summaryrefslogtreecommitdiff
path: root/pkg/systemd/generate/containers.go
blob: 92c6d8865bbcc0d171c74ae80af216c7f0466c26 (plain)
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
329
330
331
332
333
334
335
336
337
338
package generate

import (
	"bytes"
	"fmt"
	"os"
	"sort"
	"strings"
	"text/template"
	"time"

	"github.com/containers/podman/v3/libpod"
	"github.com/containers/podman/v3/pkg/domain/entities"
	"github.com/containers/podman/v3/version"
	"github.com/pkg/errors"
	"github.com/sirupsen/logrus"
	"github.com/spf13/pflag"
)

// containerInfo contains data required for generating a container's systemd
// unit file.
type containerInfo struct {
	// ServiceName of the systemd service.
	ServiceName string
	// Name or ID of the container.
	ContainerNameOrID string
	// StopTimeout sets the timeout Podman waits before killing the container
	// during service stop.
	StopTimeout uint
	// RestartPolicy of the systemd unit (e.g., no, on-failure, always).
	RestartPolicy string
	// PIDFile of the service. Required for forking services. Must point to the
	// PID of the associated conmon process.
	PIDFile string
	// ContainerIDFile to be used in the unit.
	ContainerIDFile string
	// GenerateTimestamp, if set the generated unit file has a time stamp.
	GenerateTimestamp bool
	// BoundToServices are the services this service binds to.  Note that this
	// service runs after them.
	BoundToServices []string
	// PodmanVersion for the header. Will be set internally. Will be auto-filled
	// if left empty.
	PodmanVersion string
	// Executable is the path to the podman executable. Will be auto-filled if
	// left empty.
	Executable string
	// RootFlags contains the root flags which were used to create the container
	// Only used with --new
	RootFlags string
	// TimeStamp at the time of creating the unit file. Will be set internally.
	TimeStamp string
	// CreateCommand is the full command plus arguments of the process the
	// container has been created with.
	CreateCommand []string
	// EnvVariable is generate.EnvVariable and must not be set.
	EnvVariable string
	// ExecStartPre of the unit.
	ExecStartPre string
	// ExecStart of the unit.
	ExecStart string
	// TimeoutStopSec of the unit.
	TimeoutStopSec uint
	// ExecStop of the unit.
	ExecStop string
	// ExecStopPost of the unit.
	ExecStopPost string
	// Removes autogenerated by Podman and timestamp if set to true
	GenerateNoHeader bool
	// If not nil, the container is part of the pod.  We can use the
	// podInfo to extract the relevant data.
	Pod *podInfo
}

const containerTemplate = headerTemplate + `
{{{{- if .BoundToServices}}}}
BindsTo={{{{- range $index, $value := .BoundToServices -}}}}{{{{if $index}}}} {{{{end}}}}{{{{ $value }}}}.service{{{{end}}}}
After={{{{- range $index, $value := .BoundToServices -}}}}{{{{if $index}}}} {{{{end}}}}{{{{ $value }}}}.service{{{{end}}}}
{{{{- end}}}}

[Service]
Environment={{{{.EnvVariable}}}}=%n
Restart={{{{.RestartPolicy}}}}
TimeoutStopSec={{{{.TimeoutStopSec}}}}
{{{{- if .ExecStartPre}}}}
ExecStartPre={{{{.ExecStartPre}}}}
{{{{- end}}}}
ExecStart={{{{.ExecStart}}}}
ExecStop={{{{.ExecStop}}}}
ExecStopPost={{{{.ExecStopPost}}}}
PIDFile={{{{.PIDFile}}}}
Type=forking

[Install]
WantedBy=multi-user.target default.target
`

// ContainerUnit generates a systemd unit for the specified container.  Based
// on the options, the return value might be the entire unit or a file it has
// been written to.
func ContainerUnit(ctr *libpod.Container, options entities.GenerateSystemdOptions) (string, string, error) {
	info, err := generateContainerInfo(ctr, options)
	if err != nil {
		return "", "", err
	}
	content, err := executeContainerTemplate(info, options)
	if err != nil {
		return "", "", err
	}
	return info.ServiceName, content, nil
}

func generateContainerInfo(ctr *libpod.Container, options entities.GenerateSystemdOptions) (*containerInfo, error) {
	timeout := ctr.StopTimeout()
	if options.StopTimeout != nil {
		timeout = *options.StopTimeout
	}

	config := ctr.Config()
	conmonPidFile := config.ConmonPidFile
	if conmonPidFile == "" {
		return nil, errors.Errorf("conmon PID file path is empty, try to recreate the container with --conmon-pidfile flag")
	}

	createCommand := []string{}
	if config.CreateCommand != nil {
		createCommand = config.CreateCommand
	} else if options.New {
		return nil, errors.Errorf("cannot use --new on container %q: no create command found", ctr.ID())
	}

	nameOrID, serviceName := containerServiceName(ctr, options)

	info := containerInfo{
		ServiceName:       serviceName,
		ContainerNameOrID: nameOrID,
		RestartPolicy:     options.RestartPolicy,
		PIDFile:           conmonPidFile,
		StopTimeout:       timeout,
		GenerateTimestamp: true,
		CreateCommand:     createCommand,
	}

	return &info, nil
}

// containerServiceName returns the nameOrID and the service name of the
// container.
func containerServiceName(ctr *libpod.Container, options entities.GenerateSystemdOptions) (string, string) {
	nameOrID := ctr.ID()
	if options.Name {
		nameOrID = ctr.Name()
	}
	serviceName := fmt.Sprintf("%s%s%s", options.ContainerPrefix, options.Separator, nameOrID)
	return nameOrID, serviceName
}

// executeContainerTemplate executes the container template on the specified
// containerInfo.  Note that the containerInfo is also post processed and
// completed, which allows for an easier unit testing.
func executeContainerTemplate(info *containerInfo, options entities.GenerateSystemdOptions) (string, error) {
	if err := validateRestartPolicy(info.RestartPolicy); err != nil {
		return "", err
	}

	// Make sure the executable is set.
	if info.Executable == "" {
		executable, err := os.Executable()
		if err != nil {
			executable = "/usr/bin/podman"
			logrus.Warnf("Could not obtain podman executable location, using default %s", executable)
		}
		info.Executable = executable
	}

	info.EnvVariable = EnvVariable
	info.ExecStart = "{{{{.Executable}}}} start {{{{.ContainerNameOrID}}}}"
	info.ExecStop = "{{{{.Executable}}}} stop {{{{if (ge .StopTimeout 0)}}}}-t {{{{.StopTimeout}}}}{{{{end}}}} {{{{.ContainerNameOrID}}}}"
	info.ExecStopPost = "{{{{.Executable}}}} stop {{{{if (ge .StopTimeout 0)}}}}-t {{{{.StopTimeout}}}}{{{{end}}}} {{{{.ContainerNameOrID}}}}"

	// Assemble the ExecStart command when creating a new container.
	//
	// Note that we cannot catch all corner cases here such that users
	// *must* manually check the generated files.  A container might have
	// been created via a Python script, which would certainly yield an
	// invalid `info.CreateCommand`.  Hence, we're doing a best effort unit
	// generation and don't try aiming at completeness.
	if options.New {
		info.PIDFile = "%t/" + info.ServiceName + ".pid"
		info.ContainerIDFile = "%t/" + info.ServiceName + ".ctr-id"
		// The create command must at least have three arguments:
		// 	/usr/bin/podman run $IMAGE
		index := 0
		for i, arg := range info.CreateCommand {
			if arg == "run" || arg == "create" {
				index = i + 1
				break
			}
		}
		if index == 0 {
			return "", errors.Errorf("container's create command is too short or invalid: %v", info.CreateCommand)
		}
		// We're hard-coding the first five arguments and append the
		// CreateCommand with a stripped command and subcommand.
		startCommand := []string{info.Executable}
		if index > 2 {
			// include root flags
			info.RootFlags = strings.Join(escapeSystemdArguments(info.CreateCommand[1:index-1]), " ")
			startCommand = append(startCommand, info.CreateCommand[1:index-1]...)
		}
		startCommand = append(startCommand,
			"run",
			"--conmon-pidfile", "{{{{.PIDFile}}}}",
			"--cidfile", "{{{{.ContainerIDFile}}}}",
			"--cgroups=no-conmon",
		)
		// If the container is in a pod, make sure that the
		// --pod-id-file is set correctly.
		if info.Pod != nil {
			podFlags := []string{"--pod-id-file", "{{{{.Pod.PodIDFile}}}}"}
			startCommand = append(startCommand, podFlags...)
			info.CreateCommand = filterPodFlags(info.CreateCommand)
		}

		// Presence check for certain flags/options.
		fs := pflag.NewFlagSet("args", pflag.ContinueOnError)
		fs.ParseErrorsWhitelist.UnknownFlags = true
		fs.Usage = func() {}
		fs.SetInterspersed(false)
		fs.BoolP("detach", "d", false, "")
		fs.String("name", "", "")
		fs.Bool("replace", false, "")
		fs.Parse(info.CreateCommand[index:])

		hasDetachParam, err := fs.GetBool("detach")
		if err != nil {
			return "", err
		}
		hasNameParam := fs.Lookup("name").Changed
		hasReplaceParam, err := fs.GetBool("replace")
		if err != nil {
			return "", err
		}

		remainingCmd := info.CreateCommand[index:]

		if !hasDetachParam {
			// Enforce detaching
			//
			// since we use systemd `Type=forking` service @see
			// https://www.freedesktop.org/software/systemd/man/systemd.service.html#Type=
			// when we generated systemd service file with the
			// --new param, `ExecStart` will have `/usr/bin/podman
			// run ...` if `info.CreateCommand` has no `-d` or
			// `--detach` param, podman will run the container in
			// default attached mode, as a result, `systemd start`
			// will wait the `podman run` command exit until failed
			// with timeout error.
			startCommand = append(startCommand, "-d")

			if fs.Changed("detach") {
				// this can only happen if --detach=false is set
				// in that case we need to remove it otherwise we
				// would overwrite the previous detach arg to false
				remainingCmd = removeDetachArg(remainingCmd, fs.NArg())
			}
		}
		if hasNameParam && !hasReplaceParam {
			// Enforce --replace for named containers.  This will
			// make systemd units more robust as it allows them to
			// start after system crashes (see
			// github.com/containers/podman/issues/5485).
			startCommand = append(startCommand, "--replace")

			if fs.Changed("replace") {
				// this can only happen if --replace=false is set
				// in that case we need to remove it otherwise we
				// would overwrite the previous replace arg to false
				remainingCmd = removeReplaceArg(remainingCmd, fs.NArg())
			}
		}
		startCommand = append(startCommand, remainingCmd...)
		startCommand = escapeSystemdArguments(startCommand)

		info.ExecStartPre = "/bin/rm -f {{{{.PIDFile}}}} {{{{.ContainerIDFile}}}}"
		info.ExecStart = strings.Join(startCommand, " ")
		info.ExecStop = "{{{{.Executable}}}} {{{{if .RootFlags}}}}{{{{ .RootFlags}}}} {{{{end}}}}stop --ignore --cidfile {{{{.ContainerIDFile}}}} {{{{if (ge .StopTimeout 0)}}}}-t {{{{.StopTimeout}}}}{{{{end}}}}"
		info.ExecStopPost = "{{{{.Executable}}}} {{{{if .RootFlags}}}}{{{{ .RootFlags}}}} {{{{end}}}}rm --ignore -f --cidfile {{{{.ContainerIDFile}}}}"
	}

	info.TimeoutStopSec = minTimeoutStopSec + info.StopTimeout

	if info.PodmanVersion == "" {
		info.PodmanVersion = version.Version.String()
	}

	if options.NoHeader {
		info.GenerateNoHeader = true
		info.GenerateTimestamp = false
	}

	if info.GenerateTimestamp {
		info.TimeStamp = fmt.Sprintf("%v", time.Now().Format(time.UnixDate))
	}
	// Sort the slices to assure a deterministic output.
	sort.Strings(info.BoundToServices)

	// Generate the template and compile it.
	//
	// Note that we need a two-step generation process to allow for fields
	// embedding other fields.  This way we can replace `A -> B -> C` and
	// make the code easier to maintain at the cost of a slightly slower
	// generation.  That's especially needed for embedding the PID and ID
	// files in other fields which will eventually get replaced in the 2nd
	// template execution.
	templ, err := template.New("container_template").Delims("{{{{", "}}}}").Parse(containerTemplate)
	if err != nil {
		return "", errors.Wrap(err, "error parsing systemd service template")
	}

	var buf bytes.Buffer
	if err := templ.Execute(&buf, info); err != nil {
		return "", err
	}

	// Now parse the generated template (i.e., buf) and execute it.
	templ, err = template.New("container_template").Delims("{{{{", "}}}}").Parse(buf.String())
	if err != nil {
		return "", errors.Wrap(err, "error parsing systemd service template")
	}

	buf = bytes.Buffer{}
	if err := templ.Execute(&buf, info); err != nil {
		return "", err
	}

	return buf.String(), nil
}