Grok

Since Camel 3.0

This component provides dataformat for processing inputs with grok patterns. Grok patterns are used to process unstructured data into structured objects - List<Map<String, Object>>.

This component is based on Java Grok library

Maven users will need to add the following dependency to their pom.xml for this component:

<dependency>
    <groupId>org.apache.camel</groupId>
    <artifactId>camel-grok</artifactId>
    <version>x.x.x</version>
    <!-- use the same version as your Camel core version -->
</dependency>

Basic usage

Extract all IP adresses from input

from("direct:in")
    .unmarshal().grok("%{IP:ip}")
    .to("log:out");

Parse Apache logs and process only 4xx responses

from("file://apacheLogs")
    .unmarshal().grok("%{COMBINEDAPACHELOG")
    .split(body()).filter(simple("${body[response]} starts with '4'"))
    .to("log:4xx")

Preregistered patterns

This component comes with preregistered patterns, which are based on Logstash patterns. All Java Grok Default Patterns are preregistered and as such could be used without manual registration.

Custom patterns

Camel Grok DataFormat supports plugable patterns, which are auto loaded from Camel Registry. You can register patterns with Java DSL and Spring DSL

Spring DSL:

<beans>
    <bean id="myCustomPatternBean" class="org.apache.camel.component.grok.GrokPattern">
        <constructor-arg value="FOOBAR"/>
        <constructor-arg value="foo|bar"/>
    </bean>
<beans>
<camelContext id="camel" xmlns="http://camel.apache.org/schema/spring">
    <route>
        <from uri="direct:in"/>
        <unmarshal>
            <grok pattern="%{FOOBAR:fooBar}"/>
        </unmarshal>
        <to uri="log:out"/>
    </route>
</camelContext>

Java DSL:

public class MyRouteBuilder extends RouteBuilder {

    @Override
    public void configure() throws Exception {
        bindToRegistry("myCustomPatternBean", new GrokPattern("FOOBAR", "foo|bar"));

        from("direct:in")
            .unmarshal().grok("%{FOOBAR:fooBar}")
            .to("log:out");
    }
}

Grok Dataformat Options

The Grok dataformat supports 4 options, which are listed below.

Name Default Java Type Description

pattern

String

The grok pattern to match lines of input

flattened

false

Boolean

Turns on flattened mode. In flattened mode the exception is thrown when there are multiple pattern matches with same key.

allowMultipleMatchesPerLine

true

Boolean

If false, every line of input is matched for pattern only once. Otherwise the line can be scanned multiple times when non-terminal pattern is used.

namedOnly

false

Boolean

Whether to capture named expressions only or not (i.e. %{IP:ip} but not ${IP})

Spring Boot Auto-Configuration

When using grok with Spring Boot make sure to use the following Maven dependency to have support for auto configuration:

<dependency>
  <groupId>org.apache.camel.springboot</groupId>
  <artifactId>camel-grok-starter</artifactId>
  <version>x.x.x</version>
  <!-- use the same version as your Camel core version -->
</dependency>

The component supports 5 options, which are listed below.

Name Description Default Type

camel.dataformat.grok.allow-multiple-matches-per-line

If false, every line of input is matched for pattern only once. Otherwise the line can be scanned multiple times when non-terminal pattern is used.

true

Boolean

camel.dataformat.grok.enabled

Whether to enable auto configuration of the grok data format. This is enabled by default.

Boolean

camel.dataformat.grok.flattened

Turns on flattened mode. In flattened mode the exception is thrown when there are multiple pattern matches with same key.

false

Boolean

camel.dataformat.grok.named-only

Whether to capture named expressions only or not (i.e. %{IP:ip} but not ${IP})

false

Boolean

camel.dataformat.grok.pattern

The grok pattern to match lines of input

String
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