WIP - Adds rudimentary support for Application Load Balancers

[sesh-kebab]

What does this pull request do? Adds a new type of Load Balancer: Application Load Balancer. Default behavior has been kept the same but you can now optionally specify --type elb|alb flag (default is elb).

An application load balancer has health check that needs to be specified differently to classic ELB's health check target. So a new property Path has been added to HealthCheck model which is used for an ALB type Load Balancer.

When creating a fargate service, you will need to specify a alb load balancer as a classic ELB isn't supported.

How should this be tested?

• Create a new Applicaiton Load Balancer using --type alb flag
• Specify the load balancer when creating a Fargate service
• Ensure that the service is accessible and Target Group health check recognizes a healthy service

Todo

• [x] Read SSL certificate information from Target Group Targets (how?)
• [x] Add wait logic when creating/deleting load balancers
• [ ] Update Load Balancer and Service unit tests for ALB cases
• [x] Update Service Read to check if the service is behind an ALB and resolve LB correctly

[diemonster]

When creating a fargate service, you will need to specify a alb load balancer as a classic ELB isn't supported.

Is this set as a default then, or can you still specify a "classic" elb for a fargate service and receive an AWS error?

[sesh-kebab]

@diemonster sorry I missed replying to the below question. You can still specify any load balancer. If you try to specify a classic load balancer when creating a fargate/stateless service, you will get an error stating fargate only supports application load balancers which is surfaced up to the client.

Is this set as a default then, or can you still specify a "classic" elb for a fargate service and receive an AWS error?

[tlake]

@sesh-kebab service get commands don't populate the LOADBALANCER column for a fargate service deployed behind an ALB. I think service read logic has to be updated to handle ALBs as well.

[sesh-kebab]

@tlake right on! will update the todo list in summary.