在Swift SOTO中使用AWS Rekognition

Question

我使用了

devhr python lambda函数

作为我的Swift Lambda函数的模型，使用

AWS的Soto

..。Lambda函数将在图像上传到S3并使用AWS Rekognition服务向DynamoDB数据库添加标签(图像中对象的描述)时由S3事件触发。我在获取

rekFunction

功能正确，我希望有人能建议如何让它工作。

到目前为止，我编写的Swift代码如下：

import AWSLambdaRuntime
import AWSLambdaEvents
import NIO
import Foundation
import SotoS3
import SotoRekognition
import SotoDynamoDB

struct Bucket: Decodable {
    let name: String
}

struct Object: Decodable {
    let key: String
}

struct MyS3: Decodable {
    let bucket: Bucket
    let object: Object
}

struct Record: Decodable {
    let s3: MyS3
}

struct Input: Decodable {
    let records: [Record]
}

struct Output: Encodable {
    let result: String
}

struct MyHandler: EventLoopLambdaHandler {
    typealias In = APIGateway.V2.Request
    typealias Out = APIGateway.V2.Response
    
    let minConfidence: Float = 50

    let awsClient: AWSClient
    
    init(context: Lambda.InitializationContext) {
        self.awsClient = AWSClient(httpClientProvider: .createNewWithEventLoopGroup(context.eventLoop))
    }
    
    func shutdown(context: Lambda.ShutdownContext) -> EventLoopFuture {
        let promise = context.eventLoop.makePromise(of: Void.self)
        awsClient.shutdown { error in
            if let error = error {
                promise.fail(error)
            } else {
                promise.succeed(())
            }
        }
        return context.eventLoop.makeSucceededFuture(())
    }

    func handle(context: Lambda.Context, event: In) -> EventLoopFuture {
        guard let input: Input = try? event.bodyObject() else {
            return context.eventLoop.makeSucceededFuture(APIGateway.V2.Response(with: APIError.requestError, statusCode: .badRequest))
        }

        for record in input.records {
            let ourBucket = record.s3.bucket.name
            let ourKey = record.s3.object.key
            
            // For each message (photo) get the bucket name and key
            rekFunction(bucket: ourBucket, key: ourKey)
        }
        let output = Output(result: "Finished!")
        let apigatewayOutput = APIGateway.V2.Response(with: output, statusCode: .ok)
        return context.eventLoop.makeSucceededFuture(apigatewayOutput)
    }
        
    func rekFunction(bucket: String, key: String) {
        let safeKey = key.replacingOccurrences(of: "%3A", with: ":")
        print("Currently processing the following image")
        print("Bucket:", bucket, " key name:", safeKey)
        var objectsDetected: [String] = []
        var imageLabels = [ "image": safeKey ]
        let s3Client = S3(client: awsClient, region: .euwest1)

        let s3Object = Rekognition.S3Object(bucket: bucket, name: safeKey)
        let image = Rekognition.Image(s3Object: s3Object)
        let rekognitionClient = Rekognition(client: awsClient)
        let detectLabelsRequest = Rekognition.DetectLabelsRequest(image: image, maxLabels: 10, minConfidence: minConfidence)
        rekognitionClient.detectLabels(detectLabelsRequest)
            .flatMap { detectLabelsResponse -> EventLoopFuture in
                if let labels = detectLabelsResponse.labels {
                    // Add all of our labels into imageLabels by iterating over response['Labels']
                    for label in labels {
                        if let name = label.name {
                            objectsDetected.append(name)
                            let itemAtt = "object\(objectsDetected.count)"
                            
                            // We now have our shiny new item ready to put into DynamoDB
                            imageLabels[itemAtt] = name
                            
                            // Instantiate a table resource object of our environment variable
                            let imageLabelsTable = // Environment("TABLE") How can I read env vars?
                            let table = SotoDynamoDB.getTable(imageLabelsTable) // python: table = dynamodb.Table(imageLabelsTable)
                            // python: table.put_item(Item=imageLabels)
                        }
                    }
                }
                return ???
            }
        
    }
    
}
Lambda.run { MyHandler(context: $0) }

Answer 1

这里有许多问题需要讨论。

因为您是从S3事件触发的。The The The

typealias应为

考虑到没有任何东西在等待结果

应该是

..。

可以使用以下命令提取环境变量

..。

至于写入DynamoDB表，最好的方法可能是使用Soto的DynamoDB可编码支持。在下面的示例中，我将假设您使用s3存储桶和密钥的组合作为密钥。

struct RekEntry: Codable {
    let key: String
    let labels: [String]
}
let entry = RekEntry(
    key: "\(bucket)/\(key)"
    labels: labels
)
let putRequest = DynamoDB.PutItemCodableInput(
    item: entry,
    tableName: Lambda.env("TABLE")
)
return dynamoDB.putItem(putRequest)

最后，从你的flatMap返回什么。首先是你的函数

需要返回一个

因为这是您从Lambda处理程序返回的内容。因此，您将映射

在前一点要作废。

func rekFunction(bucket: String, key: String) -> EventLoopFuture {
    ...
    return rekognitionClient.detectLabels(detectLabelsRequest)
        .flatMap {
            ...
            return dynamoDB.putItem(putRequest)
        }
        .map { _ in }
}

我希望这包括了所有的内容。