Splunk Cloud Ingest Processor Pipeline Preview Successful but Transformed Events Not Reaching Destination After Publication

A pipeline was created in Splunk Cloud Ingest Processor to filter Azure Network Flow Logs, extract fields, and route transformed events to a destination index.

During preview testing, the pipeline displayed the expected output and extracted fields correctly. However, after the pipeline was published, the transformed events were not visible in the destination index. The original events continued to arrive through the thru[|into $destination] path, indicating that connectivity to the destination was functioning correctly.

The investigation focused on determining why transformed events shown in preview were not appearing in the destination after publication.

Validation confirmed:

• Destination connectivity was operational.
• Other pipelines using the same destination were functioning normally.
• Original events were successfully forwarded through the thru path.
• The issue was isolated to the transformed events generated after extraction and expansion operations.
• Incremental testing was performed by simplifying the pipeline and reintroducing commands one at a time.
• Testing identified that transformed events became visible only after a valid _raw payload was reconstructed.

The final pipeline included extraction of flow tuple data, field parsing, event expansion, rebuilding of the _raw field, assignment of the sourcetype az_network_flowlogs, and routing to the target index.

The implemented approach included:

1. Extracting the required values from the original event.
2. Expanding and parsing the extracted records.
3. Reconstructing a valid _raw event payload using the parsed fields.
4. Assigning the desired sourcetype az_network_flowlogs.
5. Assigning the target index.
6. Sending the reconstructed events to the configured destination.

After implementing the _raw reconstruction, the transformed events were successfully processed and indexed as expected.

Verification confirmed:

• Events reached the destination index.
• The expected sourcetype was applied.
• Data was searchable in the target environment.
• No additional concerns were reported.