App Engine apps are easy to create, easy to maintain, and easy to scale as your traffic and data storage needs change. With App Engine, there are no servers to maintain. You simply upload your app and it's ready to go.
App Engine apps automatically scale based on incoming traffic. Load balancing, microservices, authorization, SQL and NoSQL databases, memory caching, traffic splitting, logging, search, versioning, rollouts and rollbacks, and security scanning are all supported natively and are highly customizable.
App Engine standard environment and App Engine flexible environment support a host of programming languages, including Java, Python, PHP, NodeJS, and Go. The two environments give developers maximum flexibility with how their app behaves. Each environment has certain strengths. For more information, see Choosing an App Engine environment.
You'll learn to deploy a Spring Boot app to App Engine standard environment. The standard environment scales down to zero instances when no one is using it and automatically scales up!
If you see a "request account button" at the top of the main Codelabs window, click it to obtain a temporary account. Otherwise ask one of the staff for a coupon with username/password.
These temporary accounts have existing projects that are set up with billing so that there are no costs associated for you with running this codelab.
Note that all these accounts will be disabled soon after the codelab is over.
Use these credentials to log into the machine or to open a new Google Cloud Console window https://console.cloud.google.com/. Accept the new account Terms of Service and any updates to Terms of Service.
Here's what you should see once logged in:
When presented with this console landing page, please select the only project available. Alternatively, from the console home page, click on "Select a Project" :
You'll use Cloud Shell, a command-line environment running in Google Cloud.
If you've never started Cloud Shell before, you'll be presented with an intermediate screen (below the fold) describing what it is. If that's the case, click Continue (and you won't ever see it again). Here's what that one-time screen looks like:
It should only take a few moments to provision and connect to Cloud Shell.
This virtual machine is loaded with all the development tools you'll need. It offers a persistent 5GB home directory and runs in Google Cloud, greatly enhancing network performance and authentication. Much, if not all, of your work in this codelab can be done with simply a browser or your Chromebook.
Once connected to Cloud Shell, you should see that you are already authenticated and that the project is already set to your project ID.
gcloud auth list
Command output
Credentialed Accounts ACTIVE ACCOUNT * <my_account>@<my_domain.com> To set the active account, run: $ gcloud config set account `ACCOUNT`
gcloud config list project
Command output
[core] project = <PROJECT_ID>
If it is not, you can set it with this command:
gcloud config set project <PROJECT_ID>
Command output
Updated property [core/project].
After Cloud Shell launches, you can use the command line to generate a new Spring Boot app with Spring Initializr.
$ curl https://start.spring.io/starter.tgz \ -d bootVersion=2.3.0.RELEASE \ -d dependencies=web \ -d baseDir=gae-standard-example | tar -xzvf - $ cd gae-standard-example
There are two ways to deploy a Java server app—either by using Maven App Engine Plugin or Gradle App Engine Plugin, or by deploying the war
package directory. You'll use Maven App Engine Plugin to deploy the app.
Update pom.xml
to include a Google Cloud plugin that simplifies the deployment process. You can use Vim, nano, or Emacs to edit the file.
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" ...>
...
<build>
<plugins>
...
<plugin>
<groupId>com.google.cloud.tools</groupId>
<artifactId>appengine-maven-plugin</artifactId>
<version>2.2.0</version>
<configuration>
<version>1</version>
<projectId>GCLOUD_CONFIG</projectId>
</configuration>
</plugin>
...
</plugins>
</build>
</project>
src/main/appengine/app.yaml
descriptor file.$ mkdir -p src/main/appengine/ $ touch src/main/appengine/app.yaml
src/main/appengine/app.yaml
file and add the following content:runtime: java11
instance_class: F1
Add a new controller that returns "hello world!"
in DemoApplication.java
.
src/main/java/com/example/demo/DemoApplication.java
package com.example.demo;
...
// Add imports
import org.springframework.web.bind.annotation.*;
@SpringBootApplication
public class DemoApplication {
public static void main(String[] args) {
SpringApplication.run(DemoApplication.class, args);
}
}
// Add the controller.
@RestController
class HelloWorldController {
@GetMapping("/")
public String hello() {
return "hello world!";
}
}
$ ./mvnw -DskipTests spring-boot:run
A tab in your browser opens and connects to the server that you started.
$ gcloud app create --region us-central You are creating an app for project [...]. WARNING: Creating an App Engine application for a project is irreversible and the region cannot be changed. More information about regions is at https://cloud.google.com/appengine/docs/locations
mvn appengine:deploy
.$ ./mvnw -DskipTests package appengine:deploy ... first time deploy may take a couple of minutes
$ gcloud app browse ... [It may print out the URL for your app]
You learned to write your first App Engine web app!