Hide keyboard shortcuts

Hot-keys on this page

r m x p   toggle line displays

j k   next/prev highlighted chunk

0   (zero) top of page

1   (one) first highlighted chunk

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

339

340

341

342

343

344

345

346

347

348

349

350

351

352

353

354

355

356

357

358

359

360

361

362

363

364

365

366

367

368

369

370

371

372

373

374

375

376

377

378

379

380

381

382

383

384

385

386

387

388

389

390

391

392

393

394

395

396

397

398

399

400

401

402

403

404

405

406

407

408

409

410

411

412

413

414

415

416

417

418

419

420

421

422

423

424

425

426

427

428

429

430

431

432

433

434

435

436

437

438

439

440

441

442

443

444

445

446

447

448

449

450

451

452

453

454

455

456

457

458

459

460

461

462

463

464

465

466

467

468

469

470

471

472

473

474

475

476

477

478

479

480

481

482

483

484

485

486

487

488

489

490

491

492

493

494

495

496

497

498

499

500

501

502

503

504

505

506

507

508

509

510

511

512

513

514

515

516

517

518

519

520

521

522

523

524

525

526

527

528

529

530

531

532

533

534

535

536

537

538

539

540

541

542

543

544

545

546

547

548

549

550

551

552

553

554

555

556

557

558

559

560

561

562

563

564

565

566

567

568

569

570

571

572

573

574

575

576

577

578

579

580

581

582

583

584

585

586

587

588

589

590

591

592

593

594

595

596

597

598

599

600

601

602

603

604

605

606

607

608

609

610

611

612

613

614

615

616

617

618

619

620

621

622

623

624

625

626

627

628

629

630

631

632

633

634

635

636

637

638

639

640

641

642

643

644

645

646

647

648

649

650

651

652

653

654

655

656

657

658

659

660

661

662

663

664

665

666

667

668

669

670

671

672

673

674

675

676

677

678

679

680

681

682

683

684

685

686

687

688

689

690

691

692

693

694

695

696

697

698

699

700

701

702

703

704

705

706

707

708

709

710

711

712

713

714

715

716

717

718

719

720

721

722

723

724

725

726

727

728

729

730

731

732

733

734

735

736

737

738

739

740

741

742

743

744

745

746

747

748

749

750

751

752

753

754

755

756

757

758

759

760

761

762

763

764

765

766

767

768

769

770

771

772

773

774

775

776

777

778

779

780

781

782

783

784

785

786

787

788

789

790

791

792

793

794

795

796

797

798

799

800

801

802

803

804

805

806

807

808

809

810

811

812

813

814

815

816

817

818

819

820

821

822

823

824

825

826

827

828

829

830

831

832

833

834

835

836

837

838

839

840

841

842

843

844

845

846

847

848

849

850

851

852

853

854

855

856

857

858

859

860

861

862

863

864

865

866

867

868

869

870

871

872

873

874

875

876

877

878

879

880

881

882

883

884

885

886

887

888

889

890

891

892

893

894

895

896

897

898

899

900

901

902

903

904

905

906

907

908

909

910

911

912

913

914

915

916

917

918

919

920

921

922

923

924

925

926

927

928

929

930

931

932

933

934

935

936

937

938

939

940

941

942

943

944

945

946

947

948

949

950

951

952

953

954

955

956

957

958

959

960

961

962

963

964

965

966

967

968

969

970

971

972

973

974

975

976

977

978

979

980

981

982

983

984

985

986

987

988

989

990

991

992

993

994

995

996

997

998

999

1000

1001

1002

1003

1004

1005

1006

1007

1008

1009

1010

1011

1012

1013

1014

1015

1016

1017

1018

1019

1020

1021

1022

1023

1024

1025

1026

1027

1028

1029

1030

1031

1032

1033

1034

1035

1036

1037

1038

1039

1040

1041

1042

1043

1044

1045

1046

1047

1048

1049

1050

1051

1052

1053

1054

1055

1056

1057

1058

1059

1060

1061

1062

1063

1064

1065

1066

1067

1068

1069

1070

1071

1072

1073

1074

1075

1076

1077

1078

1079

1080

1081

1082

1083

1084

1085

1086

1087

1088

1089

1090

1091

1092

1093

1094

1095

1096

1097

1098

1099

1100

1101

1102

1103

1104

1105

1106

1107

1108

1109

1110

1111

1112

1113

1114

1115

1116

1117

1118

1119

1120

1121

1122

1123

1124

1125

1126

1127

1128

1129

1130

1131

1132

1133

1134

1135

1136

1137

1138

1139

1140

1141

1142

1143

1144

1145

1146

1147

1148

1149

1150

1151

1152

1153

1154

1155

1156

1157

1158

1159

1160

1161

1162

1163

1164

1165

1166

1167

1168

1169

1170

1171

1172

1173

1174

1175

1176

1177

1178

1179

1180

1181

1182

1183

1184

1185

1186

1187

1188

1189

1190

1191

1192

1193

1194

1195

1196

1197

1198

1199

1200

1201

1202

1203

1204

1205

1206

1207

1208

1209

1210

1211

1212

1213

1214

1215

1216

1217

1218

1219

1220

1221

1222

1223

1224

1225

1226

1227

1228

1229

1230

1231

1232

1233

1234

1235

1236

1237

1238

1239

1240

1241

1242

1243

1244

1245

1246

1247

1248

1249

1250

1251

1252

1253

1254

1255

1256

1257

1258

1259

1260

1261

1262

1263

1264

1265

1266

1267

1268

1269

1270

1271

1272

1273

1274

1275

1276

1277

1278

1279

1280

1281

1282

1283

1284

1285

1286

1287

1288

1289

1290

1291

1292

1293

1294

1295

1296

1297

1298

1299

1300

1301

1302

1303

1304

1305

1306

1307

1308

1309

1310

1311

1312

1313

1314

1315

1316

1317

1318

1319

1320

1321

1322

1323

1324

1325

1326

1327

1328

1329

1330

1331

1332

1333

1334

1335

1336

1337

1338

1339

1340

1341

1342

1343

1344

1345

1346

1347

1348

1349

1350

1351

1352

1353

1354

1355

1356

1357

1358

1359

1360

1361

1362

1363

1364

1365

1366

1367

1368

1369

1370

1371

1372

1373

1374

1375

1376

1377

1378

1379

1380

1381

1382

1383

1384

1385

1386

1387

1388

1389

1390

1391

1392

1393

1394

1395

1396

1397

1398

1399

1400

1401

1402

1403

1404

1405

1406

1407

1408

1409

1410

1411

1412

1413

1414

1415

1416

1417

1418

1419

1420

1421

1422

1423

1424

1425

1426

1427

1428

1429

1430

1431

1432

1433

1434

1435

1436

1437

1438

1439

1440

1441

1442

1443

1444

1445

1446

1447

1448

1449

1450

1451

1452

1453

1454

1455

1456

1457

1458

1459

1460

1461

1462

1463

1464

1465

1466

1467

1468

1469

1470

1471

1472

1473

1474

1475

1476

1477

1478

1479

1480

1481

1482

1483

1484

1485

1486

1487

1488

1489

1490

1491

1492

1493

1494

1495

1496

1497

1498

1499

1500

1501

1502

1503

1504

1505

# Copyright 2001-2016 by Vinay Sajip. All Rights Reserved. 

# 

# Permission to use, copy, modify, and distribute this software and its 

# documentation for any purpose and without fee is hereby granted, 

# provided that the above copyright notice appear in all copies and that 

# both that copyright notice and this permission notice appear in 

# supporting documentation, and that the name of Vinay Sajip 

# not be used in advertising or publicity pertaining to distribution 

# of the software without specific, written prior permission. 

# VINAY SAJIP DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING 

# ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL 

# VINAY SAJIP BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR 

# ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER 

# IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT 

# OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 

 

""" 

Additional handlers for the logging package for Python. The core package is 

based on PEP 282 and comments thereto in comp.lang.python. 

 

Copyright (C) 2001-2016 Vinay Sajip. All Rights Reserved. 

 

To use, simply 'import logging.handlers' and log away! 

""" 

 

import logging, socket, os, pickle, struct, time, re 

from stat import ST_DEV, ST_INO, ST_MTIME 

import queue 

try: 

import threading 

except ImportError: #pragma: no cover 

threading = None 

 

# 

# Some constants... 

# 

 

DEFAULT_TCP_LOGGING_PORT = 9020 

DEFAULT_UDP_LOGGING_PORT = 9021 

DEFAULT_HTTP_LOGGING_PORT = 9022 

DEFAULT_SOAP_LOGGING_PORT = 9023 

SYSLOG_UDP_PORT = 514 

SYSLOG_TCP_PORT = 514 

 

_MIDNIGHT = 24 * 60 * 60 # number of seconds in a day 

 

class BaseRotatingHandler(logging.FileHandler): 

""" 

Base class for handlers that rotate log files at a certain point. 

Not meant to be instantiated directly. Instead, use RotatingFileHandler 

or TimedRotatingFileHandler. 

""" 

def __init__(self, filename, mode, encoding=None, delay=False): 

""" 

Use the specified filename for streamed logging 

""" 

logging.FileHandler.__init__(self, filename, mode, encoding, delay) 

self.mode = mode 

self.encoding = encoding 

self.namer = None 

self.rotator = None 

 

def emit(self, record): 

""" 

Emit a record. 

 

Output the record to the file, catering for rollover as described 

in doRollover(). 

""" 

try: 

if self.shouldRollover(record): 

self.doRollover() 

logging.FileHandler.emit(self, record) 

except Exception: 

self.handleError(record) 

 

def rotation_filename(self, default_name): 

""" 

Modify the filename of a log file when rotating. 

 

This is provided so that a custom filename can be provided. 

 

The default implementation calls the 'namer' attribute of the 

handler, if it's callable, passing the default name to 

it. If the attribute isn't callable (the default is None), the name 

is returned unchanged. 

 

:param default_name: The default name for the log file. 

""" 

if not callable(self.namer): 

result = default_name 

else: 

result = self.namer(default_name) 

return result 

 

def rotate(self, source, dest): 

""" 

When rotating, rotate the current log. 

 

The default implementation calls the 'rotator' attribute of the 

handler, if it's callable, passing the source and dest arguments to 

it. If the attribute isn't callable (the default is None), the source 

is simply renamed to the destination. 

 

:param source: The source filename. This is normally the base 

filename, e.g. 'test.log' 

:param dest: The destination filename. This is normally 

what the source is rotated to, e.g. 'test.log.1'. 

""" 

if not callable(self.rotator): 

# Issue 18940: A file may not have been created if delay is True. 

if os.path.exists(source): 

os.rename(source, dest) 

else: 

self.rotator(source, dest) 

 

class RotatingFileHandler(BaseRotatingHandler): 

""" 

Handler for logging to a set of files, which switches from one file 

to the next when the current file reaches a certain size. 

""" 

def __init__(self, filename, mode='a', maxBytes=0, backupCount=0, encoding=None, delay=False): 

""" 

Open the specified file and use it as the stream for logging. 

 

By default, the file grows indefinitely. You can specify particular 

values of maxBytes and backupCount to allow the file to rollover at 

a predetermined size. 

 

Rollover occurs whenever the current log file is nearly maxBytes in 

length. If backupCount is >= 1, the system will successively create 

new files with the same pathname as the base file, but with extensions 

".1", ".2" etc. appended to it. For example, with a backupCount of 5 

and a base file name of "app.log", you would get "app.log", 

"app.log.1", "app.log.2", ... through to "app.log.5". The file being 

written to is always "app.log" - when it gets filled up, it is closed 

and renamed to "app.log.1", and if files "app.log.1", "app.log.2" etc. 

exist, then they are renamed to "app.log.2", "app.log.3" etc. 

respectively. 

 

If maxBytes is zero, rollover never occurs. 

""" 

# If rotation/rollover is wanted, it doesn't make sense to use another 

# mode. If for example 'w' were specified, then if there were multiple 

# runs of the calling application, the logs from previous runs would be 

# lost if the 'w' is respected, because the log file would be truncated 

# on each run. 

if maxBytes > 0: 

mode = 'a' 

BaseRotatingHandler.__init__(self, filename, mode, encoding, delay) 

self.maxBytes = maxBytes 

self.backupCount = backupCount 

 

def doRollover(self): 

""" 

Do a rollover, as described in __init__(). 

""" 

if self.stream: 

self.stream.close() 

self.stream = None 

if self.backupCount > 0: 

for i in range(self.backupCount - 1, 0, -1): 

sfn = self.rotation_filename("%s.%d" % (self.baseFilename, i)) 

dfn = self.rotation_filename("%s.%d" % (self.baseFilename, 

i + 1)) 

if os.path.exists(sfn): 

if os.path.exists(dfn): 

os.remove(dfn) 

os.rename(sfn, dfn) 

dfn = self.rotation_filename(self.baseFilename + ".1") 

if os.path.exists(dfn): 

os.remove(dfn) 

self.rotate(self.baseFilename, dfn) 

if not self.delay: 

self.stream = self._open() 

 

def shouldRollover(self, record): 

""" 

Determine if rollover should occur. 

 

Basically, see if the supplied record would cause the file to exceed 

the size limit we have. 

""" 

if self.stream is None: # delay was set... 

self.stream = self._open() 

if self.maxBytes > 0: # are we rolling over? 

msg = "%s\n" % self.format(record) 

self.stream.seek(0, 2) #due to non-posix-compliant Windows feature 

if self.stream.tell() + len(msg) >= self.maxBytes: 

return 1 

return 0 

 

class TimedRotatingFileHandler(BaseRotatingHandler): 

""" 

Handler for logging to a file, rotating the log file at certain timed 

intervals. 

 

If backupCount is > 0, when rollover is done, no more than backupCount 

files are kept - the oldest ones are deleted. 

""" 

def __init__(self, filename, when='h', interval=1, backupCount=0, encoding=None, delay=False, utc=False, atTime=None): 

BaseRotatingHandler.__init__(self, filename, 'a', encoding, delay) 

self.when = when.upper() 

self.backupCount = backupCount 

self.utc = utc 

self.atTime = atTime 

# Calculate the real rollover interval, which is just the number of 

# seconds between rollovers. Also set the filename suffix used when 

# a rollover occurs. Current 'when' events supported: 

# S - Seconds 

# M - Minutes 

# H - Hours 

# D - Days 

# midnight - roll over at midnight 

# W{0-6} - roll over on a certain day; 0 - Monday 

# 

# Case of the 'when' specifier is not important; lower or upper case 

# will work. 

if self.when == 'S': 

self.interval = 1 # one second 

self.suffix = "%Y-%m-%d_%H-%M-%S" 

self.extMatch = r"^\d{4}-\d{2}-\d{2}_\d{2}-\d{2}-\d{2}(\.\w+)?$" 

elif self.when == 'M': 

self.interval = 60 # one minute 

self.suffix = "%Y-%m-%d_%H-%M" 

self.extMatch = r"^\d{4}-\d{2}-\d{2}_\d{2}-\d{2}(\.\w+)?$" 

elif self.when == 'H': 

self.interval = 60 * 60 # one hour 

self.suffix = "%Y-%m-%d_%H" 

self.extMatch = r"^\d{4}-\d{2}-\d{2}_\d{2}(\.\w+)?$" 

elif self.when == 'D' or self.when == 'MIDNIGHT': 

self.interval = 60 * 60 * 24 # one day 

self.suffix = "%Y-%m-%d" 

self.extMatch = r"^\d{4}-\d{2}-\d{2}(\.\w+)?$" 

elif self.when.startswith('W'): 

self.interval = 60 * 60 * 24 * 7 # one week 

if len(self.when) != 2: 

raise ValueError("You must specify a day for weekly rollover from 0 to 6 (0 is Monday): %s" % self.when) 

if self.when[1] < '0' or self.when[1] > '6': 

raise ValueError("Invalid day specified for weekly rollover: %s" % self.when) 

self.dayOfWeek = int(self.when[1]) 

self.suffix = "%Y-%m-%d" 

self.extMatch = r"^\d{4}-\d{2}-\d{2}(\.\w+)?$" 

else: 

raise ValueError("Invalid rollover interval specified: %s" % self.when) 

 

self.extMatch = re.compile(self.extMatch, re.ASCII) 

self.interval = self.interval * interval # multiply by units requested 

# The following line added because the filename passed in could be a 

# path object (see Issue #27493), but self.baseFilename will be a string 

filename = self.baseFilename 

if os.path.exists(filename): 

t = os.stat(filename)[ST_MTIME] 

else: 

t = int(time.time()) 

self.rolloverAt = self.computeRollover(t) 

 

def computeRollover(self, currentTime): 

""" 

Work out the rollover time based on the specified time. 

""" 

result = currentTime + self.interval 

# If we are rolling over at midnight or weekly, then the interval is already known. 

# What we need to figure out is WHEN the next interval is. In other words, 

# if you are rolling over at midnight, then your base interval is 1 day, 

# but you want to start that one day clock at midnight, not now. So, we 

# have to fudge the rolloverAt value in order to trigger the first rollover 

# at the right time. After that, the regular interval will take care of 

# the rest. Note that this code doesn't care about leap seconds. :) 

if self.when == 'MIDNIGHT' or self.when.startswith('W'): 

# This could be done with less code, but I wanted it to be clear 

if self.utc: 

t = time.gmtime(currentTime) 

else: 

t = time.localtime(currentTime) 

currentHour = t[3] 

currentMinute = t[4] 

currentSecond = t[5] 

currentDay = t[6] 

# r is the number of seconds left between now and the next rotation 

if self.atTime is None: 

rotate_ts = _MIDNIGHT 

else: 

rotate_ts = ((self.atTime.hour * 60 + self.atTime.minute)*60 + 

self.atTime.second) 

 

r = rotate_ts - ((currentHour * 60 + currentMinute) * 60 + 

currentSecond) 

if r < 0: 

# Rotate time is before the current time (for example when 

# self.rotateAt is 13:45 and it now 14:15), rotation is 

# tomorrow. 

r += _MIDNIGHT 

currentDay = (currentDay + 1) % 7 

result = currentTime + r 

# If we are rolling over on a certain day, add in the number of days until 

# the next rollover, but offset by 1 since we just calculated the time 

# until the next day starts. There are three cases: 

# Case 1) The day to rollover is today; in this case, do nothing 

# Case 2) The day to rollover is further in the interval (i.e., today is 

# day 2 (Wednesday) and rollover is on day 6 (Sunday). Days to 

# next rollover is simply 6 - 2 - 1, or 3. 

# Case 3) The day to rollover is behind us in the interval (i.e., today 

# is day 5 (Saturday) and rollover is on day 3 (Thursday). 

# Days to rollover is 6 - 5 + 3, or 4. In this case, it's the 

# number of days left in the current week (1) plus the number 

# of days in the next week until the rollover day (3). 

# The calculations described in 2) and 3) above need to have a day added. 

# This is because the above time calculation takes us to midnight on this 

# day, i.e. the start of the next day. 

if self.when.startswith('W'): 

day = currentDay # 0 is Monday 

if day != self.dayOfWeek: 

if day < self.dayOfWeek: 

daysToWait = self.dayOfWeek - day 

else: 

daysToWait = 6 - day + self.dayOfWeek + 1 

newRolloverAt = result + (daysToWait * (60 * 60 * 24)) 

if not self.utc: 

dstNow = t[-1] 

dstAtRollover = time.localtime(newRolloverAt)[-1] 

if dstNow != dstAtRollover: 

if not dstNow: # DST kicks in before next rollover, so we need to deduct an hour 

addend = -3600 

else: # DST bows out before next rollover, so we need to add an hour 

addend = 3600 

newRolloverAt += addend 

result = newRolloverAt 

return result 

 

def shouldRollover(self, record): 

""" 

Determine if rollover should occur. 

 

record is not used, as we are just comparing times, but it is needed so 

the method signatures are the same 

""" 

t = int(time.time()) 

if t >= self.rolloverAt: 

return 1 

return 0 

 

def getFilesToDelete(self): 

""" 

Determine the files to delete when rolling over. 

 

More specific than the earlier method, which just used glob.glob(). 

""" 

dirName, baseName = os.path.split(self.baseFilename) 

fileNames = os.listdir(dirName) 

result = [] 

prefix = baseName + "." 

plen = len(prefix) 

for fileName in fileNames: 

if fileName[:plen] == prefix: 

suffix = fileName[plen:] 

if self.extMatch.match(suffix): 

result.append(os.path.join(dirName, fileName)) 

if len(result) < self.backupCount: 

result = [] 

else: 

result.sort() 

result = result[:len(result) - self.backupCount] 

return result 

 

def doRollover(self): 

""" 

do a rollover; in this case, a date/time stamp is appended to the filename 

when the rollover happens. However, you want the file to be named for the 

start of the interval, not the current time. If there is a backup count, 

then we have to get a list of matching filenames, sort them and remove 

the one with the oldest suffix. 

""" 

if self.stream: 

self.stream.close() 

self.stream = None 

# get the time that this sequence started at and make it a TimeTuple 

currentTime = int(time.time()) 

dstNow = time.localtime(currentTime)[-1] 

t = self.rolloverAt - self.interval 

if self.utc: 

timeTuple = time.gmtime(t) 

else: 

timeTuple = time.localtime(t) 

dstThen = timeTuple[-1] 

if dstNow != dstThen: 

if dstNow: 

addend = 3600 

else: 

addend = -3600 

timeTuple = time.localtime(t + addend) 

dfn = self.rotation_filename(self.baseFilename + "." + 

time.strftime(self.suffix, timeTuple)) 

if os.path.exists(dfn): 

os.remove(dfn) 

self.rotate(self.baseFilename, dfn) 

if self.backupCount > 0: 

for s in self.getFilesToDelete(): 

os.remove(s) 

if not self.delay: 

self.stream = self._open() 

newRolloverAt = self.computeRollover(currentTime) 

while newRolloverAt <= currentTime: 

newRolloverAt = newRolloverAt + self.interval 

#If DST changes and midnight or weekly rollover, adjust for this. 

if (self.when == 'MIDNIGHT' or self.when.startswith('W')) and not self.utc: 

dstAtRollover = time.localtime(newRolloverAt)[-1] 

if dstNow != dstAtRollover: 

if not dstNow: # DST kicks in before next rollover, so we need to deduct an hour 

addend = -3600 

else: # DST bows out before next rollover, so we need to add an hour 

addend = 3600 

newRolloverAt += addend 

self.rolloverAt = newRolloverAt 

 

class WatchedFileHandler(logging.FileHandler): 

""" 

A handler for logging to a file, which watches the file 

to see if it has changed while in use. This can happen because of 

usage of programs such as newsyslog and logrotate which perform 

log file rotation. This handler, intended for use under Unix, 

watches the file to see if it has changed since the last emit. 

(A file has changed if its device or inode have changed.) 

If it has changed, the old file stream is closed, and the file 

opened to get a new stream. 

 

This handler is not appropriate for use under Windows, because 

under Windows open files cannot be moved or renamed - logging 

opens the files with exclusive locks - and so there is no need 

for such a handler. Furthermore, ST_INO is not supported under 

Windows; stat always returns zero for this value. 

 

This handler is based on a suggestion and patch by Chad J. 

Schroeder. 

""" 

def __init__(self, filename, mode='a', encoding=None, delay=False): 

logging.FileHandler.__init__(self, filename, mode, encoding, delay) 

self.dev, self.ino = -1, -1 

self._statstream() 

 

def _statstream(self): 

if self.stream: 

sres = os.fstat(self.stream.fileno()) 

self.dev, self.ino = sres[ST_DEV], sres[ST_INO] 

 

def reopenIfNeeded(self): 

""" 

Reopen log file if needed. 

 

Checks if the underlying file has changed, and if it 

has, close the old stream and reopen the file to get the 

current stream. 

""" 

# Reduce the chance of race conditions by stat'ing by path only 

# once and then fstat'ing our new fd if we opened a new log stream. 

# See issue #14632: Thanks to John Mulligan for the problem report 

# and patch. 

try: 

# stat the file by path, checking for existence 

sres = os.stat(self.baseFilename) 

except FileNotFoundError: 

sres = None 

# compare file system stat with that of our stream file handle 

if not sres or sres[ST_DEV] != self.dev or sres[ST_INO] != self.ino: 

if self.stream is not None: 

# we have an open file handle, clean it up 

self.stream.flush() 

self.stream.close() 

self.stream = None # See Issue #21742: _open () might fail. 

# open a new file handle and get new stat info from that fd 

self.stream = self._open() 

self._statstream() 

 

def emit(self, record): 

""" 

Emit a record. 

 

If underlying file has changed, reopen the file before emitting the 

record to it. 

""" 

self.reopenIfNeeded() 

logging.FileHandler.emit(self, record) 

 

 

class SocketHandler(logging.Handler): 

""" 

A handler class which writes logging records, in pickle format, to 

a streaming socket. The socket is kept open across logging calls. 

If the peer resets it, an attempt is made to reconnect on the next call. 

The pickle which is sent is that of the LogRecord's attribute dictionary 

(__dict__), so that the receiver does not need to have the logging module 

installed in order to process the logging event. 

 

To unpickle the record at the receiving end into a LogRecord, use the 

makeLogRecord function. 

""" 

 

def __init__(self, host, port): 

""" 

Initializes the handler with a specific host address and port. 

 

When the attribute *closeOnError* is set to True - if a socket error 

occurs, the socket is silently closed and then reopened on the next 

logging call. 

""" 

logging.Handler.__init__(self) 

self.host = host 

self.port = port 

if port is None: 

self.address = host 

else: 

self.address = (host, port) 

self.sock = None 

self.closeOnError = False 

self.retryTime = None 

# 

# Exponential backoff parameters. 

# 

self.retryStart = 1.0 

self.retryMax = 30.0 

self.retryFactor = 2.0 

 

def makeSocket(self, timeout=1): 

""" 

A factory method which allows subclasses to define the precise 

type of socket they want. 

""" 

if self.port is not None: 

result = socket.create_connection(self.address, timeout=timeout) 

else: 

result = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM) 

result.settimeout(timeout) 

try: 

result.connect(self.address) 

except OSError: 

result.close() # Issue 19182 

raise 

return result 

 

def createSocket(self): 

""" 

Try to create a socket, using an exponential backoff with 

a max retry time. Thanks to Robert Olson for the original patch 

(SF #815911) which has been slightly refactored. 

""" 

now = time.time() 

# Either retryTime is None, in which case this 

# is the first time back after a disconnect, or 

# we've waited long enough. 

if self.retryTime is None: 

attempt = True 

else: 

attempt = (now >= self.retryTime) 

if attempt: 

try: 

self.sock = self.makeSocket() 

self.retryTime = None # next time, no delay before trying 

except OSError: 

#Creation failed, so set the retry time and return. 

if self.retryTime is None: 

self.retryPeriod = self.retryStart 

else: 

self.retryPeriod = self.retryPeriod * self.retryFactor 

if self.retryPeriod > self.retryMax: 

self.retryPeriod = self.retryMax 

self.retryTime = now + self.retryPeriod 

 

def send(self, s): 

""" 

Send a pickled string to the socket. 

 

This function allows for partial sends which can happen when the 

network is busy. 

""" 

if self.sock is None: 

self.createSocket() 

#self.sock can be None either because we haven't reached the retry 

#time yet, or because we have reached the retry time and retried, 

#but are still unable to connect. 

if self.sock: 

try: 

self.sock.sendall(s) 

except OSError: #pragma: no cover 

self.sock.close() 

self.sock = None # so we can call createSocket next time 

 

def makePickle(self, record): 

""" 

Pickles the record in binary format with a length prefix, and 

returns it ready for transmission across the socket. 

""" 

ei = record.exc_info 

if ei: 

# just to get traceback text into record.exc_text ... 

dummy = self.format(record) 

# See issue #14436: If msg or args are objects, they may not be 

# available on the receiving end. So we convert the msg % args 

# to a string, save it as msg and zap the args. 

d = dict(record.__dict__) 

d['msg'] = record.getMessage() 

d['args'] = None 

d['exc_info'] = None 

# Issue #25685: delete 'message' if present: redundant with 'msg' 

d.pop('message', None) 

s = pickle.dumps(d, 1) 

slen = struct.pack(">L", len(s)) 

return slen + s 

 

def handleError(self, record): 

""" 

Handle an error during logging. 

 

An error has occurred during logging. Most likely cause - 

connection lost. Close the socket so that we can retry on the 

next event. 

""" 

if self.closeOnError and self.sock: 

self.sock.close() 

self.sock = None #try to reconnect next time 

else: 

logging.Handler.handleError(self, record) 

 

def emit(self, record): 

""" 

Emit a record. 

 

Pickles the record and writes it to the socket in binary format. 

If there is an error with the socket, silently drop the packet. 

If there was a problem with the socket, re-establishes the 

socket. 

""" 

try: 

s = self.makePickle(record) 

self.send(s) 

except Exception: 

self.handleError(record) 

 

def close(self): 

""" 

Closes the socket. 

""" 

self.acquire() 

try: 

sock = self.sock 

if sock: 

self.sock = None 

sock.close() 

logging.Handler.close(self) 

finally: 

self.release() 

 

class DatagramHandler(SocketHandler): 

""" 

A handler class which writes logging records, in pickle format, to 

a datagram socket. The pickle which is sent is that of the LogRecord's 

attribute dictionary (__dict__), so that the receiver does not need to 

have the logging module installed in order to process the logging event. 

 

To unpickle the record at the receiving end into a LogRecord, use the 

makeLogRecord function. 

 

""" 

def __init__(self, host, port): 

""" 

Initializes the handler with a specific host address and port. 

""" 

SocketHandler.__init__(self, host, port) 

self.closeOnError = False 

 

def makeSocket(self): 

""" 

The factory method of SocketHandler is here overridden to create 

a UDP socket (SOCK_DGRAM). 

""" 

if self.port is None: 

family = socket.AF_UNIX 

else: 

family = socket.AF_INET 

s = socket.socket(family, socket.SOCK_DGRAM) 

return s 

 

def send(self, s): 

""" 

Send a pickled string to a socket. 

 

This function no longer allows for partial sends which can happen 

when the network is busy - UDP does not guarantee delivery and 

can deliver packets out of sequence. 

""" 

if self.sock is None: 

self.createSocket() 

self.sock.sendto(s, self.address) 

 

class SysLogHandler(logging.Handler): 

""" 

A handler class which sends formatted logging records to a syslog 

server. Based on Sam Rushing's syslog module: 

http://www.nightmare.com/squirl/python-ext/misc/syslog.py 

Contributed by Nicolas Untz (after which minor refactoring changes 

have been made). 

""" 

 

# from <linux/sys/syslog.h>: 

# ====================================================================== 

# priorities/facilities are encoded into a single 32-bit quantity, where 

# the bottom 3 bits are the priority (0-7) and the top 28 bits are the 

# facility (0-big number). Both the priorities and the facilities map 

# roughly one-to-one to strings in the syslogd(8) source code. This 

# mapping is included in this file. 

# 

# priorities (these are ordered) 

 

LOG_EMERG = 0 # system is unusable 

LOG_ALERT = 1 # action must be taken immediately 

LOG_CRIT = 2 # critical conditions 

LOG_ERR = 3 # error conditions 

LOG_WARNING = 4 # warning conditions 

LOG_NOTICE = 5 # normal but significant condition 

LOG_INFO = 6 # informational 

LOG_DEBUG = 7 # debug-level messages 

 

# facility codes 

LOG_KERN = 0 # kernel messages 

LOG_USER = 1 # random user-level messages 

LOG_MAIL = 2 # mail system 

LOG_DAEMON = 3 # system daemons 

LOG_AUTH = 4 # security/authorization messages 

LOG_SYSLOG = 5 # messages generated internally by syslogd 

LOG_LPR = 6 # line printer subsystem 

LOG_NEWS = 7 # network news subsystem 

LOG_UUCP = 8 # UUCP subsystem 

LOG_CRON = 9 # clock daemon 

LOG_AUTHPRIV = 10 # security/authorization messages (private) 

LOG_FTP = 11 # FTP daemon 

 

# other codes through 15 reserved for system use 

LOG_LOCAL0 = 16 # reserved for local use 

LOG_LOCAL1 = 17 # reserved for local use 

LOG_LOCAL2 = 18 # reserved for local use 

LOG_LOCAL3 = 19 # reserved for local use 

LOG_LOCAL4 = 20 # reserved for local use 

LOG_LOCAL5 = 21 # reserved for local use 

LOG_LOCAL6 = 22 # reserved for local use 

LOG_LOCAL7 = 23 # reserved for local use 

 

priority_names = { 

"alert": LOG_ALERT, 

"crit": LOG_CRIT, 

"critical": LOG_CRIT, 

"debug": LOG_DEBUG, 

"emerg": LOG_EMERG, 

"err": LOG_ERR, 

"error": LOG_ERR, # DEPRECATED 

"info": LOG_INFO, 

"notice": LOG_NOTICE, 

"panic": LOG_EMERG, # DEPRECATED 

"warn": LOG_WARNING, # DEPRECATED 

"warning": LOG_WARNING, 

} 

 

facility_names = { 

"auth": LOG_AUTH, 

"authpriv": LOG_AUTHPRIV, 

"cron": LOG_CRON, 

"daemon": LOG_DAEMON, 

"ftp": LOG_FTP, 

"kern": LOG_KERN, 

"lpr": LOG_LPR, 

"mail": LOG_MAIL, 

"news": LOG_NEWS, 

"security": LOG_AUTH, # DEPRECATED 

"syslog": LOG_SYSLOG, 

"user": LOG_USER, 

"uucp": LOG_UUCP, 

"local0": LOG_LOCAL0, 

"local1": LOG_LOCAL1, 

"local2": LOG_LOCAL2, 

"local3": LOG_LOCAL3, 

"local4": LOG_LOCAL4, 

"local5": LOG_LOCAL5, 

"local6": LOG_LOCAL6, 

"local7": LOG_LOCAL7, 

} 

 

#The map below appears to be trivially lowercasing the key. However, 

#there's more to it than meets the eye - in some locales, lowercasing 

#gives unexpected results. See SF #1524081: in the Turkish locale, 

#"INFO".lower() != "info" 

priority_map = { 

"DEBUG" : "debug", 

"INFO" : "info", 

"WARNING" : "warning", 

"ERROR" : "error", 

"CRITICAL" : "critical" 

} 

 

def __init__(self, address=('localhost', SYSLOG_UDP_PORT), 

facility=LOG_USER, socktype=None): 

""" 

Initialize a handler. 

 

If address is specified as a string, a UNIX socket is used. To log to a 

local syslogd, "SysLogHandler(address="/dev/log")" can be used. 

If facility is not specified, LOG_USER is used. If socktype is 

specified as socket.SOCK_DGRAM or socket.SOCK_STREAM, that specific 

socket type will be used. For Unix sockets, you can also specify a 

socktype of None, in which case socket.SOCK_DGRAM will be used, falling 

back to socket.SOCK_STREAM. 

""" 

logging.Handler.__init__(self) 

 

self.address = address 

self.facility = facility 

self.socktype = socktype 

 

if isinstance(address, str): 

self.unixsocket = True 

# Syslog server may be unavailable during handler initialisation. 

# C's openlog() function also ignores connection errors. 

# Moreover, we ignore these errors while logging, so it not worse 

# to ignore it also here. 

try: 

self._connect_unixsocket(address) 

except OSError: 

pass 

else: 

self.unixsocket = False 

if socktype is None: 

socktype = socket.SOCK_DGRAM 

host, port = address 

ress = socket.getaddrinfo(host, port, 0, socktype) 

if not ress: 

raise OSError("getaddrinfo returns an empty list") 

for res in ress: 

af, socktype, proto, _, sa = res 

err = sock = None 

try: 

sock = socket.socket(af, socktype, proto) 

if socktype == socket.SOCK_STREAM: 

sock.connect(sa) 

break 

except OSError as exc: 

err = exc 

if sock is not None: 

sock.close() 

if err is not None: 

raise err 

self.socket = sock 

self.socktype = socktype 

 

def _connect_unixsocket(self, address): 

use_socktype = self.socktype 

if use_socktype is None: 

use_socktype = socket.SOCK_DGRAM 

self.socket = socket.socket(socket.AF_UNIX, use_socktype) 

try: 

self.socket.connect(address) 

# it worked, so set self.socktype to the used type 

self.socktype = use_socktype 

except OSError: 

self.socket.close() 

if self.socktype is not None: 

# user didn't specify falling back, so fail 

raise 

use_socktype = socket.SOCK_STREAM 

self.socket = socket.socket(socket.AF_UNIX, use_socktype) 

try: 

self.socket.connect(address) 

# it worked, so set self.socktype to the used type 

self.socktype = use_socktype 

except OSError: 

self.socket.close() 

raise 

 

def encodePriority(self, facility, priority): 

""" 

Encode the facility and priority. You can pass in strings or 

integers - if strings are passed, the facility_names and 

priority_names mapping dictionaries are used to convert them to 

integers. 

""" 

if isinstance(facility, str): 

facility = self.facility_names[facility] 

if isinstance(priority, str): 

priority = self.priority_names[priority] 

return (facility << 3) | priority 

 

def close(self): 

""" 

Closes the socket. 

""" 

self.acquire() 

try: 

self.socket.close() 

logging.Handler.close(self) 

finally: 

self.release() 

 

def mapPriority(self, levelName): 

""" 

Map a logging level name to a key in the priority_names map. 

This is useful in two scenarios: when custom levels are being 

used, and in the case where you can't do a straightforward 

mapping by lowercasing the logging level name because of locale- 

specific issues (see SF #1524081). 

""" 

return self.priority_map.get(levelName, "warning") 

 

ident = '' # prepended to all messages 

append_nul = True # some old syslog daemons expect a NUL terminator 

 

def emit(self, record): 

""" 

Emit a record. 

 

The record is formatted, and then sent to the syslog server. If 

exception information is present, it is NOT sent to the server. 

""" 

try: 

msg = self.format(record) 

if self.ident: 

msg = self.ident + msg 

if self.append_nul: 

msg += '\000' 

 

# We need to convert record level to lowercase, maybe this will 

# change in the future. 

prio = '<%d>' % self.encodePriority(self.facility, 

self.mapPriority(record.levelname)) 

prio = prio.encode('utf-8') 

# Message is a string. Convert to bytes as required by RFC 5424 

msg = msg.encode('utf-8') 

msg = prio + msg 

if self.unixsocket: 

try: 

self.socket.send(msg) 

except OSError: 

self.socket.close() 

self._connect_unixsocket(self.address) 

self.socket.send(msg) 

elif self.socktype == socket.SOCK_DGRAM: 

self.socket.sendto(msg, self.address) 

else: 

self.socket.sendall(msg) 

except Exception: 

self.handleError(record) 

 

class SMTPHandler(logging.Handler): 

""" 

A handler class which sends an SMTP email for each logging event. 

""" 

def __init__(self, mailhost, fromaddr, toaddrs, subject, 

credentials=None, secure=None, timeout=5.0): 

""" 

Initialize the handler. 

 

Initialize the instance with the from and to addresses and subject 

line of the email. To specify a non-standard SMTP port, use the 

(host, port) tuple format for the mailhost argument. To specify 

authentication credentials, supply a (username, password) tuple 

for the credentials argument. To specify the use of a secure 

protocol (TLS), pass in a tuple for the secure argument. This will 

only be used when authentication credentials are supplied. The tuple 

will be either an empty tuple, or a single-value tuple with the name 

of a keyfile, or a 2-value tuple with the names of the keyfile and 

certificate file. (This tuple is passed to the `starttls` method). 

A timeout in seconds can be specified for the SMTP connection (the 

default is one second). 

""" 

logging.Handler.__init__(self) 

if isinstance(mailhost, (list, tuple)): 

self.mailhost, self.mailport = mailhost 

else: 

self.mailhost, self.mailport = mailhost, None 

if isinstance(credentials, (list, tuple)): 

self.username, self.password = credentials 

else: 

self.username = None 

self.fromaddr = fromaddr 

if isinstance(toaddrs, str): 

toaddrs = [toaddrs] 

self.toaddrs = toaddrs 

self.subject = subject 

self.secure = secure 

self.timeout = timeout 

 

def getSubject(self, record): 

""" 

Determine the subject for the email. 

 

If you want to specify a subject line which is record-dependent, 

override this method. 

""" 

return self.subject 

 

def emit(self, record): 

""" 

Emit a record. 

 

Format the record and send it to the specified addressees. 

""" 

try: 

import smtplib 

from email.message import EmailMessage 

import email.utils 

 

port = self.mailport 

if not port: 

port = smtplib.SMTP_PORT 

smtp = smtplib.SMTP(self.mailhost, port, timeout=self.timeout) 

msg = EmailMessage() 

msg['From'] = self.fromaddr 

msg['To'] = ','.join(self.toaddrs) 

msg['Subject'] = self.getSubject(record) 

msg['Date'] = email.utils.localtime() 

msg.set_content(self.format(record)) 

if self.username: 

if self.secure is not None: 

smtp.ehlo() 

smtp.starttls(*self.secure) 

smtp.ehlo() 

smtp.login(self.username, self.password) 

smtp.send_message(msg) 

smtp.quit() 

except Exception: 

self.handleError(record) 

 

class NTEventLogHandler(logging.Handler): 

""" 

A handler class which sends events to the NT Event Log. Adds a 

registry entry for the specified application name. If no dllname is 

provided, win32service.pyd (which contains some basic message 

placeholders) is used. Note that use of these placeholders will make 

your event logs big, as the entire message source is held in the log. 

If you want slimmer logs, you have to pass in the name of your own DLL 

which contains the message definitions you want to use in the event log. 

""" 

def __init__(self, appname, dllname=None, logtype="Application"): 

logging.Handler.__init__(self) 

try: 

import win32evtlogutil, win32evtlog 

self.appname = appname 

self._welu = win32evtlogutil 

if not dllname: 

dllname = os.path.split(self._welu.__file__) 

dllname = os.path.split(dllname[0]) 

dllname = os.path.join(dllname[0], r'win32service.pyd') 

self.dllname = dllname 

self.logtype = logtype 

self._welu.AddSourceToRegistry(appname, dllname, logtype) 

self.deftype = win32evtlog.EVENTLOG_ERROR_TYPE 

self.typemap = { 

logging.DEBUG : win32evtlog.EVENTLOG_INFORMATION_TYPE, 

logging.INFO : win32evtlog.EVENTLOG_INFORMATION_TYPE, 

logging.WARNING : win32evtlog.EVENTLOG_WARNING_TYPE, 

logging.ERROR : win32evtlog.EVENTLOG_ERROR_TYPE, 

logging.CRITICAL: win32evtlog.EVENTLOG_ERROR_TYPE, 

} 

except ImportError: 

print("The Python Win32 extensions for NT (service, event "\ 

"logging) appear not to be available.") 

self._welu = None 

 

def getMessageID(self, record): 

""" 

Return the message ID for the event record. If you are using your 

own messages, you could do this by having the msg passed to the 

logger being an ID rather than a formatting string. Then, in here, 

you could use a dictionary lookup to get the message ID. This 

version returns 1, which is the base message ID in win32service.pyd. 

""" 

return 1 

 

def getEventCategory(self, record): 

""" 

Return the event category for the record. 

 

Override this if you want to specify your own categories. This version 

returns 0. 

""" 

return 0 

 

def getEventType(self, record): 

""" 

Return the event type for the record. 

 

Override this if you want to specify your own types. This version does 

a mapping using the handler's typemap attribute, which is set up in 

__init__() to a dictionary which contains mappings for DEBUG, INFO, 

WARNING, ERROR and CRITICAL. If you are using your own levels you will 

either need to override this method or place a suitable dictionary in 

the handler's typemap attribute. 

""" 

return self.typemap.get(record.levelno, self.deftype) 

 

def emit(self, record): 

""" 

Emit a record. 

 

Determine the message ID, event category and event type. Then 

log the message in the NT event log. 

""" 

if self._welu: 

try: 

id = self.getMessageID(record) 

cat = self.getEventCategory(record) 

type = self.getEventType(record) 

msg = self.format(record) 

self._welu.ReportEvent(self.appname, id, cat, type, [msg]) 

except Exception: 

self.handleError(record) 

 

def close(self): 

""" 

Clean up this handler. 

 

You can remove the application name from the registry as a 

source of event log entries. However, if you do this, you will 

not be able to see the events as you intended in the Event Log 

Viewer - it needs to be able to access the registry to get the 

DLL name. 

""" 

#self._welu.RemoveSourceFromRegistry(self.appname, self.logtype) 

logging.Handler.close(self) 

 

class HTTPHandler(logging.Handler): 

""" 

A class which sends records to a Web server, using either GET or 

POST semantics. 

""" 

def __init__(self, host, url, method="GET", secure=False, credentials=None, 

context=None): 

""" 

Initialize the instance with the host, the request URL, and the method 

("GET" or "POST") 

""" 

logging.Handler.__init__(self) 

method = method.upper() 

if method not in ["GET", "POST"]: 

raise ValueError("method must be GET or POST") 

if not secure and context is not None: 

raise ValueError("context parameter only makes sense " 

"with secure=True") 

self.host = host 

self.url = url 

self.method = method 

self.secure = secure 

self.credentials = credentials 

self.context = context 

 

def mapLogRecord(self, record): 

""" 

Default implementation of mapping the log record into a dict 

that is sent as the CGI data. Overwrite in your class. 

Contributed by Franz Glasner. 

""" 

return record.__dict__ 

 

def emit(self, record): 

""" 

Emit a record. 

 

Send the record to the Web server as a percent-encoded dictionary 

""" 

try: 

import http.client, urllib.parse 

host = self.host 

if self.secure: 

h = http.client.HTTPSConnection(host, context=self.context) 

else: 

h = http.client.HTTPConnection(host) 

url = self.url 

data = urllib.parse.urlencode(self.mapLogRecord(record)) 

if self.method == "GET": 

if (url.find('?') >= 0): 

sep = '&' 

else: 

sep = '?' 

url = url + "%c%s" % (sep, data) 

h.putrequest(self.method, url) 

# support multiple hosts on one IP address... 

# need to strip optional :port from host, if present 

i = host.find(":") 

if i >= 0: 

host = host[:i] 

# See issue #30904: putrequest call above already adds this header 

# on Python 3.x. 

# h.putheader("Host", host) 

if self.method == "POST": 

h.putheader("Content-type", 

"application/x-www-form-urlencoded") 

h.putheader("Content-length", str(len(data))) 

if self.credentials: 

import base64 

s = ('%s:%s' % self.credentials).encode('utf-8') 

s = 'Basic ' + base64.b64encode(s).strip().decode('ascii') 

h.putheader('Authorization', s) 

h.endheaders() 

if self.method == "POST": 

h.send(data.encode('utf-8')) 

h.getresponse() #can't do anything with the result 

except Exception: 

self.handleError(record) 

 

class BufferingHandler(logging.Handler): 

""" 

A handler class which buffers logging records in memory. Whenever each 

record is added to the buffer, a check is made to see if the buffer should 

be flushed. If it should, then flush() is expected to do what's needed. 

""" 

def __init__(self, capacity): 

""" 

Initialize the handler with the buffer size. 

""" 

logging.Handler.__init__(self) 

self.capacity = capacity 

self.buffer = [] 

 

def shouldFlush(self, record): 

""" 

Should the handler flush its buffer? 

 

Returns true if the buffer is up to capacity. This method can be 

overridden to implement custom flushing strategies. 

""" 

return (len(self.buffer) >= self.capacity) 

 

def emit(self, record): 

""" 

Emit a record. 

 

Append the record. If shouldFlush() tells us to, call flush() to process 

the buffer. 

""" 

self.buffer.append(record) 

if self.shouldFlush(record): 

self.flush() 

 

def flush(self): 

""" 

Override to implement custom flushing behaviour. 

 

This version just zaps the buffer to empty. 

""" 

self.acquire() 

try: 

self.buffer = [] 

finally: 

self.release() 

 

def close(self): 

""" 

Close the handler. 

 

This version just flushes and chains to the parent class' close(). 

""" 

try: 

self.flush() 

finally: 

logging.Handler.close(self) 

 

class MemoryHandler(BufferingHandler): 

""" 

A handler class which buffers logging records in memory, periodically 

flushing them to a target handler. Flushing occurs whenever the buffer 

is full, or when an event of a certain severity or greater is seen. 

""" 

def __init__(self, capacity, flushLevel=logging.ERROR, target=None, 

flushOnClose=True): 

""" 

Initialize the handler with the buffer size, the level at which 

flushing should occur and an optional target. 

 

Note that without a target being set either here or via setTarget(), 

a MemoryHandler is no use to anyone! 

 

The ``flushOnClose`` argument is ``True`` for backward compatibility 

reasons - the old behaviour is that when the handler is closed, the 

buffer is flushed, even if the flush level hasn't been exceeded nor the 

capacity exceeded. To prevent this, set ``flushOnClose`` to ``False``. 

""" 

BufferingHandler.__init__(self, capacity) 

self.flushLevel = flushLevel 

self.target = target 

# See Issue #26559 for why this has been added 

self.flushOnClose = flushOnClose 

 

def shouldFlush(self, record): 

""" 

Check for buffer full or a record at the flushLevel or higher. 

""" 

return (len(self.buffer) >= self.capacity) or \ 

(record.levelno >= self.flushLevel) 

 

def setTarget(self, target): 

""" 

Set the target handler for this handler. 

""" 

self.target = target 

 

def flush(self): 

""" 

For a MemoryHandler, flushing means just sending the buffered 

records to the target, if there is one. Override if you want 

different behaviour. 

 

The record buffer is also cleared by this operation. 

""" 

self.acquire() 

try: 

if self.target: 

for record in self.buffer: 

self.target.handle(record) 

self.buffer = [] 

finally: 

self.release() 

 

def close(self): 

""" 

Flush, if appropriately configured, set the target to None and lose the 

buffer. 

""" 

try: 

if self.flushOnClose: 

self.flush() 

finally: 

self.acquire() 

try: 

self.target = None 

BufferingHandler.close(self) 

finally: 

self.release() 

 

 

class QueueHandler(logging.Handler): 

""" 

This handler sends events to a queue. Typically, it would be used together 

with a multiprocessing Queue to centralise logging to file in one process 

(in a multi-process application), so as to avoid file write contention 

between processes. 

 

This code is new in Python 3.2, but this class can be copy pasted into 

user code for use with earlier Python versions. 

""" 

 

def __init__(self, queue): 

""" 

Initialise an instance, using the passed queue. 

""" 

logging.Handler.__init__(self) 

self.queue = queue 

 

def enqueue(self, record): 

""" 

Enqueue a record. 

 

The base implementation uses put_nowait. You may want to override 

this method if you want to use blocking, timeouts or custom queue 

implementations. 

""" 

self.queue.put_nowait(record) 

 

def prepare(self, record): 

""" 

Prepares a record for queuing. The object returned by this method is 

enqueued. 

 

The base implementation formats the record to merge the message 

and arguments, and removes unpickleable items from the record 

in-place. 

 

You might want to override this method if you want to convert 

the record to a dict or JSON string, or send a modified copy 

of the record while leaving the original intact. 

""" 

# The format operation gets traceback text into record.exc_text 

# (if there's exception data), and also puts the message into 

# record.message. We can then use this to replace the original 

# msg + args, as these might be unpickleable. We also zap the 

# exc_info attribute, as it's no longer needed and, if not None, 

# will typically not be pickleable. 

self.format(record) 

record.msg = record.message 

record.args = None 

record.exc_info = None 

return record 

 

def emit(self, record): 

""" 

Emit a record. 

 

Writes the LogRecord to the queue, preparing it for pickling first. 

""" 

try: 

self.enqueue(self.prepare(record)) 

except Exception: 

self.handleError(record) 

 

if threading: 

class QueueListener(object): 

""" 

This class implements an internal threaded listener which watches for 

LogRecords being added to a queue, removes them and passes them to a 

list of handlers for processing. 

""" 

_sentinel = None 

 

def __init__(self, queue, *handlers, respect_handler_level=False): 

""" 

Initialise an instance with the specified queue and 

handlers. 

""" 

self.queue = queue 

self.handlers = handlers 

self._thread = None 

self.respect_handler_level = respect_handler_level 

 

def dequeue(self, block): 

""" 

Dequeue a record and return it, optionally blocking. 

 

The base implementation uses get. You may want to override this method 

if you want to use timeouts or work with custom queue implementations. 

""" 

return self.queue.get(block) 

 

def start(self): 

""" 

Start the listener. 

 

This starts up a background thread to monitor the queue for 

LogRecords to process. 

""" 

self._thread = t = threading.Thread(target=self._monitor) 

t.daemon = True 

t.start() 

 

def prepare(self , record): 

""" 

Prepare a record for handling. 

 

This method just returns the passed-in record. You may want to 

override this method if you need to do any custom marshalling or 

manipulation of the record before passing it to the handlers. 

""" 

return record 

 

def handle(self, record): 

""" 

Handle a record. 

 

This just loops through the handlers offering them the record 

to handle. 

""" 

record = self.prepare(record) 

for handler in self.handlers: 

if not self.respect_handler_level: 

process = True 

else: 

process = record.levelno >= handler.level 

if process: 

handler.handle(record) 

 

def _monitor(self): 

""" 

Monitor the queue for records, and ask the handler 

to deal with them. 

 

This method runs on a separate, internal thread. 

The thread will terminate if it sees a sentinel object in the queue. 

""" 

q = self.queue 

has_task_done = hasattr(q, 'task_done') 

while True: 

try: 

record = self.dequeue(True) 

if record is self._sentinel: 

break 

self.handle(record) 

if has_task_done: 

q.task_done() 

except queue.Empty: 

break 

 

def enqueue_sentinel(self): 

""" 

This is used to enqueue the sentinel record. 

 

The base implementation uses put_nowait. You may want to override this 

method if you want to use timeouts or work with custom queue 

implementations. 

""" 

self.queue.put_nowait(self._sentinel) 

 

def stop(self): 

""" 

Stop the listener. 

 

This asks the thread to terminate, and then waits for it to do so. 

Note that if you don't call this before your application exits, there 

may be some records still left on the queue, which won't be processed. 

""" 

self.enqueue_sentinel() 

self._thread.join() 

self._thread = None