// Batch sends a request to Cockroach via RPC. Errors which are retryable are
// retried with backoff in a loop using the default retry options. Other errors
// sending the request are retried indefinitely using the same client command
// ID to avoid reporting failure when in fact the command may have gone through
// and been executed successfully. We retry here to eventually get through with
// the same client command ID and be given the cached response.
func (s *rpcSender) Send(ctx context.Context, ba roachpb.BatchRequest) (*roachpb.BatchResponse, *roachpb.Error) {
var err error
var br roachpb.BatchResponse
for r := retry.Start(s.retryOpts); r.Next(); {
select {
case <-s.client.Healthy():
default:
err = fmt.Errorf("failed to send RPC request %s: client is unhealthy", method)
log.Warning(err)
continue
}
if err = s.client.Call(method, &ba, &br); err != nil {
br.Reset() // don't trust anyone.
// Assume all errors sending request are retryable. The actual
// number of things that could go wrong is vast, but we don't
// want to miss any which should in theory be retried with the
// same client command ID. We log the error here as a warning so
// there's visibility that this is happening. Some of the errors
// we'll sweep up in this net shouldn't be retried, but we can't
// really know for sure which.
log.Warningf("failed to send RPC request %s: %s", method, err)
continue
}
// On successful post, we're done with retry loop.
break
}
if err != nil {
return nil, roachpb.NewError(err)
}
pErr := br.Error
br.Error = nil
return &br, pErr
}
