Aerospike UDF module not found - aerospike

Question

I'm writing a stream UDF for Aerospike 3.6.2, and I'd like to put some code in a separate Lua module. I followed the example exactly and created a file mymodule.lua with the following contents:
local exports = {}
function exports.one()
return 1
end
function exports.two()
return 2
end
return exports
and put my UDF in a file testUdf.lua:
local MM = require('mymodule')
local function three()
return MM.one() + MM.two()
end
function testUdf(stream)
local type = three()
local testFilter = function(record)
return record.campaignType == type
end
return stream : filter(testFilter)
end
I register both modules and execute a query from the Java client:
LuaConfig.SourceDirectory = this.udfPath;
List<RegisterTask> tasks = new ArrayList<>();
for (String udfName : new String[] { "mymodule.lua", "testUdf.lua" }) {
File udf = new File (this.udfPath, udfName);
tasks.add (this.aerospike.register (null, udf.getPath(), udfName, Language.LUA));
}
tasks.stream().forEach (RegisterTask::waitTillComplete);
Statement stmt = new Statement();
stmt.setNamespace (getRawFactNamespace());
stmt.setSetName (SET_FACT);
stmt.setFilters (Filter.equal (BIN_PRODUCT_CODE, "UX"));
stmt.setBinNames (FACT_BINS);
int count = 0;
try (ResultSet rs = this.aerospike.queryAggregate (null, stmt, "testUdf", "testUdf")) {
while (rs.next()) {
count++;
}
}
I see the lua files, with the correct contents, on both of my test Aerospike servers in aerospike/var/udf/lua, which is where mod-lua.user-path points to in aerospike.conf. I logged package.path and it includes the aerospike/var/udf/lua directory as well.
But when I invoke my UDF, I get the following error:
Exception in thread "main" com.aerospike.client.AerospikeException: org.luaj.vm2.LuaError: testUdf:1 module 'mymodule' not found: mymodule
no field package.preload['mymodule']
mymodule.lua
no class 'mymodule'
stack traceback:
testUdf:1: in main chunk
[Java]: in ?
at com.aerospike.client.query.QueryExecutor.checkForException(QueryExecutor.java:122)
at com.aerospike.client.query.ResultSet.next(ResultSet.java:78)
...
Caused by: org.luaj.vm2.LuaError: testUdf:1 module 'mymodule' not found: mymodule
no field package.preload['mymodule']
mymodule.lua
no class 'mymodule'
stack traceback:
testUdf:1: in main chunk
[Java]: in ?
at org.luaj.vm2.LuaValue.error(Unknown Source)
at org.luaj.vm2.lib.PackageLib$require.call(Unknown Source)
at org.luaj.vm2.LuaClosure.execute(Unknown Source)
at org.luaj.vm2.LuaClosure.onInvoke(Unknown Source)
at org.luaj.vm2.LuaClosure.invoke(Unknown Source)
at org.luaj.vm2.LuaValue.invoke(Unknown Source)
at com.aerospike.client.lua.LuaInstance.loadPackage(LuaInstance.java:113)
at com.aerospike.client.query.QueryAggregateExecutor.runThreads(QueryAggregateExecutor.java:92)
at com.aerospike.client.query.QueryAggregateExecutor.run(QueryAggregateExecutor.java:77)
What am I doing wrong?