Supporting local (mock) AWS endpoints for testing

[marceldegraaf]

We're wondering if it is currently possible (and if not, if you would be interested in a PR) to configure local mock endpoints in aws-go. We would love to use something like fake_sns or fake_sqs to test our SNS/SQS integration locally.

[stripecodahale]

This isn't currently possible, but it would be a welcome change.

[marceldegraaf]

Thanks, we'll look into submitting a PR for this.

[marceldegraaf]

Hi @stripecodahale, my colleague @mrdg and I have discussed a possible implementation for this feature. We want to quickly run that by you before we start hacking on it :-).

So, our proposal is to add an overrides map to the endpoints package, containing tuples of service name (e.g. "ec2") and endpoint (e.g. "http://localhost:1234"). This overrides map has precedence over the existing code in endpoints.Lookup(), allowing one to override one or more service endpoints for local testing.

If you're OK with this, we'll submit the PR as soon as possible.

[stripecodahale]

As long as the overrides are for specific regions — e.g. endpoints.Add("test1", etc)—it sounds good.

[marceldegraaf]

I'm not sure I understand what you mean. Can you elaborate on what the region specifier should do in the context of a local service endpoint override? Thanks 😄

[stripecodahale]

Sorry, that was vague. I'm going through email before having coffee. :)

I mean, I'd want to provide the ability to add test regions with specific endpoints rather than redefine the behavior of existing regions. Essentially, just add a region name to the (service, endpoint) tuple.

This way, test code could e.g. safely depend on a test-1 region instead of modifying the behavior of an existing region.

[marceldegraaf]

Heh, no problem!

Alright, sounds good. We'll probably have a PR for this in the coming days.