What causes "Failed to set artifact key: %v" in argoproj/argo-workflows?

Check the resolved artifact location type; use s3/gcs/azure/oss which support keys.

Failed to set artifact key

Error message

Failed to set artifact key: %v

What it means

After building the new storage key (uploads/<namespace>/<uuid>/<filename>), the server calls outputArtifact.SetKey(newKey). SetKey only supports keys for artifact location types that have a key concept (s3, oss, gcs, etc.); for unsupported location types it returns an error, surfaced as HTTP 500. This indicates the resolved artifact location type cannot hold the generated key.

Solutions

Check the resolved artifact location type; use s3/gcs/azure/oss which support keys.
Inspect the full error (%v of SetKey) in the response to identify the unsupported type.
Fix the artifact definition or default artifact repository so it points at a key-capable backend.
If it persists with a valid configuration, file a bug with the artifact YAML and Argo version.

Defensive patterns

Strategy: validation

Validate before calling

# Only key-capable backends support upload keys
kubectl -n $NS get workflowtemplate $TPL -o jsonpath='{range .spec.arguments.artifacts[*]}{.name}{": "}{.s3}{.gcs}{.azure}{.oss}{"\n"}{end}'

Type guard

function hasKeyCapableLocation(artifact) {
  return Boolean(artifact.s3 || artifact.gcs || artifact.azure || artifact.oss);
}

Try / catch

catch (e) {
  if (e.status === 500 && e.body.includes('Failed to set artifact key')) {
    log.error('resolved artifact location type cannot hold an upload key; fix artifact repository config', e);
  }
}

Prevention

Use s3/gcs/azure/oss locations for uploaded artifacts.
Avoid combining incompatible location fields on one artifact.
Re-check artifact YAML after Argo version upgrades for new/changed location types.
Read the appended SetKey error detail to identify the offending location type.

When it happens

Trigger: The resolved artifact location is of a type without key support (e.g. some http/raw-derived or misconfigured location); a custom/default artifact repository resolution produced a location type SetKey does not handle; a bug or unusual artifact configuration where ArtifactLocation has a backend that lacks a Key field.

Common situations: Default artifact repository configured with a backend whose location type doesn't accept keys; artifact fields combining incompatible location blocks; upgrades where new location types were added but the upload path wasn't updated.

Related errors

AI-assisted analysis of argoproj/argo-workflows@35bff19146 (2026-09-03). Data as JSON: /api/errors/e74aa7e9abc6f918. Report an issue: GitHub.

Appendix: source

Thrown at server/artifacts/artifact_server.go:248

	originalKey, _ := artifactCopy.GetKey()
	// Sanitize filename to prevent path traversal attacks. path.Base only
	// recognises '/' as a separator, so normalise Windows-style '\' first.
	sanitizedFilename := path.Base(strings.ReplaceAll(header.Filename, "\\", "/"))
	if sanitizedFilename == "." || sanitizedFilename == "/" || sanitizedFilename == "" {
		http.Error(w, "Invalid filename", http.StatusBadRequest)
		return
	}
	// Replace the key with uploaded file path under uploads/
	newKey := fmt.Sprintf("uploads/%s/%s/%s", namespace, uploadUUID, sanitizedFilename)
	if validateErr := sutils.ValidateUploadedArtifactKey(namespace, newKey); validateErr != nil {
		a.serverInternalError(ctx, fmt.Errorf("generated artifact key failed self-validation: %w", validateErr), w)
		return
	}

	// Create a copy of the artifact for uploading (using artifactCopy which has resolved location)
	outputArtifact := artifactCopy.DeepCopy()
	if setErr := outputArtifact.SetKey(newKey); setErr != nil {
		http.Error(w, fmt.Sprintf("Failed to set artifact key: %v", setErr), http.StatusInternalServerError)
		return
	}

	a.logger.WithFields(logging.Fields{
		"originalKey": originalKey,
		"newKey":      newKey,
	}).Info(ctx, "Uploading artifact with new key")

	// Get the driver for the artifact
	kubeClient := auth.GetKubeClient(ctx)
	driver, err := a.artDriverFactory(ctx, outputArtifact, resources{kubeClient, namespace})
	if err != nil {
		http.Error(w, fmt.Sprintf("Failed to create artifact driver: %v", err), http.StatusInternalServerError)
		return
	}

	// Upload using SaveStream
	if err := driver.SaveStream(ctx, file, outputArtifact); err != nil {

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