Use UpdateFunctionConfiguration with an Amazon SDK or CLI

    /// <summary>
    /// Update the code of a Lambda function.
    /// </summary>
    /// <param name="functionName">The name of the function to update.</param>
    /// <param name="functionHandler">The code that performs the function's actions.</param>
    /// <param name="environmentVariables">A dictionary of environment variables.</param>
    /// <returns>A Boolean value indicating the success of the action.</returns>
    public async Task<bool> UpdateFunctionConfigurationAsync(
        string functionName,
        string functionHandler,
        Dictionary<string, string> environmentVariables)
    {
        var request = new UpdateFunctionConfigurationRequest
        {
            Handler = functionHandler,
            FunctionName = functionName,
            Environment = new Amazon.Lambda.Model.Environment { Variables = environmentVariables },
        };

        var response = await _lambdaService.UpdateFunctionConfigurationAsync(request);

        Console.WriteLine(response.LastModified);

        return response.HttpStatusCode == System.Net.HttpStatusCode.OK;
    }

        Aws::Client::ClientConfiguration clientConfig;
        // Optional: Set to the AWS Region in which the bucket was created (overrides config file).
        // clientConfig.region = "us-east-1";

    Aws::Lambda::LambdaClient client(clientConfig);

        Aws::Lambda::Model::UpdateFunctionConfigurationRequest request;
        request.SetFunctionName(LAMBDA_NAME);
        Aws::Lambda::Model::Environment environment;
        environment.AddVariables("LOG_LEVEL", "DEBUG");
        request.SetEnvironment(environment);

        Aws::Lambda::Model::UpdateFunctionConfigurationOutcome outcome = client.UpdateFunctionConfiguration(
                request);

        if (outcome.IsSuccess()) {
            std::cout << "The lambda configuration was successfully updated."
                      << std::endl;
            break;
        }

        else {
            std::cerr << "Error with Lambda::UpdateFunctionConfiguration. "
                      << outcome.GetError().GetMessage()
                      << std::endl;
        }

To modify the configuration of a function

The following update-function-configuration example modifies the memory size to be 256 MB for the unpublished ($LATEST) version of the my-function function.

aws lambda update-function-configuration \
    --function-name  my-function \
    --memory-size 256

Output:

{
    "FunctionName": "my-function",
    "LastModified": "2019-09-26T20:28:40.438+0000",
    "RevisionId": "e52502d4-9320-4688-9cd6-152a6ab7490d",
    "MemorySize": 256,
    "Version": "$LATEST",
    "Role": "arn:aws:iam::123456789012:role/service-role/my-function-role-uy3l9qyq",
    "Timeout": 3,
    "Runtime": "nodejs10.x",
    "TracingConfig": {
        "Mode": "PassThrough"
    },
    "CodeSha256": "5tT2qgzYUHaqwR716pZ2dpkn/0J1FrzJmlKidWoaCgk=",
    "Description": "",
    "VpcConfig": {
        "SubnetIds": [],
        "VpcId": "",
        "SecurityGroupIds": []
    },
    "CodeSize": 304,
    "FunctionArn": "arn:aws:lambda:us-west-2:123456789012:function:my-function",
    "Handler": "index.handler"
}

For more information, see Amazon Lambda Function Configuration in the Amazon Lambda Developer Guide.

// FunctionWrapper encapsulates function actions used in the examples.
// It contains an AWS Lambda service client that is used to perform user actions.
type FunctionWrapper struct {
	LambdaClient *lambda.Client
}



// UpdateFunctionConfiguration updates a map of environment variables configured for
// the Lambda function specified by functionName.
func (wrapper FunctionWrapper) UpdateFunctionConfiguration(functionName string, envVars map[string]string) {
	_, err := wrapper.LambdaClient.UpdateFunctionConfiguration(context.TODO(), &lambda.UpdateFunctionConfigurationInput{
		FunctionName: aws.String(functionName),
		Environment:  &types.Environment{Variables: envVars},
	})
	if err != nil {
		log.Panicf("Couldn't update configuration for %v. Here's why: %v", functionName, err)
	}
}

const updateFunctionConfiguration = (funcName) => {
  const client = new LambdaClient({});
  const config = readFileSync(`${dirname}../functions/config.json`).toString();
  const command = new UpdateFunctionConfigurationCommand({
    ...JSON.parse(config),
    FunctionName: funcName,
  });
  return client.send(command);
};

    public function updateFunctionConfiguration($functionName, $handler, $environment = '')
    {
        return $this->lambdaClient->updateFunctionConfiguration([
            'FunctionName' => $functionName,
            'Handler' => "$handler.lambda_handler",
            'Environment' => $environment,
        ]);
    }

Example 1: This example updates the existing Lambda Function Configuration

Update-LMFunctionConfiguration -FunctionName "MylambdaFunction123" -Handler "lambda_function.launch_instance" -Timeout 600 -Environment_Variable @{ "envvar1"="value";"envvar2"="value" } -Role arn:aws:iam::123456789101:role/service-role/lambda -DeadLetterConfig_TargetArn arn:aws:sns:us-east-1: 123456789101:MyfirstTopic

class LambdaWrapper:
    def __init__(self, lambda_client, iam_resource):
        self.lambda_client = lambda_client
        self.iam_resource = iam_resource


    def update_function_configuration(self, function_name, env_vars):
        """
        Updates the environment variables for a Lambda function.

        :param function_name: The name of the function to update.
        :param env_vars: A dict of environment variables to update.
        :return: Data about the update, including the status.
        """
        try:
            response = self.lambda_client.update_function_configuration(
                FunctionName=function_name, Environment={"Variables": env_vars}
            )
        except ClientError as err:
            logger.error(
                "Couldn't update function configuration %s. Here's why: %s: %s",
                function_name,
                err.response["Error"]["Code"],
                err.response["Error"]["Message"],
            )
            raise
        else:
            return response

class LambdaWrapper
  attr_accessor :lambda_client

  def initialize
    @lambda_client = Aws::Lambda::Client.new
    @logger = Logger.new($stdout)
    @logger.level = Logger::WARN
  end

  # Updates the environment variables for a Lambda function.
  # @param function_name: The name of the function to update.
  # @param log_level: The log level of the function.
  # @return: Data about the update, including the status.
  def update_function_configuration(function_name, log_level)
    @lambda_client.update_function_configuration({
                                                   function_name: function_name,
                                                   environment: {
                                                     variables: {
                                                       "LOG_LEVEL" => log_level
                                                     }
                                                   }
                                                 })
    @lambda_client.wait_until(:function_updated_v2, { function_name: function_name}) do |w|
      w.max_attempts = 5
      w.delay = 5
    end
  rescue Aws::Lambda::Errors::ServiceException => e
    @logger.error("There was an error updating configurations for #{function_name}:\n #{e.message}")
  rescue Aws::Waiters::Errors::WaiterFailed => e
    @logger.error("Failed waiting for #{function_name} to activate:\n #{e.message}")
  end

    /** Update the environment for a function. */
    pub async fn update_function_configuration(
        &self,
        environment: Environment,
    ) -> Result<UpdateFunctionConfigurationOutput, anyhow::Error> {
        info!(
            ?environment,
            "Updating environment for {}", self.lambda_name
        );
        let updated = self
            .lambda_client
            .update_function_configuration()
            .function_name(self.lambda_name.clone())
            .environment(environment)
            .send()
            .await
            .map_err(anyhow::Error::from)?;

        self.wait_for_function_ready().await?;

        Ok(updated)
    }

    TRY.
        oo_result = lo_lmd->updatefunctionconfiguration(     " oo_result is returned for testing purposes. "
              iv_functionname = iv_function_name
              iv_runtime = iv_runtime
              iv_description  = 'Updated Lambda function'
              iv_memorysize  = iv_memory_size
          ).

        MESSAGE 'Lambda function configuration/settings updated.' TYPE 'I'.
      CATCH /aws1/cx_lmdcodesigningcfgno00.
        MESSAGE 'Code signing configuration does not exist.' TYPE 'E'.
      CATCH /aws1/cx_lmdcodeverification00.
        MESSAGE 'Code signature failed one or more validation checks for signature mismatch or expiration.' TYPE 'E'.
      CATCH /aws1/cx_lmdinvalidcodesigex.
        MESSAGE 'Code signature failed the integrity check.' TYPE 'E'.
      CATCH /aws1/cx_lmdinvparamvalueex.
        MESSAGE 'The request contains a non-valid parameter.' TYPE 'E'.
      CATCH /aws1/cx_lmdresourceconflictex.
        MESSAGE 'Resource already exists or another operation is in progress.' TYPE 'E'.
      CATCH /aws1/cx_lmdresourcenotfoundex.
        MESSAGE 'The requested resource does not exist.' TYPE 'E'.
      CATCH /aws1/cx_lmdserviceexception.
        MESSAGE 'An internal problem was encountered by the AWS Lambda service.' TYPE 'E'.
      CATCH /aws1/cx_lmdtoomanyrequestsex.
        MESSAGE 'The maximum request throughput was reached.' TYPE 'E'.
    ENDTRY.