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From Otto Fowler <ottobackwa...@gmail.com>
Subject Re: Custom Controller Service
Date Wed, 25 Apr 2018 12:28:10 GMT
Or you could just call every time you needed properties more likely.
This would still be custom unless integrated….


On April 25, 2018 at 08:26:57, Otto Fowler (ottobackwards@gmail.com) wrote:

Can services work with other controller services?
Maybe a PropertiesControllerService, FilePropertiesControllerService could
work with your service?
the PCS could fire events on property changes etc.



On April 25, 2018 at 08:05:27, Mike Thomsen (mikerthomsen@gmail.com) wrote:

Shot in the dark here, but what you try to do is create a custom connection
pool service that uses dynamic properties to build a "pool of connection
pools." You could then use the property names as hints for where to send
the queries.

On Wed, Apr 25, 2018 at 6:19 AM Rishab Prasad <rishabprasad005@gmail.com>
wrote:

> 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?
>

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