfSessionPreferences remoteSessionCapabilities,
 211             final Rpcs deviceRpc) {
 212         // NetconfDevice.SchemaSetup can complete after NetconfDeviceCommunicator was closed. In that case do nothing,
 213         // since salFacade.onDeviceDisconnected was already called.
 214         if (!connected) {
 215             LOG.warn("{}: Device communicator was closed before schema setup finished.", id);
 216             return;
 217         }
 218
 219         final var messageTransformer = new NetconfMessageTransformer(deviceSchema.mountContext(), true,
 220             resolveBaseSchema(remoteSessionCapabilities.isNotificationsSupported()));
 221
 222         // Order is important here: salFacade has to see the device come up and then the notificationHandler can deliver
 223         // whatever notifications have been held back
 224         salFacade.onDeviceConnected(deviceSchema, remoteSessionCapabilities,
 225             new RemoteDeviceServices(deviceRpc, deviceActionFactory == null ? null
 226                 : deviceActionFactory.createDeviceAction(messageTransformer, listener)));
 227         notificationHandler.onRemoteSchemaUp(messageTransformer);
 228
 229         LOG.info("{}: Netconf connector initialized successfully", id);
 230     }
 231
 232     private void handleSalInitializationFailure(final RemoteDeviceCommunicator listener, final Throwable cause) {
 233         LOG.warn("{}: Unexpected error resolving device sources", id, cause);
 234         listener.close();
 235         cleanupInitialization();
 236         salFacade.onDeviceFailed(cause);
 237     }
 238
 239     private synchronized void cleanupInitialization() {
 240         connected = false;
 241         notificationHandler.onRemoteSchemaDown();
 242         sourceRegistrations.forEach(Registration::close);
 243         sourceRegistrations.clear();
 244     }
 245
 246     private synchronized void setConnected(final boolean connected) {
 247         this.connected = connected;
 248     }
 249
 250     private ListenableFuture<SchemaResult> assembleSchemaContext(final DeviceSources deviceSources,
 251             final NetconfSessionPreferences remoteSessionCapabilities) {
 252         LOG.debug("{}: Resolved device sources to {}", id, deviceSources);
 253
 254         sourceRegistrations.addAll(deviceSources.register(schemaRegistry));
 255
 256         return new SchemaSetup(deviceSources, remoteSessionCapabilities).startResolution();
 257     }
 258
 259     private ListenableFuture<@NonNull MountPointContext> createMountPointContext(
 260             final EffectiveModelContext schemaContext, final BaseSchema baseSchema,
 261             final NetconfDeviceCommunicator listener) {
 262         final MountPointContext emptyContext = MountPointContext.of(schemaContext);
 263         if (schemaContext.findModule(SchemaMountConstants.RFC8528_MODULE).isEmpty()) {
 264             return Futures.immediateFuture(emptyContext);
 265         }
 266
 267         // Create a temporary RPC invoker and acquire the mount point tree
 268         LOG.debug("{}: Acquiring available mount points", id);
 269         final NetconfDeviceRpc deviceRpc = new NetconfDeviceRpc(schemaContext, listener,
 270             new NetconfMessageTransformer(emptyContext, false, baseSchema));
 271
 272         return Futures.transform(deviceRpc.invokeRpc(NetconfMessageTransformUtil.NETCONF_GET_QNAME,
 273             Builders.containerBuilder().withNodeIdentifier(NETCONF_GET_NODEID)
 274                 .withChild(NetconfMessageTransformUtil.toFilterStructure(RFC8528_SCHEMA_MOUNTS, schemaContext))
 275                 .build()), rpcResult -> processSchemaMounts(rpcResult, emptyContext), MoreExecutors.directExecutor());
 276     }
 277
 278     private MountPointContext processSchemaMounts(final DOMRpcResult rpcResult, final MountPointContext emptyContext) {
 279         final var errors = rpcResult.errors();
 280         if (!errors.isEmpty()) {
 281             LOG.warn("{}: Schema-mounts acquisition resulted in errors {}", id, errors);
 282         }
 283         final var schemaMounts = rpcResult.value();
 284         if (schemaMounts == null) {
 285             LOG.debug("{}: device does not define any schema mounts", id);
 286             return emptyContext;
 287         }
 288
 289         return DeviceMountPointContext.create(emptyContext, schemaMounts);
 290     }
 291
 292     @Override
 293     public void onRemoteSessionDown() {
 294         cleanupInitialization();
 295         salFacade.onDeviceDisconnected();
 296     }
 297
 298     @Override
 299     public void onNotification(final NetconfMessage notification) {
 300         notificationHandler.handleNotification(notification);
 301     }
 302
 303     private BaseSchema resolveBaseSchema(final boolean notificationSupport) {
 304         return notificationSupport ? baseSchemas.getBaseSchemaWithNotifications() : baseSchemas.getBaseSchema();
 305     }
 306
 307     protected NetconfDeviceRpc getDeviceSpecificRpc(final MountPointContext result,
 308             final RemoteDeviceCommunicator listener, final BaseSchema schema) {
 309         return new NetconfDeviceRpc(result.getEffectiveModelContext(), listener,
 310             new NetconfMessageTransformer(result, true, schema));
 311     }
 312
 313     /**
 314      * Just a transfer object containing schema related dependencies. Injected in constructor.
 315      */
 316     public static class SchemaResourcesDTO {
 317         private final SchemaSourceRegistry schemaRegistry;
 318         private final SchemaRepository schemaRepository;
 319         private final EffectiveModelContextFactory schemaContextFactory;
 320         private final NetconfDeviceSchemasResolver stateSchemasResolver;
 321
 322         public SchemaResourcesDTO(final SchemaSourceRegistry schemaRegistry,
 323                                   final SchemaRepository schemaRepository,
 324                                   final EffectiveModelContextFactory schemaContextFactory,
 325                                   final NetconfDeviceSchemasResolver deviceSchemasResolver) {
 326             this.schemaRegistry = requireNonNull(schemaRegistry);
 327             this.schemaRepository = requireNonNull(schemaRepository);
 328             this.schemaContextFactory = requireNonNull(schemaContextFactory);
 329             stateSchemasResolver = requireNonNull(deviceSchemasResolver);
 330         }
 331
 332         public SchemaSourceRegistry getSchemaRegistry() {
 333             return schemaRegistry;
 334         }
 335
 336         public SchemaRepository getSchemaRepository() {
 337             return schemaRepository;
 338         }
 339
 340         public EffectiveModelContextFactory getSchemaContextFactory() {
 341             return schemaContextFactory;
 342         }
 343
 344         public NetconfDeviceSchemasResolver getStateSchemasResolver() {
 345             return stateSchemasResolver;
 346         }
 347     }
 348
 349     /**
 350      * A dedicated exception to indicate when we fail to setup an {@link EffectiveModelContext}.
 351      */
 352     public static final class EmptySchemaContextException extends Exception {
 353         @Serial
 354         private static final long serialVersionUID = 1L;
 355
 356         public EmptySchemaContextException(final String message) {
 357             super(message);
 358         }
 359     }
 360
 361     /**
 362      * {@link NetconfDeviceCapabilities} and {@link EffectiveModelContext}.
 363      */
 364     private record SchemaResult(
 365         @NonNull NetconfDeviceCapabilities capabilities,
 366         @NonNull EffectiveModelContext modelContext) {
 367
 368         SchemaResult {
 369             requireNonNull(capabilities);
 370             requireNonNull(modelContext);
 371         }
 372     }
 373
 374     /**
 375      * Schema builder that tries to build schema context from provided sources or biggest subset of it.
 376      */
 377     private final class SchemaSetup implements FutureCallback<EffectiveModelContext> {
 378         private final SettableFuture<SchemaResult> resultFuture = SettableFuture.create();
 379
 380         private final Set<AvailableCapability> nonModuleBasedCapabilities = new HashSet<>();
 381         private final Map<QName, FailureReason> unresolvedCapabilites = new HashMap<>();
 382         private final Set<AvailableCapability> resolvedCapabilities = new HashSet<>();
 383
 384         private final DeviceSources deviceSources;
 385         private final NetconfSessionPreferences remoteSessionCapabilities;
 386
 387         private Collection<SourceIdentifier> requiredSources;
 388
 389         SchemaSetup(final DeviceSources deviceSources, final NetconfSessionPreferences remoteSessionCapabilities) {
 390             this.deviceSources = deviceSources;
 391             this.remoteSessionCapabilities = remoteSessionCapabilities;
 392
 393             // If device supports notifications and does not contain necessary modules, add them automatically
 394             if (remoteSessionCapabilities.containsNonModuleCapability(CapabilityURN.NOTIFICATION)) {
 395                 // FIXME: mutable collection modification!
 396                 deviceSources.getRequiredSourcesQName().addAll(List.of(
 397                     org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.netconf.notification._1._0.rev080714
 398                         .$YangModuleInfoImpl.getInstance().getName(),
 399                     org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.yang.types.rev130715
 400                         .$YangModuleInfoImpl.getInstance().getName())
 401                 );
 402             }
 403
 404             requiredSources = deviceSources.getRequiredSources();
 405             final Collection<SourceIdentifier> missingSources = filterMissingSources(requiredSources);
 406
 407             addUnresolvedCapabilities(getQNameFromSourceIdentifiers(missingSources),
 408                 UnavailableCapability.FailureReason.MissingSource);
 409             requiredSources.removeAll(missingSources);
 410         }
 411
 412         ListenableFuture<SchemaResult> startResolution() {
 413             trySetupSchema();
 414             return resultFuture;
 415         }
 416
 417         @Override
 418         public void onSuccess(final EffectiveModelContext result) {
 419             LOG.debug("{}: Schema context built successfully from {}", id, requiredSources);
 420
 421             final Collection<QName> filteredQNames = Sets.difference(deviceSources.getRequiredSourcesQName(),
 422                     unresolvedCapabilites.keySet());
 423             resolvedCapabilities.addAll(filteredQNames.stream()
 424                 .map(capability -> new AvailableCapabilityBuilder()
 425                     .setCapability(capability.toString())
 426                     .setCapabilityOrigin(remoteSessionCapabilities.capabilityOrigin(capability))
 427                     .build())
 428                 .collect(Collectors.toList()));
 429
 430             nonModuleBasedCapabilities.addAll(remoteSessionCapabilities.nonModuleCaps().keySet().stream()
 431                 .map(capability -> new AvailableCapabilityBuilder()
 432                     .setCapability(capability)
 433                     .setCapabilityOrigin(remoteSessionCapabilities.capabilityOrigin(capability))
 434                     .build())
 435                 .collect(Collectors.toList()));
 436
 437
 438             resultFuture.set(new SchemaResult(new NetconfDeviceCapabilities(ImmutableMap.copyOf(unresolvedCapabilites),
 439                 ImmutableSet.copyOf(resolvedCapabilities), ImmutableSet.copyOf(nonModuleBasedCapabilities)), result));
 440         }
 441
 442         @Override
 443         public void onFailure(final Throwable cause) {
 444             // schemaBuilderFuture.checkedGet() throws only SchemaResolutionException
 445             // that might be wrapping a MissingSchemaSourceException so we need to look
 446             // at the cause of the exception to make sure we don't misinterpret it.
 447             if (cause instanceof MissingSchemaSourceException) {
 448                 requiredSources = handleMissingSchemaSourceException((MissingSchemaSourceException) cause);
 449             } else if (cause instanceof SchemaResolutionException) {
 450                 requiredSources = handleSchemaResolutionException((SchemaResolutionException) cause);
 451             } else {
 452                 LOG.debug("Unhandled failure", cause);
 453                 resultFuture.setException(cause);
 454                 // No more trying...
 455                 return;
 456             }
 457
 458             trySetupSchema();
 459         }
 460
 461         private void trySetupSchema() {
 462             if (!requiredSources.isEmpty()) {
 463                 // Initiate async resolution, drive it back based on the result
 464                 LOG.trace("{}: Trying to build schema context from {}", id, requiredSources);
 465                 Futures.addCallback(schemaContextFactory.createEffectiveModelContext(requiredSources), this,
 466                     MoreExecutors.directExecutor());
 467             } else {
 468                 LOG.debug("{}: no more sources for schema context", id);
 469                 resultFuture.setException(new EmptySchemaContextException(id + ": No more sources for schema context"));
 470             }
 471         }
 472
 473         private List<SourceIdentifier> filterMissingSources(final Collection<SourceIdentifier> origSources) {
 474             return origSources.parallelStream().filter(sourceIdentifier -> {
 475                 try {
 476                     schemaRepository.getSchemaSource(sourceIdentifier, YangTextSchemaSource.class).get();
 477                     return false;
 478                 } catch (InterruptedException | ExecutionException e) {
 479                     return true;
 480                 }
 481             }).collect(Collectors.toList());
 482         }
 483
 484         private void addUnresolvedCapabilities(final Collection<QName> capabilities, final FailureReason reason) {
 485             for (QName s : capabilities) {
 486                 unresolvedCapabilites.put(s, reason);
 487             }
 488         }
 489
 490         private List<SourceIdentifier> handleMissingSchemaSourceException(
 491                 final MissingSchemaSourceException exception) {
 492             // In case source missing, try without it
 493             final SourceIdentifier missingSource = exception.getSourceId();
 494             LOG.warn("{}: Unable to build schema context, missing source {}, will reattempt without it",
 495                 id, missingSource);
 496             LOG.debug("{}: Unable to build schema context, missing source {}, will reattempt without it",
 497                 id, missingSource, exception);
 498             final var qNameOfMissingSource = getQNameFromSourceIdentifiers(Sets.newHashSet(missingSource));
 499             if (!qNameOfMissingSource.isEmpty()) {
 500                 addUnresolvedCapabilities(qNameOfMissingSource, UnavailableCapability.FailureReason.MissingSource);
 501             }
 502             return stripUnavailableSource(missingSource);
 503         }
 504
 505         private Collection<SourceIdentifier> handleSchemaResolutionException(
 506                 final SchemaResolutionException resolutionException) {
 507             // In case resolution error, try only with resolved sources
 508             // There are two options why schema resolution exception occurred : unsatisfied imports or flawed model
 509             // FIXME Do we really have assurance that these two cases cannot happen at once?
 510             if (resolutionException.getFailedSource() != null) {
 511                 // flawed model - exclude it
 512                 final SourceIdentifier failedSourceId = resolutionException.getFailedSource();
 513                 LOG.warn("{}: Unable to build schema context, failed to resolve source {}, will reattempt without it",
 514                     id, failedSourceId);
 515                 LOG.warn("{}: Unable to build schema context, failed to resolve source {}, will reattempt without it",
 516                     id, failedSourceId, resolutionException);
 517                 addUnresolvedCapabilities(getQNameFromSourceIdentifiers(List.of(failedSourceId)),
 518                         UnavailableCapability.FailureReason.UnableToResolve);
 519                 return stripUnavailableSource(resolutionException.getFailedSource());
 520             }
 521             // unsatisfied imports
 522             addUnresolvedCapabilities(
 523                 getQNameFromSourceIdentifiers(resolutionException.getUnsatisfiedImports().keySet()),
 524                 UnavailableCapability.FailureReason.UnableToResolve);
 525             LOG.warn("{}: Unable to build schema context, unsatisfied imports {}, will reattempt with resolved only",
 526                 id, resolutionException.getUnsatisfiedImports());
 527             LOG.debug("{}: Unable to build schema context, unsatisfied imports {}, will reattempt with resolved only",
 528                 id, resolutionException.getUnsatisfiedImports(), resolutionException);
 529             return resolutionException.getResolvedSources();
 530         }
 531
 532         private List<SourceIdentifier> stripUnavailableSource(final SourceIdentifier sourceIdToRemove) {
 533             final var tmp = new ArrayList<>(requiredSources);
 534             checkState(tmp.remove(sourceIdToRemove), "%s: Trying to remove %s from %s failed", id, sourceIdToRemove,
 535                 requiredSources);
 536             return tmp;
 537         }
 538
 539         private Collection<QName> getQNameFromSourceIdentifiers(final Collection<SourceIdentifier> identifiers) {
 540             final Collection<QName> qNames = Collections2.transform(identifiers, this::getQNameFromSourceIdentifier);
 541
 542             if (qNames.isEmpty()) {
 543                 LOG.debug("{}: Unable to map any source identifiers to a capability reported by device : {}", id,
 544                         identifiers);
 545             }
 546             return Collections2.filter(qNames, Predicates.notNull());
 547         }
 548
 549         private QName getQNameFromSourceIdentifier(final SourceIdentifier identifier) {
 550             // Required sources are all required and provided merged in DeviceSourcesResolver
 551             for (final QName qname : deviceSources.getRequiredSourcesQName()) {
 552                 if (!qname.getLocalName().equals(identifier.name().getLocalName())) {
 553                     continue;
 554                 }
 555
 556                 if (Objects.equals(identifier.revision(), qname.getRevision().orElse(null))) {
 557                     return qname;
 558                 }
 559             }
 560             LOG.warn("Unable to map identifier to a devices reported capability: {} Available: {}",identifier,
 561                     deviceSources.getRequiredSourcesQName());
 562             // return null since we cannot find the QName,
 563             // this capability will be removed from required sources and not reported as unresolved-capability
 564             return null;
 565         }
 566     }
 567 }