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 of the associated resource as the SourceArn. 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: [^\s]+

Update requires: Replacement

SourceAccount

For Amazon S3, the ID of the account that owns the resource. Use this together with SourceArn to ensure that the resource is owned by the specified account. It is possible for an Amazon S3 bucket to be deleted by its owner and recreated by another account.

Required: No

Type: String

Maximum: 12

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.

Note that Lambda configures the comparison using the StringLike operator.

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

Cross Account Invoke

Grant account 123456789012 permission to invoke a function resource named function created in the same template.

YAML

  permission:
    Type: AWS::Lambda::Permission
    Properties:
      FunctionName: !GetAtt function.Arn
      Action: lambda:InvokeFunction
      Principal: 123456789012

Amazon S3 Notifications

Grant Amazon S3 permission to invoke a function resource named function created in the same template, to process notifications for a bucket resource named bucket.

JSON

"s3Permission": {
    "Type": "AWS::Lambda::Permission",
    "Properties": {
        "FunctionName": {
            "Fn::GetAtt": [
                "function",
                "Arn"
            ]
        },
        "Action": "lambda:InvokeFunction",
        "Principal": "s3.amazonaws.com",
        "SourceAccount": {
            "Ref": "AWS::AccountId"
        },
        "SourceArn": {
            "Fn::GetAtt": [
                "bucket",
                "Arn"
            ]
        }
    }
}

YAML

s3Permission:
  Type: AWS::Lambda::Permission
  Properties:
    FunctionName: !GetAtt function.Arn
    Action: lambda:InvokeFunction
    Principal: s3.amazonaws.com
    SourceAccount: !Ref 'AWS::AccountId'
    SourceArn: !GetAtt bucket.Arn