Unable to open JDBC Connection for DDL execution\n\tat after deploying my spring boot app on google cloud / app engine - spring-boot

Question

After deploying my spring boot on google cloud platform app engine 'standard', and then try to visit the website I get Error: Server Error in browser. Then I visit the log on google cloud I get error:
"logMessage": "org.eclipse.jetty.annotations.ServletContainerInitializersStarter doStart: \norg.springframework.beans.factory.BeanCreationException: Error creating bean with name 'entityManagerFactory' defined in class path resource [org/springframework/boot/autoconfigure/orm/jpa/HibernateJpaConfiguration.class]: Invocation of init method failed; nested exception is javax.persistence.PersistenceException: [PersistenceUnit: default] Unable to build Hibernate SessionFactory; nested exception is org.hibernate.exception.JDBCConnectionException: Unable to open JDBC Connection for DDL execution\n\tat
I tried to change the datasourceurl multiple time, but still not succeeded yet.
My properties file:
spring.mvc.view.prefix=/WEB-INF/views/
spring.mvc.view.suffix=.jsp
database=mysql
spring.datasource.driverClassName=com.mysql.jdbc.Driver
spring.datasource.url=jdbc:mysql://google/myBlog?cloudSqlInstance=reviewcontainerblog&socketFactory=com.google.cloud.sql.mysql.SocketFactory
spring.datasource.username=user
spring.datasource.password=password
#JPA
spring.jpa.hibernate.ddl-auto=update
spring.jpa.show-sql=true
spring.jpa.database-platform=org.hibernate.dialect.MySQL57InnoDBDialect
my pom file :
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<packaging>war</packaging>
<groupId>com.reviewcontainer</groupId>
<artifactId>ReviewContainer</artifactId>
<version>0.0.3-SNAPSHOT</version>
<name>ReviewContainer</name>
<description>Review Container is Blog App</description>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.1.5.RELEASE</version>
</parent>
<properties>
<java.version>1.8</java.version>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<maven.compiler.target>1.8</maven.compiler.target>
<maven.compiler.source>1.8</maven.compiler.source>
<start-class>com.reviewcontainer.Application</start-class>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
<exclusions>
<!--Exclude the Tomcat dependency-->
<exclusion>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-el</artifactId>
</exclusion>
<exclusion>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-websocket</artifactId>
</exclusion>
<exclusion>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-tomcat</artifactId>
</exclusion>
</exclusions>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
</dependency>
<!-- https://mvnrepository.com/artifact/org.springframework.boot/spring-boot-actuator -->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-actuator</artifactId>
</dependency>
<!--https://mvnrepository.com/artifact/org.springframework.boot/spring-boot-autoconfigure -->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-autoconfigure</artifactId>
</dependency>
<!--tomcat embed jasper help REST to be converted to JSP-->
<dependency>
<groupId>org.apache.tomcat.embed</groupId>
<artifactId>tomcat-embed-jasper</artifactId>
</dependency>
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>jstl</artifactId>
<version>1.2</version>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<scope>runtime</scope>
<version>8.0.16</version>
</dependency>
<!-- https://mvnrepository.com/artifact/org.webjars/jquery -->
<dependency>
<groupId>org.webjars</groupId>
<artifactId>jquery</artifactId>
<version>3.3.1-1</version>
</dependency>
<!-- https://mvnrepository.com/artifact/org.webjars/bootstrap -->
<dependency>
<groupId>org.webjars</groupId>
<artifactId>bootstrap</artifactId>
<version>4.2.1</version>
</dependency>
<dependency>
<groupId>org.springframework.security</groupId>
<artifactId>spring-security-taglibs</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-security</artifactId>
</dependency>
<dependency>
<groupId>javax.servlet.jsp</groupId>
<artifactId>javax.servlet.jsp-api</artifactId>
<version>2.3.3</version>
</dependency>
<!-- https://mvnrepository.com/artifact/com.google.cloud.sql/mysql-socket-factory -->
<dependency>
<groupId>com.google.cloud.sql</groupId>
<artifactId>mysql-socket-factory</artifactId>
<version>1.0.13</version>
</dependency>
<dependency>
<groupId>javax.xml.bind</groupId>
<artifactId>jaxb-api</artifactId>
<version>2.3.0</version>
</dependency>
<!--Spring JDBC, Cloud GCP SQL Starter -->
<!-- https://mvnrepository.com/artifact/org.springframework.boot/spring-boot-starter-jdbc -->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-jdbc</artifactId>
<version>2.1.5.RELEASE</version>
</dependency>
</dependencies>
<build>
<finalName>ReviewContainer</finalName>
<resources>
<resource>
<directory>src/main/resources</directory>
<filtering>true</filtering>
</resource>
</resources>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
<executions>
<execution>
<goals>
<goal>repackage</goal>
</goals>
<configuration>
<mainClass>${start-class}</mainClass>
</configuration>
</execution>
</executions>
</plugin>
<plugin>
<groupId>com.google.cloud.tools</groupId>
<artifactId>appengine-maven-plugin</artifactId>
<version>2.0.0</version>
<configuration>
<deploy.projectId>reviewcontainer</deploy.projectId>
<deploy.version>rc-003-snapshot</deploy.version>
</configuration>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-war-plugin</artifactId>
<version>2.3</version>
<configuration>
<failOnMissingWebXml>false</failOnMissingWebXml>
<archiveClasses>true</archiveClasses>
<webResources>
<resource>
<directory>${basedir}/src/main/webapp/WEB-INF</directory>
<filtering>true</filtering>
<targetPath>WEB-INF</targetPath>
</resource>
</webResources>
</configuration>
</plugin>
</plugins>
</build>
</project>
"logMessage": "org.eclipse.jetty.annotations.ServletContainerInitializersStarter doStart: \norg.springframework.beans.factory.BeanCreationException: Error creating bean with name 'entityManagerFactory' defined in class path resource [org/springframework/boot/autoconfigure/orm/jpa/HibernateJpaConfiguration.class]: Invocation of init method failed; nested exception is javax.persistence.PersistenceException: [PersistenceUnit: default] Unable to build Hibernate SessionFactory; nested exception is org.hibernate.exception.JDBCConnectionException: Unable to open JDBC Connection for DDL execution\n\tat

Answer 1

I believe your problem is located on properties file:
spring.datasource.url=jdbc:mysql://google/myBlog?cloudSqlInstance=reviewcontainerblog&socketFactory=com.google.cloud.sql.mysql.SocketFactory
If you check here on google's community tutorial and at Google Cloud Platform's Github page on "Creating the JDBC URL" :
spring.datasource.url=jdbc:mysql://google/petclinic?cloudSqlInstance=INSTANCE_CONNECTION_NAME&socketFactory=com.google.cloud.sql.mysql.SocketFactory
jdbc:mysql://google/<DATABASE_NAME>?cloudSqlInstance=<INSTANCE_CONNECTION_NAME>&socketFactory=com.google.cloud.sql.mysql.SocketFactory&useSSL=false&user=<MYSQL_USER_NAME>&password=<MYSQL_USER_PASSWORD>
So, it is the Instance Connection Name and NOT the instance name. You can check this documentation from Google community tutorials which is quick helpful even if is for Flexible environment. Try it and let me know.
You can also check this article which provides some other workaround on how to connect to CloudSQL from your Spring Application