// NegotiateVersion queries the server's supported api versions to find
// a version that both client and server support.
// - If no version is provided, try registered client versions in order of
// preference.
// - If version is provided and the server does not support it,
// return an error.
func NegotiateVersion(client DiscoveryInterface, requiredGV *schema.GroupVersion, clientRegisteredGVs []schema.GroupVersion) (*schema.GroupVersion, error) {
clientVersions := sets.String{}
for _, gv := range clientRegisteredGVs {
clientVersions.Insert(gv.String())
}
groups, err := client.ServerGroups()
if err != nil {
// This is almost always a connection error, and higher level code should treat this as a generic error,
// not a negotiation specific error.
return nil, err
}
versions := metav1.ExtractGroupVersions(groups)
serverVersions := sets.String{}
for _, v := range versions {
serverVersions.Insert(v)
}
// If version explicitly requested verify that both client and server support it.
// If server does not support warn, but try to negotiate a lower version.
if requiredGV != nil {
if !clientVersions.Has(requiredGV.String()) {
return nil, fmt.Errorf("client does not support API version %q; client supported API versions: %v", requiredGV, clientVersions)
}
// If the server supports no versions, then we should just use the preferredGV
// This can happen because discovery fails due to 403 Forbidden errors
if len(serverVersions) == 0 {
return requiredGV, nil
}
if serverVersions.Has(requiredGV.String()) {
return requiredGV, nil
}
// If we are using an explicit config version the server does not support, fail.
return nil, fmt.Errorf("server does not support API version %q", requiredGV)
}
for _, clientGV := range clientRegisteredGVs {
if serverVersions.Has(clientGV.String()) {
// Version was not explicitly requested in command config (--api-version).
// Ok to fall back to a supported version with a warning.
// TODO: caesarxuchao: enable the warning message when we have
// proper fix. Please refer to issue #14895.
// if len(version) != 0 {
// glog.Warningf("Server does not support API version '%s'. Falling back to '%s'.", version, clientVersion)
// }
t := clientGV
return &t, nil
}
}
// if we have no server versions and we have no required version, choose the first clientRegisteredVersion
if len(serverVersions) == 0 && len(clientRegisteredGVs) > 0 {
return &clientRegisteredGVs[0], nil
}
return nil, fmt.Errorf("failed to negotiate an api version; server supports: %v, client supports: %v",
serverVersions, clientVersions)
}
// SwaggerSchema retrieves and parses the swagger API schema the server supports.
func (d *DiscoveryClient) SwaggerSchema(version schema.GroupVersion) (*swagger.ApiDeclaration, error) {
if version.Empty() {
return nil, fmt.Errorf("groupVersion cannot be empty")
}
groupList, err := d.ServerGroups()
if err != nil {
return nil, err
}
groupVersions := metav1.ExtractGroupVersions(groupList)
// This check also takes care the case that kubectl is newer than the running endpoint
if stringDoesntExistIn(version.String(), groupVersions) {
return nil, fmt.Errorf("API version: %v is not supported by the server. Use one of: %v", version, groupVersions)
}
var path string
if len(d.LegacyPrefix) > 0 && version == v1.SchemeGroupVersion {
path = "/swaggerapi" + d.LegacyPrefix + "/" + version.Version
} else {
path = "/swaggerapi/apis/" + version.Group + "/" + version.Version
}
body, err := d.restClient.Get().AbsPath(path).Do().Raw()
if err != nil {
return nil, err
}
var schema swagger.ApiDeclaration
err = json.Unmarshal(body, &schema)
if err != nil {
return nil, fmt.Errorf("got '%s': %v", string(body), err)
}
return &schema, nil
}