4bee884fae
CNI is developed by more than just CoreOS, Inc and the copyright is retained by all CNI contributors (for their respective contributed code).
118 lines
2.5 KiB
Go
118 lines
2.5 KiB
Go
// Copyright 2014 CNI authors
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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// Package skel provides skeleton code for a CNI plugin.
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// In particular, it implements argument parsing and validation.
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package skel
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import (
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"fmt"
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"io/ioutil"
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"log"
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"os"
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"github.com/appc/cni/pkg/types"
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)
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// CmdArgs captures all the arguments passed in to the plugin
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// via both env vars and stdin
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type CmdArgs struct {
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ContainerID string
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Netns string
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IfName string
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Args string
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Path string
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StdinData []byte
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}
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// PluginMain is the "main" for a plugin. It accepts
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// two callback functions for add and del commands.
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func PluginMain(cmdAdd, cmdDel func(_ *CmdArgs) error) {
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var cmd, contID, netns, ifName, args, path string
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vars := []struct {
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name string
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val *string
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req bool
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}{
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{"CNI_COMMAND", &cmd, true},
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{"CNI_CONTAINERID", &contID, false},
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{"CNI_NETNS", &netns, true},
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{"CNI_IFNAME", &ifName, true},
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{"CNI_ARGS", &args, false},
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{"CNI_PATH", &path, true},
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}
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argsMissing := false
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for _, v := range vars {
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*v.val = os.Getenv(v.name)
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if v.req && *v.val == "" {
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log.Printf("%v env variable missing", v.name)
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argsMissing = true
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}
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}
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if argsMissing {
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dieMsg("required env variables missing")
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}
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stdinData, err := ioutil.ReadAll(os.Stdin)
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if err != nil {
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dieMsg("error reading from stdin: %v", err)
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}
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cmdArgs := &CmdArgs{
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ContainerID: contID,
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Netns: netns,
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IfName: ifName,
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Args: args,
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Path: path,
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StdinData: stdinData,
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}
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switch cmd {
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case "ADD":
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err = cmdAdd(cmdArgs)
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case "DEL":
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err = cmdDel(cmdArgs)
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default:
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dieMsg("unknown CNI_COMMAND: %v", cmd)
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}
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if err != nil {
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if e, ok := err.(*types.Error); ok {
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// don't wrap Error in Error
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dieErr(e)
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}
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dieMsg(err.Error())
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}
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}
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func dieMsg(f string, args ...interface{}) {
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e := &types.Error{
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Code: 100,
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Msg: fmt.Sprintf(f, args...),
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}
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dieErr(e)
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}
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func dieErr(e *types.Error) {
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if err := e.Print(); err != nil {
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log.Print("Error writing error JSON to stdout: ", err)
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}
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os.Exit(1)
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}
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