Google Cloud Bigtable coprocessor support

Question

Google Cloud BigTable doesn't support coprocessors:

Coprocessors are not supported. You cannot create classes that implement the interface org.apache.hadoop.hbase.coprocessor.

https://cloud.google.com/bigtable/docs/hbase-differences

I can understand that coprocessors require deployment of customer code (jars) on each Tablet (RS) node. Still, Endpoint coprocessors are vital to HBase applications to ensure data locality in some scenarios. HBase extensions such as Apache Phoenix rely on Observer coprocessors for maintaining secondary indexes, so lack of coprocessor support looks like a major area of incompatibility to me.

Is Coprocessor support possible in the future and what workarounds exist for executing custom Java "stored procedures" on BigTable Tablets?

UPDATE 1: List of Apache Phoenix coprosessors:

• GroupedAggregateRegionObserver
• Indexer
• MetaDataEndpointImpl
• MetaDataRegionObserver
• ScanRegionObserver
• SequenceRegionObserver
• ServerCachingEndpointImpl
• UngroupedAggregateRegionObserver

Answer 1

Custom co-processors are not supported as of June 1, 2015.