Java 11 Cloud SDK 的 appengine:run 是什么？

Question

tl;dr: 我怎么能运行 this project locally, in a way that Datastore will work? (Zip download link here.)

我正在将使用 App Engine 和 Datastore 的 Java 8 项目迁移到 Java 11。

使用 Java 8，我使用基于 Cloud SDK 的 App Engine plugin 使用 mvn appengine:run 在本地运行服务器并使用 [= 部署到实时服务器18=].

我按照 this guide 告诉我删除 appengine-web.xml 文件并改用 app.yaml..

要部署到实时服务器，我仍然可以使用 mvn appengine:deploy，无论是否使用 Datastore，都可以正常工作。

要在本地部署，我运行 mvn package exec:java。这适用于运行没有 Datastore 的基本服务器，但如果我添加一些 example Datastore code，则会出现此错误：

java.lang.IllegalArgumentException: A project ID is required for this service but could not be determined from the builder or the environment. Please set a project ID using the builder.

我知道这是因为我没有本地 App Engine 环境运行ning。但是，如果我尝试使用 mvn appengine:run 运行本地服务器，则会收到此错误，抱怨缺少 appengine-web.xml 文件：

[ERROR] Failed to execute goal com.google.cloud.tools:appengine-maven-plugin:2.2.0:run (default-cli) on project datastore-hello-world:
Failed to run devappserver: java.nio.file.NoSuchFileException:
C:\Users\kevin\Documents\GitHub\HappyCoding\examples\google-cloud\google-cloud-example-projects\datastore-hello-world\target\datastore-hello-world-1\WEB-INF\appengine-web.xml -> [Help 1]

所以我在需要运行 mvn appengine:run 需要 appengine-web.xml 和需要更新到 Java 11 之间徘徊，后者表示要使用 [=20] =] 而不是 appengine-web.xml.

Java 11 App Engine docs 本地只说运行ning:

To test your application's functionality before deploying, run your application in your local environment with the development tools that you usually use.

以上 GitHub and zip 链接包含整个项目（总共 5 个文件），但为了将我的代码直接包含在问题中，以下是最重要的文件：

pom.xml

<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>

  <groupId>io.happycoding</groupId>
  <artifactId>datastore-hello-world</artifactId>
  <version>1</version>

  <properties>
    <!-- App Engine currently supports Java 11 -->
    <maven.compiler.source>11</maven.compiler.source>
    <maven.compiler.target>11</maven.compiler.target>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <jetty.version>9.4.31.v20200723</jetty.version>

    <!-- Project-specific properties -->
    <mainClass>io.happycoding.ServerMain</mainClass>
    <googleCloudProjectId>YOUR_PROJECT_ID_HERE</googleCloudProjectId>
  </properties>

  <dependencies>
    <!-- Java Servlets API -->
    <dependency>
      <groupId>javax.servlet</groupId>
      <artifactId>javax.servlet-api</artifactId>
      <version>4.0.1</version>
    </dependency>

    <!-- Jetty -->
    <dependency>
      <groupId>org.eclipse.jetty</groupId>
      <artifactId>jetty-server</artifactId>
      <version>${jetty.version}</version>
    </dependency>
    <dependency>
      <groupId>org.eclipse.jetty</groupId>
      <artifactId>jetty-annotations</artifactId>
      <version>${jetty.version}</version>
    </dependency>

    <!-- Datastore -->
    <dependency>
      <groupId>com.google.cloud</groupId>
      <artifactId>google-cloud-datastore</artifactId>
      <version>1.104.0</version>
    </dependency>
  </dependencies>

  <build>
    <plugins>
      <!-- Copy static resources like html files into the output jar file. -->
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-resources-plugin</artifactId>
        <version>2.7</version>
        <executions>
          <execution>
            <id>copy-web-resources</id>
            <phase>compile</phase>
            <goals><goal>copy-resources</goal></goals>
            <configuration>
              <outputDirectory>
                ${project.build.directory}/classes/META-INF/resources
              </outputDirectory>
              <resources>
                <resource><directory>./src/main/webapp</directory></resource>
              </resources>
            </configuration>
          </execution>
        </executions>
      </plugin>

      <!-- Package everything into a single executable jar file. -->
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-shade-plugin</artifactId>
        <version>3.2.4</version>
        <executions>
          <execution>
            <phase>package</phase>
            <goals><goal>shade</goal></goals>
            <configuration>
              <createDependencyReducedPom>false</createDependencyReducedPom>
              <transformers>
                <transformer implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
                  <mainClass>${mainClass}</mainClass>
                </transformer>
              </transformers>
            </configuration>
          </execution>
        </executions>
      </plugin>

      <!-- Exec plugin for deploying the local server. -->
      <plugin>
        <groupId>org.codehaus.mojo</groupId>
        <artifactId>exec-maven-plugin</artifactId>
        <version>3.0.0</version>
        <executions>
          <execution>
            <goals>
              <goal>java</goal>
            </goals>
          </execution>
        </executions>
        <configuration>
          <mainClass>${mainClass}</mainClass>
        </configuration>
      </plugin>

      <!-- App Engine plugin for deploying to the live site. -->
      <plugin>
        <groupId>com.google.cloud.tools</groupId>
        <artifactId>appengine-maven-plugin</artifactId>
        <version>2.2.0</version>
        <configuration>
          <projectId>${googleCloudProjectId}</projectId>
          <version>1</version>
        </configuration>
      </plugin>
    </plugins>
  </build>
</project>

ServerMain.java

package io.happycoding;

import java.net.URL;
import org.eclipse.jetty.annotations.AnnotationConfiguration;
import org.eclipse.jetty.server.Handler;
import org.eclipse.jetty.server.handler.DefaultHandler;
import org.eclipse.jetty.server.Server;
import org.eclipse.jetty.servlet.DefaultServlet;
import org.eclipse.jetty.webapp.Configuration;
import org.eclipse.jetty.webapp.WebAppContext;
import org.eclipse.jetty.webapp.WebInfConfiguration;

/**
 * Starts up the server, including a DefaultServlet that handles static files,
 * and any servlet classes annotated with the @WebServlet annotation.
 */
public class ServerMain {

  public static void main(String[] args) throws Exception {

    // Create a server that listens on port 8080.
    Server server = new Server(8080);
    WebAppContext webAppContext = new WebAppContext();
    server.setHandler(webAppContext);

    // Load static content from inside the jar file.
    URL webAppDir =
        ServerMain.class.getClassLoader().getResource("META-INF/resources");
    webAppContext.setResourceBase(webAppDir.toURI().toString());

    // Enable annotations so the server sees classes annotated with @WebServlet.
    webAppContext.setConfigurations(new Configuration[]{ 
      new AnnotationConfiguration(),
      new WebInfConfiguration(), 
    });

    // Look for annotations in the classes directory (dev server) and in the
    // jar file (live server)
    webAppContext.setAttribute(
        "org.eclipse.jetty.server.webapp.ContainerIncludeJarPattern", 
        ".*/target/classes/|.*\.jar");

    // Handle static resources, e.g. html files.
    webAppContext.addServlet(DefaultServlet.class, "/");

    // Start the server! 
    server.start();
    System.out.println("Server started!");

    // Keep the main thread alive while the server is running.
    server.join();
  }
}

HelloWorldServlet.java

package io.happycoding.servlets;

import com.google.cloud.datastore.Datastore;
import com.google.cloud.datastore.DatastoreOptions;
import com.google.cloud.datastore.Entity;
import com.google.cloud.datastore.Key;
import java.io.IOException;

import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

@WebServlet("/hello")
public class HelloWorldServlet extends HttpServlet {

  @Override
  public void doGet(HttpServletRequest request, HttpServletResponse response)
      throws IOException {

    Datastore datastore = DatastoreOptions.getDefaultInstance().getService();

    String kind = "Task";
    // The name/ID for the new entity
    String name = "sampletask1";
    // The Cloud Datastore key for the new entity
    Key taskKey = datastore.newKeyFactory().setKind(kind).newKey(name);

    // Prepares the new entity
    Entity task = Entity.newBuilder(taskKey)
        .set("description", "Buy milk")
        .build();

    // Saves the entity
    datastore.put(task);

    System.out.printf("Saved %s: %s%n", task.getKey().getName(), task.getString("description"));

    //Retrieve entity
    Entity retrieved = datastore.get(taskKey);

    response.setContentType("text/html;");
    response.getWriter().println("<h1>Hello world!</h1>");
    response.getWriter().println("Retrieved: " + taskKey.getName() + ": " + retrieved.getString("description"));
  }
}

如何在本地运行 Java 11 App Engine 服务器以便 Datastore 正常工作？

Answer 1

基于 guillaume blaquiere's suggestion in their , I tried following this guide 在本地手动运行ning 数据存储。

我在一个命令行中运行 gcloud beta emulators datastore start，这似乎运行没问题，然后我在另一个命令行中运行 $(gcloud beta emulators datastore env-init)，并且我收到此错误：

ERROR: (gcloud.beta.emulators.datastore.env-init)
Unable to find env.yaml in the data_dir 
[/tmp/tmp.zolNZC8fnr/emulators/datastore]. 
Please ensure you have started the appropriate emulator.

我回到运行数据存储所在的第一个命令行，我注意到输出中的这一行：

Storage: /tmp/tmp.sxkNeaNHxo/emulators/datastore/WEB-INF/appengine-generated/local_db.bin

我将该目录路径复制到 data-dir 参数中：

$(gcloud beta emulators datastore env-init --data-dir=/tmp/tmp.sxkNeaNHxo/emulators/datastore)

该命令似乎成功了（没有输出）所以我运行我的本地服务器：mvn package exec:java

最后，这似乎在本地有效。

总结一下：

步骤 1： 运行此命令：gcloud beta emulators datastore start

第 2 步： 在输出中，找到如下所示的行：

Storage: /tmp/tmp.sxkNeaNHxo/emulators/datastore/WEB-INF/appengine-generated/local_db.bin

复制 /tmp/tmp.YOUR_PATH_HERE/emulators/datastore 路径。

第三步：在不同的命令行中，运行这条命令，粘贴到刚刚复制的路径中：

$(gcloud beta emulators datastore env-init --data-dir=/tmp/tmp.YOUR_PATH_HERE/emulators/datastore)

第 4 步： 在第二个命令行中，运行您的本地服务器：mvn package exec:java

这感觉很复杂（而且没有记录），所以我仍然非常愿意接受有关如何简化它的建议。但就目前而言，这至少有效。

Java 11 Cloud SDK 的 appengine:run 是什么？

What's the equivalent of appengine:run for the Java 11 Cloud SDK?

java

google-app-engine

maven

google-cloud-datastore

google-cloud-platform