I have a Lua script which is designed to filter records based on the value of the "age" bin. The filter_by_age function is used to filter the stream of records, and the count_records function is used to count the number of records that meet the age condit

Feature Discussion User Defined Functions (UDF)
1 
public class AerospikeStreamExample {
    public static void main(String[] args) {
        AerospikeClient client = new AerospikeClient("15.206.70.97", 3000);

        // Register the Lua script
        String luaScript =
                "local function filter_by_age(record)\n" +
                "  if record.age then\n" +
                "    if record.age < 30 then\n" +
                "      return true\n" +
                "    end\n" +
                "  end\n" +
                "  return false\n" +
                "end\n" +
                "\n" +
                "function count_records(stream)\n" +
                "  local filtered_stream = stream:filter(filter_by_age)\n" +
                "  local count = filtered_stream:count()\n" +
                "  return count or 0\n" +
                "end\n";

        RegisterTask task = client.registerUdfString(null, luaScript, "stream_example.lua", Language.LUA);
        if (task.isDone()) {
            System.out.println("UDF registered successfully.");
        } else {
            System.err.println("Failed to register UDF.");
        }

        // Create a stream using a query
        String namespace = "test";
        String set = "User2";
        Statement statement = new Statement();
        statement.setNamespace(namespace);
        statement.setSetName(set);
        statement.setBinNames("age"); // Change "value" to "age" as per the Lua script


        // Process the stream result
        try {
            ResultSet resultSet = client.queryAggregate(null, statement, "stream_example", "count_records");

            long count = 0;
            while (resultSet.next()) {
                Object result = resultSet.getObject();
                count = (long) result;
                System.out.println("Number of records with age < 30: " + count);
            }
 
            if (count == 0) {
                System.out.println("No records found with age < 30.");
            }
        } catch (AerospikeException e) {
            e.printStackTrace();
        }
        client.close();
    }
}

I have posted the lua script UDF along with the java client code for your reference.

2

Thanks for posting this! I assume you are simply sharing this for others who may try to do something similar. If there was any question or issue, feel free to clarify that but thanks again for the input!

3

Hi @meher I have this Lua script which is designed to filter records based on the value of the “age” bin. The filter_by_age function is used to filter the stream of records, and the count_records function is used to count the number of records that meet the age condition (age < 30) within the stream. But I am not able to get the desired result by executing the Lua Script UDFs in stream.

4

Oh, I see… I am not an expert in aggregation and didn’t have a chance to look at the details but let’s see if someone else has any clues.