Manage UDFs

The Aerospike Rusts client can be used to register User-Defined Functions (UDFs). UDFs are written in the Lua programming language that execute in the Aerospike server process. These functions can be grouped together into Lua packages and registered with the Aerospike server cluster. Here is an example Lua package:

-- Validate value before writing.
function writeWithValidation(r,name,value)
    if (value >= 1 and value <= 10) then
      if not aerospike:exists(r) then
        aerospike:create(r)
      end
      r[name] = value
      aerospike:update(r)
    else
        error("1000:Invalid value")
    end
end

-- Set a particular bin only if record does not already exist.
function writeUnique(r,name,value)
    if not aerospike:exists(r) then
        aerospike:create(r)
        r[name] = value
        aerospike:update(r)
    end
end

The UDF Lua package can be created in one of the following formats:

• ASCII Text File
• String

Register UDF in ASCII Text File

client.register_udf(&WritePolicy::default(), "/home/user/udf/example.lua", "example.lua", UDFLang::Lua).unwrap();

The UDF Lua package will be registered on all server’s in the cluster. /home/user/udf/example.lua is location of the Lua package on the client’s filesystem. example.lua is the filename of the Lua package relative to each server’s configured mod-lua user-path in aerospike.conf.

mod-lua {
    user-path /opt/aerospike/usr/udf/lua
}

In this configuration, the Lua package’s full path on each server’s filesystem will be /opt/aerospike/usr/udf/lua/example.lua.

The registration is asynchronous on the server. The server will immediately return an acknowledgement of the registration command and then register the UDF with other servers in the cluster. The client has the option of waiting for the registration task to complete using the returned RegisterTask instance.

Register UDF in a String

let code = r#"
-- Validate value before writing.
function writeWithValidation(r,name,value)
    if (value >= 1 and value <= 10) then
      if not aerospike:exists(r) then
        aerospike:create(r)
      end
      r[name] = value
      aerospike:update(r)
    else
        error("1000:Invalid value")
    end
end

-- Set a particular bin only if record does not already exist.
function writeUnique(r,name,value)
    if not aerospike:exists(r) then
        aerospike:create(r)
        r[name] = value
        aerospike:update(r)
    end
end
"#;

client.register_udf(&WritePolicy::default(), code.as_bytes(), "example.lua", UDFLang::Lua).unwrap();

example.lua is the filename of the Lua package relative to each server’s configured mod-lua user-path in aerospike.conf.