Re: [jira] [Created] (NIFI-810) Create Annotation that indicates that a Processor cannot be scheduled to run without an incoming connection

[Joe Skora <js...@gmail.com>]

Instead of a binary choice controlled solely in the source code, how about
an optional property that specifies a different run schedule for processors
if they don't have an incoming connection?

It could be set to prevent scheduling or to occasionally trigger the
processor allowing it to send status or alerts, or perhaps to bring it's
data source back online.  It could also allow the control to be in the flow
manager's control, instead of just the developer's.


On Tue, Aug 4, 2015 at 2:20 PM, Mark Payne (JIRA) <ji...@apache.org> wrote:

> Mark Payne created NIFI-810:
> -------------------------------
>
>              Summary: Create Annotation that indicates that a Processor
> cannot be scheduled to run without an incoming connection
>                  Key: NIFI-810
>                  URL: https://issues.apache.org/jira/browse/NIFI-810
>              Project: Apache NiFi
>           Issue Type: Improvement
>           Components: Extensions
>             Reporter: Mark Payne
>
>
> Currently, if a Processor has no incoming connections but is started, it
> will continually without ever accomplishing anything. We should have an
> annotation, perhaps @RequiresInput, that indicates that the Processor
> should not be scheduled to run unless it has an incoming connection.
>
>
>
> --
> This message was sent by Atlassian JIRA
> (v6.3.4#6332)
>

RE: [jira] [Created] (NIFI-810) Create Annotation that indicates that a Processor cannot be scheduled to run without an incoming connection

[Mark Payne <ma...@hotmail.com>]

Joe,

Can you outline your use case a bit better?

The way that I am looking at it, the Processor developer knows whether it makes sense for the Processor to
be scheduled even without an incoming FlowFile. Take, for example, CompressContent. It would never make sense
to schedule it if there's not going to be any input. So I think it makes sense in this case to indicate that the
Processor cannot be scheduled to run because it has no incoming connections. In fact, I would even err on
the side of marking the Processor invalid, just as we do with a Processor that doesn't have all of its
Relationships accounted for (either connected or auto-terminated).

Though it's entirely possible that I am just completely overlooking something :)

Thanks
-mark

----------------------------------------
> Date: Wed, 5 Aug 2015 15:29:55 -0400
> Subject: Re: [jira] [Created] (NIFI-810) Create Annotation that indicates that a Processor cannot be scheduled to run without an incoming connection
> From: jskora@gmail.com
> To: dev@nifi.apache.org
>
> Instead of a binary choice controlled solely in the source code, how about
> an optional property that specifies a different run schedule for processors
> if they don't have an incoming connection?
>
> It could be set to prevent scheduling or to occasionally trigger the
> processor allowing it to send status or alerts, or perhaps to bring it's
> data source back online. It could also allow the control to be in the flow
> manager's control, instead of just the developer's.
>
>
> On Tue, Aug 4, 2015 at 2:20 PM, Mark Payne (JIRA) <ji...@apache.org> wrote:
>
>> Mark Payne created NIFI-810:
>> -------------------------------
>>
>> Summary: Create Annotation that indicates that a Processor
>> cannot be scheduled to run without an incoming connection
>> Key: NIFI-810
>> URL: https://issues.apache.org/jira/browse/NIFI-810
>> Project: Apache NiFi
>> Issue Type: Improvement
>> Components: Extensions
>> Reporter: Mark Payne
>>
>>
>> Currently, if a Processor has no incoming connections but is started, it
>> will continually without ever accomplishing anything. We should have an
>> annotation, perhaps @RequiresInput, that indicates that the Processor
>> should not be scheduled to run unless it has an incoming connection.
>>
>>
>>
>> --
>> This message was sent by Atlassian JIRA
>> (v6.3.4#6332)
>>