summaryrefslogtreecommitdiff
path: root/caddyconfig/httpcaddyfile/builtins.go
blob: 7fdd3e8a4f3fc0a1e20a85abd481ed5145bedb07 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
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
// Copyright 2015 Matthew Holt and The Caddy Authors
//
// 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.

package httpcaddyfile

import (
	"encoding/base64"
	"encoding/pem"
	"fmt"
	"html"
	"net/http"
	"os"
	"reflect"
	"strconv"
	"strings"

	"github.com/caddyserver/caddy/v2"
	"github.com/caddyserver/caddy/v2/caddyconfig"
	"github.com/caddyserver/caddy/v2/caddyconfig/caddyfile"
	"github.com/caddyserver/caddy/v2/modules/caddyhttp"
	"github.com/caddyserver/caddy/v2/modules/caddytls"
	"github.com/caddyserver/certmagic"
	"github.com/mholt/acmez/acme"
	"go.uber.org/zap/zapcore"
)

func init() {
	RegisterDirective("bind", parseBind)
	RegisterDirective("tls", parseTLS)
	RegisterHandlerDirective("root", parseRoot)
	RegisterHandlerDirective("redir", parseRedir)
	RegisterHandlerDirective("respond", parseRespond)
	RegisterHandlerDirective("abort", parseAbort)
	RegisterHandlerDirective("error", parseError)
	RegisterHandlerDirective("route", parseRoute)
	RegisterHandlerDirective("handle", parseHandle)
	RegisterDirective("handle_errors", parseHandleErrors)
	RegisterDirective("log", parseLog)
}

// parseBind parses the bind directive. Syntax:
//
//     bind <addresses...>
//
func parseBind(h Helper) ([]ConfigValue, error) {
	var lnHosts []string
	for h.Next() {
		lnHosts = append(lnHosts, h.RemainingArgs()...)
	}
	return h.NewBindAddresses(lnHosts), nil
}

// parseTLS parses the tls directive. Syntax:
//
//     tls [<email>|internal]|[<cert_file> <key_file>] {
//         protocols <min> [<max>]
//         ciphers   <cipher_suites...>
//         curves    <curves...>
//         client_auth {
//             mode                   [request|require|verify_if_given|require_and_verify]
//             trusted_ca_cert        <base64_der>
//             trusted_ca_cert_file   <filename>
//             trusted_leaf_cert      <base64_der>
//             trusted_leaf_cert_file <filename>
//         }
//         alpn      <values...>
//         load      <paths...>
//         ca        <acme_ca_endpoint>
//         ca_root   <pem_file>
//         dns       <provider_name> [...]
//         on_demand
//         eab    <key_id> <mac_key>
//         issuer <module_name> [...]
//     }
//
func parseTLS(h Helper) ([]ConfigValue, error) {
	cp := new(caddytls.ConnectionPolicy)
	var fileLoader caddytls.FileLoader
	var folderLoader caddytls.FolderLoader
	var certSelector caddytls.CustomCertSelectionPolicy
	var acmeIssuer *caddytls.ACMEIssuer
	var keyType string
	var internalIssuer *caddytls.InternalIssuer
	var issuers []certmagic.Issuer
	var onDemand bool

	for h.Next() {
		// file certificate loader
		firstLine := h.RemainingArgs()
		switch len(firstLine) {
		case 0:
		case 1:
			if firstLine[0] == "internal" {
				internalIssuer = new(caddytls.InternalIssuer)
			} else if !strings.Contains(firstLine[0], "@") {
				return nil, h.Err("single argument must either be 'internal' or an email address")
			} else {
				if acmeIssuer == nil {
					acmeIssuer = new(caddytls.ACMEIssuer)
				}
				acmeIssuer.Email = firstLine[0]
			}

		case 2:
			certFilename := firstLine[0]
			keyFilename := firstLine[1]

			// tag this certificate so if multiple certs match, specifically
			// this one that the user has provided will be used, see #2588:
			// https://github.com/caddyserver/caddy/issues/2588 ... but we
			// must be careful about how we do this; being careless will
			// lead to failed handshakes
			//
			// we need to remember which cert files we've seen, since we
			// must load each cert only once; otherwise, they each get a
			// different tag... since a cert loaded twice has the same
			// bytes, it will overwrite the first one in the cache, and
			// only the last cert (and its tag) will survive, so any conn
			// policy that is looking for any tag other than the last one
			// to be loaded won't find it, and TLS handshakes will fail
			// (see end of issue #3004)
			//
			// tlsCertTags maps certificate filenames to their tag.
			// This is used to remember which tag is used for each
			// certificate files, since we need to avoid loading
			// the same certificate files more than once, overwriting
			// previous tags
			tlsCertTags, ok := h.State["tlsCertTags"].(map[string]string)
			if !ok {
				tlsCertTags = make(map[string]string)
				h.State["tlsCertTags"] = tlsCertTags
			}

			tag, ok := tlsCertTags[certFilename]
			if !ok {
				// haven't seen this cert file yet, let's give it a tag
				// and add a loader for it
				tag = fmt.Sprintf("cert%d", len(tlsCertTags))
				fileLoader = append(fileLoader, caddytls.CertKeyFilePair{
					Certificate: certFilename,
					Key:         keyFilename,
					Tags:        []string{tag},
				})
				// remember this for next time we see this cert file
				tlsCertTags[certFilename] = tag
			}
			certSelector.AnyTag = append(certSelector.AnyTag, tag)

		default:
			return nil, h.ArgErr()
		}

		var hasBlock bool
		for nesting := h.Nesting(); h.NextBlock(nesting); {
			hasBlock = true

			switch h.Val() {
			case "protocols":
				args := h.RemainingArgs()
				if len(args) == 0 {
					return nil, h.SyntaxErr("one or two protocols")
				}
				if len(args) > 0 {
					if _, ok := caddytls.SupportedProtocols[args[0]]; !ok {
						return nil, h.Errf("Wrong protocol name or protocol not supported: '%s'", args[0])
					}
					cp.ProtocolMin = args[0]
				}
				if len(args) > 1 {
					if _, ok := caddytls.SupportedProtocols[args[1]]; !ok {
						return nil, h.Errf("Wrong protocol name or protocol not supported: '%s'", args[1])
					}
					cp.ProtocolMax = args[1]
				}

			case "ciphers":
				for h.NextArg() {
					if !caddytls.CipherSuiteNameSupported(h.Val()) {
						return nil, h.Errf("Wrong cipher suite name or cipher suite not supported: '%s'", h.Val())
					}
					cp.CipherSuites = append(cp.CipherSuites, h.Val())
				}

			case "curves":
				for h.NextArg() {
					if _, ok := caddytls.SupportedCurves[h.Val()]; !ok {
						return nil, h.Errf("Wrong curve name or curve not supported: '%s'", h.Val())
					}
					cp.Curves = append(cp.Curves, h.Val())
				}

			case "client_auth":
				cp.ClientAuthentication = &caddytls.ClientAuthentication{}
				for nesting := h.Nesting(); h.NextBlock(nesting); {
					subdir := h.Val()
					switch subdir {
					case "mode":
						if !h.Args(&cp.ClientAuthentication.Mode) {
							return nil, h.ArgErr()
						}
						if h.NextArg() {
							return nil, h.ArgErr()
						}

					case "trusted_ca_cert",
						"trusted_leaf_cert":
						if !h.NextArg() {
							return nil, h.ArgErr()
						}
						if subdir == "trusted_ca_cert" {
							cp.ClientAuthentication.TrustedCACerts = append(cp.ClientAuthentication.TrustedCACerts, h.Val())
						} else {
							cp.ClientAuthentication.TrustedLeafCerts = append(cp.ClientAuthentication.TrustedLeafCerts, h.Val())
						}

					case "trusted_ca_cert_file",
						"trusted_leaf_cert_file":
						if !h.NextArg() {
							return nil, h.ArgErr()
						}
						filename := h.Val()
						certDataPEM, err := os.ReadFile(filename)
						if err != nil {
							return nil, err
						}
						block, _ := pem.Decode(certDataPEM)
						if block == nil || block.Type != "CERTIFICATE" {
							return nil, h.Errf("no CERTIFICATE pem block found in %s", h.Val())
						}
						if subdir == "trusted_ca_cert_file" {
							cp.ClientAuthentication.TrustedCACerts = append(cp.ClientAuthentication.TrustedCACerts,
								base64.StdEncoding.EncodeToString(block.Bytes))
						} else {
							cp.ClientAuthentication.TrustedLeafCerts = append(cp.ClientAuthentication.TrustedLeafCerts,
								base64.StdEncoding.EncodeToString(block.Bytes))
						}

					default:
						return nil, h.Errf("unknown subdirective for client_auth: %s", subdir)
					}
				}

			case "alpn":
				args := h.RemainingArgs()
				if len(args) == 0 {
					return nil, h.ArgErr()
				}
				cp.ALPN = args

			case "load":
				folderLoader = append(folderLoader, h.RemainingArgs()...)

			case "ca":
				arg := h.RemainingArgs()
				if len(arg) != 1 {
					return nil, h.ArgErr()
				}
				if acmeIssuer == nil {
					acmeIssuer = new(caddytls.ACMEIssuer)
				}
				acmeIssuer.CA = arg[0]

			case "key_type":
				arg := h.RemainingArgs()
				if len(arg) != 1 {
					return nil, h.ArgErr()
				}
				keyType = arg[0]

			case "eab":
				arg := h.RemainingArgs()
				if len(arg) != 2 {
					return nil, h.ArgErr()
				}
				if acmeIssuer == nil {
					acmeIssuer = new(caddytls.ACMEIssuer)
				}
				acmeIssuer.ExternalAccount = &acme.EAB{
					KeyID:  arg[0],
					MACKey: arg[1],
				}

			case "issuer":
				if !h.NextArg() {
					return nil, h.ArgErr()
				}
				modName := h.Val()
				modID := "tls.issuance." + modName
				unm, err := caddyfile.UnmarshalModule(h.Dispenser, modID)
				if err != nil {
					return nil, err
				}
				issuer, ok := unm.(certmagic.Issuer)
				if !ok {
					return nil, h.Errf("module %s (%T) is not a certmagic.Issuer", modID, unm)
				}
				issuers = append(issuers, issuer)

			case "dns":
				if !h.NextArg() {
					return nil, h.ArgErr()
				}
				provName := h.Val()
				if acmeIssuer == nil {
					acmeIssuer = new(caddytls.ACMEIssuer)
				}
				if acmeIssuer.Challenges == nil {
					acmeIssuer.Challenges = new(caddytls.ChallengesConfig)
				}
				if acmeIssuer.Challenges.DNS == nil {
					acmeIssuer.Challenges.DNS = new(caddytls.DNSChallengeConfig)
				}
				modID := "dns.providers." + provName
				unm, err := caddyfile.UnmarshalModule(h.Dispenser, modID)
				if err != nil {
					return nil, err
				}
				acmeIssuer.Challenges.DNS.ProviderRaw = caddyconfig.JSONModuleObject(unm, "name", provName, h.warnings)

			case "resolvers":
				args := h.RemainingArgs()
				if len(args) == 0 {
					return nil, h.ArgErr()
				}
				if acmeIssuer == nil {
					acmeIssuer = new(caddytls.ACMEIssuer)
				}
				if acmeIssuer.Challenges == nil {
					acmeIssuer.Challenges = new(caddytls.ChallengesConfig)
				}
				if acmeIssuer.Challenges.DNS == nil {
					acmeIssuer.Challenges.DNS = new(caddytls.DNSChallengeConfig)
				}
				acmeIssuer.Challenges.DNS.Resolvers = args

			case "ca_root":
				arg := h.RemainingArgs()
				if len(arg) != 1 {
					return nil, h.ArgErr()
				}
				if acmeIssuer == nil {
					acmeIssuer = new(caddytls.ACMEIssuer)
				}
				acmeIssuer.TrustedRootsPEMFiles = append(acmeIssuer.TrustedRootsPEMFiles, arg[0])

			case "on_demand":
				if h.NextArg() {
					return nil, h.ArgErr()
				}
				onDemand = true

			default:
				return nil, h.Errf("unknown subdirective: %s", h.Val())
			}
		}

		// a naked tls directive is not allowed
		if len(firstLine) == 0 && !hasBlock {
			return nil, h.ArgErr()
		}
	}

	// begin building the final config values
	configVals := []ConfigValue{}

	// certificate loaders
	if len(fileLoader) > 0 {
		configVals = append(configVals, ConfigValue{
			Class: "tls.cert_loader",
			Value: fileLoader,
		})
	}
	if len(folderLoader) > 0 {
		configVals = append(configVals, ConfigValue{
			Class: "tls.cert_loader",
			Value: folderLoader,
		})
	}

	// some tls subdirectives are shortcuts that implicitly configure issuers, and the
	// user can also configure issuers explicitly using the issuer subdirective; the
	// logic to support both would likely be complex, or at least unintuitive
	if len(issuers) > 0 && (acmeIssuer != nil || internalIssuer != nil) {
		return nil, h.Err("cannot mix issuer subdirective (explicit issuers) with other issuer-specific subdirectives (implicit issuers)")
	}
	if acmeIssuer != nil && internalIssuer != nil {
		return nil, h.Err("cannot create both ACME and internal certificate issuers")
	}

	// now we should either have: explicitly-created issuers, or an implicitly-created
	// ACME or internal issuer, or no issuers at all
	switch {
	case len(issuers) > 0:
		for _, issuer := range issuers {
			configVals = append(configVals, ConfigValue{
				Class: "tls.cert_issuer",
				Value: issuer,
			})
		}

	case acmeIssuer != nil:
		// implicit ACME issuers (from various subdirectives) - use defaults; there might be more than one
		defaultIssuers := caddytls.DefaultIssuers()

		// if a CA endpoint was set, override multiple implicit issuers since it's a specific one
		if acmeIssuer.CA != "" {
			defaultIssuers = []certmagic.Issuer{acmeIssuer}
		}

		for _, issuer := range defaultIssuers {
			switch iss := issuer.(type) {
			case *caddytls.ACMEIssuer:
				issuer = acmeIssuer
			case *caddytls.ZeroSSLIssuer:
				iss.ACMEIssuer = acmeIssuer
			}
			configVals = append(configVals, ConfigValue{
				Class: "tls.cert_issuer",
				Value: issuer,
			})
		}

	case internalIssuer != nil:
		configVals = append(configVals, ConfigValue{
			Class: "tls.cert_issuer",
			Value: internalIssuer,
		})
	}

	// certificate key type
	if keyType != "" {
		configVals = append(configVals, ConfigValue{
			Class: "tls.key_type",
			Value: keyType,
		})
	}

	// on-demand TLS
	if onDemand {
		configVals = append(configVals, ConfigValue{
			Class: "tls.on_demand",
			Value: true,
		})
	}

	// custom certificate selection
	if len(certSelector.AnyTag) > 0 {
		cp.CertSelection = &certSelector
	}

	// connection policy -- always add one, to ensure that TLS
	// is enabled, because this directive was used (this is
	// needed, for instance, when a site block has a key of
	// just ":5000" - i.e. no hostname, and only on-demand TLS
	// is enabled)
	configVals = append(configVals, ConfigValue{
		Class: "tls.connection_policy",
		Value: cp,
	})

	return configVals, nil
}

// parseRoot parses the root directive. Syntax:
//
//     root [<matcher>] <path>
//
func parseRoot(h Helper) (caddyhttp.MiddlewareHandler, error) {
	var root string
	for h.Next() {
		if !h.NextArg() {
			return nil, h.ArgErr()
		}
		root = h.Val()
		if h.NextArg() {
			return nil, h.ArgErr()
		}
	}
	return caddyhttp.VarsMiddleware{"root": root}, nil
}

// parseRedir parses the redir directive. Syntax:
//
//     redir [<matcher>] <to> [<code>]
//
func parseRedir(h Helper) (caddyhttp.MiddlewareHandler, error) {
	if !h.Next() {
		return nil, h.ArgErr()
	}

	if !h.NextArg() {
		return nil, h.ArgErr()
	}
	to := h.Val()

	var code string
	if h.NextArg() {
		code = h.Val()
	}

	var body string
	switch code {
	case "permanent":
		code = "301"
	case "temporary", "":
		code = "302"
	case "html":
		// Script tag comes first since that will better imitate a redirect in the browser's
		// history, but the meta tag is a fallback for most non-JS clients.
		const metaRedir = `<!DOCTYPE html>
<html>
	<head>
		<title>Redirecting...</title>
		<script>window.location.replace("%s");</script>
		<meta http-equiv="refresh" content="0; URL='%s'">
	</head>
	<body>Redirecting to <a href="%s">%s</a>...</body>
</html>
`
		safeTo := html.EscapeString(to)
		body = fmt.Sprintf(metaRedir, safeTo, safeTo, safeTo, safeTo)
		code = "302"
	default:
		codeInt, err := strconv.Atoi(code)
		if err != nil {
			return nil, h.Errf("Not a supported redir code type or not valid integer: '%s'", code)
		}
		if codeInt < 300 || codeInt > 399 {
			return nil, h.Errf("Redir code not in the 3xx range: '%v'", codeInt)
		}
	}

	return caddyhttp.StaticResponse{
		StatusCode: caddyhttp.WeakString(code),
		Headers:    http.Header{"Location": []string{to}},
		Body:       body,
	}, nil
}

// parseRespond parses the respond directive.
func parseRespond(h Helper) (caddyhttp.MiddlewareHandler, error) {
	sr := new(caddyhttp.StaticResponse)
	err := sr.UnmarshalCaddyfile(h.Dispenser)
	if err != nil {
		return nil, err
	}
	return sr, nil
}

// parseAbort parses the abort directive.
func parseAbort(h Helper) (caddyhttp.MiddlewareHandler, error) {
	h.Next() // consume directive
	for h.Next() || h.NextBlock(0) {
		return nil, h.ArgErr()
	}
	return &caddyhttp.StaticResponse{Abort: true}, nil
}

// parseError parses the error directive.
func parseError(h Helper) (caddyhttp.MiddlewareHandler, error) {
	se := new(caddyhttp.StaticError)
	err := se.UnmarshalCaddyfile(h.Dispenser)
	if err != nil {
		return nil, err
	}
	return se, nil
}

// parseRoute parses the route directive.
func parseRoute(h Helper) (caddyhttp.MiddlewareHandler, error) {
	sr := new(caddyhttp.Subroute)

	allResults, err := parseSegmentAsConfig(h)
	if err != nil {
		return nil, err
	}

	for _, result := range allResults {
		switch handler := result.Value.(type) {
		case caddyhttp.Route:
			sr.Routes = append(sr.Routes, handler)
		case caddyhttp.Subroute:
			// directives which return a literal subroute instead of a route
			// means they intend to keep those handlers together without
			// them being reordered; we're doing that anyway since we're in
			// the route directive, so just append its handlers
			sr.Routes = append(sr.Routes, handler.Routes...)
		default:
			return nil, h.Errf("%s directive returned something other than an HTTP route or subroute: %#v (only handler directives can be used in routes)", result.directive, result.Value)
		}
	}

	return sr, nil
}

func parseHandle(h Helper) (caddyhttp.MiddlewareHandler, error) {
	return ParseSegmentAsSubroute(h)
}

func parseHandleErrors(h Helper) ([]ConfigValue, error) {
	subroute, err := ParseSegmentAsSubroute(h)
	if err != nil {
		return nil, err
	}
	return []ConfigValue{
		{
			Class: "error_route",
			Value: subroute,
		},
	}, nil
}

// parseLog parses the log directive. Syntax:
//
//     log {
//         output <writer_module> ...
//         format <encoder_module> ...
//         level  <level>
//     }
//
func parseLog(h Helper) ([]ConfigValue, error) {
	return parseLogHelper(h, nil)
}

// parseLogHelper is used both for the parseLog directive within Server Blocks,
// as well as the global "log" option for configuring loggers at the global
// level. The parseAsGlobalOption parameter is used to distinguish any differing logic
// between the two.
func parseLogHelper(h Helper, globalLogNames map[string]struct{}) ([]ConfigValue, error) {
	// When the globalLogNames parameter is passed in, we make
	// modifications to the parsing behavior.
	parseAsGlobalOption := globalLogNames != nil

	var configValues []ConfigValue
	for h.Next() {
		// Logic below expects that a name is always present when a
		// global option is being parsed.
		var globalLogName string
		if parseAsGlobalOption {
			if h.NextArg() {
				globalLogName = h.Val()

				// Only a single argument is supported.
				if h.NextArg() {
					return nil, h.ArgErr()
				}
			} else {
				// If there is no log name specified, we
				// reference the default logger. See the
				// setupNewDefault function in the logging
				// package for where this is configured.
				globalLogName = "default"
			}

			// Verify this name is unused.
			_, used := globalLogNames[globalLogName]
			if used {
				return nil, h.Err("duplicate global log option for: " + globalLogName)
			}
			globalLogNames[globalLogName] = struct{}{}
		} else {
			// No arguments are supported for the server block log directive
			if h.NextArg() {
				return nil, h.ArgErr()
			}
		}

		cl := new(caddy.CustomLog)

		for h.NextBlock(0) {
			switch h.Val() {
			case "output":
				if !h.NextArg() {
					return nil, h.ArgErr()
				}
				moduleName := h.Val()

				// can't use the usual caddyfile.Unmarshaler flow with the
				// standard writers because they are in the caddy package
				// (because they are the default) and implementing that
				// interface there would unfortunately create circular import
				var wo caddy.WriterOpener
				switch moduleName {
				case "stdout":
					wo = caddy.StdoutWriter{}
				case "stderr":
					wo = caddy.StderrWriter{}
				case "discard":
					wo = caddy.DiscardWriter{}
				default:
					modID := "caddy.logging.writers." + moduleName
					unm, err := caddyfile.UnmarshalModule(h.Dispenser, modID)
					if err != nil {
						return nil, err
					}
					var ok bool
					wo, ok = unm.(caddy.WriterOpener)
					if !ok {
						return nil, h.Errf("module %s (%T) is not a WriterOpener", modID, unm)
					}
				}
				cl.WriterRaw = caddyconfig.JSONModuleObject(wo, "output", moduleName, h.warnings)

			case "format":
				if !h.NextArg() {
					return nil, h.ArgErr()
				}
				moduleName := h.Val()
				moduleID := "caddy.logging.encoders." + moduleName
				unm, err := caddyfile.UnmarshalModule(h.Dispenser, moduleID)
				if err != nil {
					return nil, err
				}
				enc, ok := unm.(zapcore.Encoder)
				if !ok {
					return nil, h.Errf("module %s (%T) is not a zapcore.Encoder", moduleID, unm)
				}
				cl.EncoderRaw = caddyconfig.JSONModuleObject(enc, "format", moduleName, h.warnings)

			case "level":
				if !h.NextArg() {
					return nil, h.ArgErr()
				}
				cl.Level = h.Val()
				if h.NextArg() {
					return nil, h.ArgErr()
				}

			case "include":
				// This configuration is only allowed in the global options
				if !parseAsGlobalOption {
					return nil, h.ArgErr()
				}
				for h.NextArg() {
					cl.Include = append(cl.Include, h.Val())
				}

			case "exclude":
				// This configuration is only allowed in the global options
				if !parseAsGlobalOption {
					return nil, h.ArgErr()
				}
				for h.NextArg() {
					cl.Exclude = append(cl.Exclude, h.Val())
				}

			default:
				return nil, h.Errf("unrecognized subdirective: %s", h.Val())
			}
		}

		var val namedCustomLog
		// Skip handling of empty logging configs
		if !reflect.DeepEqual(cl, new(caddy.CustomLog)) {
			if parseAsGlobalOption {
				// Use indicated name for global log options
				val.name = globalLogName
				val.log = cl
			} else {
				// Construct a log name for server log streams
				logCounter, ok := h.State["logCounter"].(int)
				if !ok {
					logCounter = 0
				}
				val.name = fmt.Sprintf("log%d", logCounter)
				cl.Include = []string{"http.log.access." + val.name}
				val.log = cl
				logCounter++
				h.State["logCounter"] = logCounter
			}
		}
		configValues = append(configValues, ConfigValue{
			Class: "custom_log",
			Value: val,
		})
	}
	return configValues, nil
}