如何使用 log4j appender for kafka 编写应用程序日志？

Question

我想使用 log4j kafka appender 将我的应用日志消息流式传输到 kafka。

我的应用程序正在使用 spring boot 和 log4j2。

我在主题中看到了启动日志消息，但没有看到应用程序中使用的日志语句。

我是否遗漏了 log4j2 配置中的任何内容？

<?xml version="1.0" encoding="UTF-8"?>
<Configuration status="debug" name="kafka-logs" 
packages="myapp.kafka.test">
<Appenders>
    <Kafka name="Kafka" topic="test-kafka-topic">
        <JSONLayout />
        <Property name="bootstrap.servers">server1,server2</Property>
    </Kafka>
    <Async name="Async">
        <AppenderRef ref="Kafka"/>
    </Async>

    <Console name="stdout" target="SYSTEM_OUT">
        <PatternLayout pattern="%d{HH:mm:ss.SSS} %-5p [%-7t] %F:%L - %m%n"/>
    </Console>

</Appenders>
<Loggers>
    <Root level="INFO">
        <AppenderRef ref="Kafka"/>
        <AppenderRef ref="stdout"/>
    </Root>
    <Logger name="org.apache.kafka" level="WARN" />
</Loggers>

pom.xml

    <dependency>
        <groupId>org.apache.logging.log4j</groupId>
        <artifactId>log4j-api</artifactId>
        <version>2.11.2</version>
    </dependency>

    <dependency>
        <groupId>org.apache.logging.log4j</groupId>
        <artifactId>log4j-core</artifactId>
        <version>2.11.2</version>
    </dependency>

    <dependency>
        <groupId>org.slf4j</groupId>
        <artifactId>slf4j-simple</artifactId>
        <version>1.7.10</version>
    </dependency>

    <dependency>
        <groupId>org.apache.kafka</groupId>
        <artifactId>kafka-log4j-appender</artifactId>
        <version>1.0.0</version>
        <exclusions>
            <exclusion>
                <groupId>log4j</groupId>
                <artifactId>log4j</artifactId>
            </exclusion>
            <exclusion>
                <groupId>org.slf4j</groupId>
                <artifactId>slf4j-log4j12</artifactId>
            </exclusion>
        </exclusions>
    </dependency>

Java 代码

@SpringBootApplication
public class TestApplication {
private static final Logger logger = 
LoggerFactory.getLogger(TestApplication.class);
public static void main(String[] args) {
  SpringApplication application = new SpringApplication(TestApplication.class);
  logger.info("Before Application Startup");
  application.run(args);
  logger.info("After Application Startup");
}
}

登录 Kafka：

  {
  "thread" : "main",
  "level" : "INFO",
  "loggerName" : "TestApplication",
  "message" : "Started TestApplication in 17.19 seconds (JVM running for 22.67)",
  "endOfBatch" : false,
  "loggerFqcn" : "org.apache.commons.logging.LogFactory$Log4jLog",
  "instant" : {
  "epochSecond" : 1555422668,
  "nanoOfSecond" : 856000000
},
"threadId" : 1,
"threadPriority" : 5
}

控制台输出：

08:51:08.856 [main] INFO  TestApplication - Started TestApplication in 17.19 seconds (JVM running for 22.67)
[main] INFO TestApplication - Testing my application from TestApplication
[main] ERROR TestApplication - Testing my application from TestApplication

Answer 1

我认为 log4j2 已经有了 Kafka appender。至于我，我在 gradle 中添加了 Kafka 客户端。所以不用加kafka-log4j-appender

compile group: 'org.apache.kafka', name: 'kafka-clients', version: '2.0.1'

Maven应该类似

Answer 2

您需要排除 spring-boot-starter-logging，如下所示

<dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
             <exclusions>
                <exclusion>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>spring-boot-starter-logging</artifactId>
                </exclusion>
                <exclusion>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>logback-classic</artifactId>
                </exclusion>
            </exclusions>
        </dependency>

Answer 3

首先，您需要在 pom.xml 文件中删除 Spring Boot 应用程序中日志的默认提供程序，它们是 Logback 并且可能是 Log-classic，然后您需要添加 log4j2 作为新的日志提供程序并添加 Kafka appender。 添加依赖项后，您需要 xml 配置文件，您可以在其中添加 Kafka appender 配置。 默认情况下，您需要在项目的资源路径中找到您的配置文件，并将其命名为“log4j2.xml”。

您可以找到许多其他Log4j2 appenders，例如 Cassandra 或 Failover appender，并将它们添加到配置文件中的 Kafka appender 旁边。您可以在下面找到适用且正确的示例。

<!--excluding logback -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
            <exclusions>
                <exclusion>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>spring-boot-starter-logging</artifactId>
                </exclusion>
                <exclusion>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>logback-classic</artifactId>
                </exclusion>
            </exclusions>
        </dependency>


<!--adding log4j2 and kafka appender-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-log4j2</artifactId>
        </dependency>
    <dependency>
        <groupId>org.apache.kafka</groupId>
        <artifactId>kafka-log4j-appender</artifactId>
        <exclusions>
            <exclusion>
                <groupId>org.slf4j</groupId>
                <artifactId>slf4j-log4j12</artifactId>
            </exclusion>
        </exclusions>
    </dependency>

Kafka appender 配置

<?xml version="1.0" encoding="UTF-8"?>
<Configuration status="info" name="kafka-appender" packages="Citydi.ElasticDemo">

    <Appenders>

        <Kafka name="kafkaLogAppender" topic="Second-Topic">
            <JSONLayout />
            <Property name="bootstrap.servers">localhost:9092</Property>
            <MarkerFilter marker="Recorder" onMatch="DENY" onMismatch="ACCEPT"/>
        </Kafka>

        <Console name="stdout" target="SYSTEM_OUT">
            <PatternLayout pattern="%d{HH:mm:ss.SSS} stdout %highlight{%-5p} [%-7t] %F:%L - %m%n"/>
            <MarkerFilter marker="Recorder" onMatch="DENY" onMismatch="ACCEPT"/>
        </Console>

    </Appenders>
    <Loggers>
        <Root level="INFO">
            <AppenderRef ref="kafkaLogAppender"/>
            <AppenderRef ref="stdout"/>
        </Root>
        <Logger name="org.apache.kafka" level="warn" />
    </Loggers>

</Configuration>