summaryrefslogtreecommitdiff
path: root/libpod/container_log_linux.go
blob: 4eb600bfe44bc6bbefe09364f8abf6481a912f13 (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
//+build linux
//+build systemd

package libpod

import (
	"context"
	"fmt"
	"strings"
	"time"

	"github.com/containers/podman/v3/libpod/define"
	"github.com/containers/podman/v3/libpod/events"
	"github.com/containers/podman/v3/libpod/logs"
	"github.com/coreos/go-systemd/v22/sdjournal"
	"github.com/pkg/errors"
	"github.com/sirupsen/logrus"
)

const (
	// journaldLogOut is the journald priority signifying stdout
	journaldLogOut = "6"

	// journaldLogErr is the journald priority signifying stderr
	journaldLogErr = "3"
)

func init() {
	logDrivers = append(logDrivers, define.JournaldLogging)
}

func (c *Container) readFromJournal(ctx context.Context, options *logs.LogOptions, logChannel chan *logs.LogLine) error {
	journal, err := sdjournal.NewJournal()
	if err != nil {
		return err
	}
	// While logs are written to the `logChannel`, we inspect each event
	// and stop once the container has died.  Having logs and events in one
	// stream prevents a race condition that we faced in #10323.

	// Add the filters for events.
	match := sdjournal.Match{Field: "SYSLOG_IDENTIFIER", Value: "podman"}
	if err := journal.AddMatch(match.String()); err != nil {
		return errors.Wrapf(err, "adding filter to journald logger: %v", match)
	}
	match = sdjournal.Match{Field: "PODMAN_ID", Value: c.ID()}
	if err := journal.AddMatch(match.String()); err != nil {
		return errors.Wrapf(err, "adding filter to journald logger: %v", match)
	}

	// Add the filter for logs.  Note the disjunction so that we match
	// either the events or the logs.
	if err := journal.AddDisjunction(); err != nil {
		return errors.Wrap(err, "adding filter disjunction to journald logger")
	}
	match = sdjournal.Match{Field: "CONTAINER_ID_FULL", Value: c.ID()}
	if err := journal.AddMatch(match.String()); err != nil {
		return errors.Wrapf(err, "adding filter to journald logger: %v", match)
	}

	if err := journal.SeekHead(); err != nil {
		return err
	}
	// API requires Next() immediately after SeekHead().
	if _, err := journal.Next(); err != nil {
		return errors.Wrap(err, "initial journal cursor")
	}

	// API requires a next|prev before getting a cursor.
	if _, err := journal.Previous(); err != nil {
		return errors.Wrap(err, "initial journal cursor")
	}

	// Note that the initial cursor may not yet be ready, so we'll do an
	// exponential backoff.
	var cursor string
	var cursorError error
	for i := 1; i <= 3; i++ {
		cursor, cursorError = journal.GetCursor()
		if err != nil {
			continue
		}
		time.Sleep(time.Duration(i*100) * time.Millisecond)
		break
	}
	if cursorError != nil {
		return errors.Wrap(cursorError, "initial journal cursor")
	}

	// We need the container's events in the same journal to guarantee
	// consistency, see #10323.
	if options.Follow && c.runtime.config.Engine.EventsLogger != "journald" {
		return errors.Errorf("using --follow with the journald --log-driver but without the journald --events-backend (%s) is not supported", c.runtime.config.Engine.EventsLogger)
	}

	options.WaitGroup.Add(1)
	go func() {
		defer func() {
			options.WaitGroup.Done()
			if err := journal.Close(); err != nil {
				logrus.Errorf("Unable to close journal: %v", err)
			}
		}()

		tailQueue := []*logs.LogLine{} // needed for options.Tail
		doTail := options.Tail > 0
		for {
			select {
			case <-ctx.Done():
				// Remote client may have closed/lost the connection.
				return
			default:
				// Fallthrough
			}

			if _, err := journal.Next(); err != nil {
				logrus.Errorf("Failed to move journal cursor to next entry: %v", err)
				return
			}
			latestCursor, err := journal.GetCursor()
			if err != nil {
				logrus.Errorf("Failed to get journal cursor: %v", err)
				return
			}

			// Hit the end of the journal.
			if cursor == latestCursor {
				if doTail {
					// Flush *once* we hit the end of the journal.
					startIndex := int64(len(tailQueue)-1) - options.Tail
					if startIndex < 0 {
						startIndex = 0
					}
					for i := startIndex; i < int64(len(tailQueue)); i++ {
						logChannel <- tailQueue[i]
					}
					tailQueue = nil
					doTail = false
				}
				// Unless we follow, quit.
				if !options.Follow {
					return
				}
				// Sleep until something's happening on the journal.
				journal.Wait(sdjournal.IndefiniteWait)
				continue
			}
			cursor = latestCursor

			entry, err := journal.GetEntry()
			if err != nil {
				logrus.Errorf("Failed to get journal entry: %v", err)
				return
			}

			entryTime := time.Unix(0, int64(entry.RealtimeTimestamp)*int64(time.Microsecond))
			if (entryTime.Before(options.Since) && !options.Since.IsZero()) || (entryTime.After(options.Until) && !options.Until.IsZero()) {
				continue
			}
			// If we're reading an event and the container exited/died,
			// then we're done and can return.
			event, ok := entry.Fields["PODMAN_EVENT"]
			if ok {
				status, err := events.StringToStatus(event)
				if err != nil {
					logrus.Errorf("Failed to translate event: %v", err)
					return
				}
				if status == events.Exited {
					return
				}
				continue
			}

			var message string
			var formatError error

			if options.Multi {
				message, formatError = journalFormatterWithID(entry)
			} else {
				message, formatError = journalFormatter(entry)
			}

			if formatError != nil {
				logrus.Errorf("Failed to parse journald log entry: %v", err)
				return
			}

			logLine, err := logs.NewJournaldLogLine(message, options.Multi)
			if err != nil {
				logrus.Errorf("Failed parse log line: %v", err)
				return
			}
			if doTail {
				tailQueue = append(tailQueue, logLine)
				continue
			}
			logChannel <- logLine
		}
	}()

	return nil
}

func journalFormatterWithID(entry *sdjournal.JournalEntry) (string, error) {
	output, err := formatterPrefix(entry)
	if err != nil {
		return "", err
	}

	id, ok := entry.Fields["CONTAINER_ID_FULL"]
	if !ok {
		return "", fmt.Errorf("no CONTAINER_ID_FULL field present in journal entry")
	}
	if len(id) > 12 {
		id = id[:12]
	}
	output += fmt.Sprintf("%s ", id)
	// Append message
	msg, err := formatterMessage(entry)
	if err != nil {
		return "", err
	}
	output += msg
	return output, nil
}

func journalFormatter(entry *sdjournal.JournalEntry) (string, error) {
	output, err := formatterPrefix(entry)
	if err != nil {
		return "", err
	}
	// Append message
	msg, err := formatterMessage(entry)
	if err != nil {
		return "", err
	}
	output += msg
	return output, nil
}

func formatterPrefix(entry *sdjournal.JournalEntry) (string, error) {
	usec := entry.RealtimeTimestamp
	tsString := time.Unix(0, int64(usec)*int64(time.Microsecond)).Format(logs.LogTimeFormat)
	output := fmt.Sprintf("%s ", tsString)
	priority, ok := entry.Fields["PRIORITY"]
	if !ok {
		return "", errors.Errorf("no PRIORITY field present in journal entry")
	}
	if priority == journaldLogOut {
		output += "stdout "
	} else if priority == journaldLogErr {
		output += "stderr "
	} else {
		return "", errors.Errorf("unexpected PRIORITY field in journal entry")
	}

	// if CONTAINER_PARTIAL_MESSAGE is defined, the log type is "P"
	if _, ok := entry.Fields["CONTAINER_PARTIAL_MESSAGE"]; ok {
		output += fmt.Sprintf("%s ", logs.PartialLogType)
	} else {
		output += fmt.Sprintf("%s ", logs.FullLogType)
	}

	return output, nil
}

func formatterMessage(entry *sdjournal.JournalEntry) (string, error) {
	// Finally, append the message
	msg, ok := entry.Fields["MESSAGE"]
	if !ok {
		return "", fmt.Errorf("no MESSAGE field present in journal entry")
	}
	msg = strings.TrimSuffix(msg, "\n")
	return msg, nil
}