How can I get AWS Lambda and Spring Boot 2.1.5 to use Log4j2.xml and log to Cloudwatch? - spring-boot

Question

In order to log to cloudwatch in a lambda, one must use this log4j2.xml:
<?xml version="1.0" encoding="UTF-8"?>
<Configuration packages="com.amazonaws.services.lambda.runtime.log4j2">
<Appenders>
<Lambda name="Lambda">
<PatternLayout>
<pattern>%d{yyyy-MM-dd HH:mm:ss} %X{AWSRequestId} %-5p %c{1}:%L - %m%n</pattern>
</PatternLayout>
</Lambda>
</Appenders>
<Loggers>
<Root level="info">
<AppenderRef ref="Lambda" />
</Root>
</Loggers>
</Configuration>
Also the following items must be in the pom.xml:
<parent>
<artifactId>spring-boot-starter-parent</artifactId>
<groupId>org.springframework.boot</groupId>
<version>2.1.5.RELEASE</version>
</parent>
...
<dependency>
<artifactId>aws-lambda-java-log4j2</artifactId>
<groupId>com.amazonaws</groupId>
<version>1.1.0</version>
</dependency>
<dependency>
<groupId>org.apache.logging.log4j</groupId>
<artifactId>log4j-core</artifactId>
<version>2.11.2</version>
</dependency>
<dependency>
<groupId>org.apache.logging.log4j</groupId>
<artifactId>log4j-api</artifactId>
<version>2.11.2</version>
</dependency>
Of course none of this works for me. It seems Spring uses Logback and I have tried shutting that off using these instructions. Nothing seems to work.
Any tips?

Answer 1

Got it! I read a post/rant where a guy noticed that AWS used a "5 year old jar" for the Cloudwatch/Lambda logging (can't find it now). So I found a Log4j2 jar that is compatible with 1.2 (log4j-1.2-api) and it worked. I had to shut off Logback in Spring and activate Log4j2. Below should take you all the way.
<dependency>
<artifactId>spring-boot-starter</artifactId>
<groupId>org.springframework.boot</groupId>
<exclusions>
<exclusion>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-logging</artifactId>
</exclusion>
</exclusions>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-log4j2</artifactId>
</dependency>
<dependency>
<artifactId>aws-lambda-java-log4j2</artifactId>
<groupId>com.amazonaws</groupId>
<version>1.1.0</version>
</dependency>
<dependency>
<groupId>org.apache.logging.log4j</groupId>
<artifactId>log4j-core</artifactId>
<version>2.11.2</version>
</dependency>
<dependency>
<groupId>org.apache.logging.log4j</groupId>
<artifactId>log4j-1.2-api</artifactId>
<version>2.11.2</version>
</dependency>
...
PS. You might need to fix this as well: log4j2 ERROR StatusLogger Unrecognized conversion specifier