Analyse the flow file at each step of the flow in Apache NiFi

Flow files, as we discussed in a previous article are basically the data that flows through your process. The files have attributed, which are metadata about the file (for example: created data; size) and content, which is the data. Processors will change either the attributes, the content or both as part of their process.

To validate our flow works as we want it to, we need to be able to check the flow file at each step. To do that, make sure all of your processors are stopped, except the first one (the one that gets or generates the flow file).

Once you have the flow file in the queue, you can right click and select ‘List Queue’.

This shows you a list of the files that are in the queue at that time. You can click the picture of an eye to view the file contents.

In this instance, we have configured the replace text block to replace anything with $helloworld. So I expect the output to be $helloworld.

Success! The file contents are as we expected