JuliusBrussee/caveman · error

bedrock base url invalid

Error message

bedrock base url invalid: %w

What it means

The Bedrock adapter parses its configured base URL (adapter BaseURL or route.BaseURL) with url.Parse before routing and signing. This error wraps the underlying parse failure — the configured endpoint is not a valid URL at all, so no upstream can be resolved.

Solutions

  1. Fix the configured base URL so it is a valid absolute https:// URL (no stray characters, quotes, or bad percent-escapes).
  2. Check route.BaseURL in caveman.yaml first (it overrides the adapter default), then the adapter-level BaseURL.
  3. Log/print the exact string being parsed — url.Parse errors usually point at the offending component.

Example fix

// before
base_url: https://bedrock-runtime.us-east-1.amazonaws.com/%zz
// after
base_url: https://bedrock-runtime.us-east-1.amazonaws.com
Defensive patterns

Strategy: validation

Validate before calling

base, err := url.Parse(cfg.BaseURL)
if err != nil {
	return fmt.Errorf("invalid bedrock base_url %q: %w", cfg.BaseURL, err)
}
if base.Scheme != "https" || base.Host == "" {
	return fmt.Errorf("bedrock base_url %q must be an absolute https URL", cfg.BaseURL)
}

Try / catch

// Go
if _, err := adapter.ResolveUpstreamURL(ctx, req, route); err != nil {
	var uerr *url.Error
	if errors.As(err, &uerr) && strings.Contains(err.Error(), "base url invalid") {
		// fail fast: fix configuration, do not retry
		return fmt.Errorf("configuration error: %w", err)
	}
	return err
}

Prevention

When it happens

Trigger: A route or adapter configured with a base URL that url.Parse rejects — e.g. containing control characters, an invalid scheme like "hxxp://", or a malformed percent-escape such as https://bedrock-runtime.us-east-1.amazonaws.com/%zz.

Common situations: Typo in caveman.yaml route base_url; pasting an endpoint with stray whitespace or quotes; a templated/interpolated URL where a variable expanded to something containing "{" "}" or spaces.

Understand the failure class

Background: "Invalid URL" errors: why new URL(), URI.parse, and reqwest::Url reject your string — missing scheme, whitespace, and bad path format — this error's family across 39 libraries.

Related errors

AI-assisted analysis of JuliusBrussee/caveman@3ee70a1026 (2026-09-20). Data as JSON: /api/errors/c8659c4142f5a2a4. Report an issue: GitHub.

Appendix: source

Thrown at proxy/providers/bedrock/routing.go:154

)

// ResolveUpstreamURL validates the endpoint kind, region, action, and model
// resource, then resolves one of two explicit Bedrock surfaces:
//
//   - Runtime: /bedrock/model/... -> bedrock-runtime.../model/...
//   - Mantle:  /bedrock/anthropic/v1/messages -> bedrock-mantle.../anthropic/...
//
// Mantle stays deployment-opt-in because its IAM service, model coverage,
// quotas, features, stream wire, and AWS invocation-logging support differ from
// Runtime. Both surfaces remain provider=bedrock in telemetry.
func (a Adapter) ResolveUpstreamURL(ctx context.Context, req *http.Request, route providers.RouteContext) (*url.URL, error) {
	baseURL := a.BaseURL
	if route.BaseURL != "" {
		baseURL = route.BaseURL
	}
	base, err := url.Parse(baseURL)
	if err != nil {
		return nil, fmt.Errorf("bedrock base url invalid: %w", err)
	}
	region, err := resolveRegion(req, base)
	if err != nil {
		return nil, err
	}

	kind := endpointKindForPath(req.URL.Path)
	if configuredKind := strings.ToLower(strings.TrimSpace(route.EndpointKind)); configuredKind != "" && configuredKind != kind {
		return nil, fmt.Errorf("bedrock configured endpoint kind %q does not allow request kind %q", configuredKind, kind)
	}
	switch kind {
	case endpointRuntime:
		if !RegionAllowed(region) {
			return nil, fmt.Errorf("bedrock region %q is not on the allowlist", region)
		}
		modelID, action := parseModelPath(req.URL.Path)
		if modelID == "" || action == "" {
			return nil, fmt.Errorf("bedrock request path %q does not name a model and action", req.URL.Path)

View on GitHub (pinned to 3ee70a1026)