Example #1
0
// 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)
}
Example #2
0
// 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
}