How do you resolve circular dependency in CloudFormation?

This resource is generated by AWS SAM automatically when the Role property for AWS::Serverless::Function is not specified. To resolve the circular dependency, you must break the loop by replacing the dynamic reference to the bucket resource.

How do I fix circular dependency error?

There are a couple of options to get rid of circular dependencies. For a longer chain, A -> B -> C -> D -> A , if one of the references is removed (for instance, the D -> A reference), the cyclic reference pattern is broken, as well. For simpler patterns, such as A -> B -> A , refactoring may be necessary.

What happens if CloudFormation fails?

If AWS CloudFormation fails to create, update, or delete your stack, you can view error messages or logs to help you learn more about the issue. Use the CloudFormation console to view the status of your stack. In the console, you can view a list of stack events while your stack is being created, updated, or deleted.

How do I avoid the unable to validate the following destination configurations error in AWS CloudFormation?

Try one of the following strategies to avoid the “Unable to validate the following destination configurations” error:

1. Specify a value for BucketName in your AWS CloudFormation template.
2. Create a stack, and then perform a stack update.

What does circular dependency occur in AWS CloudFormation?

What is a circular dependency? Resource A is dependent on Resource B, and Resource B is dependent on Resource A. When AWS CloudFormation assesses that this type of condition exists, you will get a circular dependency error because AWS CloudFormation is unable to clearly determine which resource should be created first.

What is Sam AWS?

The AWS Serverless Application Model (SAM) is an open-source framework for building serverless applications. It provides shorthand syntax to express functions, APIs, databases, and event source mappings. With just a few lines per resource, you can define the application you want and model it using YAML.

What causes circular dependency?

The reason for the circular dependency is that the dependency list of Test1 (and of Test2) is wider than expected. Indeed, by quickly looking at the code, one would say that both Test1 and Test2 depend on the value of Product Name, because Product Name is the only column used in the filter expression.

What is circular dependency problem?

A circular dependency is where Project A depends on something in Project B and project B depends on something in Project A. This means to compile Project A you must first compile Project B, but you can’t do that as B requires A to be compiled. This is the problem that circular dependencies cause.

How do I fix delete failed CloudFormation?

Resolution

1. Open the AWS CloudFormation console.
2. Choose the stack that’s stuck in DELETE_FAILED status.
3. Choose Delete. Note: A window opens and lists the resources that failed to delete.
4. In the window, select all the resources that you want to retain, and then choose Delete stack.

How do you retry CloudFormation?

In the console, select the stack set that contains the stack on which the operation failed. In the Actions menu, choose Edit StackSet details to retry creating or updating stacks. On the Specify template page, to use the same AWS CloudFormation template, keep the default option, Use current template.

What is SNS topic in AWS?

An Amazon SNS topic is a logical access point that acts as a communication channel. A topic lets you group multiple endpoints (such as AWS Lambda, Amazon SQS, HTTP/S, or an email address).

How do I find my canonical ID on AWS?

Choose Permissions, and then scroll down to the Access Control List section. At the top of the page, under Access for bucket owner, the canonical user ID for the AWS account appears.

How do I use implicit dependencies in AWS CloudFormation?

Using DependsOn, you can specify that Resource A needs to be created before Resource B. AWS CloudFormation also has implicit dependencies when utilizing the intrinsic function Ref. You can use Ref to reference information from another resource.

How does AWS CloudFormation handle multiple resources in a template?

When you define multiple resources in a template, AWS CloudFormation tries to create those resources in a parallel fashion (for speed) while also trying to extract correct dependencies based on the use of references when necessary. However, you can control resource-creation order by utilizing the DependsOn attribute within a resource.

How do I avoid hardcoding names in AWS CloudFormation?

To avoid hardcoding names, we can allow AWS CloudFormation to autogenerate names for us, but this can sometimes lead to circular dependency errors as well. In our next example, instead of moving the resource out, we will assign a name by using pseudo parameters to avoid the circular dependency.

When should I override default parallelism in AWS CloudFormation?

Override default parallelism when creating, updating, or deleting resources. AWS CloudFormation creates, updates, and deletes resources in parallel to the extent possible. It automatically determines which resources in a template can be parallelized and which have dependencies that require other operations to finish first.