published by bot

(https://github.com/kubernetes/contrib/tree/master/mungegithub)

copied from https://github.com/kubernetes/kubernetes.git, branch master,
last commit is 71ba8a90f0a4f3a307cffeb8f8566d13277cb135

discovery/helper.go

@@ -0,0 +1,135 @@
+/*
+Copyright 2016 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package discovery
+
+import (
+	"fmt"
+
+	"k8s.io/client-go/pkg/api/unversioned"
+	"k8s.io/client-go/pkg/util/sets"
+	"k8s.io/client-go/pkg/version"
+	"k8s.io/client-go/rest"
+	// Import solely to initialize client auth plugins.
+	_ "k8s.io/client-go/plugin/pkg/client/auth"
+)
+
+// MatchesServerVersion queries the server to compares the build version
+// (git hash) of the client with the server's build version. It returns an error
+// if it failed to contact the server or if the versions are not an exact match.
+func MatchesServerVersion(client DiscoveryInterface, c *rest.Config) error {
+	var err error
+	if client == nil {
+		client, err = NewDiscoveryClientForConfig(c)
+		if err != nil {
+			return err
+		}
+	}
+	cVer := version.Get()
+	sVer, err := client.ServerVersion()
+	if err != nil {
+		return fmt.Errorf("couldn't read version from server: %v\n", err)
+	}
+	// GitVersion includes GitCommit and GitTreeState, but best to be safe?
+	if cVer.GitVersion != sVer.GitVersion || cVer.GitCommit != sVer.GitCommit || cVer.GitTreeState != sVer.GitTreeState {
+		return fmt.Errorf("server version (%#v) differs from client version (%#v)!\n", sVer, cVer)
+	}
+
+	return nil
+}
+
+// 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, but not default config (explicitly requested via
+//   commandline flag), and is unsupported by the server, print a warning to
+//   stderr and try client's registered versions in order of preference.
+// - If version is config default, and the server does not support it,
+//   return an error.
+func NegotiateVersion(client DiscoveryInterface, c *rest.Config, requestedGV *unversioned.GroupVersion, clientRegisteredGVs []unversioned.GroupVersion) (*unversioned.GroupVersion, error) {
+	var err error
+	if client == nil {
+		client, err = NewDiscoveryClientForConfig(c)
+		if err != nil {
+			return nil, err
+		}
+	}
+	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 := unversioned.ExtractGroupVersions(groups)
+	serverVersions := sets.String{}
+	for _, v := range versions {
+		serverVersions.Insert(v)
+	}
+
+	// If no version requested, use config version (may also be empty).
+	// make a copy of the original so we don't risk mutating input here or in the returned value
+	var preferredGV *unversioned.GroupVersion
+	switch {
+	case requestedGV != nil:
+		t := *requestedGV
+		preferredGV = &t
+	case c.GroupVersion != nil:
+		t := *c.GroupVersion
+		preferredGV = &t
+	}
+
+	// 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 preferredGV != nil {
+		if !clientVersions.Has(preferredGV.String()) {
+			return nil, fmt.Errorf("client does not support API version %q; client supported API versions: %v", preferredGV, 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 preferredGV, nil
+		}
+		if serverVersions.Has(preferredGV.String()) {
+			return preferredGV, nil
+		}
+		// If we are using an explicit config version the server does not support, fail.
+		if (c.GroupVersion != nil) && (*preferredGV == *c.GroupVersion) {
+			return nil, fmt.Errorf("server does not support API version %q", preferredGV)
+		}
+	}
+
+	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
+		}
+	}
+	return nil, fmt.Errorf("failed to negotiate an api version; server supports: %v, client supports: %v",
+		serverVersions, clientVersions)
+}