Added log prefix in logback

src/main/config/logback.xml

@@ -1,7 +1,7 @@
 <configuration>
   <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
     <encoder>
-      <pattern>%.-1p %d{MM-dd HH:mm:ss.SSS} %t %c{30}:%L %X{clientId}|%X{sessionId}:%X{messageId}:%X{fileId}] %m%n</pattern>
+      <pattern>[s3proxy] %.-1p %d{MM-dd HH:mm:ss.SSS} %t %c{30}:%L %X{clientId}|%X{sessionId}:%X{messageId}:%X{fileId}] %m%n</pattern>
     </encoder>
     <filter class="ch.qos.logback.classic.filter.ThresholdFilter">
       <level>${LOG_LEVEL:-info}</level>