Table of Contents(中文说明)

• 1. Redis-replicator
  • 1.1. Brief introduction
  • 1.2. QQ group
  • 1.3. Contract author
• 2. Install
  • 2.1. Requirements
  • 2.2. Maven dependency
  • 2.3. Install from source code
  • 2.4. Select a version
• 3. Simple usage
  • 3.1. Replication via socket
  • 3.2. Read rdb file
  • 3.3. Read aof file
  • 3.4. Read mixed file
    • 3.4.1. Mixed file format
    • 3.4.2. Mixed file redis configuration
    • 3.4.3. Using replicator read mixed file
  • 3.5. Backup remote rdb snapshot
  • 3.6. Backup remote commands
  • 3.7. Other examples
• 4. Advanced topics
  • 4.1. Command extension
    • 4.1.1. Write a command
    • 4.1.2. Write a command parser
    • 4.1.3. Register this parser
    • 4.1.4. Handle command event
    • 4.1.5. Put them together
  • 4.2. Module extension
    • 4.2.1. Compile redis test modules
    • 4.2.2. Open comment in redis.conf
    • 4.2.3. Write a module parser
    • 4.2.4. Write a command parser
    • 4.2.5. Register this module parser and command parser and handle event
    • 4.2.6. Put them together
  • 4.3. Write your own rdb parser
  • 4.4. Event timeline
  • 4.5. Redis URI
• 5. Other topics
  • 5.1. Built-in command parser
  • 5.2. EOFException
  • 5.3. Trace event log
  • 5.4. SSL connection
  • 5.5. Auth
  • 5.6. Avoid full sync
  • 5.7. FullSyncEvent
  • 5.8. Handle raw bytes
  • 5.9. Handle huge key value pair
• 6. Contributors
• 7. References
• 8. Supported by
  • 8.1. YourKit
  • 8.2. IntelliJ IDEA
  • 8.3. Redisson

1. Redis-replicator

1.1. Brief introduction

Redis Replicator implement Redis Replication protocol written in java. It can parse, filter, broadcast the RDB and AOF events in a real time manner. It also can synchronize redis data to your local cache or to database. The following I mentioned Command which means Writable Command(e.g. set,hmset) in Redis and excludes the Readable Command(e.g. get,hmget)

1.2. QQ group

479688557

1.3. Contract author

chen.bao.yi@gmail.com

2. Install

2.1. Requirements

jdk 1.7+
maven-3.2.3+
redis 2.6 - 4.0.x

2.2. Maven dependency

    <dependency>
        <groupId>com.moilioncircle</groupId>
        <artifactId>redis-replicator</artifactId>
        <version>2.4.6</version>
    </dependency>

2.3. Install from source code

    $mvn clean install package -Dmaven.test.skip=true

2.4. Select a version

redis version	redis-replicator version
[2.6, 4.0.x]	[2.3.0, ]
[2.6, 4.0-RC3]	[2.1.0, 2.2.0]
[2.6, 3.2.x]	[1.0.18](not supported)

3. Simple usage

3.1. Replication via socket

        Replicator replicator = new RedisReplicator("redis://127.0.0.1:6379");
        replicator.addRdbListener(new RdbListener.Adaptor() {
            @Override
            public void handle(Replicator replicator, KeyValuePair<?> kv) {
                System.out.println(kv);
            }
        });
        replicator.addCommandListener(new CommandListener() {
            @Override
            public void handle(Replicator replicator, Command command) {
                System.out.println(command);
            }
        });
        replicator.open();

3.2. Read rdb file

        Replicator replicator = new RedisReplicator("redis:///path/to/dump.rdb");
        replicator.addRdbListener(new RdbListener.Adaptor() {
            @Override
            public void handle(Replicator replicator, KeyValuePair<?> kv) {
                System.out.println(kv);
            }
        });

        replicator.open();

3.3. Read aof file

        Replicator replicator = new RedisReplicator("redis:///path/to/appendonly.aof");
        replicator.addCommandListener(new CommandListener() {
            @Override
            public void handle(Replicator replicator, Command command) {
                System.out.println(command);
            }
        });
        replicator.open();

3.4. Read mixed file

3.4.1. Mixed file format

    [RDB file][AOF tail]

3.4.2. Mixed file redis configuration

    aof-use-rdb-preamble yes

3.4.3. Using replicator read mixed file

        final Replicator replicator = new RedisReplicator("redis:///path/to/appendonly.aof");
        replicator.addRdbListener(new RdbListener.Adaptor() {
            @Override
            public void handle(Replicator replicator, KeyValuePair<?> kv) {
                System.out.println(kv);
            }
        });
        replicator.addCommandListener(new CommandListener() {
            @Override
            public void handle(Replicator replicator, Command command) {
                System.out.println(command);
            }
        });

        replicator.open();

3.5. Backup remote rdb snapshot

See RdbBackupExample.java

3.6. Backup remote commands

See CommandBackupExample.java

3.7. Other examples

See examples

4. Advanced topics

4.1. Command extension

4.1.1. Write a command

    public static class YourAppendCommand implements Command {
        private final String key;
        private final String value;
    
        public YourAppendCommand(String key, String value) {
            this.key = key;
            this.value = value;
        }
        
        public String getKey() {
            return key;
        }
        
        public String getValue() {
            return value;
        }
    
        @Override
        public String toString() {
            return "YourAppendCommand{" +
                "key='" + key + '\'' +
                ", value='" + value + '\'' +
                '}';
            }
        }
    }

4.1.2. Write a command parser

    public class YourAppendParser implements CommandParser<YourAppendCommand> {

        @Override
        public YourAppendCommand parse(Object[] command) {
            return new YourAppendCommand(new String((byte[]) command[1], UTF_8), new String((byte[]) command[2], UTF_8));
        }
    }

4.1.3. Register this parser

    Replicator replicator = new RedisReplicator("redis://127.0.0.1:6379");
    replicator.addCommandParser(CommandName.name("APPEND"),new YourAppendParser());

4.1.4. Handle command event

    replicator.addCommandListener(new CommandListener() {
        @Override
        public void handle(Replicator replicator, Command command) {
            if(command instanceof YourAppendCommand){
                YourAppendCommand appendCommand = (YourAppendCommand)command;
                // your code goes here
            }
        }
    });

4.1.5. Put them together

See CommandExtensionExample.java

4.2. Module extension

4.2.1. Compile redis test modules

    $cd /path/to/redis-4.0-rc2/src/modules
    $make

4.2.2. Open comment in redis.conf

    loadmodule /path/to/redis-4.0-rc2/src/modules/hellotype.so

4.2.3. Write a module parser

    public class HelloTypeModuleParser implements ModuleParser<HelloTypeModule> {

        @Override
        public HelloTypeModule parse(RedisInputStream in, int version) throws IOException {
            DefaultRdbModuleParser parser = new DefaultRdbModuleParser(in);
            int elements = parser.loadUnsigned(version).intValue();
            long[] ary = new long[elements];
            int i = 0;
            while (elements-- > 0) {
                ary[i++] = parser.loadSigned(version);
            }
            return new HelloTypeModule(ary);
        }
    }

    public class HelloTypeModule implements Module {
        private final long[] value;

        public HelloTypeModule(long[] value) {
            this.value = value;
        }

        public long[] getValue() {
            return value;
        }

        @Override
        public String toString() {
            return "HelloTypeModule{" +
                    "value=" + Arrays.toString(value) +
                    '}';
        }
    }

4.2.4. Write a command parser

    public class HelloTypeParser implements CommandParser<HelloTypeCommand> {
        @Override
        public HelloTypeCommand parse(Object[] command) {
            String key = new String((byte[]) command[1], Constants.UTF_8);
            long value = Long.parseLong(new String((byte[]) command[2], Constants.UTF_8));
            return new HelloTypeCommand(key, value);
        }
    }

    public class HelloTypeCommand implements Command {
        private final String key;
        private final long value;

        public long getValue() {
            return value;
        }

        public String getKey() {
            return key;
        }

        public HelloTypeCommand(String key, long value) {
            this.key = key;
            this.value = value;
        }

        @Override
        public String toString() {
            return "HelloTypeCommand{" +
                    "key='" + key + '\'' +
                    ", value=" + value +
                    '}';
        }

    }

4.2.5. Register this module parser and command parser and handle event

    public static void main(String[] args) throws IOException {
        Replicator replicator = new RedisReplicator("redis://127.0.0.1:6379");
        replicator.addCommandParser(CommandName.name("hellotype.insert"), new HelloTypeParser());
        replicator.addModuleParser("hellotype", 0, new HelloTypeModuleParser());
        replicator.addRdbListener(new RdbListener.Adaptor() {
            @Override
            public void handle(Replicator replicator, KeyValuePair<?> kv) {
                if (kv instanceof KeyStringValueModule) {
                    System.out.println(kv);
                }
            }
        });

        replicator.addCommandListener(new CommandListener() {
            @Override
            public void handle(Replicator replicator, Command command) {
                if (command instanceof HelloTypeCommand) {
                    System.out.println(command);
                }
            }
        });

        replicator.open();
    }

4.2.6. Put them together

See ModuleExtensionExample.java

4.3. Write your own rdb parser

• Extends RdbVisitor
• Register your RdbVisitor to Replicator using setRdbVisitor method.

4.4. Event timeline

     |                     full resynchronization              |  partial resynchronization  |
     ↓-----------<--------------<-------------<----------<-----↓--------------<--------------↑
     ↓                                                         ↓                             ↑ <-reconnect    
 connect->------->-------------->------------->---------->-------------------->--------------x <-disconnect
               ↓              ↓          ↓            ↓                   ↓
          prefullsync    auxfields...  rdbs...   postfullsync            cmds...       

4.5. Redis URI

Before redis-replicator-2.4.0, We construct RedisReplicator like the following:

Replicator replicator = new RedisReplicator("127.0.0.1", 6379, Configuration.defaultSetting());
Replicator replicator = new RedisReplicator(new File("/path/to/dump.rdb", FileType.RDB, Configuration.defaultSetting());
Replicator replicator = new RedisReplicator(new File("/path/to/appendonly.aof", FileType.AOF, Configuration.defaultSetting());
Replicator replicator = new RedisReplicator(new File("/path/to/appendonly.aof", FileType.MIXED, Configuration.defaultSetting());

After redis-replicator-2.4.0, We introduced a new concept(Redis URI) which simplify the constructor of RedisReplicator.

Replicator replicator = new RedisReplicator("redis://127.0.0.1:6379");
Replicator replicator = new RedisReplicator("redis:///path/to/dump.rdb");
Replicator replicator = new RedisReplicator("redis:///path/to/appendonly.aof");

// configuration setting example
Replicator replicator = new RedisReplicator("redis://127.0.0.1:6379?authPassword=foobared&readTimeout=10000&ssl=yes");
Replicator replicator = new RedisReplicator("redis:///path/to/dump.rdb?rateLimit=1000000");

5. Other topics

5.1. Built-in command parser

commands	commands	commands	commands	commands	commands
PING	APPEND	SET	SETEX	MSET	DEL
SADD	HMSET	HSET	LSET	EXPIRE	EXPIREAT
GETSET	HSETNX	MSETNX	PSETEX	SETNX	SETRANGE
HDEL	UNLINK	SREM	LPOP	LPUSH	LPUSHX
LRem	RPOP	RPUSH	RPUSHX	ZREM	ZINTERSTORE
INCR	DECR	INCRBY	PERSIST	SELECT	FLUSHALL
FLUSHDB	HINCRBY	ZINCRBY	MOVE	SMOVE	BRPOPLPUSH
PFCOUNT	PFMERGE	SDIFFSTORE	RENAMENX	PEXPIREAT	SINTERSTORE
ZADD	BITFIELD	SUNIONSTORE	RESTORE	LINSERT	ZREMRANGEBYLEX
GEOADD	PEXPIRE	ZUNIONSTORE	EVAL	SCRIPT	ZREMRANGEBYRANK
PUBLISH	BITOP	SETBIT	SWAPDB	PFADD	ZREMRANGEBYSCORE
RENAME	MULTI	EXEC	LTRIM	RPOPLPUSH	SORT

5.2. EOFException

• Adjust redis server setting like the following. more details please refer to redis.conf

    client-output-buffer-limit slave 0 0 0

WARNNING: this setting may run out of memory of redis server in some cases.

5.3. Trace event log

• Set log level to debug
• If you are using log4j2, add logger like the following:

    <Logger name="com.moilioncircle" level="debug">
        <AppenderRef ref="YourAppender"/>
    </Logger>

    Configuration.defaultSetting().setVerbose(true);
    // redis uri
    "redis://127.0.0.1:6379?verbose=yes"

5.4. SSL connection

    System.setProperty("javax.net.ssl.trustStore", "/path/to/truststore");
    System.setProperty("javax.net.ssl.trustStorePassword", "password");
    System.setProperty("javax.net.ssl.trustStoreType", "your_type");
    Configuration.defaultSetting().setSsl(true);
    //optional setting
    Configuration.defaultSetting().setSslSocketFactory(sslSocketFactory);
    Configuration.defaultSetting().setSslParameters(sslParameters);
    Configuration.defaultSetting().setHostnameVerifier(hostnameVerifier);

5.5. Auth

    Configuration.defaultSetting().setAuthPassword("foobared");
    // redis uri
    "redis://127.0.0.1:6379?authPassword=foobared"

5.6. Avoid full sync

• Adjust redis server setting like the following

    repl-backlog-size
    repl-backlog-ttl
    repl-ping-slave-periods

repl-ping-slave-period MUST less than Configuration.getReadTimeout(), default Configuration.getReadTimeout() is 30 seconds

5.7. FullSyncEvent

        Replicator replicator = new RedisReplicator("redis://127.0.0.1:6379");
        final long start = System.currentTimeMillis();
        final AtomicInteger acc = new AtomicInteger(0);
        replicator.addRdbListener(new RdbListener() {
            @Override
            public void preFullSync(Replicator replicator) {
                System.out.println("pre full sync");
            }

            @Override
            public void handle(Replicator replicator, KeyValuePair<?> kv) {
                acc.incrementAndGet();
            }

            @Override
            public void postFullSync(Replicator replicator, long checksum) {
                long end = System.currentTimeMillis();
                System.out.println("time elapsed:" + (end - start));
                System.out.println("rdb event count:" + acc.get());
            }
        });
        replicator.open();

5.8. Handle raw bytes

• For any KeyValuePair type except KeyStringValueModule, we can get the raw bytes. In some cases(e.g. HyperLogLog),this is very useful.

        Replicator replicator = new RedisReplicator("redis://127.0.0.1:6379");
        replicator.addRdbListener(new RdbListener.Adaptor() {
            @Override
            public void handle(Replicator replicator, KeyValuePair<?> kv) {
                if (kv instanceof KeyStringValueString) {
                    KeyStringValueString ksvs = (KeyStringValueString) kv;
                    byte[] rawValue = ksvs.getRawValue();
                    // handle raw bytes value
                } else if (kv instanceof KeyStringValueHash) {
                    KeyStringValueHash ksvh = (KeyStringValueHash) kv;
                    Map<byte[], byte[]> rawValue = ksvh.getRawValue();
                    // handle raw bytes value
                } else {
                    ...
                }
            }
        });
        replicator.open();

For easy operation, the key of return type Map<byte[], byte[]> of KeyStringValueHash.getRawValue, we can get and put the key as value type

KeyStringValueHash ksvh = (KeyStringValueHash) kv;
Map<byte[], byte[]> rawValue = ksvh.getRawValue();
byte[] value = new byte[]{2};
rawValue.put(new byte[]{1}, value);
System.out.println(rawValue.get(new byte[]{1}) == value) //will print true 

Commands also support raw bytes.

SetCommand set = (SetCommand) command;
byte[] rawKey = set.getRawKey();
byte[] rawValue = set.getRawValue();

5.9. Handle huge key value pair

According to 4.3. Write your own rdb parser, This tool built in an Iterable Rdb Parser so that handle huge key value pair.
More details please refer to:
[1] HugeKVFileExample.java
[2] HugeKVSocketExample.java

6. Contributors

• Leon Chen
• Adrian Yao
• Trydofor
• Argun
• Sean Pan
• Special thanks to Kevin Zheng

7. References

• rdb.c
• Redis RDB File Format
• Redis Protocol specification
• Redis Replication

8. Supported by

8.1. YourKit

YourKit is kindly supporting this open source project with its full-featured Java Profiler.
YourKit, LLC is the creator of innovative and intelligent tools for profiling
Java and .NET applications. Take a look at YourKit's leading software products:
YourKit Java Profiler and YourKit .NET Profiler.

8.2. IntelliJ IDEA

IntelliJ IDEA is a Java integrated development environment (IDE) for developing computer software.
It is developed by JetBrains (formerly known as IntelliJ), and is available as an Apache 2 Licensed community edition,
and in a proprietary commercial edition. Both can be used for commercial development.

8.3. Redisson

Redisson is Redis based In-Memory Data Grid for Java offers distributed objects and services (BitSet, Set, Multimap, SortedSet, Map, List, Queue, BlockingQueue, Deque, BlockingDeque, Semaphore, Lock, AtomicLong, CountDownLatch, Publish / Subscribe, Bloom filter, Remote service, Spring cache, Executor service, Live Object service, Scheduler service) backed by Redis server. Redisson provides more convenient and easiest way to work with Redis. Redisson objects provides a separation of concern, which allows you to keep focus on the data modeling and application logic.