Flink运行时动态更改日志级别

背景

Flink On Yarn Cluster的模式, 任务提交时使用的FLINK_CONFG_DIR下的log4j.properties, 无法动态去更改日志的输出级别; 官方不支持通过传参指定日志配置文件, 详情查看YarnConfigOptionsInternal类上的说明

如果想针对不同的任务, 指定日志输出级别, 那么只能在启动的时候通过export命令重新指定一下FLINK_CONFG_DIR, 这样终究不是太方便, 下面便讲讲如何让通过代码去更改.

YarnConfigOptionsInternal内置参数

CDH下 log4j.properties

CDH Flink环境脚本

CODE

LogDyDemo测试类

import org.apache.logging.log4j.Level;
import org.apache.logging.log4j.spi.LoggerContext;
import org.apache.logging.slf4j.Log4jLoggerFactory;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.util.Set;
public class LogDyDemo {
    private static final Logger logger = LoggerFactory.getLogger("tmp_test");
    public static void main(String[] args) {
        //方式一,本地和flink运行生效
        Log4jLoggerFactory fac = (Log4jLoggerFactory)LoggerFactory.getILoggerFactory();
        Set loggerContexts = fac.getLoggerContexts();
        org.apache.logging.log4j.core.LoggerContext  next = (org.apache.logging.log4j.core.LoggerContext)
                loggerContexts.iterator().next();
        next.getRootLogger().get().setLevel(Level.DEBUG);
        next.updateLoggers();
        
        //方式二, flink上实测可行,但本地不生效
        org.apache.logging.log4j.core.LoggerContext context = org.apache.logging.log4j.core.LoggerContext.getContext();
        context.getRootLogger().get().setLevel(Level.DEBUG);
        context.updateLoggers();
        
        logger.debug("log_print test=========>");
        logger.info("log_print test=========>");
        logger.warn("log_print test=========>");
        logger.error("log_print test=========>");
    }
}

log4j2.properties里的rootLogger的级别是INFO, 代码中改为了DEBUG, 两种方式二选一即可, 日志中能输出所有级别, 则测试通过

测试通过

Flink测试类

在Task端通过静态代码块进行初始化, Flink默认使用log4j2, 所以下面只针对这种方式; 打包放到服务器上运行, 打包时建议将引用的maven依赖范围改为privode , 以减少运行时的class冲突

public class FlinkDemo {
    public static void main(String[] args) throws Exception {
        ExecutionEnvironment env = ExecutionEnvironment.getExecutionEnvironment();
        DataSet text = env.fromElements(
                "Who's there?",
                "I think I hear them. Stand, ho! Who's there?");
        DataSet> wordCounts = text.flatMap(new LineSplitter()).groupBy(0).sum(1);
        wordCounts.print();
    }

    public static class LineSplitter implements FlatMapFunction> {
        public static final Logger logger = LoggerFactory.getLogger(LineSplitter.class);
        static {
            Log4jLoggerFactory fac = (Log4jLoggerFactory) LoggerFactory.getILoggerFactory();
            Set loggerContexts = fac.getLoggerContexts();
            org.apache.logging.log4j.core.LoggerContext next = (org.apache.logging.log4j.core.LoggerContext)
                    loggerContexts.iterator().next();
            next.getRootLogger().get().setLevel(Level.DEBUG);
            next.updateLoggers();
        }
        @Override
        public void flatMap(String line, Collector> collector) throws Exception {
            logger.debug("log_print test=========>");
            logger.info("log_print test=========>");
            logger.warn("log_print test=========>");
            logger.error("log_print test=========>");

            for (String word : line.split(" ")) {
                collector.collect(new Tuple2(word, 1));
            }
        }
    }
}

Yarn运行测试通过

log4j2.properties

下面的log4j配置是从flink的源码下dist子项目中复制过来的; Flink官方默认使用的是log4j2, 本地运行时需要改一下文件名称, appender.main.fileName也要改一下, 不然会报错

monitorInterval=30
rootLogger.level = INFO
rootLogger.appenderRef.file.ref = MainAppender

logger.akka.name = akka
logger.akka.level = INFO
logger.kafka.name= org.apache.kafka
logger.kafka.level = INFO
logger.hadoop.name = org.apache.hadoop
logger.hadoop.level = INFO
logger.zookeeper.name = org.apache.zookeeper
logger.zookeeper.level = INFO

# Log all infos in the given file
appender.main.name = MainAppender
appender.main.type = RollingFile
appender.main.append = true
appender.main.fileName = logs/demo_run.log
appender.main.filePattern = logs/demo_run.log.%i
appender.main.layout.type = PatternLayout
appender.main.layout.pattern = %d{yyyy-MM-dd HH:mm:ss,SSS} %-5p %-60c %x - %m%n
appender.main.policies.type = Policies
appender.main.policies.size.type = SizeBasedTriggeringPolicy
appender.main.policies.size.size = 100MB
appender.main.policies.startup.type = OnStartupTriggeringPolicy
appender.main.strategy.type = DefaultRolloverStrategy
appender.main.strategy.max = ${env:MAX_LOG_FILE_NUMBER:-10}

pom.xml

    
        
            org.apache.logging.log4j
            log4j-core
            2.12.1
        
        
            org.apache.logging.log4j
            log4j-slf4j-impl
            2.12.1
        
        
            org.apache.flink
            flink-clients_2.11
            1.13.1