[TF-13396] Build new decoded error

[laurenolivia]

Description

When an HTTP response returns a 404, the details of the error are not logged. Currently, the error returns a string indicating the resource is not found. This PR builds an error that logs more info to help investigate what may be causing 404s.

Testing plan

External links

Output from tests

Including output from tests may require access to a TFE instance. Ignore this section if you have no environment to test against.

$ TFE_ADDRESS="https://example" TFE_TOKEN="example" go test ./... -v -run TestFunctionsAffectedByChange

...

[brandonc]

This looks like a useful tool, but it doesn't help for types that are already response errors that can be decoded, like the ones returned by checkResponseCode.

You could add a function that can decode the contents of a variety of errors, starting with ErrResourceNotFound, that can be built with a response body and work in tandem with checkResponseCode.

It's important that the existing message does not change for ErrResourceNotFound. The additional decoded details should be available from a different field and not from the Error() method.

type ErrResourceNotFound {
  Details []string
}

func (ErrResourceNotFound) Error() string {
  return "resource not found" // <-- this is the important compatibility part
}

func NewErrorFromResponse(response *http.Response) error {
  decodedDetails, err := decodeErrorPayload(response)
  if err != nil {
    // There aren't any error details so this error isn't a 'jsonapi error'
    return fmt.Errorf("could not decode jsonapi error details from this response: %w", err)
  }
  
  switch response.StatusCode {
  case 404:
    return ErrResourceNotFound{Details: decodedDetails}
  // etc
  }
  
  return nil
}

[brandonc]

Also don't forget unit tests

[laurenolivia]

@brandonc I'm wondering what you think about refactoring checkResponseCode to use the new struct

type ResError struct {
StatusCode   int
Info        []string
Base        error 
}

and then return ResError in checkResponseCode?

For example:

switch r.StatusCode {
case 400:
    ResError.Base = ErrInvalidIncludeValue
case 404:
    ResError.Base = ErrResourceNotFound
// etc
}

return ResError

[laurenolivia]

Unit tests will need to be updated because the error will be wrapped with this 👆 solution.
Likely tests that check for equality:

assert.Equal(t, ErrResourceNotFound, err)

[laurenolivia]

It’s been determined that this fix is a breaking change in go-tfe. At this time, we don’t have any plans to release V2. The original intent was to force more context in the output of a 404 due to a recurring flaky test in the provider. We’ve determined that any solution breaks go-tfe. Closing this PR for now.