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 <batman...@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 <alopre...@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
>> alopre...@apache.org
>> *alopresto.apa...@gmail.com <alopresto.apa...@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 <batman...@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 <ijokaruma...@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 <batman...@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
>>
>>
>>
>>
