AndroidAPS/app/src/main/assets/logback.xml

<configuration>
  <!-- Create a file appender for a log in the application's data directory -->
  <property name="EXT_FILES_DIR" value="${EXT_DIR:-/sdcard}/Android/data/${PACKAGE_NAME}/files"/>
  <appender name="file" class="ch.qos.logback.core.rolling.RollingFileAppender">
    <file>${EXT_FILES_DIR}/AndroidAPS.log</file>
	<rollingPolicy class="ch.qos.logback.core.rolling.TimeBasedRollingPolicy">
            <!-- daily rollover. Make sure the path matches the one in the file element or else
             the rollover logs are placed in the working directory. -->
            <fileNamePattern>${EXT_FILES_DIR}/AndroidAPS._%d{yyyy-MM-dd}_%d{HH-mm-ss, aux}_.%i.zip</fileNamePattern>

            <timeBasedFileNamingAndTriggeringPolicy class="ch.qos.logback.core.rolling.SizeAndTimeBasedFNATP">
                <maxFileSize>5MB</maxFileSize>
            </timeBasedFileNamingAndTriggeringPolicy>
            <!-- keep 30 days' worth of history -->
            <maxHistory>120</maxHistory>
	</rollingPolicy>
    <encoder>
      <pattern>%d{HH:mm:ss.SSS} [%thread] %-5level [%file:%line]: %msg%n</pattern>
    </encoder>
  </appender>

    <appender name="logcat" class="ch.qos.logback.classic.android.LogcatAppender">
	  <tagEncoder>
		  <pattern>%logger{0}</pattern>
	  </tagEncoder>
    <encoder>
      <pattern>[%thread] %-5level [%file:%line]: %msg%n</pattern>
    </encoder>
  </appender>
  
  <!-- Write INFO (and higher-level) messages to the log file -->
  <root level="DEBUG">
    <appender-ref ref="file" />
	<appender-ref ref="logcat" />
  </root>
</configuration>