This sample demonstrates how to deploy a Spring Boot application on Google App Engine.
See the Google App Engine standard environment documentation for more detailed instructions.
- Java 8
- Maven (at least 3.5)
- Google Cloud SDK (aka gcloud command line tool)
-
Download and initialize the Cloud SDK
gcloud init
-
Create an App Engine app within the current Google Cloud Project
gcloud app create
mvn appengine:run
To use vist: http://localhost:8080/
mvn appengine:deploy
To use vist: https://YOUR-PROJECT-ID.appspot.com
mvn verify
As you add / modify the source code (src/main/java/...
) it's very useful to add unit testing
to (src/main/test/...
). The following resources are quite useful:
For further information, consult the Java App Engine documentation.
You must use WAR packaging to deploy into Google App Engine Standard.
If you generate a Spring Boot project from start.spring.io, make sure you switch to the full version view of the initializer site, and select WAR packaging.
If you have an existing JAR
packaging project, you can convert it into a WAR
project by:
- In
pom.xml
, change<packaging>jar</packaging>
to<packaging>war</packaging>
- Create a new
SpringBootServletInitializer
implementation:
public class ServletInitializer extends SpringBootServletInitializer {
@Override
protected SpringApplicationBuilder configure(SpringApplicationBuilder application) {
return application.sources(YourApplication.class);
}
}
Google App Engine Standard deploys your WAR
into a Jetty server. Spring Boot's starter
includes Tomcat by default. This will introduce conflicts. Exclude Tomcat dependencies:
<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>
Do not include the Jetty dependencies. But you must include Servlet API dependency:
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>javax.servlet-api</artifactId>
<version>3.1.0</version>
<scope>provided</scope>
</dependency>
In the pom.xml
, add the App Engine Standard plugin:
<plugin>
<groupId>com.google.cloud.tools</groupId>
<artifactId>appengine-maven-plugin</artifactId>
<version>1.3.1</version>
</plugin>
This plugin is used to run local development server as well as deploying the application into Google App Engine.
Add a src/main/webapp/WEB-INF/appengine-web.xml
:
<appengine-web-app xmlns="http://appengine.google.com/ns/1.0">
<version>1</version>
<threadsafe>true</threadsafe>
<runtime>java8</runtime>
</appengine-web-app>
This configure is required for applications running in Google App Engine.
Spring Boot's default logging bridge conflicts with Jetty's logging system.
To be able to capture the Spring Boot startup logs, you need to exclude
org.slf4j:jul-to-slf4j
dependency. The easiest way to do this is to
set the dependency scope to provided
, so that it won't be included in
the WAR
file:
<!-- Exclude any jul-to-slf4j -->
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>jul-to-slf4j</artifactId>
<scope>provided</scope>
</dependency>
With Spring Boot >= 1.5.6, you may run into out of memory errors on startup. Please follow these instructions to work around this issue:
- Inside src/main/resources, adding a logging.properties file with:
.level = INFO
- Inside src/main/webapp/WEB-INF/appengine-web.xml, add a config that points to the new logging.properties file.
<property name="java.util.logging.config.file" value="WEB-INF/classes/logging.properties"/>