1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
|
// Copyright 2015 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 invoke
import (
"context"
"encoding/json"
"fmt"
"os"
"github.com/containernetworking/cni/pkg/types"
"github.com/containernetworking/cni/pkg/types/create"
"github.com/containernetworking/cni/pkg/version"
)
// Exec is an interface encapsulates all operations that deal with finding
// and executing a CNI plugin. Tests may provide a fake implementation
// to avoid writing fake plugins to temporary directories during the test.
type Exec interface {
ExecPlugin(ctx context.Context, pluginPath string, stdinData []byte, environ []string) ([]byte, error)
FindInPath(plugin string, paths []string) (string, error)
Decode(jsonBytes []byte) (version.PluginInfo, error)
}
// Plugin must return result in same version as specified in netconf; but
// for backwards compatibility reasons if the result version is empty use
// config version (rather than technically correct 0.1.0).
// https://github.com/containernetworking/cni/issues/895
func fixupResultVersion(netconf, result []byte) (string, []byte, error) {
versionDecoder := &version.ConfigDecoder{}
confVersion, err := versionDecoder.Decode(netconf)
if err != nil {
return "", nil, err
}
var rawResult map[string]interface{}
if err := json.Unmarshal(result, &rawResult); err != nil {
return "", nil, fmt.Errorf("failed to unmarshal raw result: %w", err)
}
// plugin output of "null" is successfully unmarshalled, but results in a nil
// map which causes a panic when the confVersion is assigned below.
if rawResult == nil {
rawResult = make(map[string]interface{})
}
// Manually decode Result version; we need to know whether its cniVersion
// is empty, while built-in decoders (correctly) substitute 0.1.0 for an
// empty version per the CNI spec.
if resultVerRaw, ok := rawResult["cniVersion"]; ok {
resultVer, ok := resultVerRaw.(string)
if ok && resultVer != "" {
return resultVer, result, nil
}
}
// If the cniVersion is not present or empty, assume the result is
// the same CNI spec version as the config
rawResult["cniVersion"] = confVersion
newBytes, err := json.Marshal(rawResult)
if err != nil {
return "", nil, fmt.Errorf("failed to remarshal fixed result: %w", err)
}
return confVersion, newBytes, nil
}
// For example, a testcase could pass an instance of the following fakeExec
// object to ExecPluginWithResult() to verify the incoming stdin and environment
// and provide a tailored response:
//
//import (
// "encoding/json"
// "path"
// "strings"
//)
//
//type fakeExec struct {
// version.PluginDecoder
//}
//
//func (f *fakeExec) ExecPlugin(pluginPath string, stdinData []byte, environ []string) ([]byte, error) {
// net := &types.NetConf{}
// err := json.Unmarshal(stdinData, net)
// if err != nil {
// return nil, fmt.Errorf("failed to unmarshal configuration: %v", err)
// }
// pluginName := path.Base(pluginPath)
// if pluginName != net.Type {
// return nil, fmt.Errorf("plugin name %q did not match config type %q", pluginName, net.Type)
// }
// for _, e := range environ {
// // Check environment for forced failure request
// parts := strings.Split(e, "=")
// if len(parts) > 0 && parts[0] == "FAIL" {
// return nil, fmt.Errorf("failed to execute plugin %s", pluginName)
// }
// }
// return []byte("{\"CNIVersion\":\"0.4.0\"}"), nil
//}
//
//func (f *fakeExec) FindInPath(plugin string, paths []string) (string, error) {
// if len(paths) > 0 {
// return path.Join(paths[0], plugin), nil
// }
// return "", fmt.Errorf("failed to find plugin %s in paths %v", plugin, paths)
//}
func ExecPluginWithResult(ctx context.Context, pluginPath string, netconf []byte, args CNIArgs, exec Exec) (types.Result, error) {
if exec == nil {
exec = defaultExec
}
stdoutBytes, err := exec.ExecPlugin(ctx, pluginPath, netconf, args.AsEnv())
if err != nil {
return nil, err
}
resultVersion, fixedBytes, err := fixupResultVersion(netconf, stdoutBytes)
if err != nil {
return nil, err
}
return create.Create(resultVersion, fixedBytes)
}
func ExecPluginWithoutResult(ctx context.Context, pluginPath string, netconf []byte, args CNIArgs, exec Exec) error {
if exec == nil {
exec = defaultExec
}
_, err := exec.ExecPlugin(ctx, pluginPath, netconf, args.AsEnv())
return err
}
// GetVersionInfo returns the version information available about the plugin.
// For recent-enough plugins, it uses the information returned by the VERSION
// command. For older plugins which do not recognize that command, it reports
// version 0.1.0
func GetVersionInfo(ctx context.Context, pluginPath string, exec Exec) (version.PluginInfo, error) {
if exec == nil {
exec = defaultExec
}
args := &Args{
Command: "VERSION",
// set fake values required by plugins built against an older version of skel
NetNS: "dummy",
IfName: "dummy",
Path: "dummy",
}
stdin := []byte(fmt.Sprintf(`{"cniVersion":%q}`, version.Current()))
stdoutBytes, err := exec.ExecPlugin(ctx, pluginPath, stdin, args.AsEnv())
if err != nil {
if err.Error() == "unknown CNI_COMMAND: VERSION" {
return version.PluginSupports("0.1.0"), nil
}
return nil, err
}
return exec.Decode(stdoutBytes)
}
// DefaultExec is an object that implements the Exec interface which looks
// for and executes plugins from disk.
type DefaultExec struct {
*RawExec
version.PluginDecoder
}
// DefaultExec implements the Exec interface
var _ Exec = &DefaultExec{}
var defaultExec = &DefaultExec{
RawExec: &RawExec{Stderr: os.Stderr},
}
|
