k3s/vendor/github.com/containernetworking/cni/pkg/version/plugin.go

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2019-01-12 04:58:27 +00:00
// Copyright 2016 CNI 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 version
import (
"encoding/json"
"fmt"
"io"
)
// PluginInfo reports information about CNI versioning
type PluginInfo interface {
// SupportedVersions returns one or more CNI spec versions that the plugin
// supports. If input is provided in one of these versions, then the plugin
// promises to use the same CNI version in its response
SupportedVersions() []string
// Encode writes this CNI version information as JSON to the given Writer
Encode(io.Writer) error
}
type pluginInfo struct {
CNIVersion_ string `json:"cniVersion"`
SupportedVersions_ []string `json:"supportedVersions,omitempty"`
}
// pluginInfo implements the PluginInfo interface
var _ PluginInfo = &pluginInfo{}
func (p *pluginInfo) Encode(w io.Writer) error {
return json.NewEncoder(w).Encode(p)
}
func (p *pluginInfo) SupportedVersions() []string {
return p.SupportedVersions_
}
// PluginSupports returns a new PluginInfo that will report the given versions
// as supported
func PluginSupports(supportedVersions ...string) PluginInfo {
if len(supportedVersions) < 1 {
panic("programmer error: you must support at least one version")
}
return &pluginInfo{
CNIVersion_: Current(),
SupportedVersions_: supportedVersions,
}
}
// PluginDecoder can decode the response returned by a plugin's VERSION command
type PluginDecoder struct{}
func (*PluginDecoder) Decode(jsonBytes []byte) (PluginInfo, error) {
var info pluginInfo
err := json.Unmarshal(jsonBytes, &info)
if err != nil {
return nil, fmt.Errorf("decoding version info: %s", err)
}
if info.CNIVersion_ == "" {
return nil, fmt.Errorf("decoding version info: missing field cniVersion")
}
if len(info.SupportedVersions_) == 0 {
if info.CNIVersion_ == "0.2.0" {
return PluginSupports("0.1.0", "0.2.0"), nil
}
return nil, fmt.Errorf("decoding version info: missing field supportedVersions")
}
return &info, nil
}