How can I resolve the error that I receive when I subscribe an AWS Lambda function to a push-based event source in AWS CloudFormation?
"I can't subscribe my AWS Lambda function to an Amazon Simple Storage Service (Amazon S3) event notification or Amazon Simple Notification Service (Amazon SNS) topic in my AWS CloudFormation stack. If I use the AWS::Lambda::EventSourceMapping resource, I receive the following error: "Unrecognized event source, must be kinesis or dynamodb stream.""
"I can't subscribe my AWS Lambda function to an Amazon Simple Storage Service (Amazon S3) event notification or Amazon Simple Notification Service (Amazon SNS) topic in my AWS CloudFormation stack. If I use the AWS::Lambda::EventSourceMapping resource, I receive the following error: "Unrecognized event source, must be kinesis or dynamodb stream."Short descriptionThe AWS::Lambda::EventSourceMapping resource is designed for pull-based event sources, such as Amazon DynamoDB event streams and Amazon Kinesis. With push-based event sources, such as Amazon S3 event notifications or Amazon SNS messages, the event source is responsible for invoking the Lambda function. For a push event source to invoke a Lambda function, the function’s resource policy must authorize a supported event source.ResolutionIn your AWS CloudFormation template, add a resource-based policy using the AWS::Lambda::Permission resource.For example, the following resource-based policy allows an Amazon SNS topic to invoke a Lambda function:"LambdaResourcePolicy": {  "Type": "AWS::Lambda::Permission",  "Properties": {    "FunctionName" : { "Ref" : "MyFunction" },    "Principal": "sns.amazonaws.com",    "Action": "lambda:InvokeFunction",    "SourceArn" : { "Ref" : "MySNSTopic" }  }}For an Amazon SNS topic event source, you must define a topic policy with the required permissions.For an Amazon S3 event source, you must have a notification configuration statement that subscribes the Lambda function to the Amazon S3 bucket. For example:{  "AWSTemplateFormatVersion": "2010-09-09",  "Parameters": {    "BucketPrefix": {      "Type": "String",      "Default": "test-bucket-name"    }  },  "Resources": {    "EncryptionServiceBucket": {      "DependsOn": "LambdaInvokePermission",      "Type": "AWS::S3::Bucket",      "Properties": {        "BucketName": {          "Fn::Sub": "${BucketPrefix}-encryption-service"        },        "NotificationConfiguration": {          "LambdaConfigurations": [            {              "Function": {                "Fn::GetAtt": [                  "AppendItemToListFunction",                  "Arn"                ]              },              "Event": "s3:ObjectCreated:*",              "Filter": {                "S3Key": {                  "Rules": [                    {                      "Name": "suffix",                      "Value": "zip"                    }                  ]                }              }            }          ]        }      }    },    "LambdaInvokePermission": {      "Type": "AWS::Lambda::Permission",      "Properties": {        "FunctionName": {          "Fn::GetAtt": [            "AppendItemToListFunction",            "Arn"          ]        },        "Action": "lambda:InvokeFunction",        "Principal": "s3.amazonaws.com",        "SourceAccount": {          "Ref": "AWS::AccountId"        },        "SourceArn": {          "Fn::Sub": "arn:aws:s3:::${BucketPrefix}-encryption-service"        }      }    },    "AppendItemToListFunction": {      "Type": "AWS::Lambda::Function",      "Properties": {        "Handler": "index.handler",        "Role": {          "Fn::GetAtt": [            "LambdaExecutionRole",            "Arn"          ]        },        "Code": {          "ZipFile": {            "Fn::Join": [              "",              [                "exports.handler = function(event, context) {",                "console.log('Received event: ', JSON.stringify(event, null, 2));",                "};"              ]            ]          }        },        "Runtime": "nodejs8.10"      }    },    "LambdaExecutionRole": {      "Type": "AWS::IAM::Role",      "Properties": {        "AssumeRolePolicyDocument": {          "Version": "2012-10-17",          "Statement": [            {              "Effect": "Allow",              "Principal": {                "Service": [                  "lambda.amazonaws.com"                ]              },              "Action": [                "sts:AssumeRole"              ]            }          ]        },        "Path": "/",        "Policies": [          {            "PolicyName": "root",            "PolicyDocument": {              "Version": "2012-10-17",              "Statement": [                {                  "Effect": "Allow",                  "Action": [                    "logs:*"                  ],                  "Resource": "arn:aws:logs:*:*:log-group:/path/<log-group-name>:log-stream:<log-stream-name>"                }              ]            }          }        ]      }    }  }}In the preceding example, the S3 bucket and notification configuration are created at the same time. The example avoids a circular dependency by using the Fn::Join intrinsic function and the DependsOn attribute to create the resources in the following order: 1) IAM role, 2) Lambda function, 3) Lambda permission, and then 4) S3 bucket. For more information, see How do I avoid the "Unable to validate the following destination configurations" error with Lambda event notifications in AWS CloudFormation?Related informationCloudFormation best practicesLambda permissionsUpdate behaviors of stack resourcesFollow"