// obtainCertificates obtains certificates from the CA server for
// the configurations in serverConfigs using client.
func obtainCertificates(client *acme.Client, serverConfigs []server.Config) ([]acme.CertificateResource, map[string]error) {
var hosts []string
for _, cfg := range serverConfigs {
hosts = append(hosts, cfg.Host)
}
return client.ObtainCertificates(hosts, true)
}
