创建 App Engine 任务

本页面演示了如何以编程方式创建 App Engine 任务并将其置于 Cloud Tasks 队列中。 通过此过程,您可以明确指定用于处理任务的服务和处理程序,并且可以选择将特定于任务的数据传递给处理程序。

您还可以微调任务的配置,例如,安排将来执行任务的时间,或者限制失败时希望重试任务的次数。如果您选择为任务指定名称,则 Cloud Tasks 可以使用该名称来确保任务重复信息删除,但必要的处理可能会增加延迟时间。

您可以根据自己的需求,用 HTTP 请求的形式创建任务。但是,如以下示例所示,使用 Google Cloud 客户端库可以帮助您管理与服务器进行低层级通信的细节,包括使用 Google 进行身份验证。

C#


using Google.Cloud.Tasks.V2;
using Google.Protobuf;
using Google.Protobuf.WellKnownTypes;
using System;

class CreateAppEngineTask
{
    public string CreateTask(
        string projectId = "YOUR-PROJECT-ID",
        string location = "us-central1",
        string queue = "my-queue",
        string payload = "Hello World!",
        int inSeconds = 0)
    {
        CloudTasksClient client = CloudTasksClient.Create();
        QueueName parent = new QueueName(projectId, location, queue);

        var response = client.CreateTask(new CreateTaskRequest
        {
            Parent = parent.ToString(),
            Task = new Task
            {
                AppEngineHttpRequest = new AppEngineHttpRequest
                {
                    HttpMethod = HttpMethod.Post,
                    RelativeUri = "/log_payload",
                    Body = ByteString.CopyFromUtf8(payload)
                },
                ScheduleTime = Timestamp.FromDateTime(
                    DateTime.UtcNow.AddSeconds(inSeconds))
            }
        });

        Console.WriteLine($"Created Task {response.Name}");
        return response.Name;
    }
}

Python

"""Create a task for a given queue with an arbitrary payload."""

from google.cloud import tasks_v2
from google.protobuf import timestamp_pb2

# Create a client.
client = tasks_v2.CloudTasksClient()

# TODO(developer): Uncomment these lines and replace with your values.
# project = 'my-project-id'
# queue = 'my-appengine-queue'
# location = 'us-central1'
# payload = 'hello'

# Construct the fully qualified queue name.
parent = client.queue_path(project, location, queue)

# Construct the request body.
task = {
        'app_engine_http_request': {  # Specify the type of request.
            'http_method': 'POST',
            'relative_uri': '/example_task_handler'
        }
}
if payload is not None:
    # The API expects a payload of type bytes.
    converted_payload = payload.encode()

    # Add the payload to the request.
    task['app_engine_http_request']['body'] = converted_payload

if in_seconds is not None:
    # Convert "seconds from now" into an rfc3339 datetime string.
    d = datetime.datetime.utcnow() + datetime.timedelta(seconds=in_seconds)

    # Create Timestamp protobuf.
    timestamp = timestamp_pb2.Timestamp()
    timestamp.FromDatetime(d)

    # Add the timestamp to the tasks.
    task['schedule_time'] = timestamp

# Use the client to build and send the task.
response = client.create_task(parent, task)

print('Created task {}'.format(response.name))
return response

请注意 requirements.txt 文件:

Flask==1.1.2
gunicorn==20.0.4
google-cloud-tasks==1.5.0

Java

// Instantiates a client.
try (CloudTasksClient client = CloudTasksClient.create()) {

  // Variables provided by the CLI.
  // projectId = "my-project-id";
  // queueName = "my-appengine-queue";
  // location = "us-central1";
  // payload = "hello";

  // Construct the fully qualified queue name.
  String queuePath = QueueName.of(projectId, location, queueName).toString();

  // Construct the task body.
  Task.Builder taskBuilder =
      Task.newBuilder()
          .setAppEngineHttpRequest(
              AppEngineHttpRequest.newBuilder()
                  .setBody(ByteString.copyFrom(payload, Charset.defaultCharset()))
                  .setRelativeUri("/tasks/create")
                  .setHttpMethod(HttpMethod.POST)
                  .build());

  if (params.hasOption(IN_SECONDS_OPTION.getOpt())) {
    // Add the scheduled time to the request.
    int seconds = Integer.parseInt(params.getOptionValue(IN_SECONDS_OPTION.getOpt()));
    taskBuilder.setScheduleTime(
        Timestamp.newBuilder()
            .setSeconds(Instant.now(Clock.systemUTC()).plusSeconds(seconds).getEpochSecond()));
  }

  // Send create task request.
  Task task = client.createTask(queuePath, taskBuilder.build());
  System.out.println("Task created: " + task.getName());
}

请注意 pom.xml 文件:

<?xml version="1.0" encoding="UTF-8"?>
<!--
Copyright 2018 Google LLC

 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
 You may obtain a copy of the License at

       http://www.apache.org/licenses/LICENSE-2.0

 Unless required by applicable law or agreed to in writing, software
 distributed under the License is distributed on an "AS IS" BASIS,
 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 See the License for the specific language governing permissions and
 limitations under the License.
-->
<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>
  <version>1.0-SNAPSHOT</version>
  <groupId>com.example.task</groupId>
  <artifactId>appengine-tasks-j8</artifactId>

  <!--
    The parent pom defines common style checks and testing strategies for our samples.
    Removing or replacing it should not affect the execution of the samples in anyway.
  -->
  <parent>
    <groupId>com.google.cloud.samples</groupId>
    <artifactId>shared-configuration</artifactId>
    <version>1.0.18</version>
    <relativePath></relativePath>
  </parent>

  <properties>
    <maven.compiler.target>1.8</maven.compiler.target>
    <maven.compiler.source>1.8</maven.compiler.source>
    <failOnMissingWebXml>false</failOnMissingWebXml>
  </properties>

  <dependencies>
    <!-- Compile/runtime dependencies -->
    <dependency>
      <groupId>javax.servlet</groupId>
      <artifactId>javax.servlet-api</artifactId>
      <version>3.1.0</version>
      <type>jar</type>
      <scope>provided</scope>
    </dependency>
    <dependency>
      <groupId>com.google.cloud</groupId>
      <artifactId>google-cloud-tasks</artifactId>
      <version>1.30.0</version>
    </dependency>
    <dependency>
      <groupId>commons-cli</groupId>
      <artifactId>commons-cli</artifactId>
      <version>1.4</version>
      <scope>compile</scope>
    </dependency>
    <!-- Test dependencies -->
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>4.13</version>
      <scope>test</scope>
    </dependency>
    <dependency>
      <groupId>com.google.truth</groupId>
      <artifactId>truth</artifactId>
      <version>1.0.1</version>
      <scope>test</scope>
    </dependency>
  </dependencies>

  <build>
    <!-- for hot reload of the web application-->
    <outputDirectory>${project.build.directory}/${project.build.finalName}/WEB-INF/classes
    </outputDirectory>
    <plugins>
      <plugin>
        <groupId>com.google.cloud.tools</groupId>
        <artifactId>appengine-maven-plugin</artifactId>
        <version>2.3.0</version>
        <configuration>
          <projectId>GCLOUD_CONFIG</projectId>
          <version>GCLOUD_CONFIG</version>
          <deploy.promote>true</deploy.promote>
          <deploy.stopPreviousVersion>true</deploy.stopPreviousVersion>
        </configuration>
      </plugin>

      <!-- <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-war-plugin</artifactId>
        <version>3.3.0</version>
      </plugin> -->

      <plugin>
        <groupId>org.codehaus.mojo</groupId>
        <artifactId>exec-maven-plugin</artifactId>
        <version>3.0.0</version>
        <configuration>
          <mainClass>com.example.task.CreateTask</mainClass>
          <cleanupDaemonThreads>false</cleanupDaemonThreads>
        </configuration>
      </plugin>
    </plugins>
  </build>
</project>

PHP

use Google\Cloud\Tasks\V2\AppEngineHttpRequest;
use Google\Cloud\Tasks\V2\CloudTasksClient;
use Google\Cloud\Tasks\V2\HttpMethod;
use Google\Cloud\Tasks\V2\Task;

/** Uncomment and populate these variables in your code */
// $projectId = 'The Google project ID';
// $locationId = 'The Location ID';
// $queueId = 'The Cloud Tasks App Engine Queue ID';
// $payload = 'The payload your task should carry to the task handler. Optional';

// Instantiate the client and queue name.
$client = new CloudTasksClient();
$queueName = $client->queueName($projectId, $locationId, $queueId);

// Create an App Engine Http Request Object.
$httpRequest = new AppEngineHttpRequest();
// The path of the HTTP request to the App Engine service.
$httpRequest->setRelativeUri('/task_handler');
// POST is the default HTTP method, but any HTTP method can be used.
$httpRequest->setHttpMethod(HttpMethod::POST);
// Setting a body value is only compatible with HTTP POST and PUT requests.
if (isset($payload)) {
    $httpRequest->setBody($payload);
}

// Create a Cloud Task object.
$task = new Task();
$task->setAppEngineHttpRequest($httpRequest);

// Send request and print the task name.
$response = $client->createTask($queueName, $task);
printf('Created task %s' . PHP_EOL, $response->getName());

请注意 composer.json 文件:

{
    "require": {
        "google/cloud-tasks": "^1.4.0"
    }
}

Go


// Command create_task constructs and adds a task to an App Engine Queue.
package main

import (
	"context"
	"fmt"

	cloudtasks "cloud.google.com/go/cloudtasks/apiv2"
	taskspb "google.golang.org/genproto/googleapis/cloud/tasks/v2"
)

// createTask creates a new task in your App Engine queue.
func createTask(projectID, locationID, queueID, message string) (*taskspb.Task, error) {
	// Create a new Cloud Tasks client instance.
	// See https://godoc.org/cloud.google.com/go/cloudtasks/apiv2
	ctx := context.Background()
	client, err := cloudtasks.NewClient(ctx)
	if err != nil {
		return nil, fmt.Errorf("NewClient: %v", err)
	}
	defer client.Close()

	// Build the Task queue path.
	queuePath := fmt.Sprintf("projects/%s/locations/%s/queues/%s", projectID, locationID, queueID)

	// Build the Task payload.
	// https://godoc.org/google.golang.org/genproto/googleapis/cloud/tasks/v2#CreateTaskRequest
	req := &taskspb.CreateTaskRequest{
		Parent: queuePath,
		Task: &taskspb.Task{
			// https://godoc.org/google.golang.org/genproto/googleapis/cloud/tasks/v2#AppEngineHttpRequest
			MessageType: &taskspb.Task_AppEngineHttpRequest{
				AppEngineHttpRequest: &taskspb.AppEngineHttpRequest{
					HttpMethod:  taskspb.HttpMethod_POST,
					RelativeUri: "/task_handler",
				},
			},
		},
	}

	// Add a payload message if one is present.
	req.Task.GetAppEngineHttpRequest().Body = []byte(message)

	createdTask, err := client.CreateTask(ctx, req)
	if err != nil {
		return nil, fmt.Errorf("cloudtasks.CreateTask: %v", err)
	}

	return createdTask, nil
}

Node.js

// Imports the Google Cloud Tasks library.
const {CloudTasksClient} = require('@google-cloud/tasks');

// Instantiates a client.
const client = new CloudTasksClient();

// TODO(developer): Uncomment these lines and replace with your values.
// const project = 'my-project-id';
// const queue = 'my-appengine-queue';
// const location = 'us-central1';
// const payload = 'Hello, World!';

// Construct the fully qualified queue name.
const parent = client.queuePath(project, location, queue);

const task = {
  appEngineHttpRequest: {
    httpMethod: 'POST',
    relativeUri: '/log_payload',
  },
};

if (payload) {
  task.appEngineHttpRequest.body = Buffer.from(payload).toString('base64');
}

if (inSeconds) {
  // The time when the task is scheduled to be attempted.
  task.scheduleTime = {
    seconds: inSeconds + Date.now() / 1000,
  };
}

console.log('Sending task:');
console.log(task);
// Send create task request.
const request = {parent, task};
const [response] = await client.createTask(request);
const name = response.name;
console.log(`Created task ${name}`);

请注意 package.json 文件:

{
  "name": "appengine-cloudtasks",
  "description": "Google App Engine Cloud Tasks example.",
  "license": "Apache-2.0",
  "author": "Google Inc.",
  "private": true,
  "engines": {
    "node": ">=10"
  },
  "files": [
    "*.js"
  ],
  "scripts": {
    "test": "mocha",
    "start": "node server.js"
  },
  "dependencies": {
    "@google-cloud/tasks": "^2.1.0",
    "body-parser": "^1.18.3",
    "express": "^4.16.3",
    "yargs": "^15.0.0"
  },
  "devDependencies": {
    "chai": "^4.2.0",
    "mocha": "^8.0.0",
    "uuid": "^8.0.0"
  }
}

Ruby

require "google/cloud/tasks"

# Create an App Engine Task
#
# @param [String] project_id Your Google Cloud Project ID.
# @param [String] location_id Your Google Cloud Project Location ID.
# @param [String] queue_id Your Google Cloud App Engine Queue ID.
# @param [String] payload The request body of your task.
# @param [Integer] seconds The delay, in seconds, to process your task.
def create_task project_id, location_id, queue_id, payload: nil, seconds: nil
  # Instantiates a client.
  client = Google::Cloud::Tasks.new

  # Construct the fully qualified queue name.
  parent = client.queue_path project_id, location_id, queue_id

  # Construct task.
  task = {
    app_engine_http_request: {
      http_method:  "POST",
      relative_uri: "/log_payload"
    }
  }

  # Add payload to task body.
  if payload
    task[:app_engine_http_request][:body] = payload
  end

  # Add scheduled time to task.
  if seconds
    timestamp = Google::Protobuf::Timestamp.new
    timestamp.seconds = Time.now.to_i + seconds.to_i
    task[:schedule_time] = timestamp
  end

  # Send create task request.
  puts "Sending task #{task}"
  response = client.create_task parent, task

  puts "Created task #{response.name}" if response.name
end

后续步骤