Jim,
You can apply Chris's solution to ExecuteScript itself, as you can add
dynamic properties there and they will evaluate the EL for you. If you
set a dynamic property "myNode" to "${ip()}", you should be able to
use myNode.evaluateAttributeExpressions().getValue().
Regards,
Matt
On Mon, Jul 19, 2021 at 5:56 AM James McMahon <[email protected]> wrote:
>
> Chris, thank you very much for suggesting a few alternatives. I'll tune my
> flow this morning and give these a try, too. I think the path suggested by
> Lars is going to prove ideal for my situation, where I want to enter my
> ExecuteScript with one flowFile and create multiple flowFiles from that in a
> loop, as I work my way through a series of directories in a python loop,
> pulling metadata from them. Since I'll be running my ES in "all node"
> configuration, if I'm on a four-node cluster my created flowFiles can be on
> any of the cluster nodes. I want to identify the host node for each of the
> created flowFiles within my script, where I need to apply that knowledge.
> Lars suggested leveraging python rather than trying to figure out how to do
> this programmatically through nifi session and flowFile objects.
> Cheers and thank very much once again,
> Jim
>
> On Mon, Jul 19, 2021 at 1:41 AM Chris Sampson <[email protected]>
> wrote:
>>
>> If you're using GenerateFlowFile, you could add a dynamic property to set an
>> attribute using the ${hostname} (or ip) on the created FlowFile.
>>
>> If you're only running Generate on a single node before load balancing the
>> FlowFile (e.g. round-robin) and the expression needs to be calculated on the
>> destination host, you could use an UpdateAttribute to create the attribute
>> before ExecuteScript but after the load balancing.
>>
>> Of course, this doesn't answer your original question about evaluating EL
>> within a script, but gives you a couple of alternate options.
>>
>> Cheers,
>>
>> Chris Sampson
>>
>> On Sun, 18 Jul 2021, 12:46 James McMahon, <[email protected]> wrote:
>>>
>>> Lars, thank you so much. I was fixated on getting the host information from
>>> the flowFile itself and overlooked the obvious. Your suggestion will be
>>> ideal. Thank you once again!
>>> Jim
>>>
>>> On Sun, Jul 18, 2021 at 12:59 AM Lars Winderling
>>> <[email protected]> wrote:
>>>>
>>>> James,
>>>>
>>>> maybe just use?
>>>> Import socket
>>>> socket.gethostname()
>>>> It will give you rather the hostname, but that should also help for
>>>> distinguishing between nodes.
>>>>
>>>> Best, Lars
>>>>
>>>> On 17 July 2021 22:25:47 CEST, James McMahon <[email protected]> wrote:
>>>>>
>>>>> Looking closely at the flowFiles I am creating,in the subsequent output
>>>>> queue, I see they have a Node Address listed in FlowFile Details. It is
>>>>> not listed in the flowfile attributes.
>>>>> That is what I need to get at programmatically in my python script. How
>>>>> can I access Node Address?
>>>>>
>>>>> On Sat, Jul 17, 2021 at 2:59 PM James McMahon <[email protected]>
>>>>> wrote:
>>>>>>
>>>>>> I have a single flowfile I generate on a periodic basis using a cron
>>>>>> scheduled GenerateFlowFile. This then flows into an ExecuteScript, where
>>>>>> I have a python script that will create multiple flowfiles from the one.
>>>>>>
>>>>>> My ExecuteScript is configured to run on all my cluster nodes. For each
>>>>>> instance of flowfile I am creating, I need to determine which cluster
>>>>>> node it associates with. There’s an expression language function called
>>>>>> ip(). Can anyone tell me how to employ ${ip()} in my python to determine
>>>>>> the cluster node the newly created flowFile is associated with?
>>>>>>
>>>>>> I’d be using this after I execute
>>>>>> flowfile = session.create()
>>>>>>
>>>>>> Thanks in advance for your help.
