Improve error handling

[jay-rah-oob]

Would it make sense to have functionality similar to the k8s api errors package? This gives simple predicate functions like errors.IsNotFound(err) or errors.IsAlreadyExists(err).

Reference: https://pkg.go.dev/k8s.io/apimachinery/pkg/api/errors

[sudomateo]

I'm not strictly opposed to this. I see two approaches we can take here.

One would be to introduce functions similar to https://pkg.go.dev/k8s.io/apimachinery/pkg/api/errors as already described. These functions can assert on content within this SDK's HTTPError type.

oxide.ErrorIsNotFound(err)
oxide.ErrorIsUnauthorized(err)

Another approach would be to introduce more concrete error types that this SDK either returns directly or wraps in a more generic error type, maybe HTTPError. Then users can use the Go's built-in errors package functionality to assert.

if errors.Is(err, oxide.CustomError) {}

var oxideErr *oxide.CustomError
if errors.As(err, &oxideErr) {}

At the moment I'm not partial to either approach. I just wanted to note them here for future discussion.

[sudomateo]

Just noting that we're discussing improved error handling in RFD 0614, which is not public currently. The RFD describes all the improvements we're looking to make to the Go SDK.

[sudomateo]

Also noting that we'll want to think about how validation errors are presented in the Go SDK as we improve validation per SSE-101 (#137).