regexlogstashlogstash-grok

how to remove /r from field value in logstash grok

We have this kind of logs collected from Winlogbeat.

AlertName=Wireless Access Point   Alert
AlertStatus=Active
AlertActiveID=8618424 
AlertDescription=
Severity=Critical

Here “AlertName” keeps changing like Network Device Alert or SQL Database alert ect …

Here we need to create new field by name “AlertName” by referring the AlertName line in above log.

We are trying it with Kibana Dev tools – Grok Debugger as below

AlertName=%{GREEDYDATA:AlertName}

And also as below

AlertName=%{GREEDYDATA:AlertName}\s*

Its creating the field but its value contains additional text “\r” at the end of its value as below;

{ "AlertName": "Wireless Access Point Alert\r" }

We tried multiple ways but unable to remove this “\r” , can some one please help us how to remove this additional value “\r”?

Solution

  • The \r (carriage return, CR) is matched by the GREEDYDATA pattern, as the regex . metacharacter also matches that symbol (mind the regex flavor is Oniguruma, as per Logstash grok docs).

    You can use a custom pattern to get rid of that trailing CR symbol:

    AlertName=(?<AlertName>[^\n\r]*)

    The pattern contains an AlertName named group that will create the field and will only match zero or more chars other than LF (line feed) and CR characters.