plugin-oauth2/plugin/grails-app/conf/logback.xml

<?xml version="1.0" encoding="UTF-8"?>
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     Licensed to the Apache Software Foundation (ASF) under one
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     to you under the Apache License, Version 2.0 (the
     "License"); you may not use this file except in compliance
     with the License.  You may obtain a copy of the License at

       http://www.apache.org/licenses/LICENSE-2.0

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     software distributed under the License is distributed on an
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     KIND, either express or implied.  See the License for the
     specific language governing permissions and limitations
     under the License.

-->
<configuration>

    <conversionRule conversionWord="clr" class="org.springframework.boot.logging.logback.ColorConverter" />
    <conversionRule conversionWord="wex" class="org.springframework.boot.logging.logback.WhitespaceThrowableProxyConverter" />

    <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
        <encoder>
            <charset>UTF-8</charset>
            <pattern>'%clr(%d{yyyy-MM-dd HH:mm:ss.SSS}){faint} %clr(%5p) %clr(---){faint} %clr([%15.15t]){faint} %clr(%-40.40logger{39}){cyan} %clr(:){faint} %m%n%wex'</pattern>
        </encoder>
    </appender>

    <root level="error">
        <appender-ref ref="STDOUT" />
    </root>
</configuration>