grpc/grpc-go · warning

endpoints list contains no addresses

Error message

endpoints list contains no addresses

What it means

Returned by resolver.ValidateEndpoints when the endpoints slice is non-empty but every Endpoint in it has an empty Addresses slice. The dual-stack/petiole logic needs at least one dialable address; endpoints with no addresses are not usable and the validation fails.

Solutions

1. Ensure each Endpoint has at least one Address (host:port) before calling ValidateEndpoints; filter out address-less endpoints upstream.
2. Check the resolver producing the Endpoint list: confirm it copies socket_addresses into Endpoint.Addresses.
3. If the source genuinely has no addresses yet (e.g. DNS returned CNAME only), surface a transient error rather than a finalized empty-address list.

Example fix

// before
eps := []resolver.Endpoint{ {HealthStatus: ...} } // Addresses nil
resolver.ValidateEndpoints(eps)
// after
eps := []resolver.Endpoint{ { Addresses: []resolver.Address{{Addr: "10.0.0.1:8080"}} } }
resolver.ValidateEndpoints(eps)

// Filter out address-less endpoints before validation.
func withAddressesOnly(eps []resolver.Endpoint) []resolver.Endpoint {
    out := eps[:0]
    for _, e := range eps { if len(e.Addresses) > 0 { out = append(out, e) } }
    return out
}

func endpointsHaveAddresses(eps []resolver.Endpoint) bool {
    for _, e := range eps { if len(e.Addresses) > 0 { return true } }
    return false
}

if err := resolver.ValidateEndpoints(eps); err != nil { if strings.Contains(err.Error(), "no addresses") { /* keep previous picker; log transient */ return } return err }

When it happens

Trigger: Calling ValidateEndpoints with a list of Endpoint structs whose Addresses field is nil or [] for all entries. Each iteration of the inner loop `for range endpoint.Addresses` returns immediately, so the function falls through to the error.

Common situations: EDS/xDS update carries localities but each locality's endpoints were stripped of addresses by a buggy filter. Custom resolver populates metadata but not Addresses. A proto conversion dropped the address field during a version upgrade.

Related errors

• endpoints list is empty
• connection active but health check failed. status=
• connection active but received health check RPC error
• could not get resolver for default scheme
• delegating_resolver: failed to determine proxy URL for…

AI-assisted analysis of grpc/grpc-go@0c51461d27 (2026-08-11). Data as JSON: /api/errors/e88afdba4166bebe. Report an issue: GitHub.

Appendix: source

Thrown at resolver/resolver.go:358

	// necessary.
	OverrideAuthority(Target) string
}

// ValidateEndpoints validates endpoints from a petiole policy's perspective.
// Petiole policies should call this before calling into their children. See
// [gRPC A61](https://github.com/grpc/proposal/blob/master/A61-IPv4-IPv6-dualstack-backends.md)
// for details.
func ValidateEndpoints(endpoints []Endpoint) error {
	if len(endpoints) == 0 {
		return errors.New("endpoints list is empty")
	}

	for _, endpoint := range endpoints {
		for range endpoint.Addresses {
			return nil
		}
	}
	return errors.New("endpoints list contains no addresses")
}

View on GitHub (pinned to 0c51461d27)