CloudFormation

MicroStack emulates AWS CloudFormation, provisioning actual MicroStack resources (S3 buckets, SQS queues, DynamoDB tables, Lambda functions, IAM roles, etc.) when a stack is created or updated. Stacks complete synchronously — CreateStack returns only after all resources are provisioned. Failed resources trigger automatic rollback, leaving the stack in ROLLBACK_COMPLETE. Change sets are also supported for staged updates.

Supported Operations

CreateStack, DescribeStacks, ListStacks, DeleteStack, UpdateStack, DescribeStackEvents, DescribeStackResource, DescribeStackResources, ListStackResources, GetTemplate, ValidateTemplate, ListExports, CreateChangeSet, DescribeChangeSet, ExecuteChangeSet, DeleteChangeSet, ListChangeSets, GetTemplateSummary, UpdateTerminationProtection, SetStackPolicy, GetStackPolicy, ListImports

Usage

var client = new AmazonCloudFormationClient(
    new BasicAWSCredentials("test", "test"),
    new AmazonCloudFormationConfig
    {
        RegionEndpoint = RegionEndpoint.USEast1,
        ServiceURL = "http://localhost:4566",
    });

// Define a simple template as JSON
var template = """
    {
      "AWSTemplateFormatVersion": "2010-09-09",
      "Parameters": {
        "QueueName": { "Type": "String", "Default": "my-queue" }
      },
      "Resources": {
        "MyQueue": {
          "Type": "AWS::SQS::Queue",
          "Properties": {
            "QueueName": { "Ref": "QueueName" }
          }
        },
        "MyBucket": {
          "Type": "AWS::S3::Bucket",
          "Properties": {
            "BucketName": "my-cfn-bucket"
          }
        }
      },
      "Outputs": {
        "QueueArn": {
          "Value": { "Fn::GetAtt": ["MyQueue", "Arn"] },
          "Export": { "Name": "my-queue-arn" }
        }
      }
    }
    """;

// Create the stack — resources are provisioned synchronously
await client.CreateStackAsync(new CreateStackRequest
{
    StackName = "my-stack",
    TemplateBody = template,
    Parameters =
    [
        new Parameter { ParameterKey = "QueueName", ParameterValue = "custom-queue" },
    ],
});

// Describe the stack
var descResp = await client.DescribeStacksAsync(new DescribeStacksRequest
{
    StackName = "my-stack",
});

Console.WriteLine(descResp.Stacks[0].StackStatus); // CREATE_COMPLETE

// Read an exported output
var exports = await client.ListExportsAsync(new ListExportsRequest());
var queueArn = exports.Exports.First(e => e.Name == "my-queue-arn").Value;
Console.WriteLine(queueArn); // arn:aws:sqs:us-east-1:...

// Delete the stack (resources are deleted too)
await client.DeleteStackAsync(new DeleteStackRequest { StackName = "my-stack" });

Change Sets

Use change sets to preview and stage stack updates before applying them.

// Create stack via change set
await client.CreateChangeSetAsync(new CreateChangeSetRequest
{
    StackName = "my-stack",
    ChangeSetName = "initial-create",
    TemplateBody = template,
    ChangeSetType = ChangeSetType.CREATE,
});

var csDesc = await client.DescribeChangeSetAsync(new DescribeChangeSetRequest
{
    StackName = "my-stack",
    ChangeSetName = "initial-create",
});
Console.WriteLine(csDesc.ChangeSetName); // initial-create

// Execute the change set to actually provision resources
await client.ExecuteChangeSetAsync(new ExecuteChangeSetRequest
{
    StackName = "my-stack",
    ChangeSetName = "initial-create",
});

var desc = await client.DescribeStacksAsync(new DescribeStacksRequest { StackName = "my-stack" });
Console.WriteLine(desc.Stacks[0].StackStatus); // CREATE_COMPLETE

Supported Resource Types

CloudFormation in MicroStack provisions real emulated resources for the following types:

AWS::S3::Bucket, AWS::S3::BucketPolicy
AWS::SQS::Queue
AWS::SNS::Topic, AWS::SNS::Subscription
AWS::DynamoDB::Table
AWS::Lambda::Function, AWS::Lambda::EventSourceMapping
AWS::IAM::Role, AWS::IAM::Policy, AWS::IAM::ManagedPolicy, AWS::IAM::InstanceProfile
AWS::KMS::Key, AWS::KMS::Alias
AWS::SSM::Parameter
AWS::SecretsManager::Secret
AWS::ECR::Repository
AWS::Kinesis::Stream
AWS::ElasticLoadBalancingV2::LoadBalancer, AWS::ElasticLoadBalancingV2::Listener, AWS::ElasticLoadBalancingV2::TargetGroup
AWS::CloudFormation::WaitConditionHandle, AWS::CloudFormation::WaitCondition (no-op)

Supported Intrinsic Functions

Ref, Fn::GetAtt, Fn::Sub, Fn::Join, Fn::Select, Fn::If, Fn::Equals, Fn::And, Fn::Or, Fn::Not, Fn::Base64, Fn::Split, Fn::FindInMap, Condition