Hi there,
Although Localstack looks quite promising, since a couple of weeks ago our team is a bit blocked due to an issue we are experiencing with CloudFormation.
Any help would be more than welcome.

Having a docker-compose like this:

```
version: '3'

services:
  gateway:
    image: app
    depends_on:
      - localstack
    environment:
      - AWS_ACCESS_KEY_ID=localkey
      - AWS_SECRET_ACCESS_KEY=localsecret

  localstack:
    container_name: localstack
    image: localstack/localstack
    expose:
      - "4567-4599"
    ports:
      - "4567-4599:4567-4599"
    environment:
      - SERVICES=iam, lambda, s3, cloudformation, sqs, sts
      - LAMBDA_EXECUTOR=docker
      - DOCKER_HOST=unix:///var/run/docker.sock
      - LAMBDA_REMOTE_DOCKER=true
      - HOSTNAME_EXTERNAL=localstack
      - HOSTNAME=localstack
      - DEBUG=1
    volumes:
      - "/tmp/localstack:/tmp/localstack"
      - "/var/run/docker.sock:/var/run/docker.sock"
```

Gateway container it is just a container with several tools pre-installed like (awscli ... ) to be used as an entry point for the inner network.

From that gateway container we can successfully run :
```
aws --endpoint-url=http://localstack:4572 s3api create-bucket --bucket serverlessdeploy --region us-east-1 --create-bucket-configuration LocationConstraint=us-east-1
```

Even upload object to it (hitting http://localstack:4572 with the following parameters):
```
{
  Body: <Buffer 7b 22 41 57 53 54 65 6d 70 6c 61 74 65 46 6f 72 6d 61 74 56 65 72 73 69 6f 6e 22 3a 22 32 30 31 30 2d 30 39 2d 30 39 22 2c 22 44 65 73 63 72 69 70 74 ... 2768 more bytes>,
  Bucket: 'mybucket',
  Key: 'whatever/local/1584035954811-2020-03-12T17:59:14.811Z/compiled-cloudformation-template.json',
  ContentType: 'application/json',
  Metadata: { filesha256: 'h003I5m1ox/MQ+ia+9zyvGQ38kOrHTI62EVft/J6aIc=' }
}
```

But when we try to create an stack hitting CloudFormation (http://localstack:4581) with the following params:
```
{
  StackName: 'whatever',
  OnFailure: 'DELETE',
  Capabilities: [ 'CAPABILITY_IAM', 'CAPABILITY_NAMED_IAM', [length]: 2 ],
  Parameters: [ [length]: 0 ],
  TemplateURL: 'http://localstack:4572/mybucket/whatever/local/1584035954811-2020-03-12T17:59:14.811Z/compiled-cloudformation-template.json',
  Tags: [ { Key: 'STAGE', Value: 'local' }, [length]: 1 ]
}
```

We receive the following error:
```
"CreateStack" (404) POST /: b'<?xml version="1.0" encoding="UTF-8"?>\n<Error>\n    <Code>NoSuchBucket</Code>\n    <Message>The specified bucket does not exist</Message>\n    <BucketName>localstack:4572</BucketName>\n    <RequestID>7a62c49f-347e-4fc4-9331-6e8eEXAMPLE</RequestID>\n</Error>'
```


## Additional Info:
 
Docker daemon it is not in the host machine

Operating System: Linux/4.14.146-119.123.amzn2.x86_64 
Localstack Version: latest (0.10.8)
Aws cli Version:  aws-cli/1.18.20 Python/3.5.3 botocore/1.15.20
Docker Version: 19.03.7, build 7141c199a2

## Edit:
If we run same steps locally (having docker daemon in the host machine) we face the following *different* issue:
```
HTTP 502
```
And the stack:
```
2020-03-13T12:45:02:ERROR:localstack.services.generic_proxy: Error forwarding request: Unable to fetch template body (code 403) from URL http://localstack:4572/mybucket/whatever/local/1584103485885-2020-03-13T12:44:45.885Z/compiled-cloudformation-template.json Traceback (most recent call last):
  File "/opt/code/localstack/localstack/services/generic_proxy.py", line 247, in forward
    listener_result = listener.forward_request(method=method,
  File "/opt/code/localstack/localstack/services/cloudformation/cloudformation_listener.py", line 172, in forward_request
    modified_request = transform_template(req_data)
  File "/opt/code/localstack/localstack/services/cloudformation/cloudformation_listener.py", line 70, in transform_template
    template_body = get_template_body(req_data)
  File "/opt/code/localstack/localstack/services/cloudformation/cloudformation_listener.py", line 115, in get_template_body
    raise Exception('Unable to fetch template body (code %s) from URL %s' % (status_code, url))
Exception: Unable to fetch template body (code 403) from URL http://localstack:4572/mybucket/whatever/local/1584103485885-2020-03-13T12:44:45.885Z/compiled-cloudformation-template.json
```

Thanks in advance.

if attribute_name in ['Arn', 'QueueArn']:
            return aws_stack.sqs_queue_arn(queue_name=self.name)
        return SQS_Queue_get_cfn_attribute_orig(self, attribute_name)
    SQS_Queue_get_cfn_attribute_orig = sqs_models.Queue.get_cfn_attribute
    sqs_models.Queue.get_cfn_attribute = SQS_Queue_get_cfn_attribute
    
    def S3_Bucket_get_cfn_attribute(self, attribute_name):
        if attribute_name in ['Arn']:
            return aws_stack.s3_bucket_arn(self.name)
        return S3_Bucket_get_cfn_attribute_orig(self, attribute_name)
    S3_Bucket_get_cfn_attribute_orig = s3_models.FakeBucket.get_cfn_attribute
    s3_models.FakeBucket.get_cfn_attribute = S3_Bucket_get_cfn_attribute
    
    @property
    def SQS_Queue_physical_resource_id(self):
        result = SQS_Queue_physical_resource_id_orig.fget(self)
        if '://' not in result:
            
            return aws_stack.get_sqs_queue_url(result)
        return result
    SQS_Queue_physical_resource_id_orig = sqs_models.Queue.physical_resource_id
    sqs_models.Queue.physical_resource_id = SQS_Queue_physical_resource_id
    
    def LogGroup_get_cfn_attribute(self, attribute_name):