This is a PoC of MongoDB AA replication based on change stream
./mongoaa [options]
--src/-s: Data sources including source and target MongoDB cluster.--database/-d: Database that you want to do AA replication.--collection/-c: Collection that you want to do AA replication.
This will replicate all changes between 127.0.0.1:27017 and 127.0.0.1:27018.
./mongoaa -s 'mongodb://127.0.0.1:27017/?replicaSet=rs0' 'mongodb://127.0.0.1:27018/?replicaSet=rs0' -d foo -c bar
A sub document __meta is added in order to record information necessary to do replication. This extra field may cause document to exceed 16MB if your document is already approaching this limit.
This script doesn't detect nor try to avoid conflict. Conflict needs to be handled by your own.
The only thing given by change stream is document key. This gives us no chance to stop the remove from triggering again in the target collection. However, as this document is already removed in source collection, the extra remove will not do anything besides causing an extra remove operation.