nifi-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From 尹文才 <batman...@gmail.com>
Subject Re: get controller service's configuration
Date Fri, 11 Aug 2017 07:01:45 GMT
Thanks for your explanation Bryan, it seems that I could only get the DBCP
controller service's driver name after something like getDrivername() is
added into the current DBCPService interface.

Regards,
Ben

2017-08-10 22:01 GMT+08:00 Bryan Bende <bbende@gmail.com>:

> The way controller services are setup you have the following...
>
> - DBCPService interface (provides getConnection()) extends
> ControllerService interface (empty interface to indicate it is a CS)
> - DBCPConnectionPool extends AbstractControllerService implements
> DBCPService
> - Processor XYZ depends on DBCPService interface
>
> The DBCPService interface is the common point between the processor
> and the implementations. The processor XYZ classpath only knows about
> the DBCPService interface, it doesn't know anything about the classes
> that implement it... there could actually be several implementations
> in different NARs, but it is up to the framework to provide access to
> these.
>
> Since the processor only depends on the interface, which in this case
> only exposes getConnection(), you can't really assume the service has
> certain properties because DBCPConnectionPool.DB_DRIVERNAME is
> specific to the DBCPConnectionPool implementation... another
> implementation may not have that property, or may call it something
> different. The interface would have to provide getDriverName() so that
> each implementation could provide that.
>
> -Bryan
>
>
> On Thu, Aug 10, 2017 at 4:33 AM, 尹文才 <batman713@gmail.com> wrote:
> > Thanks Andy, I've tried your approach, in my case the controller service
> is
> > a DBCPConnectionPool and when I tried to get driver class name property
> > through context.getProperty(DBCPConnectionPool.DB_
> DRIVERNAME).getValue(),
> > but I the value is null. The AbstractControllerService class does have a
> > method getConfigurationContext() to get configuration context, but the
> > method is protected. So I still didn't find a feasible way to get the
> > controller service's properties.
> >
> > Regards,
> > Ben
> >
> > 2017-08-10 12:18 GMT+08:00 Andy LoPresto <alopresto@apache.org>:
> >
> >> You can get the current property values of a controller service from the
> >> processor by using the ProcessContext object. For example, in GetHTTP
> [1],
> >> in the @OnScheduled method, you could do:
> >>
> >> context.getControllerServiceLookup().getControllerService("my-
> >> controller-service-id”);
> >>
> >> context.getProperty("controller-service-property-name");
> >> context.getProperty(SomeControllerService.
> CONSTANT_PROPERTY_DESCRIPTOR);
> >>
> >> I forget if context.getProperty() will give the controller service
> >> properties as well as the processor properties. If it doesn’t, you can
> cast
> >> the retrieved ControllerService into AbstractControllerService or the
> >> concrete class and access available properties directly from the
> >> encapsulated ConfigurationContext.
> >>
> >> [1] https://github.com/apache/nifi/blob/master/nifi-nar-
> >> bundles/nifi-standard-bundle/nifi-standard-processors/src/
> >> main/java/org/apache/nifi/processors/standard/GetHTTP.java#L295
> >>
> >> Andy LoPresto
> >> alopresto@apache.org
> >> *alopresto.apache@gmail.com <alopresto.apache@gmail.com>*
> >> PGP Fingerprint: 70EC B3E5 98A6 5A3F D3C4  BACE 3C6E F65B 2F7D EF69
> >>
> >> On Aug 9, 2017, at 6:57 PM, 尹文才 <batman713@gmail.com> wrote:
> >>
> >> Thanks Koji, I checked the link you provided and I think getting a
> >> DataSource is no different than getting the DBCP service(they could just
> >> get the connection). Actually I was trying to get the configured driver
> >> class to check the database type.
> >>
> >> Regards,
> >> Ben
> >>
> >> 2017-08-10 9:29 GMT+08:00 Koji Kawamura <ijokarumawak@gmail.com>:
> >>
> >> Hi Ben,
> >>
> >> I'm not aware of ways to obtain configurations of a controller from a
> >> processor. Those should be encapsulated inside a controller service.
> >> If you'd like to create DataSource instance instead of just obtaining
> >> a connection, this discussion might be helpful:
> >> https://github.com/apache/nifi/pull/1417
> >>
> >> Although I would not recommend, if you really need to obtain all
> >> configurations, you can do so by calling NiFi REST API from your
> >> processor.
> >>
> >> Thanks,
> >> Koji
> >>
> >> On Thu, Aug 10, 2017 at 10:09 AM, 尹文才 <batman713@gmail.com> wrote:
> >>
> >> Hi guys, I have a customized processor with a DBCP controller service as
> >>
> >> a
> >>
> >> property. I could get the DBCP controller service in my code, but does
> >> anyone know how to obtain all the configurations of the DBCP controller
> >> service in java code(e.g. Database Connection URL, Database Driver
> >> Location, etc) Thanks.
> >>
> >> Regards,
> >> Ben
> >>
> >>
> >>
> >>
>

Mime
  • Unnamed multipart/alternative (inline, None, 0 bytes)
View raw message