"task-log" RollingFile Appender

This appender manages scheduled task logs with automatic file rotation.

Configuration example:

<RollingFile name="task-log" fileName="logs/tasks.log" filePattern="logs/tasks-%d{yyyy-MM-dd}.log">
    <ThresholdFilter level="DEBUG"/>
    <PatternLayout pattern="%d{yyyy-MM-dd HH:mm:ss},%m%n"/>
    <Policies>
        <SizeBasedTriggeringPolicy size="1000KB"/>
    </Policies>
    <DefaultRolloverStrategy max="100"/>
</RollingFile>

The task log is a CSV-type log. It differs from other logs as it only takes a snapshot of the scheduled tasks' state at a given time T. It can be used to analyze system load but cannot show all tasks that have been executed. Each log line format consists of 4 sections and 10 columns. Taking the following example, here's the explanation of each column:

2025-01-28 15:43:54,1,0,,5,1,2025-01-28 15:43:43,10,0,

Log details:

1. 2025-01-28 15:43:54: Snapshot date and time
2. Section for high priority tasks
3. Section for medium priority tasks
4. Section for low priority tasks

Column details:

• 2025-01-28 15:43:54: Snapshot date and time
• 1: Identifier indicating the low priority tasks section (1 = Low priority, 5 = Medium priority, 10 = High priority)
• 0: Number of low priority tasks currently running
• `` : Date and time of the oldest low priority task not yet executed
• 5: Identifier indicating the medium priority tasks section (1 = Low priority, 5 = Medium priority, 10 = High priority)
• 1: Number of medium priority tasks currently running
• 2025-01-28 15:43:43: Date and time of the oldest medium priority task not yet executed
• 10: Identifier indicating the high priority tasks section (1 = Low priority, 5 = Medium priority, 10 = High priority)
• 0: Number of high priority tasks currently running
• `` : Date and time of the oldest high priority task not yet executed

Basic Configuration

• Name: task-log
• Output file: logs/tasks.log
• Archive file pattern: logs/tasks-[DATE].log

Log Format

The pattern %d{yyyy-MM-dd HH:mm:ss},%m%n defines the following format:

• %d{yyyy-MM-dd HH:mm:ss} : Date and time in specified format
• , : Separator (comma)
• %m : Log message
• %n : Line break

Rotation Policy

• SizeBasedTriggeringPolicy: 1000KB (1MB) per file
• DefaultRolloverStrategy: Maximum 100 archive files
• Rotation creates a new file when:
  • Current file reaches 1MB
  • A new day begins (based on date pattern)

Filter

• ThresholdFilter: Minimum level DEBUG
• All messages of level DEBUG or higher will be recorded
• Format particularly suitable for:
  • Export to analysis tools (CSV-like format)
  • Historical analysis with significant retention (100 files)

References

• Log4j2 RollingFile Appender