forked from kelseyhightower/confd
/
resource.go
325 lines (309 loc) · 9.15 KB
/
resource.go
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
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
// Copyright (c) 2013 Kelsey Hightower. All rights reserved.
// Use of this source code is governed by the Apache License, Version 2.0
// that can be found in the LICENSE file.
package template
import (
"bytes"
"crypto/md5"
"errors"
"fmt"
"io"
"io/ioutil"
"os"
"os/exec"
"path"
"path/filepath"
"strconv"
"syscall"
"text/template"
"github.com/BurntSushi/toml"
"github.com/kelseyhightower/confd/config"
"github.com/kelseyhightower/confd/etcd/etcdutil"
"github.com/kelseyhightower/confd/log"
)
// TemplateResourceConfig holds the parsed template resource.
type TemplateResourceConfig struct {
TemplateResource TemplateResource `toml:"template"`
}
// TemplateResource is the representation of a parsed template resource.
type TemplateResource struct {
Dest string
FileMode os.FileMode
Gid int
Keys []string
Mode string
Uid int
ReloadCmd string `toml:"reload_cmd"`
CheckCmd string `toml:"check_cmd"`
StageFile *os.File
Src string
Vars map[string]interface{}
etcdClient etcdutil.EtcdClient
}
// NewTemplateResourceFromPath creates a TemplateResource using a decoded file path
// and the supplied EtcdClient as input.
// It returns a TemplateResource and an error if any.
func NewTemplateResourceFromPath(path string, c etcdutil.EtcdClient) (*TemplateResource, error) {
if c == nil {
return nil, errors.New("A valid EtcdClient is required.")
}
var tc *TemplateResourceConfig
log.Debug("Loading template resource from " + path)
_, err := toml.DecodeFile(path, &tc)
if err != nil {
return nil, fmt.Errorf("Cannot process template resource %s - %s", path, err.Error())
}
tc.TemplateResource.etcdClient = c
return &tc.TemplateResource, nil
}
// setVars sets the Vars for template resource.
func (t *TemplateResource) setVars() error {
var err error
log.Debug("Retrieving keys from etcd")
log.Debug("Key prefix set to " + config.Prefix())
t.Vars, err = etcdutil.GetValues(t.etcdClient, config.Prefix(), t.Keys)
if err != nil {
return err
}
return nil
}
// createStageFile stages the src configuration file by processing the src
// template and setting the desired owner, group, and mode. It also sets the
// StageFile for the template resource.
// It returns an error if any.
func (t *TemplateResource) createStageFile() error {
t.Src = filepath.Join(config.TemplateDir(), t.Src)
log.Debug("Using source template " + t.Src)
if !isFileExist(t.Src) {
return errors.New("Missing template: " + t.Src)
}
temp, err := ioutil.TempFile("", "")
if err != nil {
os.Remove(temp.Name())
return err
}
log.Debug("Compiling source template " + t.Src)
tplFuncMap := make(template.FuncMap)
tplFuncMap["Base"] = path.Base
tmpl := template.Must(template.New(path.Base(t.Src)).Funcs(tplFuncMap).ParseFiles(t.Src))
if err = tmpl.Execute(temp, t.Vars); err != nil {
return err
}
// Set the owner, group, and mode on the stage file now to make it easier to
// compare against the destination configuration file later.
os.Chmod(temp.Name(), t.FileMode)
os.Chown(temp.Name(), t.Uid, t.Gid)
t.StageFile = temp
return nil
}
// sync compares the staged and dest config files and attempts to sync them
// if they differ. sync will run a config check command if set before
// overwriting the target config file. Finally, sync will run a reload command
// if set to have the application or service pick up the changes.
// It returns an error if any.
func (t *TemplateResource) sync() error {
staged := t.StageFile.Name()
defer os.Remove(staged)
log.Debug("Comparing candidate config to " + t.Dest)
ok, err := sameConfig(staged, t.Dest)
if err != nil {
log.Error(err.Error())
}
if config.Noop() {
log.Warning("Noop mode enabled " + t.Dest + " will not be modified")
return nil
}
if !ok {
log.Info("Target config " + t.Dest + " out of sync")
if t.CheckCmd != "" {
if err := t.check(); err != nil {
return errors.New("Config check failed: " + err.Error())
}
}
log.Debug("Overwriting target config " + t.Dest)
if err := os.Rename(staged, t.Dest); err != nil {
return err
}
if t.ReloadCmd != "" {
if err := t.reload(); err != nil {
return err
}
}
log.Info("Target config " + t.Dest + " has been updated")
} else {
log.Info("Target config " + t.Dest + " in sync")
}
return nil
}
// check executes the check command to validate the staged config file. The
// command is modified so that any references to src template are substituted
// with a string representing the full path of the staged file. This allows the
// check to be run on the staged file before overwriting the destination config
// file.
// It returns nil if the check command returns 0 and there are no other errors.
func (t *TemplateResource) check() error {
var cmdBuffer bytes.Buffer
data := make(map[string]string)
data["src"] = t.StageFile.Name()
tmpl, err := template.New("checkcmd").Parse(t.CheckCmd)
if err != nil {
return err
}
if err := tmpl.Execute(&cmdBuffer, data); err != nil {
return err
}
log.Debug("Running " + cmdBuffer.String())
c := exec.Command("/bin/sh", "-c", cmdBuffer.String())
if err := c.Run(); err != nil {
return err
}
return nil
}
// reload executes the reload command.
// It returns nil if the reload command returns 0.
func (t *TemplateResource) reload() error {
log.Debug("Running " + t.ReloadCmd)
c := exec.Command("/bin/sh", "-c", t.ReloadCmd)
if err := c.Run(); err != nil {
return err
}
return nil
}
// process is a convenience function that wraps calls to the three main tasks
// required to keep local configuration files in sync. First we gather vars
// from etcd, then we stage a candidate configuration file, and finally sync
// things up.
// It returns an error if any.
func (t *TemplateResource) process() error {
if err := t.setFileMode(); err != nil {
return err
}
if err := t.setVars(); err != nil {
return err
}
if err := t.createStageFile(); err != nil {
return err
}
if err := t.sync(); err != nil {
return err
}
return nil
}
// setFileMode sets the FileMode.
func (t *TemplateResource) setFileMode() error {
if t.Mode == "" {
if !isFileExist(t.Dest) {
t.FileMode = 0644
} else {
fi, err := os.Stat(t.Dest)
if err != nil {
return err
}
t.FileMode = fi.Mode()
}
} else {
mode, err := strconv.ParseUint(t.Mode, 0, 32)
if err != nil {
return err
}
t.FileMode = os.FileMode(mode)
}
return nil
}
// ProcessTemplateResources is a convenience function that loads all the
// template resources and processes them serially. Called from main.
// It returns a list of errors if any.
func ProcessTemplateResources(c etcdutil.EtcdClient) []error {
runErrors := make([]error, 0)
var err error
if c == nil {
runErrors = append(runErrors, errors.New("An etcd client is required"))
return runErrors
}
log.Debug("Loading template resources from confdir " + config.ConfDir())
if !isFileExist(config.ConfDir()) {
log.Warning(fmt.Sprintf("Cannot load template resources confdir '%s' does not exist", config.ConfDir()))
return runErrors
}
paths, err := filepath.Glob(filepath.Join(config.ConfigDir(), "*toml"))
if err != nil {
runErrors = append(runErrors, err)
return runErrors
}
for _, p := range paths {
log.Debug("Processing template resource " + p)
t, err := NewTemplateResourceFromPath(p, c)
if err != nil {
runErrors = append(runErrors, err)
log.Error(err.Error())
continue
}
if err := t.process(); err != nil {
runErrors = append(runErrors, err)
log.Error(err.Error())
continue
}
log.Debug("Processing of template resource " + p + " complete")
}
return runErrors
}
// fileStat return a fileInfo describing the named file.
func fileStat(name string) (fi fileInfo, err error) {
if isFileExist(name) {
f, err := os.Open(name)
defer f.Close()
if err != nil {
return fi, err
}
stats, _ := f.Stat()
fi.Uid = stats.Sys().(*syscall.Stat_t).Uid
fi.Gid = stats.Sys().(*syscall.Stat_t).Gid
fi.Mode = stats.Sys().(*syscall.Stat_t).Mode
h := md5.New()
io.Copy(h, f)
fi.Md5 = fmt.Sprintf("%x", h.Sum(nil))
return fi, nil
} else {
return fi, errors.New("File not found")
}
}
// sameConfig reports whether src and dest config files are equal.
// Two config files are equal when they have the same file contents and
// Unix permissions. The owner, group, and mode must match.
// It return false in other cases.
func sameConfig(src, dest string) (bool, error) {
if !isFileExist(dest) {
return false, nil
}
d, err := fileStat(dest)
if err != nil {
return false, err
}
s, err := fileStat(src)
if err != nil {
return false, err
}
if d.Uid != s.Uid {
log.Info(fmt.Sprintf("%s has UID %d should be %d", dest, d.Uid, s.Uid))
}
if d.Gid != s.Gid {
log.Info(fmt.Sprintf("%s has GID %d should be %d", dest, d.Gid, s.Gid))
}
if d.Mode != s.Mode {
log.Info(fmt.Sprintf("%s has mode %s should be %s", dest, os.FileMode(d.Mode), os.FileMode(s.Mode)))
}
if d.Md5 != s.Md5 {
log.Info(fmt.Sprintf("%s has md5sum %s should be %s", dest, d.Md5, s.Md5))
}
if d.Uid != s.Uid || d.Gid != s.Gid || d.Mode != s.Mode || d.Md5 != s.Md5 {
return false, nil
}
return true, nil
}
// isFileExist reports whether path exits.
func isFileExist(fpath string) bool {
if _, err := os.Stat(fpath); os.IsNotExist(err) {
return false
}
return true
}