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# 启动 Amazon Rekognition Custom Labels 模型
<a name="rm-start"></a>

您可以使用控制台或操作开始运行 Amazon Rekognition 自定义标签模型。[StartProjectVersion](https://docs.aws.amazon.com/rekognition/latest/APIReference/API_StartProjectVersion)

**重要**  
您需要为模型运行的小时数和模型在运行时使用的推理单元数付费。有关更多信息，请参阅 [运行经过训练的 Amazon Rekognition Custom Labels 模型](running-model.md)。

启动模型可能需要几分钟才能完成。要检查模型的当前就绪状态，请查看项目或用途的详细信息页面[DescribeProjectVersions](https://docs.aws.amazon.com/rekognition/latest/APIReference/API_DescribeProjectVersions)。

模型启动后 [DetectCustomLabels](https://docs.aws.amazon.com/rekognition/latest/APIReference/API_DetectCustomLabels)，您可以使用模型来分析图像。有关更多信息，请参阅 [使用经过训练的模型分析图像](detecting-custom-labels.md)。控制台还提供了调用 `DetectCustomLabels` 的示例代码。

**Topics**
+ [启动 Amazon Rekognition Custom Labels 模型（控制台）](#rm-start-console)
+ [启动 Amazon Rekognition Custom Labels 模型 (SDK)](#rm-start-sdk)

## 启动 Amazon Rekognition Custom Labels 模型（控制台）
<a name="rm-start-console"></a>

按照以下过程通过控制台启动运行 Amazon Rekognition Custom Labels 模型。您可以直接从控制台启动模型，也可以使用控制台提供的 AWS SDK 代码。

**启动模型（控制台）**

1. 打开亚马逊 Rekognition 控制台，网址为[https://console.aws.amazon.com/rekognition/](https://console.aws.amazon.com/rekognition/)。

1. 选择**使用自定义标签**。

1. 选择**开始**。

1. 在左侧导航窗格中，选择**项目**。

1. 在**项目**资源页面上，选择包含要启动的已训练模型的项目。

1. 在**模型**部分中，选择要启动的模型。

1. 选择**使用模型**选项卡。

1. 执行下列操作之一：

------
#### [ Start model using the console ]

   在**启动或停止模型**部分中，执行以下操作：

   1. 选择要使用的推理单元的数量。有关更多信息，请参阅 [运行经过训练的 Amazon Rekognition Custom Labels 模型](running-model.md)。

   1. 选择**启动**。

   1. 在**启动模型**对话框中，选择**启动**。

------
#### [ Start model using the AWS SDK ]

   在**使用模型**部分中，执行以下操作：

   1. 选择 **API 代码**。

   1. 选择 **AWS CLI** 或 **Python**。

   1. 在**启动模型**中，复制示例代码。

   1. 使用示例代码启动模型。有关更多信息，请参阅 [启动 Amazon Rekognition Custom Labels 模型 (SDK)](#rm-start-sdk)。

------

1. 要返回到项目概述页面，请在页面顶部选择项目名称。

1. 在**模型**部分中，检查模型的状态。当模型状态为 **RUNNING** 时，就可以使用模型来分析图像。有关更多信息，请参阅 [使用经过训练的模型分析图像](detecting-custom-labels.md)。

## 启动 Amazon Rekognition Custom Labels 模型 (SDK)
<a name="rm-start-sdk"></a>

您可以通过调用 [StartProjectVersion](https://docs.aws.amazon.com/rekognition/latest/APIReference/API_StartProjectVersion)API 并在`ProjectVersionArn`输入参数中传递模型的 Amazon 资源名称 (ARN) 来启动模型。此外，还需要指定要使用的推理单元数量。有关更多信息，请参阅 [运行经过训练的 Amazon Rekognition Custom Labels 模型](running-model.md)。

模型可能需要一段时间才能启动。本主题中的 Python 和 Java 示例使用 waiter 来等待模型启动。waiter 是一种实用程序方法，用于轮询是否发生了特定状态。或者，您可以通过致电来查看当前状态[DescribeProjectVersions](https://docs.aws.amazon.com/rekognition/latest/APIReference/API_DescribeProjectVersions)。

**启动模型 (SDK)**

1. 如果您尚未这样做，请安装并配置 AWS CLI 和 AWS SDKs。有关更多信息，请参阅 [步骤 4：设置 AWS CLI 和 AWS SDKs](su-awscli-sdk.md)。

1. 使用以下示例代码启动模型。

------
#### [ CLI ]

   将 `project-version-arn` 的值更改为要启动的模型的 ARN。将 `--min-inference-units` 的值更改为要使用的推理单元数。（可选）将 `--max-inference-units` 更改为 Amazon Rekognition Custom Labels 可用于自动扩缩模型的最大推理单元数。

   ```
   aws rekognition start-project-version  --project-version-arn model_arn \
      --min-inference-units minimum number of units \
      --max-inference-units maximum number of units \
      --profile custom-labels-access
   ```

------
#### [ Python ]

   提供以下命令行参数：
   + `project_arn`：包含要启动的模型的项目的 ARN。
   + `model_arn`：要启动的模型的 ARN。
   + `min_inference_units`：要使用的推理单元数。
   + （可选）`--max_inference_units`：Amazon Rekognition Custom Labels 可用于自动扩缩模型的最大推理单元数。

   ```
   # Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
   # SPDX-License-Identifier: Apache-2.0
   
   """
   Purpose
   Shows how to start running an Amazon Lookout for Vision model.
   """
   
   import argparse
   import logging
   import boto3
   from botocore.exceptions import ClientError
   
   logger = logging.getLogger(__name__)
   
   
   def get_model_status(rek_client, project_arn, model_arn):
       """
       Gets the current status of an Amazon Rekognition Custom Labels model
       :param rek_client: The Amazon Rekognition Custom Labels Boto3 client.
       :param project_name:  The name of the project that you want to use.
       :param model_arn:  The name of the model that you want the status for.
       :return: The model status
       """
   
       logger.info("Getting status for %s.", model_arn)
   
       # Extract the model version from the model arn.
       version_name = (model_arn.split("version/", 1)[1]).rpartition('/')[0]
   
       models = rek_client.describe_project_versions(ProjectArn=project_arn,
                                                     VersionNames=[version_name])
   
       for model in models['ProjectVersionDescriptions']:
   
           logger.info("Status: %s", model['StatusMessage'])
           return model["Status"]
   
       error_message = f"Model {model_arn} not found."
       logger.exception(error_message)
       raise Exception(error_message)
   
   
   def start_model(rek_client, project_arn, model_arn, min_inference_units, max_inference_units=None):
       """
       Starts the hosting of an Amazon Rekognition Custom Labels model.
       :param rek_client: The Amazon Rekognition Custom Labels Boto3 client.
       :param project_name:  The name of the project that contains the
       model that you want to start hosting.
       :param min_inference_units: The number of inference units to use for hosting.
       :param max_inference_units: The number of inference units to use for auto-scaling
       the model. If not supplied, auto-scaling does not happen.
       """
   
       try:
           # Start the model
           logger.info(f"Starting model: {model_arn}. Please wait....")
   
           if max_inference_units is None:
               rek_client.start_project_version(ProjectVersionArn=model_arn,
                                                MinInferenceUnits=int(min_inference_units))
           else:
               rek_client.start_project_version(ProjectVersionArn=model_arn,
                                                MinInferenceUnits=int(
                                                    min_inference_units),
                                                MaxInferenceUnits=int(max_inference_units))
   
           # Wait for the model to be in the running state
           version_name = (model_arn.split("version/", 1)[1]).rpartition('/')[0]
           project_version_running_waiter = rek_client.get_waiter(
               'project_version_running')
           project_version_running_waiter.wait(
               ProjectArn=project_arn, VersionNames=[version_name])
   
           # Get the running status
           return get_model_status(rek_client, project_arn, model_arn)
   
       except ClientError as err:
           logger.exception("Client error: Problem starting model: %s", err)
           raise
   
   
   def add_arguments(parser):
       """
       Adds command line arguments to the parser.
       :param parser: The command line parser.
       """
   
       parser.add_argument(
           "project_arn", help="The ARN of the project that contains that the model you want to start."
       )
       parser.add_argument(
           "model_arn", help="The ARN of the model that you want to start."
       )
       parser.add_argument(
           "min_inference_units", help="The minimum number of inference units to use."
       )
       parser.add_argument(
           "--max_inference_units",  help="The maximum number of inference units to use for auto-scaling the model.", required=False
       )
   
   
   def main():
   
       logging.basicConfig(level=logging.INFO,
                           format="%(levelname)s: %(message)s")
   
       try:
   
           # Get command line arguments.
           parser = argparse.ArgumentParser(usage=argparse.SUPPRESS)
           add_arguments(parser)
           args = parser.parse_args()
   
           # Start the model.
           session = boto3.Session(profile_name='custom-labels-access')
           rekognition_client = session.client("rekognition")
           
           status = start_model(rekognition_client,
                                args.project_arn, args.model_arn,
                                args.min_inference_units,
                                args.max_inference_units)
   
           print(f"Finished starting model: {args.model_arn}")
           print(f"Status: {status}")
   
       except ClientError as err:
           error_message = f"Client error: Problem starting model: {err}"
           logger.exception(error_message)
           print(error_message)
   
       except Exception as err:
           error_message = f"Problem starting model:{err}"
           logger.exception(error_message)
           print(error_message)
   
   
   if __name__ == "__main__":
       main()
   ```

------
#### [ Java V2 ]

   提供以下命令行参数：
   + `project_arn`：包含要启动的模型的项目的 ARN。
   + `model_arn`：要启动的模型的 ARN。
   + `min_inference_units`：要使用的推理单元数。
   + （可选）`max_inference_units`：Amazon Rekognition Custom Labels 可用于自动扩缩模型的最大推理单元数。如果不指定值，则不会进行自动扩缩。

   ```
   /*
      Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
      SPDX-License-Identifier: Apache-2.0
   */
   package com.example.rekognition;
   
   import software.amazon.awssdk.auth.credentials.ProfileCredentialsProvider;
   import software.amazon.awssdk.core.waiters.WaiterResponse;
   import software.amazon.awssdk.regions.Region;
   import software.amazon.awssdk.services.rekognition.RekognitionClient;
   import software.amazon.awssdk.services.rekognition.model.DescribeProjectVersionsRequest;
   import software.amazon.awssdk.services.rekognition.model.DescribeProjectVersionsResponse;
   import software.amazon.awssdk.services.rekognition.model.ProjectVersionDescription;
   import software.amazon.awssdk.services.rekognition.model.ProjectVersionStatus;
   import software.amazon.awssdk.services.rekognition.model.RekognitionException;
   import software.amazon.awssdk.services.rekognition.model.StartProjectVersionRequest;
   import software.amazon.awssdk.services.rekognition.model.StartProjectVersionResponse;
   import software.amazon.awssdk.services.rekognition.waiters.RekognitionWaiter;
   
   import java.util.Optional;
   import java.util.logging.Level;
   import java.util.logging.Logger;
   
   public class StartModel {
   
       public static final Logger logger = Logger.getLogger(StartModel.class.getName());
       
       
       
       public static int findForwardSlash(String modelArn, int n) {
   
           int start = modelArn.indexOf('/');
           while (start >= 0 && n > 1) {
               start = modelArn.indexOf('/', start + 1);
               n -= 1;
           }
           return start;
   
       }
   
       public static void startMyModel(RekognitionClient rekClient, String projectArn, String modelArn,
               Integer minInferenceUnits, Integer maxInferenceUnits
               ) throws Exception, RekognitionException {
   
           try {
               
               logger.log(Level.INFO, "Starting model: {0}", modelArn);
               
               StartProjectVersionRequest startProjectVersionRequest = null;
               
               if (maxInferenceUnits == null) {
                   startProjectVersionRequest = StartProjectVersionRequest.builder()
                       .projectVersionArn(modelArn)
                       .minInferenceUnits(minInferenceUnits)
                       .build();
               }
               else {
                   startProjectVersionRequest = StartProjectVersionRequest.builder()
                           .projectVersionArn(modelArn)
                           .minInferenceUnits(minInferenceUnits)
                           .maxInferenceUnits(maxInferenceUnits)
                           .build();
                   
               }
   
               StartProjectVersionResponse response = rekClient.startProjectVersion(startProjectVersionRequest);
   
               logger.log(Level.INFO, "Status: {0}", response.statusAsString() );
               
               
               // Get the model version
   
               int start = findForwardSlash(modelArn, 3) + 1;
               int end = findForwardSlash(modelArn, 4);
   
               String versionName = modelArn.substring(start, end);
   
   
               // wait until model starts
   
               DescribeProjectVersionsRequest describeProjectVersionsRequest = DescribeProjectVersionsRequest.builder()
                       .versionNames(versionName)
                       .projectArn(projectArn)
                       .build();
   
               RekognitionWaiter waiter = rekClient.waiter();
   
               WaiterResponse<DescribeProjectVersionsResponse> waiterResponse = waiter
                       .waitUntilProjectVersionRunning(describeProjectVersionsRequest);
   
               Optional<DescribeProjectVersionsResponse> optionalResponse = waiterResponse.matched().response();
   
               DescribeProjectVersionsResponse describeProjectVersionsResponse = optionalResponse.get();
   
               for (ProjectVersionDescription projectVersionDescription : describeProjectVersionsResponse
                       .projectVersionDescriptions()) {
                   if(projectVersionDescription.status() == ProjectVersionStatus.RUNNING) {
                       logger.log(Level.INFO, "Model is running" );
                    
                   }
                   else {
                       String error = "Model training failed: " + projectVersionDescription.statusAsString() + " "
                               + projectVersionDescription.statusMessage() + " " + modelArn;
                       logger.log(Level.SEVERE, error);
                       throw new Exception(error);
                   }
                   
               }
   
   
           } catch (RekognitionException e) {
               logger.log(Level.SEVERE, "Could not start model: {0}", e.getMessage());
               throw e;
           }
   
       }
   
       public static void main(String[] args) {
   
           String modelArn = null;
           String projectArn = null;
           Integer minInferenceUnits = null;
           Integer maxInferenceUnits = null;
           
   
   
   
           final String USAGE = "\n" + "Usage: " + "<project_name> <version_name> <min_inference_units> <max_inference_units>\n\n" + "Where:\n"
                   + "   project_arn - The ARN of the project that contains the model that you want to start. \n\n"
                   + "   model_arn - The ARN of the model version that you want to start.\n\n"
                   + "   min_inference_units - The number of inference units to start the model with.\n\n"
                   + "   max_inference_units - The maximum number of inference units that Custom Labels can use to "
                   + "   automatically scale the model. If the value is null, automatic scaling doesn't happen.\n\n";
   
           if (args.length < 3  || args.length >4) {
               System.out.println(USAGE);
               System.exit(1);
           }
   
           projectArn = args[0];
           modelArn = args[1];
           minInferenceUnits=Integer.parseInt(args[2]);
           
           if (args.length == 4) {
               maxInferenceUnits = Integer.parseInt(args[3]);
           }
     
           try {
   
   
               // Get the Rekognition client.
               RekognitionClient rekClient = RekognitionClient.builder()
               .credentialsProvider(ProfileCredentialsProvider.create("custom-labels-access"))
               .region(Region.US_WEST_2)
               .build();
   
               // Start the model.
               startMyModel(rekClient, projectArn, modelArn, minInferenceUnits, maxInferenceUnits);
               
   
               System.out.println(String.format("Model started: %s", modelArn));
   
               rekClient.close();
   
           } catch (RekognitionException rekError) {
               logger.log(Level.SEVERE, "Rekognition client error: {0}", rekError.getMessage());
               System.exit(1);
           } catch (Exception rekError) {
               logger.log(Level.SEVERE, "Error: {0}", rekError.getMessage());
               System.exit(1);
           }
   
           
   
       }
   
   }
   ```

------