logback.xml

<!--
 Copyright 2023 Google LLC

 Licensed 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

 Unless required by applicable law or agreed to in writing, software
 distributed under the License is distributed on an "AS IS" BASIS,
 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 See the License for the specific language governing permissions and
 limitations under the License.
-->

<configuration>
  <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
    <!-- [START opentelemetry_instrumentation_logbackxml] -->
    <encoder class="net.logstash.logback.encoder.LogstashEncoder">
      <!-- Format JSON logs for the Logging agent
      https://cloud.google.com/logging/docs/structured-logging#special-payload-fields -->
      <provider class="net.logstash.logback.composite.loggingevent.LoggingEventPatternJsonProvider">
        <pattern>
          {
            "logging.googleapis.com/trace": "%mdc{trace_id}",
            "logging.googleapis.com/spanId": "%mdc{span_id}",
            "logging.googleapis.com/trace_sampled": "#asBoolean{%replace(%mdc{trace_flags}){'01', 'true'}}"
          }
        </pattern>
      </provider>

      <!-- Rename fields for the Logging agent -->
      <fieldNames>
        <level>severity</level>
        <timestamp>timestamp</timestamp>
        <levelValue>[ignore]</levelValue>
      </fieldNames>

      <!-- Exclude tracing MDC keys which are handled above -->
      <excludeMdcKeyName>trace_id</excludeMdcKeyName>
      <excludeMdcKeyName>span_id</excludeMdcKeyName>
      <excludeMdcKeyName>trace_flags</excludeMdcKeyName>
    </encoder>
    <!-- [END opentelemetry_instrumentation_logbackxml] -->
  </appender>

  <root level="INFO">
    <appender-ref ref="STDOUT"/>
  </root>

</configuration>