How to replace text with value of attribute in Nifi ReplaceText processor?

Question

I want to replace some of the content of flowfile(based on rgex which I have) with the attribute value of attribute say var1 which is 123 (shown in image). I am doing this with Replace Text Processor in Nifi but the contents are not getting replaced instead the flow file is getting dropped.

Answer 1

You can use the following flow as an example to achieve the regex replacement.

The individual processor configurations are below:

GenerateFlowFile: This generates a flow file with some content. In this case, the content is This is my content.

UpdateAttribute: This adds an attribute with key=var1 and value=123.

ReplaceText: This looks for matches of the regex and replaces with the value of attribute var1. So, This is my content will be transformed to This is my 123.

OriginalContent: This is to see the actual content before the replace. It uses a PutFile processor.

UpdatedContent: This is to see the updated content. It uses a PutFile processor.

Verification

After the flow has run one time, you can verify the contents by looking at the generated files.

$ cat original/5601958271012409 
This is my content

$ cat updated/5601958271012409 
This is my 123