Cannot execute appengine-mapreduce using DatastoreInput with query filters

Question

when I try to use datastore Query with a filter like this :

Query billQuery = new Query("Bill"); billQuery.setFilter(new Query.FilterPredicate("payedOn", Query.FilterOperator.GREATER_THAN, new Date()));

and trying to run : new MapReduceSpecification.Builder, List>>>(new DatastoreInput(billQuery, mapShardCount), new SimpleCounter("BillID"), new CountReducer(), new InMemoryOutput>()) .setKeyMarshaller(Marshallers.getStringMarshaller()) .setValueMarshaller(Marshallers.getLongMarshaller()) .setJobName("MapReduceTest count") .setNumReducers(reduceShardCount) .build();

I get this exception :

java.lang.IllegalArgumentException: payedOn: com.google.appengine.api.datastore.Entity is not a supported property type.

where 'paidOn' is property with Date value in a datastore entity.

This ewxample is very similar to that in the [example] :

so I guess I'm doing something wrong, but I have no idea, it is a standard datastore query. Any suggestions?

Answer 1

This is a bug in this line: https://github.com/GoogleCloudPlatform/appengine-mapreduce/blob/master/java/src/main/java/com/google/appengine/tools/mapreduce/inputs/DatastoreShardStrategy.java#L386 Until fixed, you could avoid the issue by supplying both bounds (upper and lower) or patch it yourself by replacing item.get(0) with item.get(0).getProperty(propertyName)