io.github.bucket4j.redis.lettuce.cas.LettuceBasedProxyManager Maven / Gradle / Ivy

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/*-
 * ========================LICENSE_START=================================
 * Bucket4j
 * %%
 * Copyright (C) 2015 - 2022 Vladimir Bukhtoyarov
 * %%
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 * =========================LICENSE_END==================================
 */

package io.github.bucket4j.redis.lettuce.cas;

import io.github.bucket4j.TimeMeter;
import io.github.bucket4j.distributed.ExpirationAfterWriteStrategy;
import io.github.bucket4j.distributed.proxy.ClientSideConfig;
import io.github.bucket4j.distributed.proxy.generic.compare_and_swap.AbstractCompareAndSwapBasedProxyManager;
import io.github.bucket4j.distributed.proxy.generic.compare_and_swap.AsyncCompareAndSwapOperation;
import io.github.bucket4j.distributed.proxy.generic.compare_and_swap.CompareAndSwapOperation;
import io.github.bucket4j.distributed.remote.RemoteBucketState;
import io.github.bucket4j.redis.AbstractRedisProxyManagerBuilder;
import io.lettuce.core.RedisClient;
import io.lettuce.core.RedisException;
import io.lettuce.core.RedisFuture;
import io.lettuce.core.ScriptOutputType;
import io.lettuce.core.api.StatefulRedisConnection;
import io.lettuce.core.api.async.RedisAsyncCommands;
import io.lettuce.core.codec.ByteArrayCodec;

import java.nio.charset.StandardCharsets;
import java.util.Objects;
import java.util.Optional;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.ExecutionException;

public class LettuceBasedProxyManager extends AbstractCompareAndSwapBasedProxyManager {

    private final RedisAsyncCommands commands;
    private final ExpirationAfterWriteStrategy expirationStrategy;

    public static LettuceBasedProxyManagerBuilder builderFor(RedisAsyncCommands redisAsyncCommands) {
        return new LettuceBasedProxyManagerBuilder(redisAsyncCommands);
    }

    public static LettuceBasedProxyManagerBuilder builderFor(StatefulRedisConnection statefulRedisConnection) {
        return new LettuceBasedProxyManagerBuilder(statefulRedisConnection.async());
    }

    public static LettuceBasedProxyManagerBuilder builderFor(RedisClient redisClient) {
        return builderFor(redisClient.connect(ByteArrayCodec.INSTANCE));
    }

    public static class LettuceBasedProxyManagerBuilder extends AbstractRedisProxyManagerBuilder {

        private final RedisAsyncCommands commands;

        private LettuceBasedProxyManagerBuilder(RedisAsyncCommands commands) {
            this.commands = Objects.requireNonNull(commands);
        }

        public LettuceBasedProxyManager build() {
            return new LettuceBasedProxyManager(this);
        }

    }

    private LettuceBasedProxyManager(LettuceBasedProxyManagerBuilder builder) {
        super(builder.getClientSideConfig());
        this.expirationStrategy = builder.getNotNullExpirationStrategy();
        this.commands = builder.commands;
    }

    @Override
    protected CompareAndSwapOperation beginCompareAndSwapOperation(byte[] key) {
        byte[][] keys = {key};
        return new CompareAndSwapOperation() {
            @Override
            public Optional getStateData() {
                RedisFuture stateFuture = commands.get(key);
                return Optional.ofNullable(getFutureValue(stateFuture));
            }

            @Override
            public boolean compareAndSwap(byte[] originalData, byte[] newData, RemoteBucketState newState) {
                return getFutureValue(compareAndSwapFuture(key, keys, originalData, newData, newState));
            }
        };
    }

    @Override
    protected AsyncCompareAndSwapOperation beginAsyncCompareAndSwapOperation(byte[] key) {
        byte[][] keys = {key};
        return new AsyncCompareAndSwapOperation() {
            @Override
            public CompletableFuture> getStateData() {
                RedisFuture stateFuture = commands.get(key);
                return convertToCompletableFuture(stateFuture)
                        .thenApply((byte[] resultBytes) -> Optional.ofNullable(resultBytes));
            }

            @Override
            public CompletableFuture compareAndSwap(byte[] originalData, byte[] newData, RemoteBucketState newState) {
                return convertToCompletableFuture(compareAndSwapFuture(key, keys, originalData, newData, newState));
            }
        };
    }

    @Override
    public void removeProxy(byte[] key) {
        RedisFuture future = commands.del(key);
        getFutureValue(future);
    }

    @Override
    protected CompletableFuture removeAsync(byte[] key) {
        RedisFuture future = commands.del(key);
        return convertToCompletableFuture(future).thenApply(bytes -> null);
    }

    @Override
    public boolean isAsyncModeSupported() {
        return true;
    }

    private RedisFuture compareAndSwapFuture(byte[] key, byte[][] keys, byte[] originalData, byte[] newData, RemoteBucketState newState) {
        long ttlMillis = calculateTtlMillis(newState);
        if (ttlMillis > 0) {
            if (originalData == null) {
                // nulls are prohibited as values, so "replace" must not be used in such cases
                String script = "return redis.call('set', KEYS[1], ARGV[1], 'nx', 'px', ARGV[2])";
                byte[][] params = {newData, encodeLong(ttlMillis)};
                return commands.eval(script, ScriptOutputType.BOOLEAN, keys, params);
            } else {
                String script =
                        "if redis.call('get', KEYS[1]) == ARGV[1] then " +
                                "redis.call('psetex', KEYS[1], ARGV[3], ARGV[2]); " +
                                "return 1; " +
                        "else " +
                                "return 0; " +
                        "end";
                byte[][] params = {originalData, newData, encodeLong(ttlMillis)};
                return commands.eval(script, ScriptOutputType.BOOLEAN, keys, params);
            }
        } else {
            if (originalData == null) {
                // nulls are prohibited as values, so "replace" must not be used in such cases
                String script = "return redis.call('set', KEYS[1], ARGV[1], 'nx')";
                byte[][] params = {newData};
                return commands.eval(script, ScriptOutputType.BOOLEAN, keys, params);
            } else {
                String script =
                        "if redis.call('get', KEYS[1]) == ARGV[1] then " +
                                "redis.call('set', KEYS[1], ARGV[2]); " +
                                "return 1; " +
                        "else " +
                                "return 0; " +
                        "end";
                byte[][] params = {originalData, newData};
                return commands.eval(script, ScriptOutputType.BOOLEAN, keys, params);
            }
        }
    }

    private  CompletableFuture convertToCompletableFuture(RedisFuture redissonFuture) {
        CompletableFuture jdkFuture = new CompletableFuture<>();
        redissonFuture.whenComplete((result, error) -> {
            if (error != null) {
                jdkFuture.completeExceptionally(error);
            } else {
                jdkFuture.complete(result);
            }
        });
        return jdkFuture;
    }

    private  V getFutureValue(RedisFuture value) {
        try {
            return value.get();
        } catch (InterruptedException e) {
            value.cancel(true);
            Thread.currentThread().interrupt();
            throw new RedisException(e);
        } catch (ExecutionException e) {
            throw e.getCause() instanceof RedisException ? (RedisException) e.getCause() :
                    new RedisException("Unexpected exception while processing command", e.getCause());
        }
    }

    private byte[] encodeLong(Long value) {
        return ("" + value).getBytes(StandardCharsets.UTF_8);
    }

    private long calculateTtlMillis(RemoteBucketState state) {
        Optional clock = getClientSideConfig().getClientSideClock();
        long currentTimeNanos = clock.isPresent() ? clock.get().currentTimeNanos() : System.currentTimeMillis() * 1_000_000;
        return expirationStrategy.calculateTimeToLiveMillis(state, currentTimeNanos);
    }
}