GoogleContainerTools/skaffold · error

uploading sources to google storage: %w

Error message

uploading sources to google storage: %w

What it means

`UploadToGCS` wraps failures from `util.CreateTarGz`, which streams a tar.gz of the artifact's source dependencies directly into a GCS object writer. The error means the sources could not be archived and uploaded to the given GCS bucket/object — either the local archive creation failed (missing files, IO errors) or the streaming write to GCS failed mid-upload.

Source

Thrown at pkg/skaffold/sources/upload.go:34

package sources

import (
	"context"
	"fmt"

	cstorage "cloud.google.com/go/storage"

	"github.com/GoogleContainerTools/skaffold/v2/pkg/skaffold/schema/latest"
	"github.com/GoogleContainerTools/skaffold/v2/pkg/skaffold/util"
)

// UploadToGCS uploads the artifact's sources to a GCS bucket.
func UploadToGCS(ctx context.Context, c *cstorage.Client, a *latest.Artifact, bucket, objectName string, dependencies []string) error {
	w := c.Bucket(bucket).Object(objectName).NewWriter(ctx)

	if err := util.CreateTarGz(ctx, w, a.Workspace, dependencies); err != nil {
		return fmt.Errorf("uploading sources to google storage: %w", err)
	}

	return w.Close()
}

View on GitHub (pinned to a1189de023)

Solutions

1. Verify GCS credentials and that the service account has Object Creator (roles/storage.objectCreator) on the bucket.
2. Confirm the bucket exists and the objectName/bucket spelling is correct.
3. Ensure all files listed in `dependencies` exist inside `a.Workspace` and are readable.
4. Check network/proxy connectivity to storage.googleapis.com and retry transient failures.

Example fix

// before
c := client.NewGCSClient(ctx) // no credentials/scopes
err := sources.UploadToGCS(ctx, c, artifact, "my-bucket", "src.tgz", deps)
// after
// grant storage.objectCreator to the SA and authenticate:
// gcloud auth application-default login  (or attach storage scope)
err := sources.UploadToGCS(ctx, c, artifact, "my-bucket", "src.tgz", verifiedDeps)

for _, dep := range dependencies {
  if _, err := os.Stat(filepath.Join(a.Workspace, dep)); err != nil {
    return fmt.Errorf("missing dependency %q before GCS upload: %w", dep, err)
  }
}
if err := c.Bucket(bucket).Objects(ctx, nil); err != nil { // probe bucket access
  return fmt.Errorf("bucket %q not accessible: %w", bucket, err)
}

err := sources.UploadToGCS(ctx, client, artifact, bucket, obj, deps)
if err != nil {
  if strings.Contains(err.Error(), "uploading sources to google storage") {
    log.Printf("GCS upload failed: %v; check credentials/bucket and retry", err)
  }
  return err
}

When it happens

Trigger: Calling `UploadToGCS(ctx, client, artifact, bucket, objectName, dependencies)` where `dependencies` reference files that don't exist under `a.Workspace`, the workspace is unreadable, the GCS credentials are missing/invalid, the bucket doesn't exist or is not writable, or the network drops during upload.

Common situations: Cloud build workflows where the GCS staging bucket name is misspelled or the service account lacks storage.objects.create; source files deleted after dependency computation; 403 from GCS due to no storage scope on the VM; flaky network interrupting the multipart upload.

Related errors

• error closing GCS writer: %w
• error copying file to GCS: %w
• failed to iterate objects: %v
• failed to read object: %v
• failed to copy object to file: %v

AI-assisted analysis of GoogleContainerTools/skaffold@a1189de023 (2026-09-05). Data as JSON: /api/errors/f3a8704a0e5548dd. Report an issue: GitHub.