Bug 8153: Enforce check-style rules for netconf - sal-netconf-connector
[netconf.git] / 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 com.google.common.base.Function;
11 import com.google.common.base.Optional;
12 import com.google.common.base.Preconditions;
13 import com.google.common.base.Predicates;
14 import com.google.common.collect.Collections2;
15 import com.google.common.collect.Lists;
16 import com.google.common.collect.Sets;
17 import com.google.common.util.concurrent.CheckedFuture;
18 import com.google.common.util.concurrent.FutureCallback;
19 import com.google.common.util.concurrent.Futures;
20 import com.google.common.util.concurrent.ListenableFuture;
21 import com.google.common.util.concurrent.ListeningExecutorService;
22 import com.google.common.util.concurrent.MoreExecutors;
23 import java.util.Collection;
24 import java.util.Collections;
25 import java.util.LinkedList;
26 import java.util.List;
27 import java.util.Set;
28 import java.util.concurrent.Callable;
29 import java.util.concurrent.ExecutorService;
30 import java.util.stream.Collectors;
31 import org.opendaylight.controller.md.sal.dom.api.DOMNotification;
32 import org.opendaylight.controller.md.sal.dom.api.DOMRpcException;
33 import org.opendaylight.controller.md.sal.dom.api.DOMRpcResult;
34 import org.opendaylight.controller.md.sal.dom.api.DOMRpcService;
35 import org.opendaylight.netconf.api.NetconfMessage;
36 import org.opendaylight.netconf.sal.connect.api.MessageTransformer;
37 import org.opendaylight.netconf.sal.connect.api.NetconfDeviceSchemas;
38 import org.opendaylight.netconf.sal.connect.api.NetconfDeviceSchemasResolver;
39 import org.opendaylight.netconf.sal.connect.api.RemoteDevice;
40 import org.opendaylight.netconf.sal.connect.api.RemoteDeviceCommunicator;
41 import org.opendaylight.netconf.sal.connect.api.RemoteDeviceHandler;
42 import org.opendaylight.netconf.sal.connect.netconf.listener.NetconfDeviceCapabilities;
43 import org.opendaylight.netconf.sal.connect.netconf.listener.NetconfDeviceCommunicator;
44 import org.opendaylight.netconf.sal.connect.netconf.listener.NetconfSessionPreferences;
45 import org.opendaylight.netconf.sal.connect.netconf.sal.NetconfDeviceRpc;
46 import org.opendaylight.netconf.sal.connect.netconf.schema.NetconfRemoteSchemaYangSourceProvider;
47 import org.opendaylight.netconf.sal.connect.netconf.schema.YangLibrarySchemaYangSourceProvider;
48 import org.opendaylight.netconf.sal.connect.netconf.schema.mapping.BaseSchema;
49 import org.opendaylight.netconf.sal.connect.netconf.schema.mapping.NetconfMessageTransformer;
50 import org.opendaylight.netconf.sal.connect.netconf.util.NetconfMessageTransformUtil;
51 import org.opendaylight.netconf.sal.connect.util.RemoteDeviceId;
52 import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.netconf.notifications.rev120206.NetconfCapabilityChange;
53 import org.opendaylight.yang.gen.v1.urn.opendaylight.netconf.node.topology.rev150114.netconf.node.connection.status.available.capabilities.AvailableCapabilityBuilder;
54 import org.opendaylight.yang.gen.v1.urn.opendaylight.netconf.node.topology.rev150114.netconf.node.connection.status.unavailable.capabilities.UnavailableCapability;
55 import org.opendaylight.yangtools.yang.common.QName;
56 import org.opendaylight.yangtools.yang.model.api.SchemaContext;
57 import org.opendaylight.yangtools.yang.model.repo.api.MissingSchemaSourceException;
58 import org.opendaylight.yangtools.yang.model.repo.api.RevisionSourceIdentifier;
59 import org.opendaylight.yangtools.yang.model.repo.api.SchemaContextFactory;
60 import org.opendaylight.yangtools.yang.model.repo.api.SchemaRepository;
61 import org.opendaylight.yangtools.yang.model.repo.api.SchemaResolutionException;
62 import org.opendaylight.yangtools.yang.model.repo.api.SchemaSourceException;
63 import org.opendaylight.yangtools.yang.model.repo.api.SchemaSourceRepresentation;
64 import org.opendaylight.yangtools.yang.model.repo.api.SourceIdentifier;
65 import org.opendaylight.yangtools.yang.model.repo.api.YangTextSchemaSource;
66 import org.opendaylight.yangtools.yang.model.repo.spi.PotentialSchemaSource;
67 import org.opendaylight.yangtools.yang.model.repo.spi.SchemaSourceProvider;
68 import org.opendaylight.yangtools.yang.model.repo.spi.SchemaSourceRegistration;
69 import org.opendaylight.yangtools.yang.model.repo.spi.SchemaSourceRegistry;
70 import org.opendaylight.yangtools.yang.parser.util.ASTSchemaSource;
71 import org.slf4j.Logger;
72 import org.slf4j.LoggerFactory;
73
74 /**
75  *  This is a mediator between NetconfDeviceCommunicator and NetconfDeviceSalFacade.
76  */
77 public class NetconfDevice
78         implements RemoteDevice<NetconfSessionPreferences, NetconfMessage, NetconfDeviceCommunicator> {
79
80     private static final Logger LOG = LoggerFactory.getLogger(NetconfDevice.class);
81
82     public static final Function<QName, SourceIdentifier> QNAME_TO_SOURCE_ID_FUNCTION =
83         input -> RevisionSourceIdentifier.create(input.getLocalName(),
84                 Optional.fromNullable(input.getFormattedRevision()));
85
86     protected final RemoteDeviceId id;
87     private final boolean reconnectOnSchemasChange;
88
89     protected final SchemaContextFactory schemaContextFactory;
90     private final RemoteDeviceHandler<NetconfSessionPreferences> salFacade;
91     private final ListeningExecutorService processingExecutor;
92     protected final SchemaSourceRegistry schemaRegistry;
93     protected final SchemaRepository schemaRepository;
94     private final NetconfDeviceSchemasResolver stateSchemasResolver;
95     private final NotificationHandler notificationHandler;
96     protected final List<SchemaSourceRegistration<? extends SchemaSourceRepresentation>> sourceRegistrations =
97             Lists.newArrayList();
98
99     // Message transformer is constructed once the schemas are available
100     private MessageTransformer<NetconfMessage> messageTransformer;
101
102     /**
103      * Create rpc implementation capable of handling RPC for monitoring and notifications
104      * even before the schemas of remote device are downloaded.
105      */
106     static NetconfDeviceRpc getRpcForInitialization(final NetconfDeviceCommunicator listener,
107                                                     final boolean notificationSupport) {
108         final BaseSchema baseSchema = notificationSupport
109                 ? BaseSchema.BASE_NETCONF_CTX_WITH_NOTIFICATIONS
110                 : BaseSchema.BASE_NETCONF_CTX;
111
112         return new NetconfDeviceRpc(baseSchema.getSchemaContext(), listener,
113                 new NetconfMessageTransformer(baseSchema.getSchemaContext(), false, baseSchema));
114     }
115
116     public NetconfDevice(final SchemaResourcesDTO schemaResourcesDTO, final RemoteDeviceId id,
117                          final RemoteDeviceHandler<NetconfSessionPreferences> salFacade,
118                          final ExecutorService globalProcessingExecutor, final boolean reconnectOnSchemasChange) {
119         this.id = id;
120         this.reconnectOnSchemasChange = reconnectOnSchemasChange;
121         this.schemaRegistry = schemaResourcesDTO.getSchemaRegistry();
122         this.schemaRepository = schemaResourcesDTO.getSchemaRepository();
123         this.schemaContextFactory = schemaResourcesDTO.getSchemaContextFactory();
124         this.salFacade = salFacade;
125         this.stateSchemasResolver = schemaResourcesDTO.getStateSchemasResolver();
126         this.processingExecutor = MoreExecutors.listeningDecorator(globalProcessingExecutor);
127         this.notificationHandler = new NotificationHandler(salFacade, id);
128     }
129
130     @Override
131     public void onRemoteSessionUp(final NetconfSessionPreferences remoteSessionCapabilities,
132                                   final NetconfDeviceCommunicator listener) {
133         // SchemaContext setup has to be performed in a dedicated thread since
134         // we are in a netty thread in this method
135         // Yang models are being downloaded in this method and it would cause a
136         // deadlock if we used the netty thread
137         // http://netty.io/wiki/thread-model.html
138         LOG.debug("{}: Session to remote device established with {}", id, remoteSessionCapabilities);
139
140         final NetconfDeviceRpc initRpc =
141                 getRpcForInitialization(listener, remoteSessionCapabilities.isNotificationsSupported());
142         final DeviceSourcesResolver task =
143                 new DeviceSourcesResolver(remoteSessionCapabilities, id, stateSchemasResolver, initRpc);
144         final ListenableFuture<DeviceSources> sourceResolverFuture = processingExecutor.submit(task);
145
146         if (shouldListenOnSchemaChange(remoteSessionCapabilities)) {
147             registerToBaseNetconfStream(initRpc, listener);
148         }
149
150         final FutureCallback<DeviceSources> resolvedSourceCallback = new FutureCallback<DeviceSources>() {
151             @Override
152             public void onSuccess(final DeviceSources result) {
153                 addProvidedSourcesToSchemaRegistry(result);
154                 setUpSchema(result);
155             }
156
157             private void setUpSchema(final DeviceSources result) {
158                 processingExecutor.submit(new SchemaSetup(result, remoteSessionCapabilities, listener));
159             }
160
161             @Override
162             public void onFailure(final Throwable throwable) {
163                 LOG.warn("{}: Unexpected error resolving device sources: {}", id, throwable);
164                 handleSalInitializationFailure(throwable, listener);
165             }
166         };
167
168         Futures.addCallback(sourceResolverFuture, resolvedSourceCallback);
169     }
170
171     private void registerToBaseNetconfStream(final NetconfDeviceRpc deviceRpc,
172                                              final NetconfDeviceCommunicator listener) {
173        // TODO check whether the model describing create subscription is present in schema
174         // Perhaps add a default schema context to support create-subscription if the model was not provided
175         // (same as what we do for base netconf operations in transformer)
176         final CheckedFuture<DOMRpcResult, DOMRpcException> rpcResultListenableFuture = deviceRpc.invokeRpc(
177             NetconfMessageTransformUtil.toPath(NetconfMessageTransformUtil.CREATE_SUBSCRIPTION_RPC_QNAME),
178             NetconfMessageTransformUtil.CREATE_SUBSCRIPTION_RPC_CONTENT);
179
180         final NotificationHandler.NotificationFilter filter = new NotificationHandler.NotificationFilter() {
181             @Override
182             public Optional<DOMNotification> filterNotification(final DOMNotification notification) {
183                 if (isCapabilityChanged(notification)) {
184                     LOG.info("{}: Schemas change detected, reconnecting", id);
185                     // Only disconnect is enough,
186                     // the reconnecting nature of the connector will take care of reconnecting
187                     listener.disconnect();
188                     return Optional.absent();
189                 }
190                 return Optional.of(notification);
191             }
192
193             private boolean isCapabilityChanged(final DOMNotification notification) {
194                 return notification.getBody().getNodeType().equals(NetconfCapabilityChange.QNAME);
195             }
196         };
197
198         Futures.addCallback(rpcResultListenableFuture, new FutureCallback<DOMRpcResult>() {
199             @Override
200             public void onSuccess(final DOMRpcResult domRpcResult) {
201                 notificationHandler.addNotificationFilter(filter);
202             }
203
204             @Override
205             public void onFailure(final Throwable throwable) {
206                 LOG.warn("Unable to subscribe to base notification stream. Schemas will not be reloaded on the fly",
207                         throwable);
208             }
209         });
210     }
211
212     private boolean shouldListenOnSchemaChange(final NetconfSessionPreferences remoteSessionCapabilities) {
213         return remoteSessionCapabilities.isNotificationsSupported() && reconnectOnSchemasChange;
214     }
215
216     void handleSalInitializationSuccess(final SchemaContext result,
217                                         final NetconfSessionPreferences remoteSessionCapabilities,
218                                         final DOMRpcService deviceRpc) {
219         final BaseSchema baseSchema =
220                 remoteSessionCapabilities.isNotificationsSupported()
221                         ? BaseSchema.BASE_NETCONF_CTX_WITH_NOTIFICATIONS : BaseSchema.BASE_NETCONF_CTX;
222         messageTransformer = new NetconfMessageTransformer(result, true, baseSchema);
223
224         updateTransformer(messageTransformer);
225         // salFacade.onDeviceConnected has to be called before the notification handler is initialized
226         salFacade.onDeviceConnected(result, remoteSessionCapabilities, deviceRpc);
227         notificationHandler.onRemoteSchemaUp(messageTransformer);
228
229         LOG.info("{}: Netconf connector initialized successfully", id);
230     }
231
232     void handleSalInitializationFailure(final Throwable throwable,
233                                         final RemoteDeviceCommunicator<NetconfMessage> listener) {
234         LOG.error("{}: Initialization in sal failed, disconnecting from device", id, throwable);
235         listener.close();
236         onRemoteSessionDown();
237         resetMessageTransformer();
238     }
239
240     /**
241      * Set the transformer to null as is in initial state.
242      */
243     private void resetMessageTransformer() {
244         updateTransformer(null);
245     }
246
247     private void updateTransformer(final MessageTransformer<NetconfMessage> transformer) {
248         messageTransformer = transformer;
249     }
250
251     private void addProvidedSourcesToSchemaRegistry(final DeviceSources deviceSources) {
252         final SchemaSourceProvider<YangTextSchemaSource> yangProvider = deviceSources.getSourceProvider();
253         for (final SourceIdentifier sourceId : deviceSources.getProvidedSources()) {
254             sourceRegistrations.add(schemaRegistry.registerSchemaSource(yangProvider,
255                     PotentialSchemaSource.create(
256                             sourceId, YangTextSchemaSource.class, PotentialSchemaSource.Costs.REMOTE_IO.getValue())));
257         }
258     }
259
260     @Override
261     public void onRemoteSessionDown() {
262         notificationHandler.onRemoteSchemaDown();
263
264         salFacade.onDeviceDisconnected();
265         for (final SchemaSourceRegistration<? extends SchemaSourceRepresentation> sourceRegistration
266                 : sourceRegistrations) {
267             sourceRegistration.close();
268         }
269         resetMessageTransformer();
270     }
271
272     @Override
273     public void onRemoteSessionFailed(final Throwable throwable) {
274         salFacade.onDeviceFailed(throwable);
275     }
276
277     @Override
278     public void onNotification(final NetconfMessage notification) {
279         notificationHandler.handleNotification(notification);
280     }
281
282     /**
283      * Just a transfer object containing schema related dependencies. Injected in constructor.
284      */
285     public static class SchemaResourcesDTO {
286         private final SchemaSourceRegistry schemaRegistry;
287         private final SchemaRepository schemaRepository;
288         private final SchemaContextFactory schemaContextFactory;
289         private final NetconfDeviceSchemasResolver stateSchemasResolver;
290
291         public SchemaResourcesDTO(final SchemaSourceRegistry schemaRegistry,
292                                   final SchemaRepository schemaRepository,
293                                   final SchemaContextFactory schemaContextFactory,
294                                   final NetconfDeviceSchemasResolver deviceSchemasResolver) {
295             this.schemaRegistry = Preconditions.checkNotNull(schemaRegistry);
296             this.schemaRepository = Preconditions.checkNotNull(schemaRepository);
297             this.schemaContextFactory = Preconditions.checkNotNull(schemaContextFactory);
298             this.stateSchemasResolver = Preconditions.checkNotNull(deviceSchemasResolver);
299         }
300
301         public SchemaSourceRegistry getSchemaRegistry() {
302             return schemaRegistry;
303         }
304
305         public SchemaRepository getSchemaRepository() {
306             return schemaRepository;
307         }
308
309         public SchemaContextFactory getSchemaContextFactory() {
310             return schemaContextFactory;
311         }
312
313         public NetconfDeviceSchemasResolver getStateSchemasResolver() {
314             return stateSchemasResolver;
315         }
316     }
317
318     /**
319      * Schema building callable.
320      */
321     private static class DeviceSourcesResolver implements Callable<DeviceSources> {
322
323         private final NetconfDeviceRpc deviceRpc;
324         private final NetconfSessionPreferences remoteSessionCapabilities;
325         private final RemoteDeviceId id;
326         private final NetconfDeviceSchemasResolver stateSchemasResolver;
327
328         DeviceSourcesResolver(final NetconfDeviceRpc deviceRpc,
329                               final NetconfSessionPreferences remoteSessionCapabilities,
330                               final RemoteDeviceId id, final NetconfDeviceSchemasResolver stateSchemasResolver) {
331             this.deviceRpc = deviceRpc;
332             this.remoteSessionCapabilities = remoteSessionCapabilities;
333             this.id = id;
334             this.stateSchemasResolver = stateSchemasResolver;
335         }
336
337         DeviceSourcesResolver(final NetconfSessionPreferences remoteSessionCapabilities, final RemoteDeviceId id,
338                                      final NetconfDeviceSchemasResolver stateSchemasResolver,
339                                      final NetconfDeviceRpc rpcForMonitoring) {
340             this(rpcForMonitoring, remoteSessionCapabilities, id, stateSchemasResolver);
341         }
342
343         @Override
344         public DeviceSources call() throws Exception {
345             final NetconfDeviceSchemas availableSchemas =
346                     stateSchemasResolver.resolve(deviceRpc, remoteSessionCapabilities, id);
347             LOG.debug("{}: Schemas exposed by ietf-netconf-monitoring: {}", id,
348                     availableSchemas.getAvailableYangSchemasQNames());
349
350             final Set<QName> requiredSources = Sets.newHashSet(remoteSessionCapabilities.getModuleBasedCaps());
351             final Set<QName> providedSources = availableSchemas.getAvailableYangSchemasQNames();
352
353             final Set<QName> requiredSourcesNotProvided = Sets.difference(requiredSources, providedSources);
354             if (!requiredSourcesNotProvided.isEmpty()) {
355                 LOG.warn("{}: Netconf device does not provide all yang models reported in hello message capabilities,"
356                         + " required but not provided: {}", id, requiredSourcesNotProvided);
357                 LOG.warn("{}: Attempting to build schema context from required sources", id);
358             }
359
360             // Here all the sources reported in netconf monitoring are merged with those reported in hello.
361             // It is necessary to perform this since submodules are not mentioned in hello but still required.
362             // This clashes with the option of a user to specify supported yang models manually in configuration
363             // for netconf-connector and as a result one is not able to fully override yang models of a device.
364             // It is only possible to add additional models.
365             final Set<QName> providedSourcesNotRequired = Sets.difference(providedSources, requiredSources);
366             if (!providedSourcesNotRequired.isEmpty()) {
367                 LOG.warn("{}: Netconf device provides additional yang models not reported in "
368                         + "hello message capabilities: {}", id, providedSourcesNotRequired);
369                 LOG.warn("{}: Adding provided but not required sources as required to prevent failures", id);
370                 LOG.debug("{}: Netconf device reported in hello: {}", id, requiredSources);
371                 requiredSources.addAll(providedSourcesNotRequired);
372             }
373
374             final SchemaSourceProvider<YangTextSchemaSource> sourceProvider;
375             if (availableSchemas instanceof LibraryModulesSchemas) {
376                 sourceProvider = new YangLibrarySchemaYangSourceProvider(id,
377                         ((LibraryModulesSchemas) availableSchemas).getAvailableModels());
378             } else {
379                 sourceProvider = new NetconfRemoteSchemaYangSourceProvider(id, deviceRpc);
380             }
381
382             return new DeviceSources(requiredSources, providedSources, sourceProvider);
383         }
384     }
385
386     /**
387      * Contains RequiredSources - sources from capabilities.
388      */
389     private static final class DeviceSources {
390         private final Set<QName> requiredSources;
391         private final Set<QName> providedSources;
392         private final SchemaSourceProvider<YangTextSchemaSource> sourceProvider;
393
394         DeviceSources(final Set<QName> requiredSources, final Set<QName> providedSources,
395                              final SchemaSourceProvider<YangTextSchemaSource> sourceProvider) {
396             this.requiredSources = requiredSources;
397             this.providedSources = providedSources;
398             this.sourceProvider = sourceProvider;
399         }
400
401         public Set<QName> getRequiredSourcesQName() {
402             return requiredSources;
403         }
404
405         public Set<QName> getProvidedSourcesQName() {
406             return providedSources;
407         }
408
409         public Collection<SourceIdentifier> getRequiredSources() {
410             return Collections2.transform(requiredSources, QNAME_TO_SOURCE_ID_FUNCTION);
411         }
412
413         public Collection<SourceIdentifier> getProvidedSources() {
414             return Collections2.transform(providedSources, QNAME_TO_SOURCE_ID_FUNCTION);
415         }
416
417         public SchemaSourceProvider<YangTextSchemaSource> getSourceProvider() {
418             return sourceProvider;
419         }
420     }
421
422     /**
423      * Schema builder that tries to build schema context from provided sources or biggest subset of it.
424      */
425     private final class SchemaSetup implements Runnable {
426         private final DeviceSources deviceSources;
427         private final NetconfSessionPreferences remoteSessionCapabilities;
428         private final RemoteDeviceCommunicator<NetconfMessage> listener;
429         private final NetconfDeviceCapabilities capabilities;
430
431         SchemaSetup(final DeviceSources deviceSources, final NetconfSessionPreferences remoteSessionCapabilities,
432                            final RemoteDeviceCommunicator<NetconfMessage> listener) {
433             this.deviceSources = deviceSources;
434             this.remoteSessionCapabilities = remoteSessionCapabilities;
435             this.listener = listener;
436             this.capabilities = remoteSessionCapabilities.getNetconfDeviceCapabilities();
437         }
438
439         @Override
440         public void run() {
441
442             final Collection<SourceIdentifier> requiredSources = deviceSources.getRequiredSources();
443             final Collection<SourceIdentifier> missingSources = filterMissingSources(requiredSources);
444
445             capabilities.addUnresolvedCapabilities(getQNameFromSourceIdentifiers(missingSources),
446                     UnavailableCapability.FailureReason.MissingSource);
447
448             requiredSources.removeAll(missingSources);
449             setUpSchema(requiredSources);
450         }
451
452         private Collection<SourceIdentifier> filterMissingSources(final Collection<SourceIdentifier> requiredSources) {
453
454             return requiredSources.parallelStream().filter(sourceIdentifier -> {
455                 boolean remove = false;
456                 try {
457                     schemaRepository.getSchemaSource(sourceIdentifier, ASTSchemaSource.class).checkedGet();
458                 } catch (SchemaSourceException e) {
459                     remove = true;
460                 }
461                 return remove;
462             }).collect(Collectors.toList());
463         }
464
465         /**
466          * Build schema context, in case of success or final failure notify device.
467          */
468         @SuppressWarnings("checkstyle:IllegalCatch")
469         private void setUpSchema(Collection<SourceIdentifier> requiredSources) {
470             while (!requiredSources.isEmpty()) {
471                 LOG.trace("{}: Trying to build schema context from {}", id, requiredSources);
472                 try {
473                     final CheckedFuture<SchemaContext, SchemaResolutionException> schemaBuilderFuture =
474                             schemaContextFactory.createSchemaContext(requiredSources);
475                     final SchemaContext result = schemaBuilderFuture.checkedGet();
476                     LOG.debug("{}: Schema context built successfully from {}", id, requiredSources);
477                     final Collection<QName> filteredQNames = Sets.difference(deviceSources.getRequiredSourcesQName(),
478                             capabilities.getUnresolvedCapabilites().keySet());
479                     capabilities.addCapabilities(filteredQNames.stream().map(entry -> new AvailableCapabilityBuilder()
480                             .setCapability(entry.toString()).setCapabilityOrigin(
481                                     remoteSessionCapabilities.getModuleBasedCapsOrigin().get(entry)).build())
482                             .collect(Collectors.toList()));
483
484                     capabilities.addNonModuleBasedCapabilities(remoteSessionCapabilities
485                             .getNonModuleCaps().stream().map(entry -> new AvailableCapabilityBuilder()
486                             .setCapability(entry).setCapabilityOrigin(
487                                             remoteSessionCapabilities.getNonModuleBasedCapsOrigin().get(entry)).build())
488                             .collect(Collectors.toList()));
489
490                     handleSalInitializationSuccess(result, remoteSessionCapabilities, getDeviceSpecificRpc(result));
491                     return;
492                 } catch (final Throwable t) {
493                     if (t instanceof MissingSchemaSourceException) {
494                         requiredSources =
495                                 handleMissingSchemaSourceException(requiredSources, (MissingSchemaSourceException) t);
496                     } else if (t instanceof SchemaResolutionException) {
497                         // schemaBuilderFuture.checkedGet() throws only SchemaResolutionException
498                         // that might be wrapping a MissingSchemaSourceException so we need to look
499                         // at the cause of the exception to make sure we don't misinterpret it.
500                         if (t.getCause() instanceof MissingSchemaSourceException) {
501                             requiredSources = handleMissingSchemaSourceException(
502                                     requiredSources, (MissingSchemaSourceException) t.getCause());
503                             continue;
504                         }
505                         requiredSources =
506                                 handleSchemaResolutionException(requiredSources, (SchemaResolutionException) t);
507                     } else {
508                         // unknown error, fail
509                         handleSalInitializationFailure(t, listener);
510                         return;
511                     }
512                 }
513             }
514             // No more sources, fail
515             final IllegalStateException cause = new IllegalStateException(id + ": No more sources for schema context");
516             handleSalInitializationFailure(cause, listener);
517             salFacade.onDeviceFailed(cause);
518         }
519
520         private Collection<SourceIdentifier> handleMissingSchemaSourceException(
521                 final Collection<SourceIdentifier> requiredSources, 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", id,
525                     missingSource);
526             LOG.debug("{}: Unable to build schema context, missing source {}, will reattempt without it",
527                     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(requiredSources, missingSource);
535         }
536
537         private Collection<SourceIdentifier> handleSchemaResolutionException(
538             final Collection<SourceIdentifier> requiredSources, 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, resolutionException);
549                 capabilities.addUnresolvedCapabilities(getQNameFromSourceIdentifiers(
550                         Collections.singleton(failedSourceId)), UnavailableCapability.FailureReason.UnableToResolve);
551                 return stripUnavailableSource(requiredSources, resolutionException.getFailedSource());
552             }
553             // unsatisfied imports
554             final Set<SourceIdentifier> unresolvedSources = resolutionException.getUnsatisfiedImports().keySet();
555             capabilities.addUnresolvedCapabilities(
556                 getQNameFromSourceIdentifiers(unresolvedSources), UnavailableCapability.FailureReason.UnableToResolve);
557             LOG.warn("{}: Unable to build schema context, unsatisfied imports {}, will reattempt with resolved only",
558                     id, resolutionException.getUnsatisfiedImports());
559             LOG.debug("{}: Unable to build schema context, unsatisfied imports {}, will reattempt with resolved only",
560                     resolutionException);
561             return resolutionException.getResolvedSources();
562         }
563
564         protected NetconfDeviceRpc getDeviceSpecificRpc(final SchemaContext result) {
565             return new NetconfDeviceRpc(result, listener, new NetconfMessageTransformer(result, true));
566         }
567
568         private Collection<SourceIdentifier> stripUnavailableSource(final Collection<SourceIdentifier> requiredSources,
569                                                                     final SourceIdentifier sourceIdToRemove) {
570             final LinkedList<SourceIdentifier> sourceIdentifiers = Lists.newLinkedList(requiredSources);
571             final boolean removed = sourceIdentifiers.remove(sourceIdToRemove);
572             Preconditions.checkState(
573                     removed, "{}: Trying to remove {} from {} failed", id, sourceIdToRemove, requiredSources);
574             return sourceIdentifiers;
575         }
576
577         private Collection<QName> getQNameFromSourceIdentifiers(final Collection<SourceIdentifier> identifiers) {
578             final Collection<QName> qNames = Collections2.transform(identifiers, this::getQNameFromSourceIdentifier);
579
580             if (qNames.isEmpty()) {
581                 LOG.debug("{}: Unable to map any source identifiers to a capability reported by device : {}", id,
582                         identifiers);
583             }
584             return Collections2.filter(qNames, Predicates.notNull());
585         }
586
587         private QName getQNameFromSourceIdentifier(final SourceIdentifier identifier) {
588             // Required sources are all required and provided merged in DeviceSourcesResolver
589             for (final QName qname : deviceSources.getRequiredSourcesQName()) {
590                 if (!qname.getLocalName().equals(identifier.getName())) {
591                     continue;
592                 }
593
594                 final String rev = getNullableRev(identifier);
595                 if (rev == null) {
596                     if (qname.getRevision() == null) {
597                         return qname;
598                     }
599                 } else if (qname.getFormattedRevision().equals(rev)) {
600                     return qname;
601                 }
602             }
603             LOG.warn("Unable to map identifier to a devices reported capability: {} Available: {}",identifier,
604                     deviceSources.getRequiredSourcesQName());
605             // return null since we cannot find the QName,
606             // this capability will be removed from required sources and not reported as unresolved-capability
607             return null;
608         }
609
610         private String getNullableRev(final SourceIdentifier identifier) {
611             final String rev = identifier.getRevision();
612             return rev == null || SourceIdentifier.NOT_PRESENT_FORMATTED_REVISION.equals(rev) ? null : rev;
613         }
614     }
615 }