AWS Lambda
Developer Guide

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CreateFunction

Creates a Lambda function. To create a function, you need a deployment package and an execution role. The deployment package contains your function code. The execution role grants the function permission to use AWS services, such as Amazon CloudWatch Logs for log streaming and AWS X-Ray for request tracing.

A function has an unpublished version, and can have published versions and aliases. The unpublished version changes when you update your function's code and configuration. A published version is a snapshot of your function code and configuration that can't be changed. An alias is a named resource that maps to a version, and can be changed to map to a different version. Use the Publish parameter to create version 1 of your function from its initial configuration.

The other parameters let you configure version-specific and function-level settings. You can modify version-specific settings later with UpdateFunctionConfiguration. Function-level settings apply to both the unpublished and published versions of the function, and include tags (TagResource) and per-function concurrency limits (PutFunctionConcurrency).

If another account or an AWS service invokes your function, use AddPermission to grant permission by creating a resource-based IAM policy. You can grant permissions at the function level, on a version, or on an alias.

To invoke your function directly, use Invoke. To invoke your function in response to events in other AWS services, create an event source mapping (CreateEventSourceMapping), or configure a function trigger in the other service. For more information, see Invoking Functions.

Request Syntax

POST /2015-03-31/functions HTTP/1.1 Content-type: application/json { "Code": { "S3Bucket": "string", "S3Key": "string", "S3ObjectVersion": "string", "ZipFile": blob }, "DeadLetterConfig": { "TargetArn": "string" }, "Description": "string", "Environment": { "Variables": { "string" : "string" } }, "FunctionName": "string", "Handler": "string", "KMSKeyArn": "string", "Layers": [ "string" ], "MemorySize": number, "Publish": boolean, "Role": "string", "Runtime": "string", "Tags": { "string" : "string" }, "Timeout": number, "TracingConfig": { "Mode": "string" }, "VpcConfig": { "SecurityGroupIds": [ "string" ], "SubnetIds": [ "string" ] } }

URI Request Parameters

The request does not use any URI parameters.

Request Body

The request accepts the following data in JSON format.

Code

The code for the function.

Type: FunctionCode object

Required: Yes

DeadLetterConfig

A dead letter queue configuration that specifies the queue or topic where Lambda sends asynchronous events when they fail processing. For more information, see Dead Letter Queues.

Type: DeadLetterConfig object

Required: No

Description

A description of the function.

Type: String

Length Constraints: Minimum length of 0. Maximum length of 256.

Required: No

Environment

Environment variables that are accessible from function code during execution.

Type: Environment object

Required: No

FunctionName

The name of the Lambda function.

Name formats

  • Function name - my-function.

  • Function ARN - arn:aws:lambda:us-west-2:123456789012:function:my-function.

  • Partial ARN - 123456789012:function:my-function.

The length constraint applies only to the full ARN. If you specify only the function name, it is limited to 64 characters in length.

Type: String

Length Constraints: Minimum length of 1. Maximum length of 140.

Pattern: (arn:(aws[a-zA-Z-]*)?:lambda:)?([a-z]{2}(-gov)?-[a-z]+-\d{1}:)?(\d{12}:)?(function:)?([a-zA-Z0-9-_]+)(:(\$LATEST|[a-zA-Z0-9-_]+))?

Required: Yes

Handler

The name of the method within your code that Lambda calls to execute your function. The format includes the file name. It can also include namespaces and other qualifiers, depending on the runtime. For more information, see Programming Model.

Type: String

Length Constraints: Maximum length of 128.

Pattern: [^\s]+

Required: Yes

KMSKeyArn

The ARN of the AWS Key Management Service (AWS KMS) key that's used to encrypt your function's environment variables. If it's not provided, AWS Lambda uses a default service key.

Type: String

Pattern: (arn:(aws[a-zA-Z-]*)?:[a-z0-9-.]+:.*)|()

Required: No

Layers

A list of function layers to add to the function's execution environment. Specify each layer by its ARN, including the version.

Type: Array of strings

Length Constraints: Minimum length of 1. Maximum length of 140.

Pattern: arn:[a-zA-Z0-9-]+:lambda:[a-zA-Z0-9-]+:\d{12}:layer:[a-zA-Z0-9-_]+:[0-9]+

Required: No

MemorySize

The amount of memory that your function has access to. Increasing the function's memory also increases its CPU allocation. The default value is 128 MB. The value must be a multiple of 64 MB.

Type: Integer

Valid Range: Minimum value of 128. Maximum value of 3008.

Required: No

Publish

Set to true to publish the first version of the function during creation.

Type: Boolean

Required: No

Role

The Amazon Resource Name (ARN) of the function's execution role.

Type: String

Pattern: arn:(aws[a-zA-Z-]*)?:iam::\d{12}:role/?[a-zA-Z_0-9+=,.@\-_/]+

Required: Yes

Runtime

The identifier of the function's runtime.

Type: String

Valid Values: nodejs8.10 | nodejs10.x | java8 | python2.7 | python3.6 | python3.7 | dotnetcore1.0 | dotnetcore2.1 | go1.x | ruby2.5 | provided

Required: Yes

Tags

A list of tags to apply to the function.

Type: String to string map

Required: No

Timeout

The amount of time that Lambda allows a function to run before stopping it. The default is 3 seconds. The maximum allowed value is 900 seconds.

Type: Integer

Valid Range: Minimum value of 1.

Required: No

TracingConfig

Set Mode to Active to sample and trace a subset of incoming requests with AWS X-Ray.

Type: TracingConfig object

Required: No

VpcConfig

For network connectivity to AWS resources in a VPC, specify a list of security groups and subnets in the VPC. When you connect a function to a VPC, it can only access resources and the internet through that VPC. For more information, see VPC Settings.

Type: VpcConfig object

Required: No

Response Syntax

HTTP/1.1 201 Content-type: application/json { "CodeSha256": "string", "CodeSize": number, "DeadLetterConfig": { "TargetArn": "string" }, "Description": "string", "Environment": { "Error": { "ErrorCode": "string", "Message": "string" }, "Variables": { "string" : "string" } }, "FunctionArn": "string", "FunctionName": "string", "Handler": "string", "KMSKeyArn": "string", "LastModified": "string", "Layers": [ { "Arn": "string", "CodeSize": number } ], "MasterArn": "string", "MemorySize": number, "RevisionId": "string", "Role": "string", "Runtime": "string", "Timeout": number, "TracingConfig": { "Mode": "string" }, "Version": "string", "VpcConfig": { "SecurityGroupIds": [ "string" ], "SubnetIds": [ "string" ], "VpcId": "string" } }

Response Elements

If the action is successful, the service sends back an HTTP 201 response.

The following data is returned in JSON format by the service.

CodeSha256

The SHA256 hash of the function's deployment package.

Type: String

CodeSize

The size of the function's deployment package, in bytes.

Type: Long

DeadLetterConfig

The function's dead letter queue.

Type: DeadLetterConfig object

Description

The function's description.

Type: String

Length Constraints: Minimum length of 0. Maximum length of 256.

Environment

The function's environment variables.

Type: EnvironmentResponse object

FunctionArn

The function's Amazon Resource Name (ARN).

Type: String

Pattern: arn:(aws[a-zA-Z-]*)?:lambda:[a-z]{2}(-gov)?-[a-z]+-\d{1}:\d{12}:function:[a-zA-Z0-9-_\.]+(:(\$LATEST|[a-zA-Z0-9-_]+))?

FunctionName

The name of the function.

Type: String

Length Constraints: Minimum length of 1. Maximum length of 170.

Pattern: (arn:(aws[a-zA-Z-]*)?:lambda:)?([a-z]{2}(-gov)?-[a-z]+-\d{1}:)?(\d{12}:)?(function:)?([a-zA-Z0-9-_\.]+)(:(\$LATEST|[a-zA-Z0-9-_]+))?

Handler

The function that Lambda calls to begin executing your function.

Type: String

Length Constraints: Maximum length of 128.

Pattern: [^\s]+

KMSKeyArn

The KMS key that's used to encrypt the function's environment variables. This key is only returned if you've configured a customer-managed CMK.

Type: String

Pattern: (arn:(aws[a-zA-Z-]*)?:[a-z0-9-.]+:.*)|()

LastModified

The date and time that the function was last updated, in ISO-8601 format (YYYY-MM-DDThh:mm:ss.sTZD).

Type: String

Layers

The function's layers.

Type: Array of Layer objects

MasterArn

For Lambda@Edge functions, the ARN of the master function.

Type: String

Pattern: arn:(aws[a-zA-Z-]*)?:lambda:[a-z]{2}(-gov)?-[a-z]+-\d{1}:\d{12}:function:[a-zA-Z0-9-_]+(:(\$LATEST|[a-zA-Z0-9-_]+))?

MemorySize

The memory that's allocated to the function.

Type: Integer

Valid Range: Minimum value of 128. Maximum value of 3008.

RevisionId

The latest updated revision of the function or alias.

Type: String

Role

The function's execution role.

Type: String

Pattern: arn:(aws[a-zA-Z-]*)?:iam::\d{12}:role/?[a-zA-Z_0-9+=,.@\-_/]+

Runtime

The runtime environment for the Lambda function.

Type: String

Valid Values: nodejs8.10 | nodejs10.x | java8 | python2.7 | python3.6 | python3.7 | dotnetcore1.0 | dotnetcore2.1 | go1.x | ruby2.5 | provided

Timeout

The amount of time that Lambda allows a function to run before stopping it.

Type: Integer

Valid Range: Minimum value of 1.

TracingConfig

The function's AWS X-Ray tracing configuration.

Type: TracingConfigResponse object

Version

The version of the Lambda function.

Type: String

Length Constraints: Minimum length of 1. Maximum length of 1024.

Pattern: (\$LATEST|[0-9]+)

VpcConfig

The function's networking configuration.

Type: VpcConfigResponse object

Errors

CodeStorageExceededException

You have exceeded your maximum total code size per account. Learn more

HTTP Status Code: 400

InvalidParameterValueException

One of the parameters in the request is invalid. For example, if you provided an IAM role for AWS Lambda to assume in the CreateFunction or the UpdateFunctionConfiguration API, that AWS Lambda is unable to assume you will get this exception.

HTTP Status Code: 400

ResourceConflictException

The resource already exists.

HTTP Status Code: 409

ResourceNotFoundException

The resource (for example, a Lambda function or access policy statement) specified in the request does not exist.

HTTP Status Code: 404

ServiceException

The AWS Lambda service encountered an internal error.

HTTP Status Code: 500

TooManyRequestsException

Request throughput limit exceeded.

HTTP Status Code: 429

See Also

For more information about using this API in one of the language-specific AWS SDKs, see the following: