errors.As fails to match any error in the chain of *azblob.InternalError with azcore.HTTPResponse or azblob.StorageError

[ArnavPrasadMicrosoft]

Bug Report

• path of package in question: https://github.com/Azure/azure-sdk-for-go/blob/main/sdk/storage/azblob

• SDK version: 0.2.0

• output of go version: 1.16

• What happened?

  • I was trying to check for a "BlobAlreadyExists" error in my project through the following piece of code:

_, err = blockBlobClient.UploadBufferToBlockBlob(ctx, data, highLevelUploadToBlockBlobOption)
if err != nil {
  // This log gets printed.
  log.WithContext(ctx).Errorf("Error while uploading buffer to block blob: %v (%T)", err, err) // Type is (*azblob.InternalError)
  var errResp azcore.HTTPResponse
  var storageErr azblob.StorageError
  if errors.As(err, &errResp) {
    // This log does not get printed.
    log.WithContext(ctx).Errorf("Caught response error: %v, status code: %d", errResp.RawResponse(), errResp.RawResponse().StatusCode)
  }
  if errors.As(err, &storageErr) {
    // This log does not get printed either.
    log.WithContext(ctx).Errorf("Caught storage error: %v", storageErr)
  }
}

• Currently, the generated azblob code that actually sends requests returns azcore.HTTPResponse when something goes wrong, but the handwritten code converts that to another type which doesn't expose the response: https://github.com/Azure/azure-sdk-for-go/blob/main/sdk/storage/azblob/zc_storage_error.go#L76

[chlowell]

Looks related to #16722

[ezavgorodniy]

Yes, and related issue was closed due to inactivity :(

[joey-laminar]

Came upon this issue too, the solution was to define storageErr as a pointer:

var storageErr *azblob.StorageError
  if errors.As(err, &storageErr) {
    log.WithContext(ctx).Errorf("Caught storage error: %v", storageErr)
  }

[tasherif-msft]

Hi @ArnavPrasadMicrosoft! Azure Core introduced https://github.com/Azure/azure-sdk-for-go/blob/main/sdk/azcore/errors.go#L14 which can be cast using:

var responseErr *azcore.ResponseError
errors.As(err, &responseErr)

this will be available in the next release.

[jhendrixMSFT]

This is correct. However, we haven't yet released an updated azblob that returns this error type.

[tasherif-msft]

@jhendrixMSFT you're correct, I have reopened the issue and updated my comment that this change should be available in the next release

[jhendrixMSFT]

This change has now been deployed in [email protected]