AWS Cloudformation Lambda S3 - 循环依赖

Question

Thanks in advance!

So I have created this Cloudformation template below and have a circular dependency error.. I know what is causing the error, but cannot think of a solution for what I'm trying to achieve..

Which is;

• Create a lambda function that has a two environment variables for two buckets I need to use in the functions code

• Create two s3 buckets, one for a file input and one for a file output

• Create a trigger that calls the lambda function when an object is added to the 1st bucket

Here is my code:

      "lambda": {
            "Type": "AWS::Lambda::Function",
            "DependsOn": [
                "s3accessrole",
                "s3rolepolicies",
                "bucket1"
            ],
            "Properties": {
                "Code": {
                    "S3Bucket": "resource-bucket",
                    "S3Key": "filepath/function.zip"
                },
                "Role": {
                    "Fn::GetAtt": [
                        "s3accessrole",
                        "Arn"
                    ]
                },
                "Timeout": 60,
                "Handler": "function.handler",
                "Runtime": "nodejs6.10",
                "MemorySize": 1024,
                "Environment": {
                    "Variables": {
                        "bucket1": {
                            "Ref": "bucket1"
                        },
                        "bucket2": {
                            "Ref": "bucket2"
                        }
                    }
                }
            },
            "Metadata": {
                "AWS::CloudFormation::Designer": {
                    "id": "XXXX"
                }
            }
        },
        "bucket1": {
            "Type": "AWS::S3::Bucket",
            "Properties": {
                "AccessControl": "Private",
                "LifecycleConfiguration": {
                    "Rules": [
                        {
                            "ExpirationInDays": "1",
                            "Id": "delete images/",
                            "Status": "Enabled"
                        }
                    ]
                },
                "VersioningConfiguration": {
                    "Status": "Suspended"
                },
                "NotificationConfiguration": {
                    "LambdaConfigurations": [
                        {
                            "Event": "s3:ObjectCreated:*",
                            "Function": {
                                "Ref": "lambda"
                            }
                        }
                    ]
                }
            },
            "Metadata": {
                "AWS::CloudFormation::Designer": {
                    "id": "XXXX"
                }
            }
        },
        "lambdaperm": {
            "Type": "AWS::Lambda::Permission",
            "Properties": {
                "Action": "lambda:InvokeFunction",
                "FunctionName": {
                    "Ref": "lambda"
                },
                "Principal": "s3.amazonaws.com",
                "SourceAccount": {
                    "Ref": "AWS::AccountId"
                },
                "SourceArn": {
                    "Fn::Join": [
                        ":",
                        [
                            "arn",
                            "aws",
                            "s3",
                            "",
                            "",
                            {
                                "Ref": "bucket1"
                            }
                        ]
                    ]
                }
            },
            "Metadata": {
                "AWS::CloudFormation::Designer": {
                    "id": "XXXX"
                }
            }
        },
        "bucket2": {
            "Type": "AWS::S3::Bucket",
            "Properties": {
                "AccessControl": "Private",
                "LifecycleConfiguration": {
                    "Rules": [
                        {
                            "ExpirationInDays": "1",
                            "Id": "delete images/",
                            "Status": "Enabled"
                        }
                    ]
                },
                "VersioningConfiguration": {
                    "Status": "Suspended"
                }
            },
            "Metadata": {
                "AWS::CloudFormation::Designer": {
                    "id": "XXXX"
                }
            }
        }

Answer 1

来自lambda函数中第一个存储桶的传入事件包含用于该存储桶的名称，因此我不需要创建环境变量。