Exemplos de Lambda usando SDK para Java 2.x

Os exemplos de código a seguir mostram como realizar ações e implementar cenários comuns usando o AWS SDK for Java 2.x com o Lambda.

Ações são trechos de código de programas maiores e devem ser executadas em contexto. Embora as ações mostrem como chamar funções de serviço específicas, é possível ver as ações contextualizadas em seus devidos cenários e exemplos entre serviços.

Cenários são exemplos de código que mostram como realizar uma tarefa específica chamando várias funções dentro do mesmo serviço.

Cada exemplo inclui um link para GitHub, onde você pode encontrar instruções sobre como configurar e executar o código no contexto.

Conceitos básicos

Os exemplos de código a seguir mostram como começar a usar o Lambda.

SDKpara Java 2.x

nota

Tem mais sobre GitHub. Encontre o exemplo completo e veja como configurar e executar no AWS Code Examples Repository.


package com.example.lambda;

import software.amazon.awssdk.regions.Region;
import software.amazon.awssdk.services.lambda.LambdaClient;
import software.amazon.awssdk.services.lambda.model.LambdaException;
import software.amazon.awssdk.services.lambda.model.ListFunctionsResponse;
import software.amazon.awssdk.services.lambda.model.FunctionConfiguration;
import java.util.List;

/**
 * Before running this Java V2 code example, set up your development
 * environment, including your credentials.
 *
 * For more information, see the following documentation topic:
 *
 * https://docs.aws.amazon.com/sdk-for-java/latest/developer-guide/get-started.html
 */
public class ListLambdaFunctions {
    public static void main(String[] args) {
        Region region = Region.US_WEST_2;
        LambdaClient awsLambda = LambdaClient.builder()
                .region(region)
                .build();

        listFunctions(awsLambda);
        awsLambda.close();
    }

    public static void listFunctions(LambdaClient awsLambda) {
        try {
            ListFunctionsResponse functionResult = awsLambda.listFunctions();
            List<FunctionConfiguration> list = functionResult.functions();
            for (FunctionConfiguration config : list) {
                System.out.println("The function name is " + config.functionName());
            }

        } catch (LambdaException e) {
            System.err.println(e.getMessage());
            System.exit(1);
        }
    }
}

Para API obter detalhes, consulte ListFunctionsem AWS SDK for Java 2.x APIReferência.

Ações

O código de exemplo a seguir mostra como usar CreateFunction.

SDKpara Java 2.x

nota

Tem mais sobre GitHub. Encontre o exemplo completo e veja como configurar e executar no AWS Code Examples Repository.


import software.amazon.awssdk.core.SdkBytes;
import software.amazon.awssdk.core.waiters.WaiterResponse;
import software.amazon.awssdk.regions.Region;
import software.amazon.awssdk.services.lambda.LambdaClient;
import software.amazon.awssdk.services.lambda.model.CreateFunctionRequest;
import software.amazon.awssdk.services.lambda.model.FunctionCode;
import software.amazon.awssdk.services.lambda.model.CreateFunctionResponse;
import software.amazon.awssdk.services.lambda.model.GetFunctionRequest;
import software.amazon.awssdk.services.lambda.model.GetFunctionResponse;
import software.amazon.awssdk.services.lambda.model.LambdaException;
import software.amazon.awssdk.services.lambda.model.Runtime;
import software.amazon.awssdk.services.lambda.waiters.LambdaWaiter;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.InputStream;

/**
 * This code example requires a ZIP or JAR that represents the code of the
 * Lambda function.
 * If you do not have a ZIP or JAR, please refer to the following document:
 *
 * https://github.com/aws-doc-sdk-examples/tree/master/javav2/usecases/creating_workflows_stepfunctions
 *
 * Also, set up your development environment, including your credentials.
 *
 * For information, see this documentation topic:
 *
 * https://docs.aws.amazon.com/sdk-for-java/latest/developer-guide/get-started.html
 */

public class CreateFunction {
    public static void main(String[] args) {

        final String usage = """

                Usage:
                    <functionName> <filePath> <role> <handler>\s

                Where:
                    functionName - The name of the Lambda function.\s
                    filePath - The path to the ZIP or JAR where the code is located.\s
                    role - The role ARN that has Lambda permissions.\s
                    handler - The fully qualified method name (for example, example.Handler::handleRequest). \s
                """;

        if (args.length != 4) {
            System.out.println(usage);
            System.exit(1);
        }

        String functionName = args[0];
        String filePath = args[1];
        String role = args[2];
        String handler = args[3];
        Region region = Region.US_WEST_2;
        LambdaClient awsLambda = LambdaClient.builder()
                .region(region)
                .build();

        createLambdaFunction(awsLambda, functionName, filePath, role, handler);
        awsLambda.close();
    }

    public static void createLambdaFunction(LambdaClient awsLambda,
            String functionName,
            String filePath,
            String role,
            String handler) {

        try {
            LambdaWaiter waiter = awsLambda.waiter();
            InputStream is = new FileInputStream(filePath);
            SdkBytes fileToUpload = SdkBytes.fromInputStream(is);

            FunctionCode code = FunctionCode.builder()
                    .zipFile(fileToUpload)
                    .build();

            CreateFunctionRequest functionRequest = CreateFunctionRequest.builder()
                    .functionName(functionName)
                    .description("Created by the Lambda Java API")
                    .code(code)
                    .handler(handler)
                    .runtime(Runtime.JAVA8)
                    .role(role)
                    .build();

            // Create a Lambda function using a waiter.
            CreateFunctionResponse functionResponse = awsLambda.createFunction(functionRequest);
            GetFunctionRequest getFunctionRequest = GetFunctionRequest.builder()
                    .functionName(functionName)
                    .build();
            WaiterResponse<GetFunctionResponse> waiterResponse = waiter.waitUntilFunctionExists(getFunctionRequest);
            waiterResponse.matched().response().ifPresent(System.out::println);
            System.out.println("The function ARN is " + functionResponse.functionArn());

        } catch (LambdaException | FileNotFoundException e) {
            System.err.println(e.getMessage());
            System.exit(1);
        }
    }
}

Para API obter detalhes, consulte CreateFunctionem AWS SDK for Java 2.x APIReferência.

O código de exemplo a seguir mostra como usar DeleteFunction.

SDKpara Java 2.x

nota

Tem mais sobre GitHub. Encontre o exemplo completo e veja como configurar e executar no AWS Code Examples Repository.


import software.amazon.awssdk.services.lambda.LambdaClient;
import software.amazon.awssdk.regions.Region;
import software.amazon.awssdk.services.lambda.model.DeleteFunctionRequest;
import software.amazon.awssdk.services.lambda.model.LambdaException;

/**
 * Before running this Java V2 code example, set up your development
 * environment, including your credentials.
 *
 * For more information, see the following documentation topic:
 *
 * https://docs.aws.amazon.com/sdk-for-java/latest/developer-guide/get-started.html
 */
public class DeleteFunction {
    public static void main(String[] args) {
        final String usage = """

                Usage:
                    <functionName>\s

                Where:
                    functionName - The name of the Lambda function.\s
                """;

        if (args.length != 1) {
            System.out.println(usage);
            System.exit(1);
        }

        String functionName = args[0];
        Region region = Region.US_EAST_1;
        LambdaClient awsLambda = LambdaClient.builder()
                .region(region)
                .build();

        deleteLambdaFunction(awsLambda, functionName);
        awsLambda.close();
    }

    public static void deleteLambdaFunction(LambdaClient awsLambda, String functionName) {
        try {
            DeleteFunctionRequest request = DeleteFunctionRequest.builder()
                    .functionName(functionName)
                    .build();

            awsLambda.deleteFunction(request);
            System.out.println("The " + functionName + " function was deleted");

        } catch (LambdaException e) {
            System.err.println(e.getMessage());
            System.exit(1);
        }
    }
}

Para API obter detalhes, consulte DeleteFunctionem AWS SDK for Java 2.x APIReferência.

O código de exemplo a seguir mostra como usar Invoke.

SDKpara Java 2.x

nota

Tem mais sobre GitHub. Encontre o exemplo completo e veja como configurar e executar no AWS Code Examples Repository.


import org.json.JSONObject;
import software.amazon.awssdk.auth.credentials.ProfileCredentialsProvider;
import software.amazon.awssdk.services.lambda.LambdaClient;
import software.amazon.awssdk.regions.Region;
import software.amazon.awssdk.services.lambda.model.InvokeRequest;
import software.amazon.awssdk.core.SdkBytes;
import software.amazon.awssdk.services.lambda.model.InvokeResponse;
import software.amazon.awssdk.services.lambda.model.LambdaException;

public class LambdaInvoke {

    /*
     * Function names appear as
     * arn:aws:lambda:us-west-2:335556666777:function:HelloFunction
     * you can retrieve the value by looking at the function in the AWS Console
     *
     * Also, set up your development environment, including your credentials.
     *
     * For information, see this documentation topic:
     *
     * https://docs.aws.amazon.com/sdk-for-java/latest/developer-guide/get-started.
     * html
     */

    public static void main(String[] args) {
        final String usage = """

                Usage:
                    <functionName>\s

                Where:
                    functionName - The name of the Lambda function\s
                """;

        if (args.length != 1) {
            System.out.println(usage);
            System.exit(1);
        }

        String functionName = args[0];
        Region region = Region.US_WEST_2;
        LambdaClient awsLambda = LambdaClient.builder()
                .region(region)
                .build();

        invokeFunction(awsLambda, functionName);
        awsLambda.close();
    }

    public static void invokeFunction(LambdaClient awsLambda, String functionName) {

        InvokeResponse res = null;
        try {
            // Need a SdkBytes instance for the payload.
            JSONObject jsonObj = new JSONObject();
            jsonObj.put("inputValue", "2000");
            String json = jsonObj.toString();
            SdkBytes payload = SdkBytes.fromUtf8String(json);

            // Setup an InvokeRequest.
            InvokeRequest request = InvokeRequest.builder()
                    .functionName(functionName)
                    .payload(payload)
                    .build();

            res = awsLambda.invoke(request);
            String value = res.payload().asUtf8String();
            System.out.println(value);

        } catch (LambdaException e) {
            System.err.println(e.getMessage());
            System.exit(1);
        }
    }
}

Para API obter detalhes, consulte Invoke in AWS SDK for Java 2.x APIReference.

Cenários

O exemplo de código a seguir mostra como:

Crie uma IAM função e uma função Lambda e, em seguida, faça o upload do código do manipulador.
Invocar essa função com um único parâmetro e receber resultados.
Atualizar o código de função e configurar usando uma variável de ambiente.
Invocar a função com novos parâmetros e receber resultados. Exibir o log de execução retornado.
Listar as funções para sua conta e limpar os recursos.

Para obter mais informações, consulte Criar uma função do Lambda no console.

SDKpara Java 2.x

nota

Tem mais sobre GitHub. Encontre o exemplo completo e veja como configurar e executar no AWS Code Examples Repository.


/*
 *  Lambda function names appear as:
 *
 *  arn:aws:lambda:us-west-2:335556666777:function:HelloFunction
 *
 *  To find this value, look at the function in the AWS Management Console.
 *
 *  Before running this Java code example, set up your development environment, including your credentials.
 *
 *  For more information, see this documentation topic:
 *
 *  https://docs.aws.amazon.com/sdk-for-java/latest/developer-guide/get-started.html
 *
 *  This example performs the following tasks:
 *
 * 1. Creates an AWS Lambda function.
 * 2. Gets a specific AWS Lambda function.
 * 3. Lists all Lambda functions.
 * 4. Invokes a Lambda function.
 * 5. Updates the Lambda function code and invokes it again.
 * 6. Updates a Lambda function's configuration value.
 * 7. Deletes a Lambda function.
 */

public class LambdaScenario {
    public static final String DASHES = new String(new char[80]).replace("\0", "-");

    public static void main(String[] args) throws InterruptedException {
        final String usage = """

                Usage:
                    <functionName> <filePath> <role> <handler> <bucketName> <key>\s

                Where:
                    functionName - The name of the Lambda function.\s
                    filePath - The path to the .zip or .jar where the code is located.\s
                    role - The AWS Identity and Access Management (IAM) service role that has Lambda permissions.\s
                    handler - The fully qualified method name (for example, example.Handler::handleRequest).\s
                    bucketName - The Amazon Simple Storage Service (Amazon S3) bucket name that contains the .zip or .jar used to update the Lambda function's code.\s
                    key - The Amazon S3 key name that represents the .zip or .jar (for example, LambdaHello-1.0-SNAPSHOT.jar).
                    """;

        if (args.length != 6) {
            System.out.println(usage);
            System.exit(1);
        }

        String functionName = args[0];
        String filePath = args[1];
        String role = args[2];
        String handler = args[3];
        String bucketName = args[4];
        String key = args[5];

        Region region = Region.US_WEST_2;
        LambdaClient awsLambda = LambdaClient.builder()
                .region(region)
                .build();

        System.out.println(DASHES);
        System.out.println("Welcome to the AWS Lambda example scenario.");
        System.out.println(DASHES);

        System.out.println(DASHES);
        System.out.println("1. Create an AWS Lambda function.");
        String funArn = createLambdaFunction(awsLambda, functionName, filePath, role, handler);
        System.out.println("The AWS Lambda ARN is " + funArn);
        System.out.println(DASHES);

        System.out.println(DASHES);
        System.out.println("2. Get the " + functionName + " AWS Lambda function.");
        getFunction(awsLambda, functionName);
        System.out.println(DASHES);

        System.out.println(DASHES);
        System.out.println("3. List all AWS Lambda functions.");
        listFunctions(awsLambda);
        System.out.println(DASHES);

        System.out.println(DASHES);
        System.out.println("4. Invoke the Lambda function.");
        System.out.println("*** Sleep for 1 min to get Lambda function ready.");
        Thread.sleep(60000);
        invokeFunction(awsLambda, functionName);
        System.out.println(DASHES);

        System.out.println(DASHES);
        System.out.println("5. Update the Lambda function code and invoke it again.");
        updateFunctionCode(awsLambda, functionName, bucketName, key);
        System.out.println("*** Sleep for 1 min to get Lambda function ready.");
        Thread.sleep(60000);
        invokeFunction(awsLambda, functionName);
        System.out.println(DASHES);

        System.out.println(DASHES);
        System.out.println("6. Update a Lambda function's configuration value.");
        updateFunctionConfiguration(awsLambda, functionName, handler);
        System.out.println(DASHES);

        System.out.println(DASHES);
        System.out.println("7. Delete the AWS Lambda function.");
        LambdaScenario.deleteLambdaFunction(awsLambda, functionName);
        System.out.println(DASHES);

        System.out.println(DASHES);
        System.out.println("The AWS Lambda scenario completed successfully");
        System.out.println(DASHES);
        awsLambda.close();
    }

    public static String createLambdaFunction(LambdaClient awsLambda,
            String functionName,
            String filePath,
            String role,
            String handler) {

        try {
            LambdaWaiter waiter = awsLambda.waiter();
            InputStream is = new FileInputStream(filePath);
            SdkBytes fileToUpload = SdkBytes.fromInputStream(is);

            FunctionCode code = FunctionCode.builder()
                    .zipFile(fileToUpload)
                    .build();

            CreateFunctionRequest functionRequest = CreateFunctionRequest.builder()
                    .functionName(functionName)
                    .description("Created by the Lambda Java API")
                    .code(code)
                    .handler(handler)
                    .runtime(Runtime.JAVA8)
                    .role(role)
                    .build();

            // Create a Lambda function using a waiter
            CreateFunctionResponse functionResponse = awsLambda.createFunction(functionRequest);
            GetFunctionRequest getFunctionRequest = GetFunctionRequest.builder()
                    .functionName(functionName)
                    .build();
            WaiterResponse<GetFunctionResponse> waiterResponse = waiter.waitUntilFunctionExists(getFunctionRequest);
            waiterResponse.matched().response().ifPresent(System.out::println);
            return functionResponse.functionArn();

        } catch (LambdaException | FileNotFoundException e) {
            System.err.println(e.getMessage());
            System.exit(1);
        }
        return "";
    }

    public static void getFunction(LambdaClient awsLambda, String functionName) {
        try {
            GetFunctionRequest functionRequest = GetFunctionRequest.builder()
                    .functionName(functionName)
                    .build();

            GetFunctionResponse response = awsLambda.getFunction(functionRequest);
            System.out.println("The runtime of this Lambda function is " + response.configuration().runtime());

        } catch (LambdaException e) {
            System.err.println(e.getMessage());
            System.exit(1);
        }
    }

    public static void listFunctions(LambdaClient awsLambda) {
        try {
            ListFunctionsResponse functionResult = awsLambda.listFunctions();
            List<FunctionConfiguration> list = functionResult.functions();
            for (FunctionConfiguration config : list) {
                System.out.println("The function name is " + config.functionName());
            }

        } catch (LambdaException e) {
            System.err.println(e.getMessage());
            System.exit(1);
        }
    }

    public static void invokeFunction(LambdaClient awsLambda, String functionName) {

        InvokeResponse res;
        try {
            // Need a SdkBytes instance for the payload.
            JSONObject jsonObj = new JSONObject();
            jsonObj.put("inputValue", "2000");
            String json = jsonObj.toString();
            SdkBytes payload = SdkBytes.fromUtf8String(json);

            InvokeRequest request = InvokeRequest.builder()
                    .functionName(functionName)
                    .payload(payload)
                    .build();

            res = awsLambda.invoke(request);
            String value = res.payload().asUtf8String();
            System.out.println(value);

        } catch (LambdaException e) {
            System.err.println(e.getMessage());
            System.exit(1);
        }
    }

    public static void updateFunctionCode(LambdaClient awsLambda, String functionName, String bucketName, String key) {
        try {
            LambdaWaiter waiter = awsLambda.waiter();
            UpdateFunctionCodeRequest functionCodeRequest = UpdateFunctionCodeRequest.builder()
                    .functionName(functionName)
                    .publish(true)
                    .s3Bucket(bucketName)
                    .s3Key(key)
                    .build();

            UpdateFunctionCodeResponse response = awsLambda.updateFunctionCode(functionCodeRequest);
            GetFunctionConfigurationRequest getFunctionConfigRequest = GetFunctionConfigurationRequest.builder()
                    .functionName(functionName)
                    .build();

            WaiterResponse<GetFunctionConfigurationResponse> waiterResponse = waiter
                    .waitUntilFunctionUpdated(getFunctionConfigRequest);
            waiterResponse.matched().response().ifPresent(System.out::println);
            System.out.println("The last modified value is " + response.lastModified());

        } catch (LambdaException e) {
            System.err.println(e.getMessage());
            System.exit(1);
        }
    }

    public static void updateFunctionConfiguration(LambdaClient awsLambda, String functionName, String handler) {
        try {
            UpdateFunctionConfigurationRequest configurationRequest = UpdateFunctionConfigurationRequest.builder()
                    .functionName(functionName)
                    .handler(handler)
                    .runtime(Runtime.JAVA11)
                    .build();

            awsLambda.updateFunctionConfiguration(configurationRequest);

        } catch (LambdaException e) {
            System.err.println(e.getMessage());
            System.exit(1);
        }
    }

    public static void deleteLambdaFunction(LambdaClient awsLambda, String functionName) {
        try {
            DeleteFunctionRequest request = DeleteFunctionRequest.builder()
                    .functionName(functionName)
                    .build();

            awsLambda.deleteFunction(request);
            System.out.println("The " + functionName + " function was deleted");

        } catch (LambdaException e) {
            System.err.println(e.getMessage());
            System.exit(1);
        }
    }
}

Para API obter detalhes, consulte os tópicos a seguir em AWS SDK for Java 2.x APIReferência.

Exemplos sem servidor

O exemplo de código a seguir mostra como implementar uma função Lambda que se conecta a um RDS banco de dados. A função faz uma solicitação simples ao banco de dados e exibe o resultado.

SDKpara Java 2.x