I'm totally new to Nifi. I'm using ExtractHL7Attributes to get hl7 data and trying to convert it into FHIR Patient format and push it to a FHIR service. Any thoughts would be really helpful.

[#1]

Here's how i configured the ExtractHL7Attributes processor,

hl7parse.png

The attributes after parsing a sample hl7 file seen from data provenance of ExtractHL7Attributes processor,

dataprovenancehl7.png

How can i get these attribute values and process it ?

Do i need to add another processor, use expression language in properties of a processor ?

[#2]

There are many processors you can use to continue your NiFi flow. I mocked up your scenario and was able to use the AttributesToJSON processor to convert all of the data into a JSON format. In that processor, you can optionally specify which columns of data inside the FlowFile you want to keep. This is one such example - you can research and experiment with many of the other processors to do data filtering and processing.

My mock NiFi flow read from a Kafka stream, used the ExtractHL7Attributes processor, converted to JSON using the AttributesToJSON processor, and wrote that data to HDFS. Let me know if I can help you out with any specific part of that chain.

[#3]

@anarasimham Thanks for the great answer.

I've used AttributesToJSON to convert it to JSON format. But i wasn't able to manipulate it to desired structure(when i used JoltTransformJSON). You can view my another question related to that in this link (https://community.hortonworks.com/questions/138833/need-to-format-values-fromin-attributestojson-proc.html?childToView=138061#answer-138061)

In between if you can share the knowledge on how to use a kafka and HDFS in NiFi, it would be really helpful.

[#4]

Sure - I wrote an article since others may want to know this information. You can check it out here:

https://community.hortonworks.com/articles/138249/nifi-in-healthcare-ingesting-hl7-data-in-nifi.html

Let me know if you have any other questions, happy to answer.