LUA Scripting

Redisson provides RScript object to execute Lua script. It has atomicity property and used to process data on Redis or Valkey side. Script could be executed in two modes:

  • Mode.READ_ONLY scripts are executed as read operation
  • Mode.READ_WRITE scripts are executed as write operation

One of the follow types returned as a script result object:

  • ReturnType.BOOLEAN - Boolean type.
  • ReturnType.INTEGER - Integer type.
  • ReturnType.MULTI - List type of user defined type.
  • ReturnType.STATUS - Lua String type.
  • ReturnType.VALUE - User defined type.
  • ReturnType.MAPVALUE - Map value type.
  • ReturnType.MAPVALUELIST - List of Map value type.

Code example:

  1. RBucket<String> bucket = redisson.getBucket("foo");
  2. bucket.set("bar");
  4. RScript script = redisson.getScript(StringCodec.INSTANCE);
  6. String r = script.eval(Mode.READ_ONLY,
  7.                        "return redis.call('get', 'foo')", 
  8.                        RScript.ReturnType.VALUE);
  10. // execute the same script stored in Redis or Valkey lua script cache
  12. // load lua script into Redis or Valkey cache to all master instances
  13. String res = script.scriptLoad("return redis.call('get', 'foo')");
  14. // res == 282297a0228f48cd3fc6a55de6316f31422f5d17
  16. // call lua script by sha digest
  17. Future<Object> r1 = redisson.getScript().evalShaAsync(Mode.READ_ONLY,
  18.    "282297a0228f48cd3fc6a55de6316f31422f5d17",
  19.    RScript.ReturnType.VALUE, Collections.emptyList());

Functions

Redisson provides RFunction object to execute Functions. It has atomicity property and used to process data on Redis or Valkey side. Function can be executed in two modes:

  • Mode.READ executes function as read operation
  • Mode.WRITE executes function as write operation

One of the follow types returned as a script result object:

  • ReturnType.BOOLEAN - Boolean type
  • ReturnType.LONG - Long type
  • ReturnType.LIST - List type of user defined type.
  • ReturnType.STRING - plain String type
  • ReturnType.VALUE - user defined type
  • ReturnType.MAPVALUE - Map Value type. Codec.getMapValueDecoder() and Codec.getMapValueEncoder() methods are used for data deserialization or serialization
  • ReturnType.MAPVALUELIST - List type, which consists of objects of Map Value type. Codec.getMapValueDecoder() and Codec.getMapValueEncoder() methods are used for data deserialization or serialization

Code example:

  1. RFunction f = redisson.getFunction();
  3. // load function
  4. f.load("lib", "redis.register_function('myfun', function(keys, args) return args[1] end)");
  6. // execute function
  7. String value = f.call(RFunction.Mode.READ, "myfun", RFunction.ReturnType.STRING, Collections.emptyList(), "test");

Code example of Async interface usage:

  1. RFunction f = redisson.getFunction();
  3. // load function
  4. RFuture<Void> loadFuture = f.loadAsync("lib", "redis.register_function('myfun', function(keys, args) return args[1] end)");
  6. // execute function
  7. RFuture<String> valueFuture = f.callAsync(RFunction.Mode.READ, "myfun", RFunction.ReturnType.STRING, Collections.emptyList(), "test");

Code example of Reactive interface usage:

  1. RedissonReactiveClient redisson = redissonClient.reactive();
  2. RFunctionReactive f = redisson.getFunction();
  4. // load function
  5. Mono<Void> loadMono = f.load("lib", "redis.register_function('myfun', function(keys, args) return args[1] end)");
  7. // execute function
  8. Mono<String> valueMono = f.callAsync(RFunction.Mode.READ, "myfun", RFunction.ReturnType.STRING, Collections.emptyList(), "test");

Code example of RxJava3 interface usage:

  1. RedissonRxClient redisson = redissonClient.rxJava();
  2. RFunctionRx f = redisson.getFunction();
  4. // load function
  5. Completable loadMono = f.load("lib", "redis.register_function('myfun', function(keys, args) return args[1] end)");
  7. // execute function
  8. Maybe<String> valueMono = f.callAsync(RFunction.Mode.READ, "myfun", RFunction.ReturnType.STRING, Collections.emptyList(), "test");