forked from twitchtv/twirp
-
Notifications
You must be signed in to change notification settings - Fork 0
/
source_relative.twirp.go
871 lines (756 loc) · 27.9 KB
/
source_relative.twirp.go
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
// Code generated by protoc-gen-twirp v5.10.1, DO NOT EDIT.
// source: source_relative.proto
/*
Package source_relative is a generated twirp stub package.
This code was generated with github.com/twitchtv/twirp/protoc-gen-twirp v5.10.1.
It is generated from these files:
source_relative.proto
*/
package source_relative
import bytes "bytes"
import strings "strings"
import context "context"
import fmt "fmt"
import ioutil "io/ioutil"
import http "net/http"
import strconv "strconv"
import jsonpb "github.com/golang/protobuf/jsonpb"
import proto "github.com/golang/protobuf/proto"
import twirp "github.com/twitchtv/twirp"
import ctxsetters "github.com/twitchtv/twirp/ctxsetters"
// Imports only used by utility functions:
import io "io"
import json "encoding/json"
import url "net/url"
// =============
// Svc Interface
// =============
type Svc interface {
Method(context.Context, *Msg) (*Msg, error)
}
// ===================
// Svc Protobuf Client
// ===================
type svcProtobufClient struct {
client HTTPClient
urls [1]string
opts twirp.ClientOptions
}
// NewSvcProtobufClient creates a Protobuf client that implements the Svc interface.
// It communicates using Protobuf and can be configured with a custom HTTPClient.
func NewSvcProtobufClient(addr string, client HTTPClient, opts ...twirp.ClientOption) Svc {
if c, ok := client.(*http.Client); ok {
client = withoutRedirects(c)
}
clientOpts := twirp.ClientOptions{}
for _, o := range opts {
o(&clientOpts)
}
prefix := urlBase(addr) + SvcPathPrefix
urls := [1]string{
prefix + "Method",
}
return &svcProtobufClient{
client: client,
urls: urls,
opts: clientOpts,
}
}
func (c *svcProtobufClient) Method(ctx context.Context, in *Msg) (*Msg, error) {
ctx = ctxsetters.WithPackageName(ctx, "twirp.internal.twirptest.source_relative")
ctx = ctxsetters.WithServiceName(ctx, "Svc")
ctx = ctxsetters.WithMethodName(ctx, "Method")
out := new(Msg)
err := doProtobufRequest(ctx, c.client, c.opts.Hooks, c.urls[0], in, out)
if err != nil {
twerr, ok := err.(twirp.Error)
if !ok {
twerr = twirp.InternalErrorWith(err)
}
callClientError(ctx, c.opts.Hooks, twerr)
return nil, err
}
callClientResponseReceived(ctx, c.opts.Hooks)
return out, nil
}
// ===============
// Svc JSON Client
// ===============
type svcJSONClient struct {
client HTTPClient
urls [1]string
opts twirp.ClientOptions
}
// NewSvcJSONClient creates a JSON client that implements the Svc interface.
// It communicates using JSON and can be configured with a custom HTTPClient.
func NewSvcJSONClient(addr string, client HTTPClient, opts ...twirp.ClientOption) Svc {
if c, ok := client.(*http.Client); ok {
client = withoutRedirects(c)
}
clientOpts := twirp.ClientOptions{}
for _, o := range opts {
o(&clientOpts)
}
prefix := urlBase(addr) + SvcPathPrefix
urls := [1]string{
prefix + "Method",
}
return &svcJSONClient{
client: client,
urls: urls,
opts: clientOpts,
}
}
func (c *svcJSONClient) Method(ctx context.Context, in *Msg) (*Msg, error) {
ctx = ctxsetters.WithPackageName(ctx, "twirp.internal.twirptest.source_relative")
ctx = ctxsetters.WithServiceName(ctx, "Svc")
ctx = ctxsetters.WithMethodName(ctx, "Method")
out := new(Msg)
err := doJSONRequest(ctx, c.client, c.opts.Hooks, c.urls[0], in, out)
if err != nil {
twerr, ok := err.(twirp.Error)
if !ok {
twerr = twirp.InternalErrorWith(err)
}
callClientError(ctx, c.opts.Hooks, twerr)
return nil, err
}
callClientResponseReceived(ctx, c.opts.Hooks)
return out, nil
}
// ==================
// Svc Server Handler
// ==================
type svcServer struct {
Svc
hooks *twirp.ServerHooks
}
func NewSvcServer(svc Svc, hooks *twirp.ServerHooks) TwirpServer {
return &svcServer{
Svc: svc,
hooks: hooks,
}
}
// writeError writes an HTTP response with a valid Twirp error format, and triggers hooks.
// If err is not a twirp.Error, it will get wrapped with twirp.InternalErrorWith(err)
func (s *svcServer) writeError(ctx context.Context, resp http.ResponseWriter, err error) {
writeError(ctx, resp, err, s.hooks)
}
// SvcPathPrefix is used for all URL paths on a twirp Svc server.
// Requests are always: POST SvcPathPrefix/method
// It can be used in an HTTP mux to route twirp requests along with non-twirp requests on other routes.
const SvcPathPrefix = "/twirp/twirp.internal.twirptest.source_relative.Svc/"
func (s *svcServer) ServeHTTP(resp http.ResponseWriter, req *http.Request) {
ctx := req.Context()
ctx = ctxsetters.WithPackageName(ctx, "twirp.internal.twirptest.source_relative")
ctx = ctxsetters.WithServiceName(ctx, "Svc")
ctx = ctxsetters.WithResponseWriter(ctx, resp)
var err error
ctx, err = callRequestReceived(ctx, s.hooks)
if err != nil {
s.writeError(ctx, resp, err)
return
}
if req.Method != "POST" {
msg := fmt.Sprintf("unsupported method %q (only POST is allowed)", req.Method)
err = badRouteError(msg, req.Method, req.URL.Path)
s.writeError(ctx, resp, err)
return
}
switch req.URL.Path {
case "/twirp/twirp.internal.twirptest.source_relative.Svc/Method":
s.serveMethod(ctx, resp, req)
return
default:
msg := fmt.Sprintf("no handler for path %q", req.URL.Path)
err = badRouteError(msg, req.Method, req.URL.Path)
s.writeError(ctx, resp, err)
return
}
}
func (s *svcServer) serveMethod(ctx context.Context, resp http.ResponseWriter, req *http.Request) {
header := req.Header.Get("Content-Type")
i := strings.Index(header, ";")
if i == -1 {
i = len(header)
}
switch strings.TrimSpace(strings.ToLower(header[:i])) {
case "application/json":
s.serveMethodJSON(ctx, resp, req)
case "application/protobuf":
s.serveMethodProtobuf(ctx, resp, req)
default:
msg := fmt.Sprintf("unexpected Content-Type: %q", req.Header.Get("Content-Type"))
twerr := badRouteError(msg, req.Method, req.URL.Path)
s.writeError(ctx, resp, twerr)
}
}
func (s *svcServer) serveMethodJSON(ctx context.Context, resp http.ResponseWriter, req *http.Request) {
var err error
ctx = ctxsetters.WithMethodName(ctx, "Method")
ctx, err = callRequestRouted(ctx, s.hooks)
if err != nil {
s.writeError(ctx, resp, err)
return
}
reqContent := new(Msg)
unmarshaler := jsonpb.Unmarshaler{AllowUnknownFields: true}
if err = unmarshaler.Unmarshal(req.Body, reqContent); err != nil {
s.writeError(ctx, resp, malformedRequestError("the json request could not be decoded"))
return
}
// Call service method
var respContent *Msg
func() {
defer ensurePanicResponses(ctx, resp, s.hooks)
respContent, err = s.Svc.Method(ctx, reqContent)
}()
if err != nil {
s.writeError(ctx, resp, err)
return
}
if respContent == nil {
s.writeError(ctx, resp, twirp.InternalError("received a nil *Msg and nil error while calling Method. nil responses are not supported"))
return
}
ctx = callResponsePrepared(ctx, s.hooks)
var buf bytes.Buffer
marshaler := &jsonpb.Marshaler{OrigName: true}
if err = marshaler.Marshal(&buf, respContent); err != nil {
s.writeError(ctx, resp, wrapInternal(err, "failed to marshal json response"))
return
}
ctx = ctxsetters.WithStatusCode(ctx, http.StatusOK)
respBytes := buf.Bytes()
resp.Header().Set("Content-Type", "application/json")
resp.Header().Set("Content-Length", strconv.Itoa(len(respBytes)))
resp.WriteHeader(http.StatusOK)
if n, err := resp.Write(respBytes); err != nil {
msg := fmt.Sprintf("failed to write response, %d of %d bytes written: %s", n, len(respBytes), err.Error())
twerr := twirp.NewError(twirp.Unknown, msg)
callError(ctx, s.hooks, twerr)
}
callResponseSent(ctx, s.hooks)
}
func (s *svcServer) serveMethodProtobuf(ctx context.Context, resp http.ResponseWriter, req *http.Request) {
var err error
ctx = ctxsetters.WithMethodName(ctx, "Method")
ctx, err = callRequestRouted(ctx, s.hooks)
if err != nil {
s.writeError(ctx, resp, err)
return
}
buf, err := ioutil.ReadAll(req.Body)
if err != nil {
s.writeError(ctx, resp, wrapInternal(err, "failed to read request body"))
return
}
reqContent := new(Msg)
if err = proto.Unmarshal(buf, reqContent); err != nil {
s.writeError(ctx, resp, malformedRequestError("the protobuf request could not be decoded"))
return
}
// Call service method
var respContent *Msg
func() {
defer ensurePanicResponses(ctx, resp, s.hooks)
respContent, err = s.Svc.Method(ctx, reqContent)
}()
if err != nil {
s.writeError(ctx, resp, err)
return
}
if respContent == nil {
s.writeError(ctx, resp, twirp.InternalError("received a nil *Msg and nil error while calling Method. nil responses are not supported"))
return
}
ctx = callResponsePrepared(ctx, s.hooks)
respBytes, err := proto.Marshal(respContent)
if err != nil {
s.writeError(ctx, resp, wrapInternal(err, "failed to marshal proto response"))
return
}
ctx = ctxsetters.WithStatusCode(ctx, http.StatusOK)
resp.Header().Set("Content-Type", "application/protobuf")
resp.Header().Set("Content-Length", strconv.Itoa(len(respBytes)))
resp.WriteHeader(http.StatusOK)
if n, err := resp.Write(respBytes); err != nil {
msg := fmt.Sprintf("failed to write response, %d of %d bytes written: %s", n, len(respBytes), err.Error())
twerr := twirp.NewError(twirp.Unknown, msg)
callError(ctx, s.hooks, twerr)
}
callResponseSent(ctx, s.hooks)
}
func (s *svcServer) ServiceDescriptor() ([]byte, int) {
return twirpFileDescriptor0, 0
}
func (s *svcServer) ProtocGenTwirpVersion() string {
return "v5.10.1"
}
func (s *svcServer) PathPrefix() string {
return SvcPathPrefix
}
// =====
// Utils
// =====
// HTTPClient is the interface used by generated clients to send HTTP requests.
// It is fulfilled by *(net/http).Client, which is sufficient for most users.
// Users can provide their own implementation for special retry policies.
//
// HTTPClient implementations should not follow redirects. Redirects are
// automatically disabled if *(net/http).Client is passed to client
// constructors. See the withoutRedirects function in this file for more
// details.
type HTTPClient interface {
Do(req *http.Request) (*http.Response, error)
}
// TwirpServer is the interface generated server structs will support: they're
// HTTP handlers with additional methods for accessing metadata about the
// service. Those accessors are a low-level API for building reflection tools.
// Most people can think of TwirpServers as just http.Handlers.
type TwirpServer interface {
http.Handler
// ServiceDescriptor returns gzipped bytes describing the .proto file that
// this service was generated from. Once unzipped, the bytes can be
// unmarshalled as a
// github.com/golang/protobuf/protoc-gen-go/descriptor.FileDescriptorProto.
//
// The returned integer is the index of this particular service within that
// FileDescriptorProto's 'Service' slice of ServiceDescriptorProtos. This is a
// low-level field, expected to be used for reflection.
ServiceDescriptor() ([]byte, int)
// ProtocGenTwirpVersion is the semantic version string of the version of
// twirp used to generate this file.
ProtocGenTwirpVersion() string
// PathPrefix returns the HTTP URL path prefix for all methods handled by this
// service. This can be used with an HTTP mux to route twirp requests
// alongside non-twirp requests on one HTTP listener.
PathPrefix() string
}
// WriteError writes an HTTP response with a valid Twirp error format (code, msg, meta).
// Useful outside of the Twirp server (e.g. http middleware), but does not trigger hooks.
// If err is not a twirp.Error, it will get wrapped with twirp.InternalErrorWith(err)
func WriteError(resp http.ResponseWriter, err error) {
writeError(context.Background(), resp, err, nil)
}
// writeError writes Twirp errors in the response and triggers hooks.
func writeError(ctx context.Context, resp http.ResponseWriter, err error, hooks *twirp.ServerHooks) {
// Non-twirp errors are wrapped as Internal (default)
twerr, ok := err.(twirp.Error)
if !ok {
twerr = twirp.InternalErrorWith(err)
}
statusCode := twirp.ServerHTTPStatusFromErrorCode(twerr.Code())
ctx = ctxsetters.WithStatusCode(ctx, statusCode)
ctx = callError(ctx, hooks, twerr)
respBody := marshalErrorToJSON(twerr)
resp.Header().Set("Content-Type", "application/json") // Error responses are always JSON
resp.Header().Set("Content-Length", strconv.Itoa(len(respBody)))
resp.WriteHeader(statusCode) // set HTTP status code and send response
_, writeErr := resp.Write(respBody)
if writeErr != nil {
// We have three options here. We could log the error, call the Error
// hook, or just silently ignore the error.
//
// Logging is unacceptable because we don't have a user-controlled
// logger; writing out to stderr without permission is too rude.
//
// Calling the Error hook would confuse users: it would mean the Error
// hook got called twice for one request, which is likely to lead to
// duplicated log messages and metrics, no matter how well we document
// the behavior.
//
// Silently ignoring the error is our least-bad option. It's highly
// likely that the connection is broken and the original 'err' says
// so anyway.
_ = writeErr
}
callResponseSent(ctx, hooks)
}
// urlBase helps ensure that addr specifies a scheme. If it is unparsable
// as a URL, it returns addr unchanged.
func urlBase(addr string) string {
// If the addr specifies a scheme, use it. If not, default to
// http. If url.Parse fails on it, return it unchanged.
url, err := url.Parse(addr)
if err != nil {
return addr
}
if url.Scheme == "" {
url.Scheme = "http"
}
return url.String()
}
// getCustomHTTPReqHeaders retrieves a copy of any headers that are set in
// a context through the twirp.WithHTTPRequestHeaders function.
// If there are no headers set, or if they have the wrong type, nil is returned.
func getCustomHTTPReqHeaders(ctx context.Context) http.Header {
header, ok := twirp.HTTPRequestHeaders(ctx)
if !ok || header == nil {
return nil
}
copied := make(http.Header)
for k, vv := range header {
if vv == nil {
copied[k] = nil
continue
}
copied[k] = make([]string, len(vv))
copy(copied[k], vv)
}
return copied
}
// newRequest makes an http.Request from a client, adding common headers.
func newRequest(ctx context.Context, url string, reqBody io.Reader, contentType string) (*http.Request, error) {
req, err := http.NewRequest("POST", url, reqBody)
if err != nil {
return nil, err
}
req = req.WithContext(ctx)
if customHeader := getCustomHTTPReqHeaders(ctx); customHeader != nil {
req.Header = customHeader
}
req.Header.Set("Accept", contentType)
req.Header.Set("Content-Type", contentType)
req.Header.Set("Twirp-Version", "v5.10.1")
return req, nil
}
// JSON serialization for errors
type twerrJSON struct {
Code string `json:"code"`
Msg string `json:"msg"`
Meta map[string]string `json:"meta,omitempty"`
}
// marshalErrorToJSON returns JSON from a twirp.Error, that can be used as HTTP error response body.
// If serialization fails, it will use a descriptive Internal error instead.
func marshalErrorToJSON(twerr twirp.Error) []byte {
// make sure that msg is not too large
msg := twerr.Msg()
if len(msg) > 1e6 {
msg = msg[:1e6]
}
tj := twerrJSON{
Code: string(twerr.Code()),
Msg: msg,
Meta: twerr.MetaMap(),
}
buf, err := json.Marshal(&tj)
if err != nil {
buf = []byte("{\"type\": \"" + twirp.Internal + "\", \"msg\": \"There was an error but it could not be serialized into JSON\"}") // fallback
}
return buf
}
// errorFromResponse builds a twirp.Error from a non-200 HTTP response.
// If the response has a valid serialized Twirp error, then it's returned.
// If not, the response status code is used to generate a similar twirp
// error. See twirpErrorFromIntermediary for more info on intermediary errors.
func errorFromResponse(resp *http.Response) twirp.Error {
statusCode := resp.StatusCode
statusText := http.StatusText(statusCode)
if isHTTPRedirect(statusCode) {
// Unexpected redirect: it must be an error from an intermediary.
// Twirp clients don't follow redirects automatically, Twirp only handles
// POST requests, redirects should only happen on GET and HEAD requests.
location := resp.Header.Get("Location")
msg := fmt.Sprintf("unexpected HTTP status code %d %q received, Location=%q", statusCode, statusText, location)
return twirpErrorFromIntermediary(statusCode, msg, location)
}
respBodyBytes, err := ioutil.ReadAll(resp.Body)
if err != nil {
return wrapInternal(err, "failed to read server error response body")
}
var tj twerrJSON
dec := json.NewDecoder(bytes.NewReader(respBodyBytes))
dec.DisallowUnknownFields()
if err := dec.Decode(&tj); err != nil || tj.Code == "" {
// Invalid JSON response; it must be an error from an intermediary.
msg := fmt.Sprintf("Error from intermediary with HTTP status code %d %q", statusCode, statusText)
return twirpErrorFromIntermediary(statusCode, msg, string(respBodyBytes))
}
errorCode := twirp.ErrorCode(tj.Code)
if !twirp.IsValidErrorCode(errorCode) {
msg := "invalid type returned from server error response: " + tj.Code
return twirp.InternalError(msg)
}
twerr := twirp.NewError(errorCode, tj.Msg)
for k, v := range tj.Meta {
twerr = twerr.WithMeta(k, v)
}
return twerr
}
// twirpErrorFromIntermediary maps HTTP errors from non-twirp sources to twirp errors.
// The mapping is similar to gRPC: https://github.com/grpc/grpc/blob/master/doc/http-grpc-status-mapping.md.
// Returned twirp Errors have some additional metadata for inspection.
func twirpErrorFromIntermediary(status int, msg string, bodyOrLocation string) twirp.Error {
var code twirp.ErrorCode
if isHTTPRedirect(status) { // 3xx
code = twirp.Internal
} else {
switch status {
case 400: // Bad Request
code = twirp.Internal
case 401: // Unauthorized
code = twirp.Unauthenticated
case 403: // Forbidden
code = twirp.PermissionDenied
case 404: // Not Found
code = twirp.BadRoute
case 429, 502, 503, 504: // Too Many Requests, Bad Gateway, Service Unavailable, Gateway Timeout
code = twirp.Unavailable
default: // All other codes
code = twirp.Unknown
}
}
twerr := twirp.NewError(code, msg)
twerr = twerr.WithMeta("http_error_from_intermediary", "true") // to easily know if this error was from intermediary
twerr = twerr.WithMeta("status_code", strconv.Itoa(status))
if isHTTPRedirect(status) {
twerr = twerr.WithMeta("location", bodyOrLocation)
} else {
twerr = twerr.WithMeta("body", bodyOrLocation)
}
return twerr
}
func isHTTPRedirect(status int) bool {
return status >= 300 && status <= 399
}
// wrapInternal wraps an error with a prefix as an Internal error.
// The original error cause is accessible by github.com/pkg/errors.Cause.
func wrapInternal(err error, prefix string) twirp.Error {
return twirp.InternalErrorWith(&wrappedError{prefix: prefix, cause: err})
}
type wrappedError struct {
prefix string
cause error
}
func (e *wrappedError) Cause() error { return e.cause }
func (e *wrappedError) Error() string { return e.prefix + ": " + e.cause.Error() }
// ensurePanicResponses makes sure that rpc methods causing a panic still result in a Twirp Internal
// error response (status 500), and error hooks are properly called with the panic wrapped as an error.
// The panic is re-raised so it can be handled normally with middleware.
func ensurePanicResponses(ctx context.Context, resp http.ResponseWriter, hooks *twirp.ServerHooks) {
if r := recover(); r != nil {
// Wrap the panic as an error so it can be passed to error hooks.
// The original error is accessible from error hooks, but not visible in the response.
err := errFromPanic(r)
twerr := &internalWithCause{msg: "Internal service panic", cause: err}
// Actually write the error
writeError(ctx, resp, twerr, hooks)
// If possible, flush the error to the wire.
f, ok := resp.(http.Flusher)
if ok {
f.Flush()
}
panic(r)
}
}
// errFromPanic returns the typed error if the recovered panic is an error, otherwise formats as error.
func errFromPanic(p interface{}) error {
if err, ok := p.(error); ok {
return err
}
return fmt.Errorf("panic: %v", p)
}
// internalWithCause is a Twirp Internal error wrapping an original error cause, accessible
// by github.com/pkg/errors.Cause, but the original error message is not exposed on Msg().
type internalWithCause struct {
msg string
cause error
}
func (e *internalWithCause) Cause() error { return e.cause }
func (e *internalWithCause) Error() string { return e.msg + ": " + e.cause.Error() }
func (e *internalWithCause) Code() twirp.ErrorCode { return twirp.Internal }
func (e *internalWithCause) Msg() string { return e.msg }
func (e *internalWithCause) Meta(key string) string { return "" }
func (e *internalWithCause) MetaMap() map[string]string { return nil }
func (e *internalWithCause) WithMeta(key string, val string) twirp.Error { return e }
// malformedRequestError is used when the twirp server cannot unmarshal a request
func malformedRequestError(msg string) twirp.Error {
return twirp.NewError(twirp.Malformed, msg)
}
// badRouteError is used when the twirp server cannot route a request
func badRouteError(msg string, method, url string) twirp.Error {
err := twirp.NewError(twirp.BadRoute, msg)
err = err.WithMeta("twirp_invalid_route", method+" "+url)
return err
}
// withoutRedirects makes sure that the POST request can not be redirected.
// The standard library will, by default, redirect requests (including POSTs) if it gets a 302 or
// 303 response, and also 301s in go1.8. It redirects by making a second request, changing the
// method to GET and removing the body. This produces very confusing error messages, so instead we
// set a redirect policy that always errors. This stops Go from executing the redirect.
//
// We have to be a little careful in case the user-provided http.Client has its own CheckRedirect
// policy - if so, we'll run through that policy first.
//
// Because this requires modifying the http.Client, we make a new copy of the client and return it.
func withoutRedirects(in *http.Client) *http.Client {
copy := *in
copy.CheckRedirect = func(req *http.Request, via []*http.Request) error {
if in.CheckRedirect != nil {
// Run the input's redirect if it exists, in case it has side effects, but ignore any error it
// returns, since we want to use ErrUseLastResponse.
err := in.CheckRedirect(req, via)
_ = err // Silly, but this makes sure generated code passes errcheck -blank, which some people use.
}
return http.ErrUseLastResponse
}
return ©
}
// doProtobufRequest makes a Protobuf request to the remote Twirp service.
func doProtobufRequest(ctx context.Context, client HTTPClient, hooks *twirp.ClientHooks, url string, in, out proto.Message) (err error) {
reqBodyBytes, err := proto.Marshal(in)
if err != nil {
return wrapInternal(err, "failed to marshal proto request")
}
reqBody := bytes.NewBuffer(reqBodyBytes)
if err = ctx.Err(); err != nil {
return wrapInternal(err, "aborted because context was done")
}
req, err := newRequest(ctx, url, reqBody, "application/protobuf")
if err != nil {
return wrapInternal(err, "could not build request")
}
ctx, err = callClientRequestPrepared(ctx, hooks, req)
if err != nil {
return err
}
req = req.WithContext(ctx)
resp, err := client.Do(req)
if err != nil {
return wrapInternal(err, "failed to do request")
}
defer func() {
cerr := resp.Body.Close()
if err == nil && cerr != nil {
err = wrapInternal(cerr, "failed to close response body")
}
}()
if err = ctx.Err(); err != nil {
return wrapInternal(err, "aborted because context was done")
}
if resp.StatusCode != 200 {
return errorFromResponse(resp)
}
respBodyBytes, err := ioutil.ReadAll(resp.Body)
if err != nil {
return wrapInternal(err, "failed to read response body")
}
if err = ctx.Err(); err != nil {
return wrapInternal(err, "aborted because context was done")
}
if err = proto.Unmarshal(respBodyBytes, out); err != nil {
return wrapInternal(err, "failed to unmarshal proto response")
}
return nil
}
// doJSONRequest makes a JSON request to the remote Twirp service.
func doJSONRequest(ctx context.Context, client HTTPClient, hooks *twirp.ClientHooks, url string, in, out proto.Message) (err error) {
reqBody := bytes.NewBuffer(nil)
marshaler := &jsonpb.Marshaler{OrigName: true}
if err = marshaler.Marshal(reqBody, in); err != nil {
return wrapInternal(err, "failed to marshal json request")
}
if err = ctx.Err(); err != nil {
return wrapInternal(err, "aborted because context was done")
}
req, err := newRequest(ctx, url, reqBody, "application/json")
if err != nil {
return wrapInternal(err, "could not build request")
}
ctx, err = callClientRequestPrepared(ctx, hooks, req)
if err != nil {
return err
}
req = req.WithContext(ctx)
resp, err := client.Do(req)
if err != nil {
return wrapInternal(err, "failed to do request")
}
defer func() {
cerr := resp.Body.Close()
if err == nil && cerr != nil {
err = wrapInternal(cerr, "failed to close response body")
}
}()
if err = ctx.Err(); err != nil {
return wrapInternal(err, "aborted because context was done")
}
if resp.StatusCode != 200 {
return errorFromResponse(resp)
}
unmarshaler := jsonpb.Unmarshaler{AllowUnknownFields: true}
if err = unmarshaler.Unmarshal(resp.Body, out); err != nil {
return wrapInternal(err, "failed to unmarshal json response")
}
if err = ctx.Err(); err != nil {
return wrapInternal(err, "aborted because context was done")
}
return nil
}
// Call twirp.ServerHooks.RequestReceived if the hook is available
func callRequestReceived(ctx context.Context, h *twirp.ServerHooks) (context.Context, error) {
if h == nil || h.RequestReceived == nil {
return ctx, nil
}
return h.RequestReceived(ctx)
}
// Call twirp.ServerHooks.RequestRouted if the hook is available
func callRequestRouted(ctx context.Context, h *twirp.ServerHooks) (context.Context, error) {
if h == nil || h.RequestRouted == nil {
return ctx, nil
}
return h.RequestRouted(ctx)
}
// Call twirp.ServerHooks.ResponsePrepared if the hook is available
func callResponsePrepared(ctx context.Context, h *twirp.ServerHooks) context.Context {
if h == nil || h.ResponsePrepared == nil {
return ctx
}
return h.ResponsePrepared(ctx)
}
// Call twirp.ServerHooks.ResponseSent if the hook is available
func callResponseSent(ctx context.Context, h *twirp.ServerHooks) {
if h == nil || h.ResponseSent == nil {
return
}
h.ResponseSent(ctx)
}
// Call twirp.ServerHooks.Error if the hook is available
func callError(ctx context.Context, h *twirp.ServerHooks, err twirp.Error) context.Context {
if h == nil || h.Error == nil {
return ctx
}
return h.Error(ctx, err)
}
func callClientResponseReceived(ctx context.Context, h *twirp.ClientHooks) {
if h == nil || h.ResponseReceived == nil {
return
}
h.ResponseReceived(ctx)
}
func callClientRequestPrepared(ctx context.Context, h *twirp.ClientHooks, req *http.Request) (context.Context, error) {
if h == nil || h.RequestPrepared == nil {
return ctx, nil
}
return h.RequestPrepared(ctx, req)
}
func callClientError(ctx context.Context, h *twirp.ClientHooks, err twirp.Error) {
if h == nil || h.Error == nil {
return
}
h.Error(ctx, err)
}
var twirpFileDescriptor0 = []byte{
// 151 bytes of a gzipped FileDescriptorProto
0x1f, 0x8b, 0x08, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02, 0xff, 0xe2, 0x12, 0x2d, 0xce, 0x2f, 0x2d,
0x4a, 0x4e, 0x8d, 0x2f, 0x4a, 0xcd, 0x49, 0x2c, 0xc9, 0x2c, 0x4b, 0xd5, 0x2b, 0x28, 0xca, 0x2f,
0xc9, 0x17, 0xd2, 0x28, 0x29, 0xcf, 0x2c, 0x2a, 0xd0, 0xcb, 0xcc, 0x2b, 0x49, 0x2d, 0xca, 0x4b,
0xcc, 0xd1, 0x03, 0x73, 0x4b, 0x52, 0x8b, 0x4b, 0xf4, 0xd0, 0xd4, 0x2b, 0xb1, 0x72, 0x31, 0xfb,
0x16, 0xa7, 0x1b, 0xe5, 0x72, 0x31, 0x07, 0x97, 0x25, 0x0b, 0xa5, 0x71, 0xb1, 0xf9, 0xa6, 0x96,
0x64, 0xe4, 0xa7, 0x08, 0xe9, 0xea, 0x11, 0x6b, 0x84, 0x9e, 0x6f, 0x71, 0xba, 0x14, 0x69, 0xca,
0x9d, 0xec, 0xa2, 0x6c, 0xd2, 0x33, 0x4b, 0x32, 0x4a, 0x93, 0xf4, 0x92, 0xf3, 0x73, 0xf5, 0x4b,
0xca, 0x33, 0x4b, 0x92, 0x33, 0x4a, 0xca, 0xf4, 0xc1, 0x9a, 0xf4, 0x61, 0x66, 0xe8, 0xc3, 0xcd,
0xd0, 0x47, 0x33, 0x23, 0x89, 0x0d, 0xec, 0x4d, 0x63, 0x40, 0x00, 0x00, 0x00, 0xff, 0xff, 0xbc,
0x3b, 0x72, 0xb8, 0xff, 0x00, 0x00, 0x00,
}