regex() Query Function

Extract new fields using a regular expression. The regular expression can contain one or more named capturing groups. Fields with the names of the groups will be added to the events. Using " in already quoted strings requires escaping. This is sometimes necessary when writing regular expressions. Humio uses JitRex which closely follows the syntax of re2j regular expressions which has a syntax very close to Java’s regular expressions. Check out the syntax.

Parameters

Name

Type

Required

Default

Description

regex

string

Yes

Specifies a regular expression. The regular expression can contain one or more named capturing groups. Fields with the names of the groups will be added to the events.

field

string

No

@rawstring

Specifies the field to run the regular expression against. Default is running against @rawstring.

strict

boolean

No

true

Specifies if events not matching the regular expression should be filtered out of the result set. Strict is the default.

flags

string

No

m

Specifies other regex flags m is multi line, i is ignore case, and d means dot (.) includes newline.

repeat

boolean

No

false

If set to true, multiple matches yields multiple events.

limit

number

No

false

Defines the maximum number of events to produce (defaults to 100). A warning is produced if this limit is exceeded, unless the parameter is specified explicitly.

The implied parameter is regex.

Examples

Extract the domain name of the http referrer field. Often this field contains a full url, so we can have many different URLs from the same site. In this case we want to count all referrals from the same domain. This will add a field named refdomain to events matching the regular expression.

humio
regex("https?://(www.)?(?<refdomain>.+?)(/|$)", field=referrer)
| groupby(refdomain, function=count()) | sort(field=_count, type=number, reverse=true)

Extract the userid from the url field. New fields are stored in a field named userid.

humio
regex(regex=".*/user/(?<userid>\S+)/pay", field=url)

Shows how to escape " in the regular expression. This is necessary because the regular expression is itself in quotes. Extract the user and message from events like: Peter: "hello" and Bob: "good morning".

humio
regex("(?<name>\S+): \"(?<msg>\S+)\"")