Hi Mark,
Thanks for your question. Unfortunately the "Database Connection URL” does not
support reading flow file attributes.
DBConnectionPool is intended to hold and reuse connections to a single data
source.
In its definition below, it only support reading from (Nifi variables in 1.X)
or environment variables or NiFI parameters because it says
ExpressionLanguageScope.ENVIRONMENT.
It needs the DB URL when the service is started and DB URL can not be changed
while the processor is running so it can not read flow file attributes to
change the data source URL.
My interpretation is that it is intentional and can not be changed in the code
without breaking the DBConnectionPool service or requiring such a major rewrite
that it would be a whole different service.
public static final PropertyDescriptor DATABASE_URL = new
PropertyDescriptor.Builder()
.name("Database Connection URL")
.description("A database connection URL used to connect to a
database. May contain database system name, host, port, database name and some
parameters."
+ " The exact syntax of a database connection URL is
specified by your DBMS.")
.addValidator(new ConnectionUrlValidator())
.required(true)
.expressionLanguageSupported(ExpressionLanguageScope.ENVIRONMENT)
.build();
I suggest you investigate the documentation on DBCPConnectionPoolLookup.
DBCPConnectionPoolLookup is implemented to allow a flow file to specify which
database to act upon.
DBCPConnectionPoolLookup holds references to DBCPConnectionPool’s and then uses
the flow file to select the desired data source.
That probably will do what you are looking for.
Sincerely,
Jim Steinebrey
> DBCPConnectionPoolLookupOn Jul 8, 2024, at 12:36 PM, Mark Moore
> <[email protected]> wrote:
>
> Hi,
>
> We are trying to create a DBCPConnectionPool service for a dynamic connection
> to different end pts and databases using flow attributes that are correctly
> evaluated elsewhere but in this field these attributes do not seem to get
> evaluated correctly.
>
> Database Connection URL : jdbc:postgresql://${endpt}:5432/${db}
> <postgresql://${endpt}:5432/$%7Bdb%7D> errors out saying connection to
> localhost:5432 is refused.
>
> Thanks
>
> Mark Moore
> Software Developer – BI & Analytics
> Time: GMT -6:00
> [email protected] <mailto:[email protected]>
> <image001.png>
