What causes "creating http request: %w" in GoogleContainerTools/skaffold?

Print/inspect the URL passed to Download; validate it has scheme://host format.

creating http request: %w

Error message

creating http request: %w

What it means

Download issues an HTTP GET via util.Download. This error means http.NewRequest failed to construct the request itself — almost always because the URL is malformed (no scheme, invalid characters, bad host). The URL parse error is wrapped.

Source

Thrown at pkg/skaffold/util/http.go:31

See the License for the specific language governing permissions and
limitations under the License.
*/

package util

import (
	"fmt"
	"io"
	"net/http"

	"github.com/GoogleContainerTools/skaffold/v2/pkg/skaffold/version"
)

func Download(url string) ([]byte, error) {
	client := http.Client{}
	req, err := http.NewRequest("GET", url, nil)
	if err != nil {
		return nil, fmt.Errorf("creating http request: %w", err)
	}
	req.Header.Set("User-Agent", version.UserAgentWithClient())
	resp, err := client.Do(req)
	if err != nil {
		return nil, err
	}
	defer resp.Body.Close()
	if resp.StatusCode != http.StatusOK {
		return nil, fmt.Errorf("http %d, error %q", resp.StatusCode, resp.Status)
	}
	return io.ReadAll(resp.Body)
}

View on GitHub (pinned to a1189de023)

Solutions

Print/inspect the URL passed to Download; validate it has scheme://host format.
Trim whitespace/quotes from config-provided URLs before use (strings.TrimSpace).
Escape path segments with url.PathEscape when interpolating user data.
Reject empty URLs early with an explicit validation check.

Example fix

// before
url := fmt.Sprintf("%s/%s", base, name) // base may be "example.com/x" without scheme
b, err := util.Download(url)
// after
u, err := nurl.Parse(strings.TrimSpace(base))
if err != nil || u.Scheme == "" {
    return nil, fmt.Errorf("invalid download URL: %q", base)
}
b, err := util.Download(u.String())

Defensive patterns

Strategy: validation

Validate before calling

u, err := url.Parse(rawURL)
if err != nil {
    return fmt.Errorf("invalid URL %q: %w", rawURL, err)
}
if u.Scheme != "http" && u.Scheme != "https" || u.Host == "" {
    return fmt.Errorf("URL must be absolute with host: %q", rawURL)
}

Type guard

func isDownloadableURL(s string) bool {
    u, err := url.Parse(strings.TrimSpace(s))
    return err == nil && (u.Scheme == "http" || u.Scheme == "https") && u.Host != ""
}

Try / catch

b, err := util.Download(url)
if err != nil && strings.Contains(err.Error(), "creating http request") {
    return fmt.Errorf("malformed download URL %q: %w", url, err)
}

Prevention

Always construct URLs with url.Parse/url.PathEscape, never raw string concat of user input
Trim whitespace and quotes from URLs read from config or env
Assert scheme and host presence before downloading

When it happens

Trigger: http.NewRequest("GET", url, nil) errors: url passed to Download is empty, missing scheme ('storage.googleapis.com/...' without https://), contains spaces or invalid control characters, or is otherwise rejected by net/url parsing.

Common situations: Building URLs by string concatenation with unescaped user input (image names, ports, endpoints) e.g. in ReadConfiguration fetching remote configs; environment-provided endpoint strings with typos; URLs read from config with surrounding whitespace or quotes.

Understand the failure class

Background: "Invalid URL" / "URL cannot be empty": fix the malformed or missing URL behind request-construction failures — this error's family across 50 libraries.

Related errors

AI-assisted analysis of GoogleContainerTools/skaffold@a1189de023 (2026-09-05). Data as JSON: /api/errors/c6097517fe85c4a6. Report an issue: GitHub.