运行可并行执行其他工作流的工作流

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本教程介绍如何创建和运行执行 多个子工作流。

在下图中，子工作流的四个并行执行为 调用。这样，父级工作流就可以并行处理分支中的数据， 并缩短总体执行时间。父级工作流会等待所有子级工作流执行完成，然后返回成功和失败执行的摘要，从而简化任何错误检测。

目标

在此教程中，您将学习以下操作：

1. 创建和部署从父级工作流接收数据的子工作流。
2. 创建并部署一个父级工作流，该工作流使用并行 for 循环来执行多个子级工作流。
3. 运行父级工作流，该工作流会调用子级工作流的并行执行 工作流。
4. 所有成功和失败的子工作流执行结果都会存储在映射中并返回。

您可以在 Google Cloud 控制台中运行以下命令，也可以在终端或 Cloud Shell 中使用 Google Cloud CLI 运行这些命令。

费用

在本文档中，您将使用 Google Cloud 的以下收费组件：

• Workflows

您可使用价格计算器根据您的预计使用情况来估算费用。 Google Cloud 新用户可能有资格申请免费试用。

准备工作

您的组织定义的安全限制条件可能会导致您无法完成以下步骤。如需了解相关问题排查信息，请参阅在受限的 Google Cloud 环境中开发应用。

控制台

1. Sign in to your Google Account.

   If you don't already have one, sign up for a new account.

2. In the Google Cloud console, on the project selector page, select or create a Google Cloud project.

   Note: If you don't plan to keep the resources that you create in this procedure, create a project instead of selecting an existing project. After you finish these steps, you can delete the project, removing all resources associated with the project.

   Go to project selector

3. Make sure that billing is enabled for your Google Cloud project.

4. Enable the Workflow Executions and Workflows APIs.

   Enable the APIs

5. Create a service account:

   1. In the Google Cloud console, go to the Create service account page.

      Go to Create service account
   2. Select your project.

   3. In the Service account name field, enter a name. The Google Cloud console fills in the Service account ID field based on this name.

      In the Service account description field, enter a description. For example, Service account for quickstart.

   4. Click Create and continue.

   5. Grant the Workflows > Workflows Invoker role to the service account.

      To grant the role, find the Select a role list, then select Workflows > Workflows Invoker.

      Note: The Role field affects which resources the service account can access in your project. You can revoke these roles or grant additional roles later.
   6. Click Continue.

   7. Click Done to finish creating the service account.

6. In the Google Cloud console, on the project selector page, select or create a Google Cloud project.

   Note: If you don't plan to keep the resources that you create in this procedure, create a project instead of selecting an existing project. After you finish these steps, you can delete the project, removing all resources associated with the project.

   Go to project selector

7. Make sure that billing is enabled for your Google Cloud project.

8. Enable the Workflow Executions and Workflows APIs.

   Enable the APIs

9. Create a service account:

   1. In the Google Cloud console, go to the Create service account page.

      Go to Create service account
   2. Select your project.

   3. In the Service account name field, enter a name. The Google Cloud console fills in the Service account ID field based on this name.

      In the Service account description field, enter a description. For example, Service account for quickstart.

   4. Click Create and continue.

   5. Grant the Workflows > Workflows Invoker role to the service account.

      To grant the role, find the Select a role list, then select Workflows > Workflows Invoker.

      Note: The Role field affects which resources the service account can access in your project. You can revoke these roles or grant additional roles later.
   6. Click Continue.

   7. Click Done to finish creating the service account.

gcloud

1. Sign in to your Google Account.

   If you don't already have one, sign up for a new account.

2. Install the Google Cloud CLI.

3. To initialize the gcloud CLI, run the following command:

   gcloud init

4. Create or select a Google Cloud project.

   Note: If you don't plan to keep the resources that you create in this procedure, create a project instead of selecting an existing project. After you finish these steps, you can delete the project, removing all resources associated with the project.

   • Create a Google Cloud project:

     gcloud projects create PROJECT_ID

     Replace PROJECT_ID with a name for the Google Cloud project you are creating.

   • Select the Google Cloud project that you created:

     gcloud config set project PROJECT_ID

     Replace PROJECT_ID with your Google Cloud project name.

5. Make sure that billing is enabled for your Google Cloud project.

6. Enable the Workflow Executions and Workflows APIs:

   gcloud services enable workflowexecutions.googleapis.com workflows.googleapis.com

7. Set up authentication:

   1. Create the service account:

      gcloud iam service-accounts create SERVICE_ACCOUNT_NAME

      Replace SERVICE_ACCOUNT_NAME with a name for the service account.

   2. Grant the roles/workflows.invoker IAM role to the service account:

      gcloud projects add-iam-policy-binding PROJECT_ID --member="serviceAccount:SERVICE_ACCOUNT_NAME@PROJECT_ID.iam.gserviceaccount.com" --role=roles/workflows.invoker

      Replace the following:

      • SERVICE_ACCOUNT_NAME: the name of the service account
      • PROJECT_ID: the project ID where you created the service account
      Note: The --role flag affects which resources the service account can access in your project. You can revoke these roles or grant additional roles later.
8. Install the Google Cloud CLI.

9. To initialize the gcloud CLI, run the following command:

   gcloud init

10. Create or select a Google Cloud project.

    Note: If you don't plan to keep the resources that you create in this procedure, create a project instead of selecting an existing project. After you finish these steps, you can delete the project, removing all resources associated with the project.

    • Create a Google Cloud project:

      gcloud projects create PROJECT_ID

      Replace PROJECT_ID with a name for the Google Cloud project you are creating.

    • Select the Google Cloud project that you created:

      gcloud config set project PROJECT_ID

      Replace PROJECT_ID with your Google Cloud project name.

11. Make sure that billing is enabled for your Google Cloud project.

12. Enable the Workflow Executions and Workflows APIs:

    gcloud services enable workflowexecutions.googleapis.com workflows.googleapis.com

13. Set up authentication:

    1. Create the service account:

       gcloud iam service-accounts create SERVICE_ACCOUNT_NAME

       Replace SERVICE_ACCOUNT_NAME with a name for the service account.

    2. Grant the roles/workflows.invoker IAM role to the service account:

       gcloud projects add-iam-policy-binding PROJECT_ID --member="serviceAccount:SERVICE_ACCOUNT_NAME@PROJECT_ID.iam.gserviceaccount.com" --role=roles/workflows.invoker

       Replace the following:

       • SERVICE_ACCOUNT_NAME: the name of the service account
       • PROJECT_ID: the project ID where you created the service account
       Note: The --role flag affects which resources the service account can access in your project. You can revoke these roles or grant additional roles later.

创建和部署子工作流

子工作流程可以接收和处理父级工作流程中的数据。子工作流通过执行以下操作来演示这一点：

• 接收整数作为参数
• 休眠 10 秒以模拟某些处理

• 返回一个指示器（基于整数是奇数还是偶数），以模拟工作流执行的成功或失败

控制台

1. 在 Google Cloud 控制台中，前往工作流页面。

   进入 Workflows

2. 点击 创建。

3. 为新工作流输入名称 workflow-child。

4. 在区域列表中，选择 us-central1。

5. 选择您之前创建的服务账号。

6. 点击下一步。

7. 在工作流编辑器中，输入工作流的定义：

   main:
     params: [args]
     steps:
       - init:
           assign:
             - iteration : ${args.iteration}
       - wait:
           call: sys.sleep
           args:
               seconds: 10
       - check_iteration_even_or_odd:
           switch:
             - condition: ${iteration % 2 == 0}
               next: raise_error
       - return_message:
           return: ${"Hello world"+iteration}
       - raise_error:
           raise: ${"Error with iteration "+iteration}

8. 点击部署。

gcloud

1. 为工作流创建源代码文件：

   touch workflow-child.yaml

2. 在文本编辑器中打开源代码文件，然后将以下工作流复制到该文件中。

   main:
     params: [args]
     steps:
       - init:
           assign:
             - iteration : ${args.iteration}
       - wait:
           call: sys.sleep
           args:
               seconds: 10
       - check_iteration_even_or_odd:
           switch:
             - condition: ${iteration % 2 == 0}
               next: raise_error
       - return_message:
           return: ${"Hello world"+iteration}
       - raise_error:
           raise: ${"Error with iteration "+iteration}

3. 部署工作流：

   gcloud workflows deploy workflow-child \
       --source=workflow-child.yaml \
       --location=us-central1 \
       --service-account=SERVICE_ACCOUNT_NAME@PROJECT_ID.iam.gserviceaccount.com

   将 SERVICE_ACCOUNT_NAME 替换为 服务账号。

创建和部署父级工作流

父工作流使用 并行 for 循环。

1. 复制工作流定义的源代码。它由以下部分组成：

   1. 该映射用于存储子工作流执行的结果。 如需了解详情，请参阅地图。

      main:
        steps:
          - init:
              assign:
                - execution_results: {} # results from each execution
                - execution_results.success: {} # successful executions saved under 'success' key
                - execution_results.failure: {} # failed executions saved under 'failure' key

   2. 系统会并行执行 for 循环以调用子工作流。 如需了解详情，请参阅 并行步骤和 迭代。

      - execute_child_workflows:
          parallel:
            shared: [execution_results]
            for:
              value: iteration
              in: [1, 2, 3, 4]
              steps:
                  - iterate:

   3. 子工作流是使用连接器调用的。子工作流的每次迭代都会传递 iteration 参数。父级工作流程会等待并存储每个子工作流程执行的结果。有关 请参阅 Workflows Executions API 连接器 和运行时参数。

      try:
        steps:
          - execute_child_workflow:
              call: googleapis.workflowexecutions.v1.projects.locations.workflows.executions.run
              args:
                workflow_id: workflow-child
                #location: ...
                #project_id: ...
                argument:
                  iteration: ${iteration}
              result: execution_result
          - save_successful_execution:
              assign:
                - execution_results.success[string(iteration)]: ${execution_result}
      except:
          as: e
          steps:
            - save_failed_execution:
                assign:
                  - execution_results.failure[string(iteration)]: ${e}

   4. 系统会返回执行结果。如需了解详情，请参阅 完成工作流的执行过程。

      - return_execution_results:
          return: ${execution_results}

2. 部署工作流：

   控制台

   1. 在 Google Cloud 控制台中，前往 Workflows 页面：

      进入 Workflows

   2. 点击 创建。

   3. 为新工作流输入名称 workflow-parent。

   4. 在区域列表中，选择 us-central1。

   5. 选择您之前创建的服务账号。

   6. 点击下一步。

   7. 在工作流编辑器中，粘贴父级工作流的定义。

   8. 点击部署。

   gcloud

   1. 为您的工作流创建源代码文件：

      touch workflow-parent.yaml

   2. 在文本编辑器中打开源代码文件，然后粘贴相应定义 父级工作流程

   3. 部署工作流：

      gcloud workflows deploy workflow-parent \
          --source=workflow-parent.yaml \
          --location=us-central1 \
          --service-account=SERVICE_ACCOUNT_NAME@PROJECT_ID.iam.gserviceaccount.com

      将 SERVICE_ACCOUNT_NAME 替换为您之前创建的服务账号的名称。

执行父级工作流

执行父级工作流，以便在对子工作流的调用中运行 并行运行。执行操作大约需要 10 秒钟才能完成。

控制台

1. 在 Google Cloud 控制台中，前往 Workflows 页面：

   进入 Workflows

2. 在 Workflows 页面上，点击 workflow-parent 工作流以转到其详情页面。

3. 在工作流详情页面上，点击 执行。

4. 再次点击执行。

5. 在输出窗格中查看工作流的结果。

   结果应类似于以下内容，表明迭代 2 和 4 出现错误，迭代 1 和 3 成功。

   "failure": {
     "2": {
       "message": "Execution failed or cancelled.",
       "operation": {
         "argument": "{\"iteration\":2}",
         "duration": "10.157992541s",
         "endTime": "2023-07-11T13:13:13.028424329Z",
         "error": {
           "context": "RuntimeError: \"Error with iteration 2\"\nin step \"raise_error\", routine \"main\", line: 18",
           "payload": "\"Error with iteration 2\"",
   ...
     "4": {
       "message": "Execution failed or cancelled.",
       "operation": {
         "argument": "{\"iteration\":4}",
         "duration": "10.157929734s",
         "endTime": "2023-07-11T13:13:13.061289142Z",
         "error": {
           "context": "RuntimeError: \"Error with iteration 4\"\nin step \"raise_error\", routine \"main\", line: 18",
           "payload": "\"Error with iteration 4\"",
   ...
   "success": {
     "1": "Hello world1",
     "3": "Hello world3"

gcloud

执行工作流：

gcloud workflows run workflow-parent \
    --location=us-central1

结果应类似于以下内容，表明迭代 2 和 4 出现错误，迭代 1 和 3 成功。

Waiting for execution [06c753e4-6947-4c62-ac0b-2a9d53fb1b8f] to complete...done.
argument: 'null'
duration: 14.065415004s
endTime: '2023-07-11T12:50:43.929023883Z'
name: projects/386837416586/locations/us-central1/workflows/workflow-parent/executions/06c753e4-6947-4c62-ac0b-2a9d53fb1b8f
result: '{"failure":{"2":{"message":"Execution failed or cancelled.","operation":{"argument":"{\"iteration\":2}","duration":"10.143718070s","endTime":"2023-07-11T12:50:40.673209821Z","error":{"context":"RuntimeError:
...
"Error with iteration 2\"\nin step \"raise_error\", routine \"main\", line: 18","payload":"\"Error
...
"Error with iteration 4\"\nin step \"raise_error\", routine \"main\", line: 18","payload":"\"Error
...
"success":{"1":"Hello world1","3":"Hello world3"}}'
startTime: '2023-07-11T12:50:29.863608879Z'
state: SUCCEEDED

您已成功创建并部署一个调用子项目的工作流 工作流，在并行分支中对子工作流执行四次迭代， 并为每个子工作流执行返回成功或失败的指示器。

清理

如果您为本教程创建了一个新项目，请删除项目。 如果您使用的是现有项目，希望保留此项目且不保留本教程中添加的任何更改，请删除为教程创建的资源。

删除项目

为了避免产生费用，最简单的方法是删除您为本教程创建的项目。

要删除项目，请执行以下操作：

注意：删除项目会产生以下影响：

• 项目中的所有内容都会被删除。如果您将现有项目用于本文档中的任务，则删除该项目后，还将删除您已在该项目中完成的任何其他工作。
• 自定义项目 ID 丢失。创建此项目时，您可能创建了要在将来使用的自定义项目 ID。要保留使用该项目 ID 的网址（例如 appspot.com 网址），请删除项目内的所选资源，而不是删除整个项目。

如果您打算探索多个架构、教程或快速入门，则重复使用项目可以帮助您避免超出项目配额限制。

1. In the Google Cloud console, go to the Manage resources page.

   Go to Manage resources

2. In the project list, select the project that you want to delete, and then click Delete.
3. In the dialog, type the project ID, and then click Shut down to delete the project.

删除教程资源

删除在本教程中创建的工作流：

gcloud workflows delete workflow-child
gcloud workflows delete workflow-parent

后续步骤

• 如需详细了解 Workflows 语法，请参阅 Workflows 语法参考文档。
• 如需详细了解 Workflows 连接器，请参阅了解连接器。