restconf/restconf-nb/src/main/java/org/opendaylight/restconf/server/spi/AbstractRestconfStreamRegistry.java

   1 /*
   2  * Copyright (c) 2023 PANTHEON.tech, s.r.o. 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.restconf.server.spi;
   9
  10 import static java.util.Objects.requireNonNull;
  11
  12 import com.google.common.annotations.VisibleForTesting;
  13 import com.google.common.util.concurrent.FutureCallback;
  14 import com.google.common.util.concurrent.Futures;
  15 import com.google.common.util.concurrent.ListenableFuture;
  16 import com.google.common.util.concurrent.MoreExecutors;
  17 import java.net.URI;
  18 import java.net.URISyntaxException;
  19 import java.util.Set;
  20 import java.util.UUID;
  21 import java.util.concurrent.ConcurrentHashMap;
  22 import java.util.concurrent.ConcurrentMap;
  23 import org.eclipse.jdt.annotation.NonNull;
  24 import org.eclipse.jdt.annotation.Nullable;
  25 import org.opendaylight.restconf.common.errors.RestconfDocumentedException;
  26 import org.opendaylight.restconf.nb.rfc8040.URLConstants;
  27 import org.opendaylight.restconf.server.api.ServerRequest;
  28 import org.opendaylight.restconf.server.spi.RestconfStream.EncodingName;
  29 import org.opendaylight.restconf.server.spi.RestconfStream.Source;
  30 import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.restconf.monitoring.rev170126.restconf.state.streams.Stream;
  31 import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.restconf.monitoring.rev170126.restconf.state.streams.stream.Access;
  32 import org.opendaylight.yangtools.yang.common.QName;
  33 import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier.NodeIdentifier;
  34 import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier.NodeIdentifierWithPredicates;
  35 import org.opendaylight.yangtools.yang.data.api.schema.MapEntryNode;
  36 import org.opendaylight.yangtools.yang.data.spi.node.ImmutableNodes;
  37 import org.slf4j.Logger;
  38 import org.slf4j.LoggerFactory;
  39
  40 /**
  41  * Reference base class for {@link RestconfStream.Registry} implementations.
  42  */
  43 public abstract class AbstractRestconfStreamRegistry implements RestconfStream.Registry {
  44     private static final Logger LOG = LoggerFactory.getLogger(AbstractRestconfStreamRegistry.class);
  45
  46     @VisibleForTesting
  47     public static final QName NAME_QNAME =  QName.create(Stream.QNAME, "name").intern();
  48     @VisibleForTesting
  49     public static final QName DESCRIPTION_QNAME = QName.create(Stream.QNAME, "description").intern();
  50     @VisibleForTesting
  51     public static final QName ENCODING_QNAME =  QName.create(Stream.QNAME, "encoding").intern();
  52     @VisibleForTesting
  53     public static final QName LOCATION_QNAME =  QName.create(Stream.QNAME, "location").intern();
  54
  55     private final ConcurrentMap<String, RestconfStream<?>> streams = new ConcurrentHashMap<>();
  56
  57     @Override
  58     public final @Nullable RestconfStream<?> lookupStream(final String name) {
  59         return streams.get(requireNonNull(name));
  60     }
  61
  62     @Override
  63     public final <T> void createStream(final ServerRequest<RestconfStream<T>> request, final URI restconfURI,
  64             final Source<T> source, final String description) {
  65         final var baseStreamLocation = baseStreamLocation(restconfURI);
  66         final var stream = allocateStream(source);
  67         final var name = stream.name();
  68         if (description.isBlank()) {
  69             throw new IllegalArgumentException("Description must be descriptive");
  70         }
  71
  72         Futures.addCallback(putStream(streamEntry(name, description, baseStreamLocation, stream.encodings())),
  73             new FutureCallback<Object>() {
  74                 @Override
  75                 public void onSuccess(final Object result) {
  76                     LOG.debug("Stream {} added", name);
  77                     request.completeWith(stream);
  78                 }
  79
  80                 @Override
  81                 public void onFailure(final Throwable cause) {
  82                     LOG.debug("Failed to add stream {}", name, cause);
  83                     streams.remove(name, stream);
  84                     request.completeWith(new RestconfDocumentedException("Failed to allocate stream " + name, cause));
  85                 }
  86             }, MoreExecutors.directExecutor());
  87     }
  88
  89     private <T> RestconfStream<T> allocateStream(final Source<T> source) {
  90         String name;
  91         RestconfStream<T> stream;
  92         do {
  93             // Use Type 4 (random) UUID. While we could just use it as a plain string, be nice to observers and anchor
  94             // it into UUID URN namespace as defined by RFC4122
  95             name = "urn:uuid:" + UUID.randomUUID().toString();
  96             stream = new RestconfStream<>(this, source, name);
  97         } while (streams.putIfAbsent(name, stream) != null);
  98
  99         return stream;
 100     }
 101
 102     protected abstract @NonNull ListenableFuture<?> putStream(@NonNull MapEntryNode stream);
 103
 104     /**
 105      * Remove a particular stream and remove its entry from operational datastore.
 106      *
 107      * @param stream Stream to remove
 108      */
 109     final void removeStream(final RestconfStream<?> stream) {
 110         // Defensive check to see if we are still tracking the stream
 111         final var name = stream.name();
 112         if (streams.get(name) != stream) {
 113             LOG.warn("Stream {} does not match expected instance {}, skipping datastore update", name, stream);
 114             return;
 115         }
 116
 117         Futures.addCallback(deleteStream(NodeIdentifierWithPredicates.of(Stream.QNAME, NAME_QNAME, name)),
 118             new FutureCallback<Object>() {
 119                 @Override
 120                 public void onSuccess(final Object result) {
 121                     LOG.debug("Stream {} removed", name);
 122                     streams.remove(name, stream);
 123                 }
 124
 125                 @Override
 126                 public void onFailure(final Throwable cause) {
 127                     LOG.warn("Failed to remove stream {}, operational datastore may be inconsistent", name, cause);
 128                     streams.remove(name, stream);
 129                 }
 130             }, MoreExecutors.directExecutor());
 131     }
 132
 133     protected abstract @NonNull ListenableFuture<?> deleteStream(@NonNull NodeIdentifierWithPredicates streamName);
 134
 135     /**
 136      * Return the base location URL of the streams service based on request URI.
 137      *
 138      * @param restconfURI request base URI, with trailing slash
 139      * @throws IllegalArgumentException if the result would have been malformed
 140      */
 141     protected static final @NonNull String baseStreamLocation(final URI restconfURI) {
 142         var scheme = restconfURI.getScheme();
 143
 144         try {
 145             return new URI(scheme, restconfURI.getRawUserInfo(), restconfURI.getHost(), restconfURI.getPort(),
 146                 restconfURI.getPath() + URLConstants.STREAMS_SUBPATH, null, null)
 147                 .toString();
 148         } catch (URISyntaxException e) {
 149             throw new IllegalArgumentException("Cannot derive streams location", e);
 150         }
 151     }
 152
 153     @VisibleForTesting
 154     public static final @NonNull MapEntryNode streamEntry(final String name, final String description,
 155             final String baseStreamLocation, final Set<EncodingName> encodings) {
 156         final var accessBuilder = ImmutableNodes.newSystemMapBuilder()
 157             .withNodeIdentifier(new NodeIdentifier(Access.QNAME));
 158         for (var encoding : encodings) {
 159             final var encodingName = encoding.name();
 160             accessBuilder.withChild(ImmutableNodes.newMapEntryBuilder()
 161                 .withNodeIdentifier(NodeIdentifierWithPredicates.of(Access.QNAME, ENCODING_QNAME, encodingName))
 162                 .withChild(ImmutableNodes.leafNode(ENCODING_QNAME, encodingName))
 163                 .withChild(ImmutableNodes.leafNode(LOCATION_QNAME,
 164                     baseStreamLocation + '/' + encodingName + '/' + name))
 165                 .build());
 166         }
 167
 168         return ImmutableNodes.newMapEntryBuilder()
 169             .withNodeIdentifier(NodeIdentifierWithPredicates.of(Stream.QNAME, NAME_QNAME, name))
 170             .withChild(ImmutableNodes.leafNode(NAME_QNAME, name))
 171             .withChild(ImmutableNodes.leafNode(DESCRIPTION_QNAME, description))
 172             .withChild(accessBuilder.build())
 173             .build();
 174     }
 175 }