Examples with GroupedActionListener org.elasticsearch.action.support.GroupedActionListener used on opensource projects

Example 11 with GroupedActionListener

use of org.elasticsearch.action.support.GroupedActionListener in project crate by crate.

the class BlobStoreRepository method writeIndexGen.

/**
 * Writing a new index generation is a three step process.
 * First, the {@link RepositoryMetadata} entry for this repository is set into a pending state by incrementing its
 * pending generation {@code P} while its safe generation {@code N} remains unchanged.
 * Second, the updated {@link RepositoryData} is written to generation {@code P + 1}.
 * Lastly, the {@link RepositoryMetadata} entry for this repository is updated to the new generation {@code P + 1} and thus
 * pending and safe generation are set to the same value marking the end of the update of the repository data.
 *
 * @param repositoryData RepositoryData to write
 * @param expectedGen    expected repository generation at the start of the operation
 * @param writeShardGens whether to write {@link ShardGenerations} to the new {@link RepositoryData} blob
 * @param listener       completion listener
 */
protected void writeIndexGen(RepositoryData repositoryData, long expectedGen, boolean writeShardGens, ActionListener<Void> listener) {
    // can not write to a read only repository
    assert isReadOnly() == false;
    final long currentGen = repositoryData.getGenId();
    if (currentGen != expectedGen) {
        // the index file was updated by a concurrent operation, so we were operating on stale
        // repository data
        listener.onFailure(new RepositoryException(metadata.name(), "concurrent modification of the index-N file, expected current generation [" + expectedGen + "], actual current generation [" + currentGen + "]"));
        return;
    }
    // Step 1: Set repository generation state to the next possible pending generation
    final StepListener<Long> setPendingStep = new StepListener<>();
    clusterService.submitStateUpdateTask("set pending repository generation [" + metadata.name() + "][" + expectedGen + "]", new ClusterStateUpdateTask() {

        private long newGen;

        @Override
        public ClusterState execute(ClusterState currentState) {
            final RepositoryMetadata meta = getRepoMetadata(currentState);
            final String repoName = metadata.name();
            final long genInState = meta.generation();
            final boolean uninitializedMeta = meta.generation() == RepositoryData.UNKNOWN_REPO_GEN || bestEffortConsistency;
            if (uninitializedMeta == false && meta.pendingGeneration() != genInState) {
                LOGGER.info("Trying to write new repository data over unfinished write, repo [{}] is at " + "safe generation [{}] and pending generation [{}]", meta.name(), genInState, meta.pendingGeneration());
            }
            assert expectedGen == RepositoryData.EMPTY_REPO_GEN || uninitializedMeta || expectedGen == meta.generation() : "Expected non-empty generation [" + expectedGen + "] does not match generation tracked in [" + meta + "]";
            // If we run into the empty repo generation for the expected gen, the repo is assumed to have been cleared of
            // all contents by an external process so we reset the safe generation to the empty generation.
            final long safeGeneration = expectedGen == RepositoryData.EMPTY_REPO_GEN ? RepositoryData.EMPTY_REPO_GEN : (uninitializedMeta ? expectedGen : genInState);
            // Regardless of whether or not the safe generation has been reset, the pending generation always increments so that
            // even if a repository has been manually cleared of all contents we will never reuse the same repository generation.
            // This is motivated by the consistency behavior the S3 based blob repository implementation has to support which does
            // not offer any consistency guarantees when it comes to overwriting the same blob name with different content.
            final long nextPendingGen = metadata.pendingGeneration() + 1;
            newGen = uninitializedMeta ? Math.max(expectedGen + 1, nextPendingGen) : nextPendingGen;
            assert newGen > latestKnownRepoGen.get() : "Attempted new generation [" + newGen + "] must be larger than latest known generation [" + latestKnownRepoGen.get() + "]";
            return ClusterState.builder(currentState).metadata(Metadata.builder(currentState.getMetadata()).putCustom(RepositoriesMetadata.TYPE, currentState.metadata().<RepositoriesMetadata>custom(RepositoriesMetadata.TYPE).withUpdatedGeneration(repoName, safeGeneration, newGen)).build()).build();
        }

        @Override
        public void onFailure(String source, Exception e) {
            listener.onFailure(new RepositoryException(metadata.name(), "Failed to execute cluster state update [" + source + "]", e));
        }

        @Override
        public void clusterStateProcessed(String source, ClusterState oldState, ClusterState newState) {
            setPendingStep.onResponse(newGen);
        }
    });
    final StepListener<RepositoryData> filterRepositoryDataStep = new StepListener<>();
    // Step 2: Write new index-N blob to repository and update index.latest
    setPendingStep.whenComplete(newGen -> threadPool().executor(ThreadPool.Names.SNAPSHOT).execute(ActionRunnable.wrap(listener, l -> {
        // BwC logic: Load snapshot version information if any snapshot is missing a version in RepositoryData so that the new
        // RepositoryData contains a version for every snapshot
        final List<SnapshotId> snapshotIdsWithoutVersion = repositoryData.getSnapshotIds().stream().filter(snapshotId -> repositoryData.getVersion(snapshotId) == null).collect(Collectors.toList());
        if (snapshotIdsWithoutVersion.isEmpty() == false) {
            final Map<SnapshotId, Version> updatedVersionMap = new ConcurrentHashMap<>();
            final GroupedActionListener<Void> loadAllVersionsListener = new GroupedActionListener<>(ActionListener.runAfter(new ActionListener<Collection<Void>>() {

                @Override
                public void onResponse(Collection<Void> voids) {
                    LOGGER.info("Successfully loaded all snapshot's version information for {} from snapshot metadata", AllocationService.firstListElementsToCommaDelimitedString(snapshotIdsWithoutVersion, SnapshotId::toString, LOGGER.isDebugEnabled()));
                }

                @Override
                public void onFailure(Exception e) {
                    LOGGER.warn("Failure when trying to load missing version information from snapshot metadata", e);
                }
            }, () -> filterRepositoryDataStep.onResponse(repositoryData.withVersions(updatedVersionMap))), snapshotIdsWithoutVersion.size());
            for (SnapshotId snapshotId : snapshotIdsWithoutVersion) {
                threadPool().executor(ThreadPool.Names.SNAPSHOT).execute(ActionRunnable.run(loadAllVersionsListener, () -> {
                    ActionListener<SnapshotInfo> snapshotInfoListener = ActionListener.delegateFailure(loadAllVersionsListener, (delegate, snapshotInfo) -> {
                        updatedVersionMap.put(snapshotId, snapshotInfo.version());
                        delegate.onResponse(null);
                    });
                    getSnapshotInfo(snapshotId, snapshotInfoListener);
                }));
            }
        } else {
            filterRepositoryDataStep.onResponse(repositoryData);
        }
    })), listener::onFailure);
    filterRepositoryDataStep.whenComplete(filteredRepositoryData -> {
        final long newGen = setPendingStep.result();
        if (latestKnownRepoGen.get() >= newGen) {
            throw new IllegalArgumentException("Tried writing generation [" + newGen + "] but repository is at least at generation [" + latestKnownRepoGen.get() + "] already");
        }
        // write the index file
        final String indexBlob = INDEX_FILE_PREFIX + Long.toString(newGen);
        LOGGER.debug("Repository [{}] writing new index generational blob [{}]", metadata.name(), indexBlob);
        writeAtomic(indexBlob, BytesReference.bytes(filteredRepositoryData.snapshotsToXContent(XContentFactory.jsonBuilder(), writeShardGens)), true);
        // write the current generation to the index-latest file
        final BytesReference genBytes;
        try (BytesStreamOutput bStream = new BytesStreamOutput()) {
            bStream.writeLong(newGen);
            genBytes = bStream.bytes();
        }
        LOGGER.debug("Repository [{}] updating index.latest with generation [{}]", metadata.name(), newGen);
        writeAtomic(INDEX_LATEST_BLOB, genBytes, false);
        // Step 3: Update CS to reflect new repository generation.
        clusterService.submitStateUpdateTask("set safe repository generation [" + metadata.name() + "][" + newGen + "]", new ClusterStateUpdateTask() {

            @Override
            public ClusterState execute(ClusterState currentState) {
                final RepositoryMetadata meta = getRepoMetadata(currentState);
                if (meta.generation() != expectedGen) {
                    throw new IllegalStateException("Tried to update repo generation to [" + newGen + "] but saw unexpected generation in state [" + meta + "]");
                }
                if (meta.pendingGeneration() != newGen) {
                    throw new IllegalStateException("Tried to update from unexpected pending repo generation [" + meta.pendingGeneration() + "] after write to generation [" + newGen + "]");
                }
                return ClusterState.builder(currentState).metadata(Metadata.builder(currentState.getMetadata()).putCustom(RepositoriesMetadata.TYPE, currentState.metadata().<RepositoriesMetadata>custom(RepositoriesMetadata.TYPE).withUpdatedGeneration(metadata.name(), newGen, newGen)).build()).build();
            }

            @Override
            public void onFailure(String source, Exception e) {
                listener.onFailure(new RepositoryException(metadata.name(), "Failed to execute cluster state update [" + source + "]", e));
            }

            @Override
            public void clusterStateProcessed(String source, ClusterState oldState, ClusterState newState) {
                threadPool.executor(ThreadPool.Names.SNAPSHOT).execute(ActionRunnable.run(listener, () -> {
                    // Delete all now outdated index files up to 1000 blobs back from the new generation.
                    // If there are more than 1000 dangling index-N cleanup functionality on repo delete will take care of them.
                    // Deleting one older than the current expectedGen is done for BwC reasons as older versions used to keep
                    // two index-N blobs around.
                    final List<String> oldIndexN = LongStream.range(Math.max(Math.max(expectedGen - 1, 0), newGen - 1000), newGen).mapToObj(gen -> INDEX_FILE_PREFIX + gen).collect(Collectors.toList());
                    try {
                        blobContainer().deleteBlobsIgnoringIfNotExists(oldIndexN);
                    } catch (IOException e) {
                        LOGGER.warn("Failed to clean up old index blobs {}", oldIndexN);
                    }
                }));
            }
        });
    }, listener::onFailure);
}