func Download()

in pkg/download/downloader.go [49:118]
64 lines of code
13 McCabe index (conditional complexity)

func Download(ctx *log.Context, downloader Downloader) (int, io.ReadCloser, error) {
	request, err := downloader.GetRequest()
	if err != nil {
		return -1, nil, errors.Wrapf(err, "failed to create http request")
	}
	requestID := request.Header.Get(xMsClientRequestIdHeaderName)
	if len(requestID) > 0 {
		ctx.Log("info", fmt.Sprintf("starting download with client request ID %s", requestID))
	}

	response, err := httpClient.Do(request)
	if err != nil {
		err = urlutil.RemoveUrlFromErr(err)
		return -1, nil, errors.Wrapf(err, "http request failed")
	}

	if response.StatusCode == http.StatusOK {
		return response.StatusCode, response.Body, nil
	}

	errString := fmt.Sprintf("Status code %d while downloading blob '%s'. Use either a public script URI that points to .sh file, Azure storage blob SAS URI or storage blob accessible by a managed identity and retry. For more information, see https://aka.ms/RunCommandManagedLinux", response.StatusCode, request.URL.Opaque)
	requestId := response.Header.Get(xMsServiceRequestIdHeaderName)
	switch downloader.(type) {
	case *blobWithMsiToken:
		switch response.StatusCode {
		case http.StatusNotFound:
			notFoundError := fmt.Sprintf("RunCommand failed to download the blob '%s' and received a response code '%s'. Make sure that the Azure blob and managed identity exist, and the identity has access to the storage blob's container with the 'Storage Blob Data Reader' role assignment. For a user-assigned identity, add it under the VM's identity. For more information, see https://aka.ms/RunCommandManagedLinux", request.URL.Opaque, response.Status)
			errString = fmt.Sprintf("%s: %s", MsiDownload404ErrorString, notFoundError)
		case http.StatusForbidden,
			http.StatusUnauthorized,
			http.StatusBadRequest,
			http.StatusConflict:
			forbiddenError := fmt.Sprintf("RunCommand failed to download the blob '%s' and received a response code '%s'. Ensure that the managed identity has access to the storage blob's container with the 'Storage Blob Data Reader' role assignment. For a user-assigned identity, add it under the VM's identity. For more information, see https://aka.ms/RunCommandManagedLinux", request.URL.Opaque, response.Status)
			errString = fmt.Sprintf("%s: %s", MsiDownload403ErrorString, forbiddenError)
		}
		break
	default:
		hostname := request.URL.Host
		switch response.StatusCode {
		case http.StatusUnauthorized:
			errString = fmt.Sprintf("RunCommand failed to download the file from %s because access was denied. Please fix the blob permissions and try again. The response code and message returned were: %q.",
				hostname,
				response.Status)
			break
		case http.StatusNotFound:
			errString = fmt.Sprintf("RunCommand failed to download the file from %s because it does not exist. Please create the blob and try again, the response code and message returned were: %q",
				hostname,
				response.Status)

		case http.StatusBadRequest:
			errString = fmt.Sprintf("RunCommand failed to download the file from %s because parts of the request were incorrectly formatted, missing, and/or invalid. The response code and message returned were: %q",
				hostname,
				response.Status)

		case http.StatusInternalServerError:
			errString = fmt.Sprintf("RunCommand failed to download the file from %s due to an issue with storage. The response code and message returned were: %q",
				hostname,
				response.Status)
		default:
			errString = fmt.Sprintf("RunCommand failed to download the file from %s because the server returned a response code and message of %q Please verify the machine has network connectivity.",
				hostname,
				response.Status)
		}
	}

	if len(requestId) > 0 {
		errString += fmt.Sprintf(" (Service request ID: %s)", requestId)
	}
	return response.StatusCode, nil, fmt.Errorf(errString)
}