-
Notifications
You must be signed in to change notification settings - Fork 2
/
executor.go
328 lines (298 loc) · 8.17 KB
/
executor.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
326
327
328
package executor
import (
"context"
"errors"
"fmt"
"io"
"os"
"os/exec"
"time"
fscmds "github.com/djdv/go-filesystem-utils/filesystem/cmds"
"github.com/djdv/go-filesystem-utils/cmd/parameters"
"github.com/djdv/go-filesystem-utils/cmd/service/daemon"
"github.com/djdv/go-filesystem-utils/cmd/service/daemon/stop"
cmds "github.com/ipfs/go-ipfs-cmds"
"github.com/multiformats/go-multiaddr"
)
var ErrCouldNotConnect = errors.New("could not connect to remote API")
// TODO check if comment is out of date
// MakeExecutor constructs a cmds-lib executor; which parses the Request and
// determines whether to execute the Command within the same local process,
// or within a remote service instance's process.
//
// If no remote addresses are provided in the request,
// and no default instances respond to our checks -
// a local service instance will be created automatically,
// and used to satisfy the request.
func MakeExecutor(request *cmds.Request, env interface{}) (cmds.Executor, error) {
// Execute the request locally if we can.
if request.Command.NoRemote ||
!request.Command.NoLocal {
return cmds.NewExecutor(request.Root), nil
}
// Everything else connects as a client.
var (
ctx = request.Context
settings = new(fscmds.Settings)
unsetArgs, errs = parameters.ParseSettings(ctx, settings,
parameters.SettingsFromCmds(request),
parameters.SettingsFromEnvironment(),
)
_, err = parameters.AccumulateArgs(ctx, unsetArgs, errs)
)
if err != nil {
return nil, err
}
var (
cmd = request.Command
serviceMaddrs = settings.ServiceMaddrs
autoExitInterval = settings.AutoExitInterval
)
return connectToOrLaunchDaemon(cmd, env, autoExitInterval, serviceMaddrs...)
}
func fLaunch(env cmds.Environment, autoExitInterval time.Duration) (cmds.Executor, error) {
if autoExitInterval == 0 { // Don't linger around forever.
autoExitInterval = 30 * time.Second
}
subCmd, serviceMaddr, err := relaunchSelfAsService(autoExitInterval)
if err != nil {
return nil, err
}
// XXX: `environment` will only be this type in our `_test` package.
// This is not supported behavior and for validation only.
cmdPtr, callerWillManageProc := env.(*exec.Cmd)
if callerWillManageProc {
// Caller must call proc.Wait() or proc.Release()
*cmdPtr = *subCmd
// Otherwise call it now.
} else if err := subCmd.Process.Release(); err != nil {
return nil, err
}
return daemon.GetClient(serviceMaddr)
}
func connectToOrLaunchDaemon(cmd *cmds.Command, env cmds.Environment,
idleCheck time.Duration, args ...multiaddr.Multiaddr) (cmds.Executor, error) {
if len(args) > 0 {
return getFirstConnection(args...)
}
var defaults []multiaddr.Multiaddr
for _, fn := range []func() ([]multiaddr.Multiaddr, error){
daemon.UserServiceMaddrs,
daemon.SystemServiceMaddrs,
} {
maddrs, err := fn()
if err != nil {
return nil, err
}
defaults = append(defaults, maddrs...)
}
client, err := connectToOrLaunchDaemon(cmd, env, idleCheck, defaults...)
if err == nil && client != nil {
return client, nil
}
if !errors.Is(err, ErrCouldNotConnect) {
return nil, err
}
// Don't launch daemon, just to stop it.
if cmd == stop.Command {
return nil, ErrCouldNotConnect
}
// Launch daemon, and try again via defaults.
return fLaunch(env, idleCheck)
}
func getFirstConnection(args ...multiaddr.Multiaddr) (cmds.Executor, error) {
var errs []error
for result := range testConnection(generateMaddrs(args...)) {
if err := result.error; err != nil {
errs = append(errs, err)
continue
}
client, err := daemon.GetClient(result.Multiaddr)
if err == nil {
return client, nil
}
errs = append(errs, err)
}
err := ErrCouldNotConnect
for _, e := range errs {
err = fmt.Errorf("%w\n\t%s", err, e)
}
return nil, err
}
type maddrResult struct {
multiaddr.Multiaddr
error
}
func generateMaddrs(maddrs ...multiaddr.Multiaddr) <-chan multiaddr.Multiaddr {
maddrChan := make(chan multiaddr.Multiaddr, len(maddrs))
go func() {
defer close(maddrChan)
for _, maddr := range maddrs {
maddrChan <- maddr
}
}()
return maddrChan
}
func testConnection(maddrs <-chan multiaddr.Multiaddr) <-chan maddrResult {
results := make(chan maddrResult, cap(maddrs))
go func() {
defer close(results)
for maddr := range maddrs {
var result maddrResult
if daemon.ServerDialable(maddr) {
result.Multiaddr = maddr
} else {
result.error = fmt.Errorf(
"could not connect to %s",
maddr.String(),
)
}
results <- result
}
}()
return results
}
// relaunchSelfAsService creates a process,
// and waits for the service to return its address.
// Caller must call either cmd.Wait or cmd.proc.Release.
func relaunchSelfAsService(exitInterval time.Duration) (*exec.Cmd, multiaddr.Multiaddr, error) {
cmd, err := selfCommand(exitInterval)
if err != nil {
return nil, nil, err
}
sio, err := setupIPC(cmd)
if err != nil {
return nil, nil, err
}
serviceMaddr, err := startAndCommunicateWith(cmd, sio)
if err != nil {
return nil, nil, err
}
if err := detatchIO(sio); err != nil {
var (
proc = cmd.Process
procState = cmd.ProcessState
killProc = procState != nil &&
!procState.Exited()
)
if killProc {
pid := proc.Pid
if procErr := proc.Kill(); procErr != nil {
err = fmt.Errorf("%w"+
"\n\tcould not kill subprocess (PID:%d): %s",
err, pid, procErr,
)
}
}
return nil, nil, fmt.Errorf("could not start background service: %w", err)
}
return cmd, serviceMaddr, nil
}
func selfCommand(exitInterval time.Duration) (*exec.Cmd, error) {
self, err := os.Executable()
if err != nil {
return nil, err
}
cwd, err := os.Getwd()
if err != nil {
return nil, err
}
cmd := exec.Command(self, daemon.CmdsPath()...)
cmd.Dir = cwd
cmd.Env = os.Environ()
if exitInterval != 0 {
cmd.Args = append(cmd.Args,
fmt.Sprintf("--%s=%s",
fscmds.AutoExitInterval().CommandLine(), exitInterval,
),
fmt.Sprintf("--%s=%s",
cmds.EncShort, cmds.JSON,
),
)
}
return cmd, nil
}
type stdio struct {
stdin io.WriteCloser
stdout, stderr io.ReadCloser
}
func setupIPC(cmd *exec.Cmd) (sio stdio, err error) {
if sio.stdin, err = cmd.StdinPipe(); err != nil {
return
}
if sio.stdout, err = cmd.StdoutPipe(); err != nil {
return
}
if sio.stderr, err = cmd.StderrPipe(); err != nil {
return
}
return
}
func startAndCommunicateWith(cmd *exec.Cmd, sio stdio) (multiaddr.Multiaddr, error) {
if err := cmd.Start(); err != nil {
return nil, err
}
const responseGrace = 10 * time.Second
ctx, cancel := context.WithTimeout(context.Background(), responseGrace)
defer cancel()
responses := daemon.ResponsesFromReaders(ctx, sio.stdout, sio.stderr)
serviceMaddr, err := getFirstServer(responses)
if err != nil {
return nil, err
}
return serviceMaddr, nil
}
func getFirstServer(results <-chan daemon.ResponseResult) (multiaddr.Multiaddr, error) {
if err := daemon.UntilStarting(results, nil); err != nil {
return nil, err
}
var (
serverMaddr multiaddr.Multiaddr
responseCallback = func(response *daemon.Response) error {
if haveWorkingServer := serverMaddr != nil; haveWorkingServer {
return nil
}
if maddr := response.ListenerMaddr; maddr != nil {
if !daemon.ServerDialable(maddr) {
return fmt.Errorf(
"service said it was ready but we could not connect (%s)",
maddr.String(),
)
}
serverMaddr = maddr
}
return nil
}
)
if err := daemon.UntilReady(results, responseCallback); err != nil {
return nil, err
}
if serverMaddr == nil {
return nil, fmt.Errorf("daemon process did not return any server addresses")
}
return serverMaddr, nil
}
func detatchIO(sio stdio) error {
if err := sendDoneSignalToRemote(sio.stdin); err != nil {
return err
}
for _, closer := range []io.Closer{sio.stdin, sio.stdout, sio.stderr} {
if err := closer.Close(); err != nil {
return err
}
}
return nil
}
func sendDoneSignalToRemote(stdinPipe io.Writer) error {
asciiEOT := [...]byte{daemon.ASCIIEOT}
bytesWrote, err := stdinPipe.Write(asciiEOT[:])
if err != nil {
return err
}
if signalLen := len(asciiEOT); signalLen != bytesWrote {
return fmt.Errorf(
"bytes written %d != len(EOT bytes)(%d): %#v",
bytesWrote, signalLen, asciiEOT)
}
return nil
}