Welcome to the AWS Code Examples Repository. This repo contains code examples used in the AWS documentation, AWS SDK Developer Guides, and more. For more information, see the Readme.md file below.
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// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
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// SPDX-License-Identifier: Apache-2.0
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// snippet-start:[lambda.swift.function.complete]
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// snippet-start:[lambda.swift.function.imports]
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import Foundation
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import AWSLambdaRuntime
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import AWSS3
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import protocol AWSClientRuntime.AWSServiceError
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import enum Smithy.ByteStream
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// snippet-end:[lambda.swift.function.imports]
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// snippet-start:[lambda.swift.function.types]
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// snippet-start:[lambda.swift.function.struct.request]
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/// Represents the contents of the requests being received from the client.
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/// This structure must be `Decodable` to indicate that its initializer
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/// converts an external representation into this type.
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struct Request: Decodable, Sendable {
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/// The request body.
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let body: String
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}
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// snippet-end:[lambda.swift.function.struct.request]
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// snippet-start:[lambda.swift.function.struct.response]
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/// The contents of the response sent back to the client. This must be
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/// `Encodable`.
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struct Response: Encodable, Sendable {
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/// The ID of the request this response corresponds to.
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let req_id: String
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/// The body of the response message.
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let body: String
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}
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// snippet-end:[lambda.swift.function.struct.response]
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// snippet-start:[lambda.swift.function.errors]
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/// The errors that the Lambda function can return.
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enum S3ExampleLambdaErrors: Error {
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/// A required environment variable is missing. The missing variable is
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/// specified.
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case noEnvironmentVariable(String)
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/// The Amazon Simple Storage Service (S3) client couldn't be created.
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case noS3Client
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}
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// snippet-end:[lambda.swift.function.errors]
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// snippet-end:[lambda.swift.function.types]
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// snippet-start:[lambda.swift.function.handler]
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/// A Swift AWS Lambda Runtime `LambdaHandler` lets you both perform needed
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/// initialization and handle AWS Lambda requests. There are other handler
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/// protocols available for other use cases.
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@main
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struct S3ExampleLambda: LambdaHandler {
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let s3Client: S3Client?
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// snippet-start:[lambda.swift.function.handler.init]
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/// Initialize the AWS Lambda runtime.
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///
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/// ^ The logger is a standard Swift logger. You can control the verbosity
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/// by setting the `LOG_LEVEL` environment variable.
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init(context: LambdaInitializationContext) async throws {
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// Display the `LOG_LEVEL` configuration for this process.
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context.logger.info(
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"Log Level env var : \(ProcessInfo.processInfo.environment["LOG_LEVEL"] ?? "info" )"
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)
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// Initialize the Amazon S3 client. This single client is used for every
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// request.
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let currentRegion = ProcessInfo.processInfo.environment["AWS_REGION"] ?? "us-east-1"
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self.s3Client = try? S3Client(region: currentRegion)
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}
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// snippet-end:[lambda.swift.function.handler.init]
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// snippet-start:[lambda.swift.function.handler.putobject]
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/// Write the specified text into a given Amazon S3 bucket. The object's
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/// name is based on the current time.
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///
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/// - Parameters:
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/// - s3Client: The `S3Client` to use when sending the object to the
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/// bucket.
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/// - bucketName: The name of the Amazon S3 bucket to put the object
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/// into.
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/// - body: The string to write into the new object.
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///
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/// - Returns: A string indicating the name of the file created in the AWS
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/// S3 bucket.
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private func putObject(client: S3Client,
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bucketName: String,
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body: String) async throws -> String {
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// Generate an almost certainly unique object name based on the current
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// timestamp.
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let objectName = "\(Int(Date().timeIntervalSince1970*1_000_000)).txt"
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// Create a Smithy `ByteStream` that represents the string to write into
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// the bucket.
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let inputStream = Smithy.ByteStream.data(body.data(using: .utf8))
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// Store the text into an object in the Amazon S3 bucket.
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let putObjectRequest = PutObjectInput(
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body: inputStream,
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bucket: bucketName,
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key: objectName
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)
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let _ = try await client.putObject(input: putObjectRequest)
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// Return the name of the file.
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return objectName
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}
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// snippet-end:[lambda.swift.function.handler.putobject]
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// snippet-start:[lambda.swift.function.handler.handle]
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/// The Lambda function's entry point. Called by the Lambda runtime.
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///
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/// - Parameters:
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/// - event: The `Request` describing the request made by the
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/// client.
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/// - context: A `LambdaContext` describing the context in
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/// which the lambda function is running.
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///
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/// - Returns: A `Response` object that will be encoded to JSON and sent
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/// to the client by the Lambda runtime.
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func handle(_ event: Request, context: LambdaContext) async throws -> Response {
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// Get the bucket name from the environment.
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guard let bucketName = ProcessInfo.processInfo.environment["BUCKET_NAME"] else {
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throw S3ExampleLambdaErrors.noEnvironmentVariable("BUCKET_NAME")
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}
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// Make sure the `S3Client` is valid.
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guard let s3Client else {
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throw S3ExampleLambdaErrors.noS3Client
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}
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// Call the `putObject` function to store the object on Amazon S3.
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var responseMessage: String
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do {
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let filename = try await putObject(
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client: s3Client,
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bucketName: bucketName,
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body: event.body)
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// Generate the response text.
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responseMessage = "The Lambda function has successfully stored your data in S3 with name \(filename)'"
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// Send the success notification to the logger.
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context.logger.info("Data successfully stored in S3.")
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} catch let error as AWSServiceError {
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// Generate the error message.
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responseMessage = "The Lambda function encountered an error and your data was not saved. Root cause: \(error.errorCode ?? "") - \(error.message ?? "")"
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// Send the error message to the logger.
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context.logger.error("Failed to upload data to Amazon S3.")
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}
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// Return the response message. The AWS Lambda runtime will send it to the
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// client.
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return Response(
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req_id: context.requestID,
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body: responseMessage)
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}
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// snippet-end:[lambda.swift.function.handler.handle]
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}
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// snippet-end:[lambda.swift.function.handler]
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// snippet-end:[lambda.swift.function.complete]
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