question Re: Unable to connect ConsumeKafka to ReplaceText in Archives of Support Questions (Read Only)

Unable to connect ConsumeKafka to ReplaceText

vinod_h_chhabri — Wed, 09 Nov 2016 15:43:17 GMT

I am trying to create a flow to take the entire content of my kafka message and insert in one column in Cassandra. I have configured ConsumeKafka so that I get one message per FlowFile. I am trying to connect the Processors as shown below:

ConsumeKafka -> ReplaceText -> PutCassandraQL

I am unable to connect ConsumeKafka to ReplaceText. Why is that?

Re: Unable to connect ConsumeKafka to ReplaceText

MattWho — Wed, 09 Nov 2016 21:01:36 GMT

@Vinod Chhabria

Could you elaborate on what you mean by "I am unable to connect ConsumeKafka to ReplaceText." Are you seeing an error when trying to do so?

Re: Unable to connect ConsumeKafka to ReplaceText

MattWho — Wed, 09 Nov 2016 22:22:38 GMT

@Vinod Chhabria

There is nothing that would prevent that connection from being allowed. Try dragging the connection again. If it still does not highlight green try the following:

Try making a copy of your replaceTEXT processor and see if you can connect to the copy. Right click on replace TEXT and select "copy" then right click on empty graph space and click "paste".

Matt

Re: Unable to connect ConsumeKafka to ReplaceText

vinod_h_chhabri — Wed, 09 Nov 2016 22:22:39 GMT

No. When I try to connect the relationship from ConsumeKafka to ReplaceText, it does not highlight it for me to be able to connect. But If I try to connect from ConsumeKafka to PutCassandraQL it highlights and lets me establish relationship. Is there something that prevents from the output of ConsumeKafka to go to ReplaceText. I thought ReplaceText could take any FlowFile with content and that is what ConsumeKafka produces.

Re: Unable to connect ConsumeKafka to ReplaceText

MattWho — Wed, 09 Nov 2016 22:23:14 GMT

Is this a standalone NiFi install or a NifI cluster?

Re: Unable to connect ConsumeKafka to ReplaceText

vinod_h_chhabri — Wed, 09 Nov 2016 22:48:39 GMT

Tried it. No luck.I even tried with creating a GenerateFlowFile processor and connect to ReplaceText. That also does not work. Is there some processor that needs to be used in conjunction with ReplaceText like ExtractText or something?

Re: Unable to connect ConsumeKafka to ReplaceText

MattWho — Sun, 18 Aug 2019 10:44:38 GMT

@Vinod Chhabria

What you are trying to do definitely works. What version of NiFi/HDF are you using? Is this a standalone NiFi or a cluster?

When you drag the connection from ConsumeKafka to ReplaceText are you seeing any component get highlighted green including the ConsumeKafka processor itself?

If so, without letting go of the mouse button drag you cursor back over the ConsumeKafka and then back to the ReplaceText. Did the highlighting of the ConsumeKafka go away? Did ReplaceText now highlight?

Thanks,

Matt

Re: Unable to connect ConsumeKafka to ReplaceText

MattWho — Wed, 09 Nov 2016 23:11:27 GMT

Processor have not notion of what processors come before or after them in a dataflow. A processor simply has an establish set of rules governing its configuration.

For example: Required properties XYZ must be set, all downstream relationships must be defined, and/or at least one upstream connection must be connected.

So in the case of the ReplaceText processor it does not know who the source of the upstream connection is. It simply cares that one exists from which to pull FlowFiles from its queue.

Re: Unable to connect ConsumeKafka to ReplaceText

vinod_h_chhabri — Wed, 09 Nov 2016 23:37:30 GMT

I do not believe this. I did two things. Deleted all ReplaceText processors. Created a new one. Then I just came out of the process group and went back in and now it connected. I did not even have to try what you suggested. I have seen this happen while connecting other processors also. The drag feature is very unstable.

Re: Unable to connect ConsumeKafka to ReplaceText

vinod_h_chhabri — Wed, 09 Nov 2016 23:38:39 GMT

Thanks a lot for helping me resolve this and especially for the quick replies.

Re: Unable to connect ConsumeKafka to ReplaceText

MattWho — Wed, 09 Nov 2016 23:44:46 GMT

@Vinod Chhabria

What browser and version are you using?

Re: Unable to connect ConsumeKafka to ReplaceText

vinod_h_chhabri — Wed, 09 Nov 2016 23:46:02 GMT

Firefox ESR v38.2.0

Re: Unable to connect ConsumeKafka to ReplaceText

MattWho — Wed, 09 Nov 2016 23:53:33 GMT

@Vinod Chhabria

We should try to keep one thread going instead of creating a new "answer" each time.

NiFi supports the following browsers:

Mozilla Firefox: current & current - 1
Google Chrome: current & current - 1
Microsoft Edge
Safari 8

The version of Firefox you are using is pretty old. If you upgrade to the current Firefox version or try using teh current version of Chrome instead, do you still see the same behavior?

Thanks,

Matt