“FlowFile has no content” but you expected content

Summary

This issue appears when a processor expects a FlowFile with body content, but the incoming FlowFile is empty.

Symptom

• The bulletin warns that the FlowFile has no content

• The processor routes the FlowFile to failure or stops processing

• Viewing content shows a zero byte file

Root Cause

One or more of the following is true:

• A previous processor created a FlowFile with attributes only

• An upstream processor removed or never wrote content

• You used UpdateAttribute or RouteOnAttribute which passes through attributes but does not create content

• The API call returned an empty body

• A split or extraction processor produced empty fragments

How to Fix It

Verify upstream behavior

Check the processor feeding this one. Confirm it actually writes content.

Inspect the FlowFile path

Use Data Provenance to see where the content was lost.

Add GenerateFlowFile for testing

If testing, make sure you start with a FlowFile that contains sample content.

Validate the API or source

For InvokeHTTP, check the response. Some endpoints legitimately return empty bodies.

Prevention

• Confirm whether each processor produces or modifies content

• Use LogAttribute before and after branches to track changes

• Test flows with real sample input to ensure content is preserved