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// Copyright 2018 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
package com.yahoo.vespa.clustercontroller.core.rpc;
import com.yahoo.compress.CompressionType;
import com.yahoo.compress.Compressor;
import com.yahoo.slime.*;
import com.yahoo.vdslib.state.ClusterState;
import com.yahoo.vespa.clustercontroller.core.AnnotatedClusterState;
import com.yahoo.vespa.clustercontroller.core.ClusterStateBundle;
import java.util.HashMap;
import java.util.Map;
/**
* Implementation of ClusterStateBundleCodec which uses structured Slime binary encoding
* to implement (de-)serialization of ClusterStateBundle instances. Encoding format is
* intentionally extensible so that we may add other information to it later.
*
* LZ4 compression is transparently applied during encoding and decompression is
* subsequently applied during decoding.
*
* Implements optional Slime-based enveloping for *WithEnvelope methods, which removes
* need to explicitly track compression metadata by the caller.
*/
public class SlimeClusterStateBundleCodec implements ClusterStateBundleCodec, EnvelopedClusterStateBundleCodec {
private static final Compressor compressor = new Compressor(CompressionType.LZ4, 3, 0.90, 1024);
@Override
public EncodedClusterStateBundle encode(ClusterStateBundle stateBundle) {
Slime slime = new Slime();
Cursor root = slime.setObject();
if (stateBundle.deferredActivation()) {
root.setBool("deferred-activation", stateBundle.deferredActivation());
}
Cursor states = root.setObject("states");
// TODO add another function that is not toString for this..!
states.setString("baseline", stateBundle.getBaselineClusterState().toString());
Cursor spaces = states.setObject("spaces");
stateBundle.getDerivedBucketSpaceStates().entrySet()
.forEach(entry -> spaces.setString(entry.getKey(), entry.getValue().toString()));
// Only bother to encode feed block state if cluster is actually blocked
if (stateBundle.getFeedBlock().map(fb -> fb.blockFeedInCluster()).orElse(false)) {
Cursor feedBlock = root.setObject("feed-block");
feedBlock.setBool("block-feed-in-cluster", true);
feedBlock.setString("description", stateBundle.getFeedBlock().get().getDescription());
}
byte[] serialized = BinaryFormat.encode(slime);
Compressor.Compression compression = compressor.compress(serialized);
return EncodedClusterStateBundle.fromCompressionBuffer(compression);
}
@Override
public ClusterStateBundle decode(EncodedClusterStateBundle encodedClusterStateBundle) {
byte[] uncompressed = compressor.decompress(encodedClusterStateBundle.getCompression());
Slime slime = BinaryFormat.decode(uncompressed);
Inspector root = slime.get();
Inspector states = root.field("states");
ClusterState baseline = ClusterState.stateFromString(states.field("baseline").asString());
Inspector spaces = states.field("spaces");
Map<String, AnnotatedClusterState> derivedStates = new HashMap<>();
spaces.traverse(((ObjectTraverser)(key, value) -> {
derivedStates.put(key, AnnotatedClusterState.withoutAnnotations(ClusterState.stateFromString(value.asString())));
}));
boolean deferredActivation = root.field("deferred-activation").asBool(); // defaults to false if not present
ClusterStateBundle.FeedBlock feedBlock = null;
Inspector fb = root.field("feed-block");
if (fb.valid() && fb.field("block-feed-in-cluster").asBool()) {
feedBlock = ClusterStateBundle.FeedBlock.blockedWithDescription(fb.field("description").asString());
}
return ClusterStateBundle.of(AnnotatedClusterState.withoutAnnotations(baseline), derivedStates,
feedBlock, deferredActivation);
}
// Technically the Slime enveloping could be its own class that is bundle codec independent, but
// realistically there won't be any other implementations. Can be trivially factored out if required.
@Override
public byte[] encodeWithEnvelope(ClusterStateBundle stateBundle) {
EncodedClusterStateBundle toEnvelope = encode(stateBundle);
Slime slime = new Slime();
Cursor root = slime.setObject();
root.setLong("compression-type", toEnvelope.getCompression().type().getCode());
root.setLong("uncompressed-size", toEnvelope.getCompression().uncompressedSize());
root.setData("data", toEnvelope.getCompression().data());
return BinaryFormat.encode(slime);
}
@Override
public ClusterStateBundle decodeWithEnvelope(byte[] encodedClusterStateBundle) {
// We expect ZK writes to be atomic, letting us not worry about partially written or corrupted blobs.
Slime slime = BinaryFormat.decode(encodedClusterStateBundle);
Inspector root = slime.get();
CompressionType compressionType = CompressionType.valueOf((byte)root.field("compression-type").asLong());
int uncompressedSize = (int)root.field("uncompressed-size").asLong();
byte[] data = root.field("data").asData();
return decode(EncodedClusterStateBundle.fromCompressionBuffer(
new Compressor.Compression(compressionType, uncompressedSize, data)));
}
}
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