Splunk Search

extract fields from json-wrapped postfix logs?

cgosnell
New Member

I have logs landing in Splunk Cloud that are normal `postfix_syslog` lines, but are wrapped in a `json` object. 3 Examples:

{"line":"May 26 21:20:53 postfix postfix/smtpd[5654]: disconnect from ip-10-0-8-152.ec2.internal[10.0.8.152] commands=0/0","source":"stdout","tag":"c38633d4c285"}

{"line":"May 26 20:54:03 postfix postfix/relay/smtp[5646]: 7EC2D34FCCBB3F9BF5AE0: to=\[email protected]\u003e, relay=none, delay=265110, delays=265050/0.03/60/0, dsn=4.4.1, status=deferred (connect to otherdomain-com.mail.protection.outlook.com[104.47.66.10]:25: Connection timed out)","source":"stdout","tag":"c38633d4c285"}

{"line":"May 26 18:48:19 postfix postfix/relay/smtp[188]: 785A2C8161D5BF5DB2B20: to=\[email protected]\u003e, relay=anotherdomain-com.mail.protection.outlook.com[104.47.59.138]:25, delay=1.7, delays=0.14/0.03/0.32/1.2, dsn=2.6.0, status=sent (250 2.6.0 \u003c20230428184817.785A2C8161D5BF5DB2B20@postfix\u003e [InternalId=19529216330946, Hostname=serial.number.prod.outlook.com] 8233 bytes in 0.374, 21.462 KB/sec Queued mail for delivery)","source":"stdout","tag":"e6a9651d6930"}

I would like to have the same fields for these logs extracted as if they were plain `postfix_syslog` lines. Simply setting source_type `postfix_syslog` does not work, a couple of fields get extracted, but most do not.

How should I deal with this?

  • Implement a source type that "calls" the `postfix_syslog` source_type on the value of the `line` json element?
  • Write a custom source type that saves the value of the `line` element to a variable `actual_log_content`,  copy/paste all the configuration of the `postfix_syslog` source type but modify it to be looking at the `actual_log_content` variable?
  • Go in and hack at the thing handing logs to Splunk to prevent it from json-wrapping the lines?

What's the right way to cope?

Labels (1)
0 Karma
Got questions? Get answers!

Join the Splunk Community Slack to learn, troubleshoot, and make connections with fellow Splunk practitioners in real time!

Meet up IRL or virtually!

Join Splunk User Groups to connect and learn in-person by region or remotely by topic or industry.

Get Updates on the Splunk Community!

A Four-Part Event Series: Full Stack Observability For the AI Era

As AI reshapes applications, infrastructure, and the way teams operate, the traditional boundaries of ...

SOC4Kafka - New Kafka Connector Powered by OpenTelemetry

The new SOC4Kafka connector, built on OpenTelemetry, enables the collection of Kafka messages and forwards ...

Event Series: Level up your SOC: Advancing with Splunk Enterprise Security

AI has fundamentally raised the stakes for security operations, and this three-part series is your guide to ...