How to deploy a springboot - war - to - Google AppEngine - Java11 - spring-boot

Question

I am trying to deploy a war packaged springboot app - Java 11
Created a brand new springboot web application (packaging war) and followed article https://cloud.google.com/appengine/docs/standard/java-gen2/war-packaging
from step1 . i.e. cloning and installing (https://github.com/GoogleCloudPlatform/java-docs-samples)
spring boot parent
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<!-- <version>2.7.2</version>-->
<version>2.5.4</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<packaging>war</packaging>
<properties>
<java.version>11</java.version>
<maven.compiler.target>11</maven.compiler.target>
<maven.compiler.source>11</maven.compiler.source>
</properties>
<dependencyManagement>
<dependencies>
<dependency>
<groupId>com.google.cloud</groupId>
<artifactId>spring-cloud-gcp-dependencies</artifactId>
<!-- <version>2.0.3</version>-->
<version>2.0.4</version>
<type>pom</type>
<scope>import</scope>
</dependency>
</dependencies>
</dependencyManagement>
Excluding tomcat from web
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
<exclusions>
<exclusion>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-tomcat</artifactId>
</exclusion>
</exclusions>
</dependency>
Added
<dependency>
<groupId>com.example.appengine.demo</groupId>
<artifactId>simple-jetty-main</artifactId>
<version>1</version>
<scope>provided</scope>
</dependency>
and plugins
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
<version>2.6.6</version>
<executions>
<execution>
<goals>
<goal>repackage</goal>
</goals>
</execution>
</executions>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-war-plugin</artifactId>
<version>3.3.2</version>
</plugin>
<plugin>
<groupId>com.google.cloud.tools</groupId>
<artifactId>appengine-maven-plugin</artifactId>
<version>2.4.2</version>
<configuration>
<version>1</version>
<projectId>GCLOUD_CONFIG</projectId>
</configuration>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-dependency-plugin</artifactId>
<version>3.1.1</version>
<executions>
<execution>
<id>copy</id>
<phase>prepare-package</phase>
<goals>
<goal>copy-dependencies</goal>
</goals>
<configuration>
<outputDirectory>
${project.build.directory}/appengine-staging
</outputDirectory>
</configuration>
</execution>
</executions>
</plugin>
</plugins>
src/main/appengine/app.yaml
runtime: java11
entrypoint: 'java -cp "*" com.example.appengine.demo.jettymain.Main myapp-0.0.1-SNAPSHOT.war'
instance_class: B2
handlers:
- url: /.*
script: this field is required, but ignored
manual_scaling:
instances: 1
resources:
cpu: 2
memory_gb: 2.3
disk_size_gb: 20
volumes:
- name: ramdisk1
volume_type: tmpfs
size_gb: 0.5
Output :
Sadly this is not what I am expecting.
Another Variation:
I remembered servlet initalizer is not added, so correct it
#SpringBootApplication
public class DashApplication extends SpringBootServletInitializer {
public static void main(String[] args) {
SpringApplication.runDashApplication.class, args);
}
#Override
protected SpringApplicationBuilder configure(SpringApplicationBuilder application) {
return application.sources(DashApplication.class);
}
}
Error:
Application thows error in the logs
"java.lang.IllegalArgumentException: Unable to instantiate
org.springframework.boot.env.EnvironmentPostProcessor
[org.springframework.boot.test.web.SpringBootTestRandomPortEnvironmentPostProcessor]
at
org.springframework.boot.util.Instantiator.instantiate(Instantiator.java:131)
at
java.base/java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:195)
What is my mistake ?
Please help - How to create a simple Java 11 , springboot , war package, and deploy to appengine

Answer 1

As mentioned in the comments section, adding spring-boot-starter-test as test dependency in pom.xml fixed the issue.
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
</dependency>
Posting the answer as community wiki for the benefit of the community that might encounter this use case in the future.