Criar tarefas do App Engine

Nesta página, mostramos como criar tarefas do App Engine de maneira programática e colocá-las em filas do Cloud Tasks. Com esse processo, é possível especificar explicitamente o serviço e o gerenciador que precisam processar a tarefa e, opcionalmente, transmitir dados específicos da tarefa para o gerenciador. O serviço Cloud Tasks encaminha a solicitação de tarefa ao gerenciador, mas esse worker está localizado no App Engine. Portanto, todas as filas direcionadas aos gerenciadores do App Engine precisam ter um aplicativo do App Engine. Os gerenciadores precisam ser executados na região em que o aplicativo do App Engine é executado. Essa região também serve como o parâmetro LOCATION_ID para suas solicitações do Cloud Tasks. Para mais informações, consulte Filas do Cloud Tasks com destinos do App Engine.

Também é possível ajustar a configuração da tarefa, como agendar um horário no futuro para execução ou limitar o número de repetições da tarefa em caso de falha. Se você optar por especificar um nome para a tarefa, o Cloud Tasks poderá usar esse nome para garantir a eliminação de duplicação, embora o processamento necessário possa aumentar a latência.

Regras de firewall do App Engine

No ambiente padrão do App Engine, o firewall pode permitir que determinado tráfego interno ignore o firewall. Isso significa que, se você definir a regra default como deny, as solicitações de determinados serviços destinados ao ambiente padrão do App Engine não serão bloqueadas. Esses são todos os tipos de tráfego solicitados na própria configuração do aplicativo ou enviados do mesmo aplicativo. As solicitações que ignoram as regras de firewall dessa maneira também incluem tarefas do App Engine no Cloud Tasks, incluindo filas de tarefas do App Engine.

Para permitir solicitações recebidas, veja a seguir os intervalos de IP para tarefas do App Engine no Cloud Tasks (incluindo as filas de tarefas do App Engine):

  • Intervalo de IP para solicitações enviadas ao ambiente padrão do App Engine: 0.1.0.2/32 (ignora a regra de firewall padrão se definida como negação)

  • Intervalo de IP para solicitações enviadas ao ambiente flexível do App Engine: 0.1.0.2/32

Criar tarefas usando as bibliotecas de cliente

Você cria tarefas na forma de uma solicitação HTTP, que pode construir como quiser. No entanto, usar as bibliotecas de cliente, como nos exemplos a seguir, pode ajudar você a gerenciar detalhes de comunicação de baixo nível com o servidor, incluindo a autenticação com o Google. Para adicionar uma tarefa a uma fila, consulte Adicionar uma tarefa a uma fila do Cloud Tasks.

C#

cloudtasks/api/TasksSample/CreateTask.cs 

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

class CreateAppEngineTask
{
    public string CreateTask(
        // TODO<developer>: call this method by passing correct values for
        // the following parameters or change the parameters' default values.
        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

appengine/flexible_python37_and_earlier/tasks/create_app_engine_queue_task.py 
"""Create a task for a given queue with an arbitrary payload."""

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

# 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' or {'param': 'value'} for application/json
# in_seconds = None

# 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": tasks_v2.HttpMethod.POST,
        "relative_uri": "/example_task_handler",
    }
}
if payload is not None:
    if isinstance(payload, dict):
        # Convert dict to JSON string
        payload = json.dumps(payload)
        # specify http content-type to application/json
        task["app_engine_http_request"]["headers"] = {
            "Content-type": "application/json"
        }
    # 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.now(tz=datetime.timezone.utc) + 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=parent, task=task)

print(f"Created task {response.name}")
return response

Observe o arquivo requirements.txt:

appengine/flexible_python37_and_earlier/tasks/requirements.txt 
Flask==3.0.0; python_version > '3.6'
Flask==2.0.3; python_version < '3.7'
gunicorn==20.1.0
google-cloud-tasks==2.13.1
Werkzeug==2.3.7

Java

appengine-java11/tasks/src/main/java/com/example/task/CreateTask.java 
import com.google.cloud.tasks.v2.AppEngineHttpRequest;
import com.google.cloud.tasks.v2.CloudTasksClient;
import com.google.cloud.tasks.v2.HttpMethod;
import com.google.cloud.tasks.v2.QueueName;
import com.google.cloud.tasks.v2.Task;
import com.google.protobuf.ByteString;
import com.google.protobuf.Timestamp;
import java.io.IOException;
import java.nio.charset.Charset;
import java.time.Clock;
import java.time.Instant;

public class CreateTask {
  public static void main(String[] args) throws IOException {
    // TODO(developer): Replace these variables before running the sample.
    String projectId = "my-project-id";
    String queue = "my-appengine-queue";
    String location = "us-central1";
    String payload = "hello";
    int seconds = 0; // Scheduled delay for the task in seconds
    createTask(projectId, queue, location, payload, seconds);
  }

  // This is an example snippet for showing best practices.
  public static void createTask(
      String projectId, String queueName, String location, String payload, int seconds)
      throws IOException {
    // Instantiates a client.
    try (CloudTasksClient client = CloudTasksClient.create()) {
      // 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());

      // Add the scheduled time to the request.
      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());
    }
  }
}

Observe o arquivo pom.xml:

appengine-java11/tasks/pom.xml 
<?xml version="1.0" encoding="UTF-8"?>
<!--
Copyright 2019 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.appengine</groupId>
  <artifactId>appengine-tasks-j11</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>1.2.0</version>
    <relativePath></relativePath>
  </parent>

  <properties>
    <maven.compiler.target>11</maven.compiler.target>
    <maven.compiler.source>11</maven.compiler.source>
  </properties>

  <!--  Using libraries-bom to manage versions.
  See https://github.com/GoogleCloudPlatform/cloud-opensource-java/wiki/The-Google-Cloud-Platform-Libraries-BOM -->
  <dependencyManagement>
    <dependencies>
      <dependency>
        <groupId>com.google.cloud</groupId>
        <artifactId>libraries-bom</artifactId>
        <version>26.27.0</version>
        <type>pom</type>
        <scope>import</scope>
      </dependency>
    </dependencies>
  </dependencyManagement>

  <dependencies>
    <dependency>
      <groupId>com.google.cloud</groupId>
      <artifactId>google-cloud-tasks</artifactId>
    </dependency>
    <!-- Test dependencies -->
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>4.13.2</version>
      <scope>test</scope>
    </dependency>
    <dependency>
      <groupId>com.google.truth</groupId>
      <artifactId>truth</artifactId>
      <version>1.1.5</version>
      <scope>test</scope>
    </dependency>
  </dependencies>
  <build>
    <finalName>tasks</finalName>
    <plugins>
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-war-plugin</artifactId>
        <version>3.4.0</version>
        <configuration>
          <failOnMissingWebXml>false</failOnMissingWebXml>
        </configuration>
      </plugin>

      <plugin>
        <groupId>org.codehaus.mojo</groupId>
        <artifactId>exec-maven-plugin</artifactId>
        <version>3.1.1</version>
        <configuration>
          <mainClass>com.example.task.CreateTask</mainClass>
          <cleanupDaemonThreads>false</cleanupDaemonThreads>
        </configuration>
      </plugin>
    </plugins>
  </build>
</project>

PHP

appengine/standard/tasks/snippets/src/create_task.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());

Observe o arquivo composer.json:

appengine/standard/tasks/snippets/composer.json 
{
    "require": {
        "google/cloud-tasks": "^1.4.0"
    }
}

Go

appengine/go11x/tasks/create_task/create_task.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 "cloud.google.com/go/cloudtasks/apiv2/cloudtaskspb"
)

// 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: %w", 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: %w", err)
	}

	return createdTask, nil
}

Node.js

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

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

async function createTask() {
  // 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: {
      headers: {
        'Content-Type': 'text/plain', // Set content type to ensure compatibility your application's request parsing
      },
      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: parent, task: task};
  const [response] = await client.createTask(request);
  const name = response.name;
  console.log(`Created task ${name}`);
}

createTask();

Observe o arquivo package.json:

cloud-tasks/snippets/package.json 
{
  "name": "appengine-cloudtasks",
  "description": "Google App Engine Cloud Tasks example.",
  "license": "Apache-2.0",
  "author": "Google Inc.",
  "private": true,
  "engines": {
    "node": ">=16.0.0"
  },
  "files": [
    "*.js"
  ],
  "scripts": {
    "test": "c8 mocha -p -j 2 --timeout 30000",
    "start": "node server.js"
  },
  "dependencies": {
    "@google-cloud/tasks": "^4.0.0",
    "express": "^4.16.3"
  },
  "devDependencies": {
    "c8": "^8.0.0",
    "chai": "^4.2.0",
    "mocha": "^10.0.0",
    "uuid": "^9.0.0"
  }
}

Ruby

appengine/cloud-tasks/create_task.rb 
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.cloud_tasks

  # Construct the fully qualified queue name.
  parent = client.queue_path project: project_id, location: location_id, queue: 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: parent, task: task

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

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