Is it possible to run a Spring Cloud AWS application on Elastic Beanstalk? - amazon-elastic-beanstalk

Question

I'm trying to run a web application of "hello world" complexity on Elastic Beanstalk. I have no problem doing this with Spring Boot on Elastic Beanstalk.
But when I try to use Spring Cloud AWS, I encounter a myriad of problems. The reference guide never mentions that running on Beanstalk is possible, so perhaps I am barking up the wrong tree?
The root problem I seem to encounter is the stackResourceRegistryFactoryBean blowing up when trying to identify the "stack" being used - i.e. the CloudFormation stack. But I'm using Elastic Beanstalk, not CloudFormation. The root exception is:
Caused by: org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.cloud.aws.core.env.stack.config.StackResourceRegistryFactoryBean]: Factory method 'stackResourceRegistryFactoryBean' threw exception; nested exception is java.lang.IllegalAccessError: tried to access class org.springframework.cloud.aws.core.env.stack.config.AutoDetectingStackNameProvider from class org.springframework.cloud.aws.autoconfigure.context.ContextStackAutoConfiguration$StackAutoDetectConfiguration
at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:189)
at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:588)
... 89 more
Caused by: java.lang.IllegalAccessError: tried to access class org.springframework.cloud.aws.core.env.stack.config.AutoDetectingStackNameProvider from class org.springframework.cloud.aws.autoconfigure.context.ContextStackAutoConfiguration$StackAutoDetectConfiguration
at org.springframework.cloud.aws.autoconfigure.context.ContextStackAutoConfiguration$StackAutoDetectConfiguration.stackResourceRegistryFactoryBean(ContextStackAutoConfiguration.java:71)
at org.springframework.cloud.aws.autoconfigure.context.ContextStackAutoConfiguration$StackAutoDetectConfiguration$$EnhancerBySpringCGLIB$$432c7658.CGLIB$stackResourceRegistryFactoryBean$0(<generated>)
at org.springframework.cloud.aws.autoconfigure.context.ContextStackAutoConfiguration$StackAutoDetectConfiguration$$EnhancerBySpringCGLIB$$432c7658$$FastClassBySpringCGLIB$$47c6e7d2.invoke(<generated>)
at org.springframework.cglib.proxy.MethodProxy.invokeSuper(MethodProxy.java:228)
...
There are tags present on the generated EC2 instance for "aws:cloudformation:stack-id" and "aws:cloudformation:stack-name" if it is relevant, and my understanding is that Beanstalk uses CloudFormation stacks behind the scenes. I've tried manually specifying the name of the stack via #EnableStackConfiguration, but since the name is generated I'd rather not do this, even if it did work.
So my questions are:
1) Is it possible to run a Spring Cloud AWS-based application on Elastic Beanstalk?
2) If so, are there any special steps required? For example, I already discovered the one about CloudFormation read access being required on the role.
3) Is there a way to disable the part of Spring Cloud AWS that attempts to obtain resource names from the stack? At this point my app doesn't need this.
thanks in advance,
k

Answer 1

Ok, so over time I've answered my own questions on this topic.
First, Elastic Beanstalk uses CloudFormation behind the scenes, so this is why there is a "stack".
Next, Spring Cloud AWS tries to make connections to DBs and such easier by binding to other resources that may have been created in the same stack. This is reasonable - if you are expecting it. If not, as #barthand says, it is probably better to turn this feature off with cloud.aws.stack.auto=false than have the app fail to start up.
Third, When using Elastic Beanstalk, you have the opportunity to associate an execution role with your instance - otherwise the code in your instance isn't able to do much of anything with the AWS SDK. To explore the resources in a CloudFormation stack, Spring Cloud AWS tries to make some API calls, and by default these are not allowed. To make them allowed, I added these permissions to the role:
"Statement": [
{
"Effect": "Allow",
"Action": [
"cloudformation:DescribeStacks",
"cloudformation:DescribeStackEvents",
"cloudformation:DescribeStackResource",
"cloudformation:DescribeStackResources",
"cloudformation:GetTemplate",
"cloudformation:List*"
],
"Resource": "*"
}
]
So to answer my original questions:
Yes it is definitely possible (and easy!) to run a Spring Cloud AWS
program in Elastic Beanstalk.
Special requirements - Need to open the permissions on the associated role to include CloudFormation read operations, or...
Disable these using cloud.aws.stack.auto=false
Hope this info helps someone in the future

Answer 2

spring-cloud-aws seems to assume by default that you're running your app using your custom CloudFormation template.
In case of Elastic Beanstalk, you simply need to tell spring-cloud-aws to resign from obtaining information about the stack automatically:
cloud.aws.stack.auto = false
Not sure why it is not mentioned in the docs. For basic Java apps, Elastic Beanstalk seems to be an obvious choice.