File size: 70,902 Bytes
fb42d3e
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
# Copyright 2025 The HuggingFace Team. All rights reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
import asyncio
import base64
import copy
import datetime
import enum
import functools
import gc
import io
import json
import re
import tempfile
import threading
import time
import uuid
from argparse import ArgumentParser, Namespace
from collections.abc import AsyncGenerator, Generator, Iterable
from contextlib import asynccontextmanager
from dataclasses import dataclass, field
from io import BytesIO
from threading import Thread
from typing import Optional, TypedDict, Union

from huggingface_hub import model_info
from huggingface_hub.constants import HF_HUB_OFFLINE
from tokenizers.decoders import DecodeStream

import transformers
from transformers.models.auto.modeling_auto import (
    MODEL_FOR_CAUSAL_LM_MAPPING_NAMES,
    MODEL_FOR_IMAGE_TEXT_TO_TEXT_MAPPING_NAMES,
)
from transformers.utils.import_utils import (
    is_fastapi_available,
    is_librosa_available,
    is_openai_available,
    is_pydantic_available,
    is_uvicorn_available,
    is_vision_available,
)

from .. import (
    AutoConfig,
    LogitsProcessorList,
    PreTrainedTokenizerFast,
    ProcessorMixin,
    TextIteratorStreamer,
)
from ..utils import is_torch_available, logging
from . import BaseTransformersCLICommand


if is_torch_available():
    import torch

    from transformers import (
        AutoProcessor,
        BitsAndBytesConfig,
        GenerationConfig,
        PreTrainedModel,
    )

    from ..generation.continuous_batching import ContinuousBatchingManager, RequestStatus

if is_librosa_available():
    import librosa

if is_vision_available():
    from PIL import Image

serve_dependencies_available = (
    is_pydantic_available() and is_fastapi_available() and is_uvicorn_available() and is_openai_available()
)
if serve_dependencies_available:
    import uvicorn
    from fastapi import FastAPI, HTTPException
    from fastapi.middleware.cors import CORSMiddleware
    from fastapi.responses import JSONResponse, StreamingResponse
    from openai.types.audio.transcription import Transcription
    from openai.types.audio.transcription_create_params import TranscriptionCreateParamsBase
    from openai.types.chat import ChatCompletionMessageParam
    from openai.types.chat.chat_completion_chunk import (
        ChatCompletionChunk,
        Choice,
        ChoiceDelta,
        ChoiceDeltaToolCall,
        ChoiceDeltaToolCallFunction,
    )
    from openai.types.chat.completion_create_params import CompletionCreateParamsStreaming
    from openai.types.responses import (
        Response,
        ResponseCompletedEvent,
        ResponseContentPartAddedEvent,
        ResponseContentPartDoneEvent,
        ResponseCreatedEvent,
        ResponseError,
        ResponseErrorEvent,
        ResponseFailedEvent,
        ResponseInProgressEvent,
        ResponseOutputItemAddedEvent,
        ResponseOutputItemDoneEvent,
        ResponseOutputMessage,
        ResponseOutputText,
        ResponseTextDeltaEvent,
        ResponseTextDoneEvent,
    )
    from openai.types.responses.response_create_params import ResponseCreateParamsStreaming
    from pydantic import BaseModel, TypeAdapter, ValidationError

    # Expand OpenAI's request input types with an optional `generation_config` field
    class TransformersResponseCreateParamsStreaming(ResponseCreateParamsStreaming, total=False):
        """
        OpenAI's ResponseCreateParamsStreaming with an additional field for the generation config (as a json string).
        """

        generation_config: str

    class TransformersCompletionCreateParamsStreaming(CompletionCreateParamsStreaming, total=False):
        """
        OpenAI's CompletionCreateParamsStreaming with additional fields for the generation config (as a json string) and passing the request_id
        """

        generation_config: str

    class TransformersTranscriptionCreateParams(TranscriptionCreateParamsBase, total=False):
        """
        OpenAI's TranscriptionCreateParamsBase with an additional field for the generation config (as a json string).
        """

        file: bytes  # Overwritten -- pydantic isn't happy with `typing.IO[bytes]`, present in the original type
        generation_config: str
        stream: bool = False

    # Contrarily to OpenAI's output types, input types are `TypedDict`, which don't have built-in validation.
    response_validator = TypeAdapter(TransformersResponseCreateParamsStreaming)
    completion_validator = TypeAdapter(TransformersCompletionCreateParamsStreaming)
    transcription_validator = TypeAdapter(TransformersTranscriptionCreateParams)

    # Define request fields that are not yet used in `transformers serve`. Receiving these fields will raise an
    # HTTPException.
    UNUSED_RESPONSE_FIELDS = {
        "background",
        "include",
        "max_tool_calls",
        "previous_response_id",
        "prompt",
        "reasoning",
        "service_tier",
        "store",
        "text",
        "tool_choice",
        "top_logprobs",
        "truncation",
        "user",
    }

    UNUSED_CHAT_COMPLETION_FIELDS = {
        "audio",
        "function_call",
        "functions",
        "logprobs",
        "max_completion_tokens",
        "metadata",
        "modalities",
        "n",
        "parallel_tool_calls",
        "prediction",
        "presence_penalty",
        "reasoning_effort",
        "response_format",
        "service_tier",
        "stop",
        "store",
        "stream_options",
        "tool_choice",
        "top_logprobs",
        "user",
        "web_search_options",
    }
    UNUSED_TRANSCRIPTION_FIELDS = {
        "chunking_strategy",
        "include",
        "language",
        "prompt",
        "response_format",
        "timestamp_granularities",
    }


logger = logging.get_logger(__name__)

# Possible tokens that indicate the start/end of a tool call
# TODO (joao, matt): streamline tool token detection logic
_TOOL_CALL_TOKENS = {
    "qwen": {
        "start": "<tool_call>",
        "end": "</tool_call>",
    },
}
_MODELS_WITH_TOOL_SUPPORT = list(_TOOL_CALL_TOKENS.keys())

X_REQUEST_ID = "x-request-id"


class Modality(enum.Enum):
    LLM = "LLM"
    VLM = "VLM"
    STT = "STT"
    TTS = "TTS"


def serve_command_factory(args: Namespace):
    """
    Factory function used to instantiate serving server from provided command line arguments.

    Returns: ServeCommand
    """
    return ServeCommand(args)


def create_generation_config_from_req(
    req: dict,
    model_generation_config: "GenerationConfig",
    **kwargs,
) -> "GenerationConfig":
    """
    Creates a generation config from the parameters of the request. If a generation config is passed in the request,
    it will be used as a baseline for parameterization. Otherwise, we will use the model's default generation config.
    Other parameters in the request will be applied on top of the baseline.

    Args:
        req (`dict`):
            The request which may optionally contain generation parameters.
        model_generation_config (`GenerationConfig`):
            The model's default generation config.
        kwargs (`dict`):
            Additional parameters to set in the generation config.

    Returns:
        The prepared `GenerationConfig` object.
    """
    # If there is a generation config in the request, it is a json string serialization from a `GenerationConfig`
    # object. For simplicity, flags set here take precedence over all other flags.
    if req.get("generation_config") is not None:
        generation_config = GenerationConfig(**json.loads(req["generation_config"]))
    else:
        generation_config = copy.deepcopy(model_generation_config)

    non_standard_kwargs = generation_config.update(**kwargs)
    # Set extra kwargs that are not in the `GenerationConfig` class (e.g. continuous batching flags)
    for k, v in non_standard_kwargs.items():
        if v is not None:
            setattr(generation_config, k, v)

    # Response-specific parameters
    if req.get("max_output_tokens") is not None:
        generation_config.max_new_tokens = int(req["max_output_tokens"])

    # Completion-specific parameters
    if req.get("max_tokens") is not None:
        generation_config.max_new_tokens = int(req["max_tokens"])
    if req.get("frequency_penalty") is not None:
        generation_config.repetition_penalty = float(req["frequency_penalty"])
    if req.get("logit_bias") is not None:
        generation_config.sequence_bias = req["logit_bias"]
    if req.get("stop") is not None:
        generation_config.stop_strings = req["stop"]
    if req.get("temperature") is not None:
        generation_config.temperature = float(req["temperature"])
        if float(req["temperature"]) == 0.0:
            generation_config.do_sample = False
    if req.get("top_p") is not None:
        generation_config.top_p = float(req["top_p"])
    if req.get("seed") is not None:
        torch.manual_seed(req["seed"])

    return generation_config


class ToolState:
    """Lightweight class to keep track of the tool call state."""

    def __init__(self):
        self.reset()

    def reset(self):
        """Reset the tool call state (assumes we're outside a tool call)."""
        self.inside_tool_call = False
        self.has_tool_name_defined = False
        self.arg_nesting_level = 0
        self.buffer = ""


class TimedModel:
    """
    A class that holds a PreTrainedModel instance and its associated processor.
    Automatically deletes the instances after a specified timeout.
    """

    def __init__(
        self,
        model: "PreTrainedModel",
        timeout_seconds: int,
        processor: Optional[Union["ProcessorMixin", "PreTrainedTokenizerFast"]] = None,
    ):
        self.model = model
        self._name_or_path = str(model.name_or_path)
        self.processor = processor
        self.timeout_seconds = timeout_seconds
        self._timer = threading.Timer(self.timeout_seconds, self.timeout_reached)
        self._timer.start()

    def reset_timer(self):
        """Reset the timer for the deletion of the instances."""
        self._timer.cancel()
        self._timer = threading.Timer(self.timeout_seconds, self.timeout_reached)
        self._timer.start()

    def delete_model(self):
        """Delete the wrapped model and processor and clean up resources."""
        if hasattr(self, "model") and self.model is not None:
            del self.model
            del self.processor
            self.model = None
            self.processor = None
            gc.collect()

            # Clear CUDA cache if available
            if torch.cuda.is_available():
                torch.cuda.empty_cache()

            # XXX: in case we manually delete the model, like on server shutdown
            self._timer.cancel()

    def timeout_reached(self):
        self.delete_model()
        logger.info(f"{self._name_or_path} was removed from memory after {self.timeout_seconds} seconds of inactivity")

    def is_deleted(self):
        """Check if the instances have been deleted."""
        return not hasattr(self, "model") or self.model is None


@dataclass
class ServeArguments:
    r"""
    Arguments for the serve CLI.

    See the metadata arg for each argument's description -- the metadata will be printed with
    `transformers serve --help`
    """

    continuous_batching: bool = field(
        default=False,
        metadata={"help": "Whether to use continuous batching for chat completions."},
    )
    device: str = field(
        default="auto",
        metadata={
            "help": "Device to use for inference; will default to `auto` and"
            "place the model on an accelerator if available."
        },
    )
    torch_dtype: Optional[str] = field(
        default=None,
        metadata={
            "help": "`torch_dtype` is deprecated! Please use `dtype` argument instead.",
            "choices": ["auto", "bfloat16", "float16", "float32"],
        },
    )
    dtype: Optional[str] = field(
        default="auto",
        metadata={
            "help": "Override the default `torch.dtype` and load the model under this dtype. If `'auto'` is passed, "
            "the dtype will be automatically derived from the model's weights.",
            "choices": ["auto", "bfloat16", "float16", "float32"],
        },
    )
    trust_remote_code: bool = field(
        default=False, metadata={"help": "Whether to trust remote code when loading a model."}
    )
    attn_implementation: Optional[str] = field(
        default=None,
        metadata={
            "help": "Which attention implementation to use; you can run --attn_implementation=flash_attention_2, in "
            "which case you must install this manually by running `pip install flash-attn --no-build-isolation`."
        },
    )
    load_in_8bit: bool = field(
        default=False,
        metadata={"help": "Whether to use 8 bit precision for the base model - works only with LoRA."},
    )
    load_in_4bit: bool = field(
        default=False,
        metadata={"help": "Whether to use 4 bit precision for the base model - works only with LoRA."},
    )
    bnb_4bit_quant_type: str = field(default="nf4", metadata={"help": "Quantization type.", "choices": ["fp4", "nf4"]})
    use_bnb_nested_quant: bool = field(default=False, metadata={"help": "Whether to use nested quantization."})

    # Serving settings
    host: str = field(default="localhost", metadata={"help": "Interface the server will listen to."})
    port: int = field(default=8000, metadata={"help": "Port the server will listen to."})
    model_timeout: int = field(
        default=300,
        metadata={"help": "Time in seconds after which a model will be removed from memory."},
    )

    # Other settings
    log_level: str = field(
        default="info", metadata={"help": "Logging level as a string. Example: 'info' or 'warning'."}
    )
    default_seed: Optional[int] = field(
        default=None, metadata={"help": "The default seed for torch, should be an integer."}
    )
    enable_cors: bool = field(
        default=False,
        metadata={
            "help": (
                "Whether to enable CORS. Some apps that make requests from external domains (e.g. Cursor) require "
                "CORS to be enabled."
            ),
        },
    )

    # TODO
    # Testing
    # As of 2025-07-11, testing on https://github.com/openai/openai-responses-starter-app/, validation on the
    # Response input is failing. The app works well without validation. Enable at some point in the future.
    input_validation: bool = field(
        default=False,
        metadata={
            "help": ("Whether to turn on strict input validation."),
        },
    )
    force_model: Optional[str] = field(
        default=None,
        metadata={
            "help": (
                "Name of the model to be forced on all requests. This is useful for testing Apps that don't allow "
                "changing models in the request."
            ),
        },
    )

    def __post_init__(self):
        """Only used for BC `torch_dtype` argument."""
        # In this case only the BC torch_dtype was given
        if self.torch_dtype is not None:
            if self.dtype is None:
                self.dtype = self.torch_dtype
            elif self.torch_dtype != self.dtype:
                raise ValueError(
                    f"`torch_dtype` {self.torch_dtype} and `dtype` {self.dtype} have different values. `torch_dtype` is deprecated and "
                    "will be removed in 4.59.0, please set `dtype` instead."
                )


class ServeCommand(BaseTransformersCLICommand):
    @staticmethod
    def register_subcommand(parser: ArgumentParser):
        """
        Register this command to argparse so it's available for the transformer-cli

        Args:
            parser: Root parser to register command-specific arguments
        """
        dataclass_types = (ServeArguments,)
        serve_parser = parser.add_parser("serve", dataclass_types=dataclass_types)
        serve_parser.set_defaults(func=serve_command_factory)

    def __init__(self, args: ServeArguments):
        if not serve_dependencies_available:
            raise ImportError(
                "Missing dependencies for the serving CLI. Please install with `pip install transformers[serving]`"
            )

        # Store and process input arguments
        self.args = args
        self.use_continuous_batching = self.args.continuous_batching
        if self.use_continuous_batching:
            default_attn_impl = ContinuousBatchingManager.default_attention_implementation()
            # checking if attn_implementation is supported by continuous batching
            if self.args.attn_implementation is None:
                self.args.attn_implementation = default_attn_impl  # default to sdpa_paged
                logger.info(f"No attn_implementation passed, defaulting to {default_attn_impl}")
            supported_attn_impl = ContinuousBatchingManager.supported_attention_implementations()
            if self.args.attn_implementation not in supported_attn_impl:
                raise ValueError(
                    f"Continuous batching only supports {supported_attn_impl} as attn_implementation, got "
                    f"{self.args.attn_implementation}"
                    f"Try setting `--attn_implementation={default_attn_impl}`"
                )
        self.enable_cors = self.args.enable_cors

        if self.args.default_seed is not None:
            torch.manual_seed(self.args.default_seed)

        # Set up logging
        transformers_logger = logging.get_logger("transformers")
        transformers_logger.setLevel(logging.log_levels[self.args.log_level.lower()])

        cb_logger = logging.get_logger("transformers.generation.continuous_batching")
        cb_logger.setLevel(logging.log_levels[self.args.log_level.lower()])

        # Internal state:
        # 1. Tracks models in memory, to prevent reloading the model unnecessarily
        self.loaded_models: dict[str, TimedModel] = {}
        self.running_continuous_batching_manager: Optional[ContinuousBatchingManager] = None

        # 2. preserves information about the last call and last KV cache, to determine whether we can reuse the KV
        # cache and avoid re-running prefil
        self.last_messages = None
        self.last_kv_cache = None
        self.last_model = None

    def _validate_request(
        self,
        request: dict,
        schema: TypedDict,
        validator: "TypeAdapter",
        unused_fields: set,
    ):
        """
        Validates the request against the schema, and checks for unexpected keys.

        Args:
            request (`dict`):
                The request to validate.
            schema (`TypedDict`):
                The schema of the request to validate. It is a `TypedDict` definition.
            validator (`TypeAdapter`):
                The validator to use to validate the request. Built from `schema`.
            unused_fields (`set`):
                Fields accepted by `schema`, but not used in `transformers serve`.

        Raises:
            HTTPException: If the request is invalid or contains unexpected or unused fields.
        """
        logger.debug(f"Validating request: {request}")

        # Validate unexpected keys -- Pydantic doesn't validate extra keys in the request.
        input_keys = set(request.keys())
        possible_keys = schema.__mutable_keys__
        unexpected_keys = input_keys - possible_keys
        if unexpected_keys:
            logger.error(f"Unexpected keys in the request: {unexpected_keys}")
            raise HTTPException(status_code=422, detail=f"Unexpected keys in the request: {unexpected_keys}")

        if self.args.input_validation:
            # Validate expected keys
            try:
                validator.validate_python(request)
            except ValidationError as e:
                logger.error(f"Validation error: {e.errors()}")
                raise HTTPException(status_code=422, detail=e.errors())

            # Validate unused fields
            unused_fields_in_request = input_keys & unused_fields
            if unused_fields_in_request:
                logger.error(f"Unused fields in the request: {unused_fields_in_request}")
                raise HTTPException(
                    status_code=422, detail=f"Unused fields in the request: {unused_fields_in_request}"
                )

    def validate_response_request(self, request: dict):
        self._validate_request(
            request=request,
            schema=TransformersResponseCreateParamsStreaming,
            validator=response_validator,
            unused_fields=UNUSED_RESPONSE_FIELDS,
        )

    def validate_chat_completion_request(self, request: dict):
        self._validate_request(
            request=request,
            schema=TransformersCompletionCreateParamsStreaming,
            validator=completion_validator,
            unused_fields=UNUSED_CHAT_COMPLETION_FIELDS,
        )

    def validate_transcription_request(self, request: dict):
        self._validate_request(
            request=request,
            schema=TransformersTranscriptionCreateParams,
            validator=transcription_validator,
            unused_fields=UNUSED_TRANSCRIPTION_FIELDS,
        )

    def build_chat_completion_chunk(
        self,
        request_id: str = "",
        content: Optional[int] = None,
        model: Optional[str] = None,
        role: Optional[str] = None,
        finish_reason: Optional[str] = None,
        tool_calls: Optional[list["ChoiceDeltaToolCall"]] = None,
        decode_stream: Optional[DecodeStream] = None,
        tokenizer: Optional[PreTrainedTokenizerFast] = None,
    ) -> str:
        """
        Builds a chunk of a streaming OpenAI Chat Completion response.

        IMPORTANT: The serialized chunk won't contain empty fields (fields with `None`). Some downstream apps,
        like Cursor, assume that when the field exists, it has data.

        Args:
            request_id (`str`):
                The request ID.
            content (`str`, *optional*):
                Content of the response from the model.
            model (`str`, *optional*):
                The model that generated the content.
            role (`str`, *optional*):
                The role of the next content, until a new role is defined.
            finish_reason (`str`, *optional*):
                The reason the generation by the model has finished.
            tool_calls (`list[ChoiceDeltaToolCall]`, *optional*):
                Data about the tool calls, when they are triggered.

        Returns:
            `str`: The built chunk, a string containing a JSON string with the payload.
        """
        if decode_stream is not None and content is not None and tokenizer is not None:
            content = decode_stream.step(tokenizer._tokenizer, content)
        chunk = ChatCompletionChunk(
            id=request_id,
            created=int(time.time()),
            model=model,
            choices=[
                Choice(
                    delta=ChoiceDelta(
                        content=content,
                        role=role,
                        tool_calls=tool_calls,
                    ),
                    index=0,
                    finish_reason=finish_reason,
                )
            ],
            system_fingerprint="",
            object="chat.completion.chunk",
        )
        return f"data: {chunk.model_dump_json(exclude_none=True)}\n\n"

    def build_response_event(self, response: "BaseModel") -> str:
        """
        Builds a event of a streaming OpenAI Response response.

        IMPORTANT: The serialized chunk won't contain empty fields (fields with `None`). Some downstream apps,
        like Cursor, assume that when the field exists, it has data.

        Args:
            response (`BaseModel`):
                The response to build an event from. One of the multiple OpenAI Response output types

        Returns:
            `str`: The built chunk, a string containing a JSON string with the payload.
        """
        return f"data: {response.model_dump_json(exclude_none=True)}\n\n"

    def run(self):
        """
        Setup and run the FastAPI server for transformers serve.

        Models will be loaded and unloaded automatically based on usage and a timeout.

        The server will expose the following endpoints:
        - POST /v1/chat/completions: Generates chat completions.
        - POST /v1/responses: Generates responses.
        - POST /v1/audio/transcriptions: Generates transcriptions from audio.
        - GET /v1/models: Lists available models for 3rd party tools.

        Requires FastAPI and Uvicorn to be installed.
        """

        @asynccontextmanager
        async def lifespan(app: FastAPI):
            yield
            for model in self.loaded_models.values():
                model.delete_model()
            if self.running_continuous_batching_manager is not None:
                self.running_continuous_batching_manager.stop(block=True, timeout=5)

        app = FastAPI(lifespan=lifespan)

        # Some apps that make requests from external domains (e.g. Cursor) require CORS to be enabled. However, for
        # security purposes, it's disabled by default
        if self.enable_cors:
            app.add_middleware(
                CORSMiddleware,
                allow_origins=["*"],
                allow_credentials=True,
                allow_methods=["*"],
                allow_headers=["*"],
            )
            logger.warning_once(
                "CORS allow origin is set to `*`. This is not recommended for production environments."
            )

        from fastapi import Request

        @app.post("/v1/chat/completions")
        def chat_completion(request: Request, body: dict):
            self.validate_chat_completion_request(request=body)

            if self.use_continuous_batching:
                output = self.continuous_batching_chat_completion(body, request.state.request_id)
            else:
                output = self.generate_chat_completion(body)
            return StreamingResponse(output, media_type="text/event-stream")

        @app.post("/v1/responses")
        def responses(request: dict):
            self.validate_response_request(request=request)

            output = self.generate_response(request)
            return StreamingResponse(output, media_type="text/event-stream")

        @app.post("/v1/audio/transcriptions")
        async def audio_transcriptions(request: Request):
            # Parses the multipart/form-data request into the request format used by other endpoints
            async with request.form() as form:
                parsed_request = TransformersTranscriptionCreateParams(
                    file=await form["file"].read(),
                    model=form["model"],
                    # TODO: add other fields
                )
                logger.debug(
                    f"Received file: {form['file'].filename}; MIME type: {form['file'].content_type}; "
                    f"size: {form['file'].size / 1024:.2f} KiB"
                )
            self.validate_transcription_request(request=parsed_request)

            output = self.generate_transcription(parsed_request)
            return StreamingResponse(output, media_type="text/event-stream")

        @app.options("/v1/models")
        @app.get("/v1/models")
        def get_all_models():
            return JSONResponse({"object": "list", "data": self.get_gen_models()})

        @app.get("/health")
        def healthcheck():
            return JSONResponse({"status": "ok"})

        @app.middleware("http")
        async def get_or_set_request_id(request: Request, call_next):
            request_id = request.headers.get(X_REQUEST_ID) or str(uuid.uuid4())
            request.state.request_id = request_id
            response = await call_next(request)
            response.headers[X_REQUEST_ID] = request_id
            return response

        uvicorn.run(app, host=self.args.host, port=self.args.port, log_level=self.args.log_level)

    @functools.cache
    def get_gen_models(self) -> list[dict[str, any]]:
        """
        This is by no means a limit to which models may be instantiated with `transformers serve`: any chat-based
        model working with generate can work.

        This is a limited list of models to ensure we have a discoverable /v1/models endpoint for third-party
        integrations.
        """
        models = [
            "Menlo/Jan-nano",
            "Menlo/Jan-nano-128k",
            "Qwen/Qwen2.5-0.5B-Instruct",
            "Qwen/Qwen2.5-3B-Instruct",
            "Qwen/Qwen2.5-7B-Instruct",
            "Qwen/Qwen2.5-14B-Instruct",
            "meta-llama/Llama-3.1-8B-Instruct",
            "meta-llama/Llama-3.2-1B-Instruct",
            "meta-llama/Llama-3.3-70B-Instruct",
            "HuggingFaceTB/SmolVLM-Instruct",
            "ibm-granite/granite-vision-3.2-2b",
            "Qwen/Qwen2.5-VL-7B-Instruct",
        ]

        if HF_HUB_OFFLINE:
            return [
                {
                    "id": model,
                    "object": "model",
                    "created": datetime.datetime.now().timestamp(),
                    "owned_by": model.split("/")[0],
                }
                for model in models
            ]
        else:
            model_infos = [model_info(model) for model in models]
            return [
                {
                    "id": model.id,
                    "object": "model",
                    "created": model.created_at.timestamp(),
                    "owned_by": model.author,
                }
                for model in model_infos
            ]

    def continuous_batching_chat_completion(self, req: dict, request_id: str) -> AsyncGenerator[str, None]:
        """
        Generates an OpenAI Chat Completion using continuous batching.

        Args:
            req (`dict`): The request to generate an OpenAI Chat Completion for.

        Returns:
            `Generator[str, None, None]`: A generator that yields the OpenAI Chat Completion chunks.
        """

        model_id_and_revision = self.process_model_name(req["model"])
        must_discard_cache = model_id_and_revision != self.last_model
        self.last_model = model_id_and_revision
        if must_discard_cache:
            # When switching models, terminate a continuous batching manager if it is running.
            if self.running_continuous_batching_manager is not None:
                self.running_continuous_batching_manager.stop(block=True, timeout=2)
                self.running_continuous_batching_manager = None
        model, processor = self.load_model_and_processor(model_id_and_revision)

        tokenizer = processor.tokenizer if hasattr(processor, "tokenizer") else processor

        generation_config = create_generation_config_from_req(
            req,
            model_generation_config=model.generation_config,
            eos_token_id=tokenizer.eos_token_id,
            pad_token_id=tokenizer.pad_token_id,
            use_cache=False,
            do_sample=False,
            scheduler="fifo",
        )

        if self.running_continuous_batching_manager is None:
            self.running_continuous_batching_manager = model.init_continuous_batching(
                generation_config=generation_config, streaming=True
            )

            # TODO (Joao, Lysandre): the logits processors should be fixed in continuous batching
            # and correctly applied in non-cb
            self.running_continuous_batching_manager.logit_processor = LogitsProcessorList()
            self.running_continuous_batching_manager.start()

        # TODO (Joao, Lysandre): this should also work with tool support
        inputs = processor.apply_chat_template(req["messages"], return_tensors="pt", add_generation_prompt=True).to(
            model.device
        )

        def stream_chat_completion(request_id, decode_stream):
            try:
                # Emit the assistant role to start the stream. Other chunks won't have a role, as it is implicit
                # they come from the assistant.
                yield self.build_chat_completion_chunk(request_id, role="assistant", model=model_id_and_revision)

                for result in self.running_continuous_batching_manager.request_id_iter(request_id):
                    if result.status == RequestStatus.FINISHED:
                        yield self.build_chat_completion_chunk(
                            request_id,
                            finish_reason="stop",
                            model=model_id_and_revision,
                        )
                        break
                    else:
                        yield self.build_chat_completion_chunk(
                            request_id=request_id,
                            content=result.generated_tokens[-1],
                            model=model_id_and_revision,
                            decode_stream=decode_stream,
                            tokenizer=tokenizer,
                        )

            except Exception as e:
                logger.error(str(e))
                self.running_continuous_batching_manager.cancel_request(request_id)
                yield f'data: {{"error": "{str(e)}"}}'

        async def cancellation_wrapper(_inputs, request_id):
            try:
                decode_stream = DecodeStream(_inputs.tolist(), False)
                # XXX: using returned request_id as safety in case it is None
                request_id = self.running_continuous_batching_manager.add_request(
                    _inputs, request_id=request_id, max_new_tokens=generation_config.max_new_tokens
                )
                for chunk in stream_chat_completion(request_id, decode_stream):
                    yield chunk
                    await asyncio.sleep(0)  # Yield control to the event loop to check for cancellations
            except asyncio.CancelledError:
                self.running_continuous_batching_manager.cancel_request(request_id)
                logger.warning(f"Request {request_id} was cancelled.")

        return cancellation_wrapper(inputs[0], request_id)

    @staticmethod
    def get_model_modality(model: "PreTrainedModel") -> Modality:
        model_classname = model.__class__.__name__
        if model_classname in MODEL_FOR_IMAGE_TEXT_TO_TEXT_MAPPING_NAMES.values():
            modality = Modality.VLM
        elif model_classname in MODEL_FOR_CAUSAL_LM_MAPPING_NAMES.values():
            modality = Modality.LLM
        else:
            raise ValueError(f"Unknown modality: {model_classname}")

        return modality

    @staticmethod
    def get_processor_inputs_from_inbound_messages(messages, modality: Modality):
        processor_inputs = []

        for message in messages:
            parsed_message = {"role": message["role"], "content": []}

            if modality == Modality.LLM:
                # Input: `content` is a string or a list of dictionaries with a "text" key.
                # Output: `content` is a string.
                if isinstance(message["content"], str):
                    parsed_content = message["content"]
                elif isinstance(message["content"], list):
                    parsed_content = []
                    for content in message["content"]:
                        if content["type"] == "text":
                            parsed_content.append(content["text"])
                    parsed_content = " ".join(parsed_content)
                parsed_message["content"] = parsed_content

            elif modality == Modality.VLM:
                # Input: `content` is a string or a list of dictionaries with a "type" key (possible types: "text",
                # "image_url").
                # Output: `content` is a list of dictionaries with a "type" key
                if isinstance(message["content"], str):
                    parsed_message["content"].append({"type": "text", "text": message["content"]})
                else:
                    for content in message["content"]:
                        if content["type"] == "text":
                            parsed_message["content"].append(content)
                        elif content["type"] == "image_url":
                            if "base64" in content["image_url"]["url"]:
                                image_data = re.sub("^data:image/.+;base64,", "", content["image_url"]["url"])
                                image = Image.open(BytesIO(base64.b64decode(image_data)))

                                file = tempfile.NamedTemporaryFile(suffix=".png", delete=False)
                                url = file.name

                                image.save(file.name)
                            else:
                                url = content["image_url"]["url"]

                            parsed_message["content"].append({"type": "image", "url": url})
            processor_inputs.append(parsed_message)
        return processor_inputs

    def generate_chat_completion(self, req: dict) -> Generator[str, None, None]:
        """
        Generates an OpenAI Chat Completion using `generate`.

        Args:
            req (`dict`): The request to generate an OpenAI Chat Completion for.

        Returns:
            `Generator[str, None, None]`: A generator that yields the OpenAI Chat Completion chunks.
        """
        if self.args.force_model is not None:
            req["model"] = self.args.force_model

        messages: Iterable[ChatCompletionMessageParam] = req["messages"]

        # HACK for tiny-agents: it sends a request after the assistant message (???). Let's assume we can't have a
        # request whose last message is from the assistant.
        if messages[-1]["role"] == "assistant":
            return

        model_id_and_revision = self.process_model_name(req["model"])
        must_discard_cache = model_id_and_revision != self.last_model

        self.last_model = model_id_and_revision
        model, processor = self.load_model_and_processor(model_id_and_revision)

        modality = self.get_model_modality(model)
        processor_inputs = self.get_processor_inputs_from_inbound_messages(messages, modality)

        # ====== TOOL PREPROCESSING LOGIC ======
        tool_model_family = None
        for supported_model_families in _MODELS_WITH_TOOL_SUPPORT:
            if supported_model_families in model.config.architectures[0].lower():
                tool_model_family = supported_model_families
                break
        # TODO: trigger 2 constrained generations after the tool call start token is emitted:
        # 1. force generation to pick from the tool names
        # 2. force generation to pick from that tool's arguments
        # ====== END OF TOOL PREPROCESSING LOGIC ======

        inputs = processor.apply_chat_template(
            processor_inputs,
            add_generation_prompt=True,
            tools=req.get("tools"),
            return_tensors="pt",
            return_dict=True,
            tokenize=True,
        )
        inputs = inputs.to(model.device)
        request_id = req.get("request_id", "req_0")

        # Temporary hack for GPTOSS 1: don't filter special tokens
        skip_special_tokens = True
        if "gptoss" in model.config.architectures[0].lower():
            skip_special_tokens = False

        generation_streamer = TextIteratorStreamer(
            processor,
            skip_special_tokens=skip_special_tokens,
            skip_prompt=True,
        )
        generation_config = create_generation_config_from_req(req, model_generation_config=model.generation_config)

        last_kv_cache = None
        if self.is_continuation(req) and not must_discard_cache:
            seq_len = self.last_kv_cache.get_seq_length()
            if inputs["input_ids"].shape[-1] > seq_len:
                last_kv_cache = self.last_kv_cache

        generation_kwargs = {
            **inputs,
            "streamer": generation_streamer,
            "generation_config": generation_config,
            "return_dict_in_generate": True,
            "past_key_values": last_kv_cache,
        }

        def stream_chat_completion(streamer, _request_id):
            # Temporary hack for GPTOS 2: filter out the CoT tokens. Full solution here implies defining new output
            # classes and piping the reasoning trace into a new field
            filter_cot = False
            cot_trace_end = None
            if "gptoss" in model.config.architectures[0].lower():
                filter_cot = True
                cot_trace_end = "<|channel|>final<|message|>"

            # Thin wrapper to save the KV cache after generation
            def generate_with_cache(**kwargs):
                generate_output = model.generate(**kwargs)
                self.last_kv_cache = generate_output.past_key_values

            thread = Thread(target=generate_with_cache, kwargs=generation_kwargs)
            results = ""

            try:
                thread.start()
                tool_state = ToolState()

                # Emit the assistant role to start the stream. Other chunks won't have a role, as it is implicit
                # they come from the assistant.
                yield self.build_chat_completion_chunk(request_id, role="assistant", model=model_id_and_revision)

                for result in streamer:
                    # Temporary hack for GPTOS 3: don't emit the final "<|return|>"
                    if "gptoss" in model.config.architectures[0].lower():
                        result = result.removesuffix("<|return|>")
                    results += result

                    # (related to temporary hack 2)
                    if filter_cot:
                        if cot_trace_end in results:  # end of reasoning trace observed -> stop filtering
                            filter_cot = False
                            continue
                        else:
                            continue

                    # ====== TOOL CALL LOGIC ======
                    if tool_model_family is not None:
                        # Start of a tool call: reset state variables, set `inside_tool_call`
                        if result.strip() == _TOOL_CALL_TOKENS[tool_model_family]["start"]:
                            tool_state.inside_tool_call = True
                            continue

                        # End of tool call: reset `inside_tool_call`, emit a `finish_reason`
                        if result.strip() == _TOOL_CALL_TOKENS[tool_model_family]["end"]:
                            tool_state.reset()
                            yield self.build_chat_completion_chunk(
                                request_id=_request_id,
                                role=None,
                                finish_reason="tool_calls",
                                model=model_id_and_revision,
                            )

                            continue
                        # Inside a tool call
                        if tool_state.inside_tool_call:
                            tool_state.buffer += result

                            # First step: extract the tool name (may need several tokens, and we can't emit a delta
                            # until we have the full name)
                            if not tool_state.has_tool_name_defined:
                                tool_name = re.search(r"\"name\": \"(.*?)\"", tool_state.buffer)
                                if tool_name is None:
                                    continue
                                else:
                                    tool_name = tool_name.group(1)
                                tool_state.has_tool_name_defined = True
                                tool = ChoiceDeltaToolCall(
                                    function=ChoiceDeltaToolCallFunction(name=tool_name),
                                    index=0,
                                    type="function",
                                    id=_request_id + "_tool_call",  # Only the first tool call delta has an id
                                )

                            # Second step: extract tool arguments. The tool arguments can be seen as a json string
                            # within the tool json string. We emit a delta for the arguments.
                            else:
                                # Empty text: skip
                                if result == "":
                                    continue
                                # Until we see the `"arguments": {` in the buffer, we skip
                                # TODO: other models will likely need more elaborate processing here
                                if '"arguments": {' not in tool_state.buffer:
                                    continue

                                # Handle nesting. We want to exclude the last } from the emitted arguments (it's
                                # closing the outermost nesting level, outside the arguments block)
                                tool_state.arg_nesting_level += result.count("{")
                                tool_state.arg_nesting_level -= result.count("}")
                                if tool_state.arg_nesting_level < 0:
                                    result = "".join(result.split("}")[:-2]) + "}"  # e.g. "4}}\n" -> "4}"

                                tool = ChoiceDeltaToolCall(
                                    function=ChoiceDeltaToolCallFunction(arguments=result),
                                    index=0,
                                    type="function",
                                )

                            yield self.build_chat_completion_chunk(
                                request_id=_request_id, role=None, tool_calls=[tool], model=model_id_and_revision
                            )
                            continue
                    # ====== END OF TOOL CALL LOGIC ======

                    # All non-tool related tokens are emitted as assistant messages. Empty text is skipped.
                    if result != "":
                        yield self.build_chat_completion_chunk(
                            _request_id, content=result, model=model_id_and_revision
                        )
                yield self.build_chat_completion_chunk(_request_id, finish_reason="stop", model=model_id_and_revision)

                thread.join()
            except Exception as e:
                logger.error(str(e))
                yield f'data: {{"error": "{str(e)}"}}'

            finally:
                thread.join()

        return stream_chat_completion(generation_streamer, request_id)

    def generate_response(self, req: dict) -> Generator[str, None, None]:
        """
        Generates an OpenAI Response using `generate`.

        Args:
            req (`dict`): The request to generate an OpenAI Response for.

        Returns:
            `Generator[str, None, None]`: A generator that yields the OpenAI Response events.
        """
        # TODO -- Implement non-streaming mode
        model_id_and_revision = self.process_model_name(req["model"])
        must_discard_cache = model_id_and_revision != self.last_model
        self.last_model = model_id_and_revision
        model, processor = self.load_model_and_processor(model_id_and_revision)

        if isinstance(req["input"], str):
            inputs = [{"role": "system", "content": req["instructions"]}] if "instructions" in req else []
            inputs.append({"role": "user", "content": req["input"]})
        elif isinstance(req["input"], list):
            if "instructions" in req:
                if req["input"][0]["role"] != "system":
                    inputs = [{"role": "system", "content": req["instructions"]}, *req["input"]]
                else:
                    inputs = req["input"]
                    inputs[0]["content"] = req["instructions"]
            else:
                inputs = req["input"]
        elif isinstance(req["input"], dict):
            inputs = [{"role": "system", "content": req["instructions"]}] if "instructions" in req else []
            inputs.append(req["input"])
        else:
            raise ValueError("inputs should be a list, dict, or str")

        inputs = processor.apply_chat_template(inputs, add_generation_prompt=True, return_tensors="pt")
        inputs = inputs.to(model.device)
        request_id = req.get("previous_response_id", "req_0")

        # Temporary hack for GPTOSS 1: don't filter special tokens
        skip_special_tokens = True
        if "gptoss" in model.config.architectures[0].lower():
            skip_special_tokens = False

        generation_streamer = TextIteratorStreamer(
            processor,
            skip_special_tokens=skip_special_tokens,
            skip_prompt=True,
        )
        generation_config = create_generation_config_from_req(req, model_generation_config=model.generation_config)

        last_kv_cache = None
        if self.is_continuation(req) and not must_discard_cache:
            seq_len = self.last_kv_cache.get_seq_length()
            if inputs["input_ids"].shape[-1] > seq_len:
                last_kv_cache = self.last_kv_cache

        generation_kwargs = {
            "inputs": inputs,
            "attention_mask": torch.ones_like(inputs),
            "streamer": generation_streamer,
            "generation_config": generation_config,
            "return_dict_in_generate": True,
            "past_key_values": last_kv_cache,
        }

        def stream_response(streamer, _request_id):
            # Temporary hack for GPTOS 2: filter out the CoT tokens. Full solution here implies defining new output
            # classes and piping the reasoning trace into a new field
            filter_cot = False
            cot_trace_end = None
            if "gptoss" in model.config.architectures[0].lower():
                filter_cot = True
                cot_trace_end = "<|channel|>final<|message|>"

            # Thin wrapper to save the KV cache after generation
            def generate_with_cache(**kwargs):
                generate_output = model.generate(**kwargs)
                self.last_kv_cache = generate_output.past_key_values

            thread = Thread(target=generate_with_cache, kwargs=generation_kwargs)
            sequence_number = 0
            output_index = 0
            content_index = 0

            try:
                thread.start()
                created_at = time.time()  # the spec expects a unix timestamp in seconds

                # We start by acknowledging the request (the request has `status="queued"`), and then by moving it to
                # in progress (`status="in_progress"`)
                response_created = ResponseCreatedEvent(
                    type="response.created",
                    sequence_number=sequence_number,
                    response=Response(
                        id=f"resp_{request_id}",
                        created_at=created_at,
                        status="queued",
                        model=model_id_and_revision,
                        instructions=req.get("instructions"),
                        text={"format": {"type": "text"}},
                        object="response",
                        tools=[],
                        output=[],
                        parallel_tool_calls=req.get("parallel_tool_calls", False),
                        tool_choice="auto",
                        metadata=req.get("metadata"),
                    ),
                )
                sequence_number += 1
                yield self.build_response_event(response_created)

                response_in_progress = ResponseInProgressEvent(
                    type="response.in_progress",
                    sequence_number=sequence_number,
                    response=Response(
                        id=f"resp_{request_id}",
                        created_at=created_at,
                        status="in_progress",
                        model=model_id_and_revision,
                        instructions=req.get("instructions"),
                        text={"format": {"type": "text"}},
                        object="response",
                        tools=[],
                        output=[],
                        parallel_tool_calls=req.get("parallel_tool_calls", False),
                        tool_choice="auto",
                        metadata=req.get("metadata"),
                    ),
                )
                sequence_number += 1
                yield self.build_response_event(response_in_progress)

                # Start the output item. Emit the assistant role to start the stream. Other chunks won't have a role,
                # as it is implicit
                response_output_item_added = ResponseOutputItemAddedEvent(
                    type="response.output_item.added",
                    sequence_number=sequence_number,
                    output_index=output_index,
                    item=ResponseOutputMessage(
                        id=f"msg_{request_id}", type="message", status="in_progress", role="assistant", content=[]
                    ),
                )
                sequence_number += 1
                yield self.build_response_event(response_output_item_added)

                # Start the content part of the event
                response_content_part_added = ResponseContentPartAddedEvent(
                    type="response.content_part.added",
                    item_id=f"msg_{request_id}",
                    sequence_number=sequence_number,
                    output_index=output_index,
                    content_index=content_index,
                    part=ResponseOutputText(type="output_text", text="", annotations=[]),
                )
                sequence_number += 1
                yield self.build_response_event(response_content_part_added)

                # Stream the actual generated text
                results = ""
                for result in streamer:
                    # Temporary hack for GPTOS 3: don't emit the final "<|return|>"
                    if "gptoss" in model.config.architectures[0].lower():
                        result = result.removesuffix("<|return|>")
                    results += result

                    # (related to temporary hack 2)
                    if filter_cot:
                        if cot_trace_end in results:  # end of reasoning trace observed -> stop filtering
                            filter_cot = False
                            results = ""  # reset the results -> results will now track the final response
                            continue
                        else:
                            continue

                    response_output_text_delta = ResponseTextDeltaEvent(
                        type="response.output_text.delta",
                        item_id=f"msg_{request_id}",
                        sequence_number=sequence_number,
                        output_index=output_index,
                        content_index=content_index,
                        delta=result,
                        logprobs=[{"token": "", "logprob": 99.9}],  # TODO: add actual logprobs
                    )
                    sequence_number += 1
                    yield self.build_response_event(response_output_text_delta)

                # Signal the end of the text generation
                response_output_text_done = ResponseTextDoneEvent(
                    type="response.output_text.done",
                    item_id=f"msg_{request_id}",
                    sequence_number=sequence_number,
                    output_index=output_index,
                    content_index=0,
                    text=results,
                    logprobs=[{"token": "", "logprob": 99.9}],  # TODO: add actual logprobs
                )
                sequence_number += 1
                yield self.build_response_event(response_output_text_done)

                # Complete the content part
                response_content_part_done = ResponseContentPartDoneEvent(
                    type="response.content_part.done",
                    item_id=f"msg_{request_id}",
                    sequence_number=sequence_number,
                    output_index=output_index,
                    content_index=content_index,
                    part=ResponseOutputText(type="output_text", text=response_output_text_done.text, annotations=[]),
                )
                sequence_number += 1
                content_index += 1
                yield self.build_response_event(response_content_part_done)

                # Complete the output item
                response_output_item_done = ResponseOutputItemDoneEvent(
                    type="response.output_item.done",
                    sequence_number=sequence_number,
                    output_index=output_index,
                    item=ResponseOutputMessage(
                        id=f"msg_{request_id}",
                        type="message",
                        status="completed",
                        role="assistant",
                        content=[response_content_part_done.part],
                        annotations=[],
                    ),
                )
                sequence_number += 1
                output_index += 1
                yield self.build_response_event(response_output_item_done)

                # Finally, Complete the event
                response_completed = ResponseCompletedEvent(
                    type="response.completed",
                    sequence_number=sequence_number,
                    response=Response(
                        id=f"resp_{request_id}",
                        created_at=created_at,
                        status="completed",
                        model=model_id_and_revision,
                        instructions=req.get("instructions"),
                        text={"format": {"type": "text"}},
                        output=[response_output_item_done.item],
                        object="response",
                        tools=[],
                        parallel_tool_calls=req.get("parallel_tool_calls", False),
                        tool_choice="auto",
                        metadata=req.get("metadata"),
                    ),
                )
                sequence_number += 1
                yield self.build_response_event(response_completed)

                thread.join()
            except Exception as e:
                logger.error(f"Exception in response generation: {str(e)}")
                error_event = ResponseErrorEvent(
                    type="error",
                    sequence_number=sequence_number,
                    message=str(e),
                )
                sequence_number += 1
                yield self.build_response_event(error_event)

                response_failed = ResponseFailedEvent(
                    type="response.failed",
                    sequence_number=sequence_number,
                    response=Response(
                        id=f"resp_{request_id}",
                        created_at=created_at,
                        status="failed",
                        model=model_id_and_revision,
                        instructions=req.get("instructions"),
                        text={"format": {"type": "text"}},
                        output=[],
                        object="response",
                        tools=[],
                        parallel_tool_calls=False,
                        tool_choice="auto",
                        metadata=req.get("metadata"),
                        error=ResponseError(
                            code="server_error",
                            message=str(e),
                        ),
                    ),
                )
                sequence_number += 1
                yield self.build_response_event(response_failed)

            finally:
                thread.join()

        return stream_response(generation_streamer, request_id)

    def generate_transcription(self, req: dict) -> Generator[str, None, None]:
        """
        Generates an OpenAI Transcription using the audio file.

        Args:
            req (`dict`): The request containing the audio file and model information.

        Returns:
            `Generator[str, None, None]`: A generator that yields the transcription result.
        """
        # TODO: implement streaming transcription (currently, it's not streaming)
        if not is_librosa_available():
            raise ImportError(
                "Missing librosa dependency for audio transcription. Please install with `pip install librosa`"
            )
        model_id_and_revision = self.process_model_name(req["model"])
        audio_model, audio_processor = self.load_audio_model_and_processor(model_id_and_revision)

        generation_streamer = TextIteratorStreamer(
            audio_processor.tokenizer, skip_special_tokens=True, skip_prompt=True
        )
        generation_config = create_generation_config_from_req(
            req, model_generation_config=audio_model.generation_config
        )

        # Read the binary audio file using librosa
        model_sampling_rate = audio_processor.feature_extractor.sampling_rate
        audio_bytes = io.BytesIO(req["file"])
        audio_array, _ = librosa.load(audio_bytes, sr=model_sampling_rate, mono=True)
        audio_inputs = audio_processor(audio_array, sampling_rate=model_sampling_rate, return_tensors="pt").to(
            audio_model.device
        )
        audio_inputs["input_features"] = audio_inputs["input_features"].to(audio_model.dtype)

        generation_kwargs = {
            "streamer": generation_streamer,
            "generation_config": generation_config,
            "return_dict_in_generate": True,
        }

        def _generate_transcription():
            generated_ids = audio_model.generate(**audio_inputs, **generation_kwargs)
            transcription_text = audio_processor.batch_decode(generated_ids.sequences, skip_special_tokens=True)[0]
            transcription = Transcription(text=transcription_text)
            yield f"{transcription.model_dump_json(exclude_none=True)}"

        return _generate_transcription()

    def is_continuation(self, req: dict) -> bool:
        """
        Determines whether the current request is a continuation of the last request. In other words, if it is the
        same chat session.

        Args:
            req (`dict`): The request to check.

        Returns:
            `True` if the request is a continuation of the last request, `False` otherwise.
        """
        messages = req.get("messages") or req.get("input")  # ChatCompletion and Response have different fields
        req_continues_last_messages = True

        # No cached messages: this is a new request
        if self.last_messages is None:
            req_continues_last_messages = False
        # The new request has no new rounds of conversation: this is a new request
        elif len(self.last_messages) >= len(messages):
            req_continues_last_messages = False
        # Otherwise, check that the last messages are a subset of the new request
        else:
            for i in range(len(self.last_messages)):
                if self.last_messages[i] != messages[i]:
                    req_continues_last_messages = False
                    break

        self.last_messages = messages
        return req_continues_last_messages

    @staticmethod
    def get_quantization_config(args: ServeArguments) -> Optional["BitsAndBytesConfig"]:
        """
        Returns the quantization config for the given CLI arguments.

        Args:
            args (`ServeArguments`): The serve arguments. May contain quantization settings, device, etc.

        Returns:
            `Optional[BitsAndBytesConfig]`: The quantization config.
        """
        if args.load_in_4bit:
            quantization_config = BitsAndBytesConfig(
                load_in_4bit=True,
                # For consistency with model weights, we use the same value as `dtype`
                bnb_4bit_compute_dtype=args.dtype,
                bnb_4bit_quant_type=args.bnb_4bit_quant_type,
                bnb_4bit_use_double_quant=args.use_bnb_nested_quant,
                bnb_4bit_quant_storage=args.dtype,
            )
        elif args.load_in_8bit:
            quantization_config = BitsAndBytesConfig(
                load_in_8bit=True,
            )
        else:
            quantization_config = None

        return quantization_config

    def process_model_name(self, model_id: str) -> str:
        """
        Applies the `force_model` CLI argument and canonicalizes the model name to the format "model_id@revision".
        If the model_id DOESN'T contain an @, it defaults to "model_id@main".

        Args:
            model_id (`str`): The model ID.

        Returns:
            `str`: The canonicalized model name to be used
        """
        if self.args.force_model is not None:
            model_id = self.args.force_model
        if "@" in model_id:
            return model_id
        return f"{model_id}@main"

    def _load_model_and_data_processor(self, model_id_and_revision: str):
        """
        Generic method to load a model and a data processor from a model ID and revision, making use of the serve CLI
        arguments.

        Args:
            model_id_and_revision (`str`):
                The model ID and revision to load.
            model_cls (`type[PreTrainedModel]`):
                The model class to load.

        Returns:
            `tuple[PreTrainedModel, Union[ProcessorMixin, PreTrainedTokenizerFast]]`: The loaded model and
            data processor (tokenizer, audio processor, etc.).
        """
        args = self.args
        logger.info(f"Loading {model_id_and_revision}")

        if "@" in model_id_and_revision:
            model_id, revision = model_id_and_revision.split("@", 1)
        else:
            model_id, revision = model_id_and_revision, "main"

        data_processor = AutoProcessor.from_pretrained(
            model_id,
            revision=revision,
            trust_remote_code=args.trust_remote_code,
        )

        dtype = args.dtype if args.dtype in ["auto", None] else getattr(torch, args.dtype)
        quantization_config = self.get_quantization_config(args)

        model_kwargs = {
            "revision": revision,
            "attn_implementation": args.attn_implementation,
            "dtype": dtype,
            "device_map": "auto",
            "trust_remote_code": args.trust_remote_code,
        }
        if quantization_config is not None:
            model_kwargs["quantization_config"] = quantization_config

        config = AutoConfig.from_pretrained(model_id, **model_kwargs)
        architecture = getattr(transformers, config.architectures[0])
        model = architecture.from_pretrained(model_id, **model_kwargs)

        if getattr(model, "hf_device_map", None) is None:
            model = model.to(args.device)

        has_default_max_length = (
            model.generation_config.max_new_tokens is None and model.generation_config.max_length == 20
        )
        has_short_max_new_tokens = (
            model.generation_config.max_new_tokens is not None and model.generation_config.max_new_tokens < 1024
        )
        if has_default_max_length or has_short_max_new_tokens:
            model.generation_config.max_new_tokens = 1024

        logger.info(f"Loaded model {model_id_and_revision}")
        return model, data_processor

    def load_model_and_processor(
        self, model_id_and_revision: str
    ) -> tuple["PreTrainedModel", PreTrainedTokenizerFast]:
        """
        Loads the text model and processor from the given model ID and revision into the ServeCommand instance.

        Args:
            model_id_and_revision (`str`):
                The model ID and revision to load.

        Returns:
            `tuple[PreTrainedModel, PreTrainedTokenizerFast]`: The loaded text model and processor.
        """
        if model_id_and_revision not in self.loaded_models or self.loaded_models[model_id_and_revision].is_deleted():
            model, processor = self._load_model_and_data_processor(model_id_and_revision)
            self.loaded_models[model_id_and_revision] = TimedModel(
                model,
                timeout_seconds=self.args.model_timeout,
                processor=processor,
            )
        else:
            self.loaded_models[model_id_and_revision].reset_timer()
            model = self.loaded_models[model_id_and_revision].model
            processor = self.loaded_models[model_id_and_revision].processor

        return model, processor

    def load_audio_model_and_processor(self, model_id_and_revision: str) -> tuple["PreTrainedModel", ProcessorMixin]:
        """
        Loads the audio model and processor from the given model ID and revision into the ServeCommand instance.

        Args:
            model_id_and_revision (`str`):
                The model ID and revision to load.

        Returns:
            `tuple[PreTrainedModel, ProcessorMixin]`: The loaded audio model and processor.
        """
        if model_id_and_revision not in self.loaded_models or self.loaded_models[model_id_and_revision].is_deleted():
            audio_model, audio_processor = self._load_model_and_data_processor(model_id_and_revision)
            self.loaded_models[model_id_and_revision] = TimedModel(
                audio_model,
                timeout_seconds=self.args.model_timeout,
                processor=audio_processor,
            )
        else:
            self.loaded_models[model_id_and_revision].reset_timer()
            audio_model = self.loaded_models[model_id_and_revision].model
            audio_processor = self.loaded_models[model_id_and_revision].processor

        return audio_model, audio_processor


if __name__ == "__main__":
    serve = ServeCommand()
    serve.run()