AWS Documentation » AWS CloudFormation » User Guide » Lambda Resource Type Reference » AWS::Lambda::Permission

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AWS::Lambda::Permission

The AWS::Lambda::Permission resource grants an AWS service or another account permission to use a function. You can apply the policy at the function level, or specify a qualifier to restrict access to a single version or alias. If you use a qualifier, the invoker must use the full Amazon Resource Name (ARN) of that version or alias to invoke the function.

To grant permission to another account, specify the account ID as the Principal. For AWS services, the principal is a domain-style identifier defined by the service, like s3.amazonaws.com or sns.amazonaws.com. For AWS services, you can also specify the ARN or owning account of the associated resource as the SourceArn or SourceAccount. If you grant permission to a service principal without specifying the source, other accounts could potentially configure resources in their account to invoke your Lambda function.

This resource adds a statement to a resource-based permission policy for the function. For more information about function policies, see Lambda Function Policies.

Syntax

To declare this entity in your AWS CloudFormation template, use the following syntax:

JSON

{
  "Type" : "AWS::Lambda::Permission",
  "Properties" : {
      "Action" : String,
      "EventSourceToken" : String,
      "FunctionName" : String,
      "Principal" : String,
      "SourceAccount" : String,
      "SourceArn" : String
    }
}

YAML

Type: AWS::Lambda::Permission
Properties: 
  Action: String
  EventSourceToken: String
  FunctionName: String
  Principal: String
  SourceAccount: String
  SourceArn: String

Properties

Action

The action that the principal can use on the function. For example, lambda:InvokeFunction or lambda:GetFunction.

Required: Yes

Type: String

Pattern: (lambda:[*]|lambda:[a-zA-Z]+|[*])

Update requires: Replacement

EventSourceToken

For Alexa Smart Home functions, a token that must be supplied by the invoker.

Required: No

Type: String

Minimum: 0

Maximum: 256

Pattern: [a-zA-Z0-9._\-]+

Update requires: Replacement

FunctionName

The name of the Lambda function, version, or alias.

Name formats

• Function name - my-function (name-only), my-function:v1 (with alias).

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

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

You can append a version number or alias to any of the formats. The length constraint applies only to the full ARN. If you specify only the function name, it is limited to 64 characters in length.

Required: Yes

Type: String

Minimum: 1

Maximum: 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-_]+))?

Update requires: Replacement

Principal

The AWS service or account that invokes the function. If you specify a service, use SourceArn or SourceAccount to limit who can invoke the function through that service.

Required: Yes

Type: String

Pattern: .*

Update requires: Replacement

SourceAccount

For AWS services, the ID of the account that owns the resource. Use this instead of SourceArn to grant permission to resources that are owned by another account (for example, all of an account's Amazon S3 buckets). Or use it together with SourceArn to ensure that the resource is owned by the specified account. For example, an Amazon S3 bucket could be deleted by its owner and recreated by another account.

Required: No

Type: String

Pattern: \d{12}

Update requires: Replacement

SourceArn

For AWS services, the ARN of the AWS resource that invokes the function. For example, an Amazon S3 bucket or Amazon SNS topic.

Required: No

Type: String

Pattern: arn:(aws[a-zA-Z0-9-]*):([a-zA-Z0-9\-])+:([a-z]{2}(-gov)?-[a-z]+-\d{1})?:(\d{12})?:(.*)

Update requires: Replacement

Examples

Function Permission

Grant Amazon S3 permission to invoke MyLambdaFunction.

JSON

"LambdaInvokePermission": {
    "Type": "AWS::Lambda::Permission",
    "Properties": {
        "FunctionName": {
            "Fn::GetAtt": [
                "MyLambdaFunction",
                "Arn"
            ]
        },
        "Action": "lambda:InvokeFunction",
        "Principal": "s3.amazonaws.com",
        "SourceAccount": {
            "Ref": "AWS::AccountId"
        },
        "SourceArn": {
            "Fn::GetAtt": [
                "MyBucket",
                "Arn"
            ]
        }
    }
}

YAML

LambdaInvokePermission:
  Type: AWS::Lambda::Permission
  Properties:
    FunctionName: !GetAtt 
      - MyLambdaFunction
      - Arn
    Action: 'lambda:InvokeFunction'
    Principal: s3.amazonaws.com
    SourceAccount: !Ref 'AWS::AccountId'
    SourceArn: !GetAtt 
      - MyBucket
      - Arn