Hi, Basically, there are 'n' number of databases that we are dealing with. We need to fetch the data from the source database into HDFS. Now since we are dealing with many databases, the source database is not static and changes every now and then. And every time the source database changes we manually need to change the value for the connection parameters in DBCPConnectionPool. Now, people suggest that for 'n' databases create 'n' connections for each database, but that is not possible because 'n' is a big number and creating that many connections in DBCPConnectionPool is not possible. So we were looking for a way where we can specify all the connection parameters in a file present in our local system and then make the DBCPConnectionPool controller service to read the values from the file. In that way we can simply change the value in the file present in the local system. No need to alter anything in the dataflow. But it turns out that FlowFile attributes are not available to the controller services as the expression language is evaluated at the time of service enable.
So can you suggest a way where I can achieve my requirement (except 'variable.registry' ) ? I am looking to develop a custom controller service that can serve the requirement but how do I make the flowfile attributes available to the service?
