使用 Cloud 用戶端程式庫執行工作流程

部署範例工作流程

定義工作流程後，請部署工作流程，以便執行。部署步驟也會驗證來源檔案是否可執行。

下列工作流程會將要求傳送至公用 API，然後傳回 API 的回應。

1. 建立名為 myFirstWorkflow.yaml 的文字檔，並在當中加入下列內容：

   # This workflow accepts an optional "searchTerm" argument for the Wikipedia API.
   # If no input arguments are provided or "searchTerm" is absent,
   # it will fetch the day of the week in Amsterdam and use it as the search term.
   
   main:
       params: [input]
       steps:
       - validateSearchTermAndRedirectToReadWikipedia:
           switch:
               - condition: '${map.get(input, "searchTerm") != null}'
                 assign:
                   - searchTerm: '${input.searchTerm}'
                 next: readWikipedia
       - getCurrentTime:
           call: http.get
           args:
               url: https://timeapi.io/api/Time/current/zone?timeZone=Europe/Amsterdam
           result: currentTime
       - setFromCallResult:
           assign:
               - searchTerm: '${currentTime.body.dayOfWeek}'
       - readWikipedia:
           call: http.get
           args:
               url: 'https://en.wikipedia.org/w/api.php'
               query:
                   action: opensearch
                   search: '${searchTerm}'
           result: wikiResult
       - returnOutput:
               return: '${wikiResult.body[1]}'

2. 建立工作流程後，您可以部署工作流程，但請勿執行工作流程：

   gcloud workflows deploy myFirstWorkflow \
       --source=myFirstWorkflow.yaml \
       --service-account=SERVICE_ACCOUNT_NAME@PROJECT_ID.iam.gserviceaccount.com \
       --location=CLOUD_REGION

   將 CLOUD_REGION 替換為工作流程的支援位置。程式碼範例中使用的預設區域為 us-central1。

取得程式碼範例

您可以從 GitHub 複製程式碼範例。

1. 將應用程式存放區範例複製到本機電腦中：

   C#

   git clone https://github.com/GoogleCloudPlatform/dotnet-docs-samples.git

   您也可以下載 zip 格式的範例檔案，然後將檔案解壓縮。

   Go

   git clone https://github.com/GoogleCloudPlatform/golang-samples.git

   您也可以下載 zip 格式的範例檔案，然後將檔案解壓縮。

   Java

   git clone https://github.com/GoogleCloudPlatform/java-docs-samples.git

   您也可以下載 zip 格式的範例檔案，然後將檔案解壓縮。

   Node.js

   git clone https://github.com/GoogleCloudPlatform/nodejs-docs-samples.git

   您也可以下載 zip 格式的範例檔案，然後將檔案解壓縮。

   Python

   git clone https://github.com/GoogleCloudPlatform/python-docs-samples.git

   您也可以下載 zip 格式的範例檔案，然後將檔案解壓縮。

2. 變更為包含 Workflows 範例程式碼的目錄：

   C#

   cd dotnet-docs-samples/workflows/api/Workflow.Samples/

   Go

   cd golang-samples/workflows/executions/

   Java

   cd java-docs-samples/workflows/cloud-client/

   Node.js

   cd nodejs-docs-samples/workflows/quickstart/

   Python

   cd python-docs-samples/workflows/cloud-client/

3. 查看程式碼範例，每個範例應用程式都會執行下列操作：

   1. 設定 Workflows 適用的 Cloud 用戶端程式庫。
   2. 執行工作流程。
   3. 輪詢工作流程的執行作業 (使用指數輪詢)，直到執行作業終止為止。
   4. 列印執行結果。

   C#

   
   using Google.Cloud.Workflows.Common.V1;
   using Google.Cloud.Workflows.Executions.V1;
   using System;
   using System.Threading;
   using System.Threading.Tasks;
   
   public class ExecuteWorkflowSample
   {
       /// <summary>
       /// Execute a workflow and return the execution operation.
       /// </summary>
       /// <param name="projectID">Your Google Cloud Project ID.</param>
       /// <param name="locationID">The region where your workflow is located.</param>
       /// <param name="workflowID">Your Workflow ID.</param>
       /// <returns>
       /// An Execute object representing the completed workflow execution.
       /// </returns>
       public async Task<Execution> ExecuteWorkflow(
           string projectId = "YOUR-PROJECT-ID",
           string locationID = "YOUR-LOCATION-ID",
           string workflowID = "YOUR-WORKFLOW-ID")
       {
           // Initialize the client.
           ExecutionsClient client = await ExecutionsClient.CreateAsync();
   
           // Build the parent location path.
           WorkflowName parent = new WorkflowName(projectId, locationID, workflowID);
   
           // Create an execution request.
           CreateExecutionRequest createExecutionRequest = new CreateExecutionRequest
           {
               ParentAsWorkflowName = parent,
           };
   
           // Execute the operation.
           Execution execution = await client.CreateExecutionAsync(createExecutionRequest);
           Console.WriteLine("- Execution started...");
   
           TimeSpan backoffDelay = TimeSpan.FromSeconds(1);
           TimeSpan maxBackoffDelay = TimeSpan.FromSeconds(16);
   
           // Keep polling the state until the execution finishes, using exponential backoff.
           while (execution.State == Execution.Types.State.Active)
           {
               await Task.Delay(backoffDelay);
   
               // Implement exponential backoff by doubling the delay, but limiting it to a practical duration.
               backoffDelay = (backoffDelay < maxBackoffDelay) ? backoffDelay * 2 : maxBackoffDelay;
   
               execution = await client.GetExecutionAsync(execution.Name);
           }
   
           // Print results.
           Console.WriteLine($"Execution finished with state: {execution.State}");
           Console.WriteLine($"Execution results: {execution.Result}");
   
           // Return the fetched execution.
           return execution;
       }
   }

   Go

   import (
   	"context"
   	"fmt"
   	"io"
   	"time"
   
   	workflowexecutions "google.golang.org/api/workflowexecutions/v1"
   )
   
   // Execute a workflow and print the execution results.
   //
   // For more information about Workflows see:
   // https://cloud.google.com/workflows/docs/overview
   func executeWorkflow(w io.Writer, projectID, workflowID, locationID string) error {
   	// TODO(developer): Uncomment and update the following lines:
   	// projectID := "YOUR_PROJECT_ID"
   	// workflowID := "YOUR_WORKFLOW_ID"
   	// locationID := "YOUR_LOCATION_ID"
   
   	ctx := context.Background()
   
   	// Construct the location path.
   	parent := fmt.Sprintf("projects/%s/locations/%s/workflows/%s", projectID, locationID, workflowID)
   
   	// Create execution client.
   	client, err := workflowexecutions.NewService(ctx)
   	if err != nil {
   		return fmt.Errorf("workflowexecutions.NewService error: %w", err)
   	}
   
   	// Get execution service.
   	service := client.Projects.Locations.Workflows.Executions
   
   	// Build and run the new workflow execution.
   	res, err := service.Create(parent, &workflowexecutions.Execution{}).Do()
   	if err != nil {
   		return fmt.Errorf("service.Create.Do error: %w", err)
   	}
   	fmt.Fprintln(w, "- Execution started...")
   
   	// Set initial value for backoff delay in one second.
   	backoffDelay := time.Second
   
   	for res.State == "ACTIVE" {
   		time.Sleep(backoffDelay)
   
   		// Request the updated state for the execution.
   		getReq := service.Get(res.Name)
   		res, err = getReq.Do()
   		if err != nil {
   			return fmt.Errorf("getReq error: %w", err)
   		}
   
   		// Double the delay to provide exponential backoff (capped at 16 seconds).
   		if backoffDelay < time.Second*16 {
   			backoffDelay *= 2
   		}
   	}
   
   	fmt.Fprintf(w, "Execution finished with state: %s\n", res.State)
   	fmt.Fprintf(w, "Execution results: %s\n", res.Result)
   
   	return nil
   }
   

   Java

   
   import com.google.cloud.workflows.executions.v1.