forked from k3s-io/kubernetes
-
Notifications
You must be signed in to change notification settings - Fork 0
/
request.go
1245 lines (1134 loc) · 38.9 KB
/
request.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
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
/*
Copyright 2014 The Kubernetes 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 rest
import (
"bytes"
"context"
"encoding/hex"
"fmt"
"io"
"io/ioutil"
"mime"
"net/http"
"net/url"
"path"
"reflect"
"strconv"
"strings"
"time"
"github.com/golang/glog"
"k8s.io/apimachinery/pkg/api/errors"
metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
"k8s.io/apimachinery/pkg/fields"
"k8s.io/apimachinery/pkg/labels"
"k8s.io/apimachinery/pkg/runtime"
"k8s.io/apimachinery/pkg/runtime/schema"
"k8s.io/apimachinery/pkg/runtime/serializer/streaming"
"k8s.io/apimachinery/pkg/util/net"
"k8s.io/apimachinery/pkg/util/sets"
"k8s.io/apimachinery/pkg/watch"
"k8s.io/client-go/pkg/api/v1"
restclientwatch "k8s.io/client-go/rest/watch"
"k8s.io/client-go/tools/metrics"
"k8s.io/client-go/util/flowcontrol"
)
var (
// specialParams lists parameters that are handled specially and which users of Request
// are therefore not allowed to set manually.
specialParams = sets.NewString("timeout")
// longThrottleLatency defines threshold for logging requests. All requests being
// throttle for more than longThrottleLatency will be logged.
longThrottleLatency = 50 * time.Millisecond
)
// HTTPClient is an interface for testing a request object.
type HTTPClient interface {
Do(req *http.Request) (*http.Response, error)
}
// ResponseWrapper is an interface for getting a response.
// The response may be either accessed as a raw data (the whole output is put into memory) or as a stream.
type ResponseWrapper interface {
DoRaw() ([]byte, error)
Stream() (io.ReadCloser, error)
}
// RequestConstructionError is returned when there's an error assembling a request.
type RequestConstructionError struct {
Err error
}
// Error returns a textual description of 'r'.
func (r *RequestConstructionError) Error() string {
return fmt.Sprintf("request construction error: '%v'", r.Err)
}
// Request allows for building up a request to a server in a chained fashion.
// Any errors are stored until the end of your call, so you only have to
// check once.
type Request struct {
// required
client HTTPClient
verb string
baseURL *url.URL
content ContentConfig
serializers Serializers
// generic components accessible via method setters
pathPrefix string
subpath string
params url.Values
headers http.Header
// structural elements of the request that are part of the Kubernetes API conventions
namespace string
namespaceSet bool
resource string
resourceName string
subresource string
timeout time.Duration
// output
err error
body io.Reader
// This is only used for per-request timeouts, deadlines, and cancellations.
ctx context.Context
backoffMgr BackoffManager
throttle flowcontrol.RateLimiter
}
// NewRequest creates a new request helper object for accessing runtime.Objects on a server.
func NewRequest(client HTTPClient, verb string, baseURL *url.URL, versionedAPIPath string, content ContentConfig, serializers Serializers, backoff BackoffManager, throttle flowcontrol.RateLimiter) *Request {
if backoff == nil {
glog.V(2).Infof("Not implementing request backoff strategy.")
backoff = &NoBackoff{}
}
pathPrefix := "/"
if baseURL != nil {
pathPrefix = path.Join(pathPrefix, baseURL.Path)
}
r := &Request{
client: client,
verb: verb,
baseURL: baseURL,
pathPrefix: path.Join(pathPrefix, versionedAPIPath),
content: content,
serializers: serializers,
backoffMgr: backoff,
throttle: throttle,
}
switch {
case len(content.AcceptContentTypes) > 0:
r.SetHeader("Accept", content.AcceptContentTypes)
case len(content.ContentType) > 0:
r.SetHeader("Accept", content.ContentType+", */*")
}
return r
}
// Prefix adds segments to the relative beginning to the request path. These
// items will be placed before the optional Namespace, Resource, or Name sections.
// Setting AbsPath will clear any previously set Prefix segments
func (r *Request) Prefix(segments ...string) *Request {
if r.err != nil {
return r
}
r.pathPrefix = path.Join(r.pathPrefix, path.Join(segments...))
return r
}
// Suffix appends segments to the end of the path. These items will be placed after the prefix and optional
// Namespace, Resource, or Name sections.
func (r *Request) Suffix(segments ...string) *Request {
if r.err != nil {
return r
}
r.subpath = path.Join(r.subpath, path.Join(segments...))
return r
}
// Resource sets the resource to access (<resource>/[ns/<namespace>/]<name>)
func (r *Request) Resource(resource string) *Request {
if r.err != nil {
return r
}
if len(r.resource) != 0 {
r.err = fmt.Errorf("resource already set to %q, cannot change to %q", r.resource, resource)
return r
}
if msgs := IsValidPathSegmentName(resource); len(msgs) != 0 {
r.err = fmt.Errorf("invalid resource %q: %v", resource, msgs)
return r
}
r.resource = resource
return r
}
// SubResource sets a sub-resource path which can be multiple segments segment after the resource
// name but before the suffix.
func (r *Request) SubResource(subresources ...string) *Request {
if r.err != nil {
return r
}
subresource := path.Join(subresources...)
if len(r.subresource) != 0 {
r.err = fmt.Errorf("subresource already set to %q, cannot change to %q", r.resource, subresource)
return r
}
for _, s := range subresources {
if msgs := IsValidPathSegmentName(s); len(msgs) != 0 {
r.err = fmt.Errorf("invalid subresource %q: %v", s, msgs)
return r
}
}
r.subresource = subresource
return r
}
// Name sets the name of a resource to access (<resource>/[ns/<namespace>/]<name>)
func (r *Request) Name(resourceName string) *Request {
if r.err != nil {
return r
}
if len(resourceName) == 0 {
r.err = fmt.Errorf("resource name may not be empty")
return r
}
if len(r.resourceName) != 0 {
r.err = fmt.Errorf("resource name already set to %q, cannot change to %q", r.resourceName, resourceName)
return r
}
if msgs := IsValidPathSegmentName(resourceName); len(msgs) != 0 {
r.err = fmt.Errorf("invalid resource name %q: %v", resourceName, msgs)
return r
}
r.resourceName = resourceName
return r
}
// Namespace applies the namespace scope to a request (<resource>/[ns/<namespace>/]<name>)
func (r *Request) Namespace(namespace string) *Request {
if r.err != nil {
return r
}
if r.namespaceSet {
r.err = fmt.Errorf("namespace already set to %q, cannot change to %q", r.namespace, namespace)
return r
}
if msgs := IsValidPathSegmentName(namespace); len(msgs) != 0 {
r.err = fmt.Errorf("invalid namespace %q: %v", namespace, msgs)
return r
}
r.namespaceSet = true
r.namespace = namespace
return r
}
// NamespaceIfScoped is a convenience function to set a namespace if scoped is true
func (r *Request) NamespaceIfScoped(namespace string, scoped bool) *Request {
if scoped {
return r.Namespace(namespace)
}
return r
}
// AbsPath overwrites an existing path with the segments provided. Trailing slashes are preserved
// when a single segment is passed.
func (r *Request) AbsPath(segments ...string) *Request {
if r.err != nil {
return r
}
r.pathPrefix = path.Join(r.baseURL.Path, path.Join(segments...))
if len(segments) == 1 && (len(r.baseURL.Path) > 1 || len(segments[0]) > 1) && strings.HasSuffix(segments[0], "/") {
// preserve any trailing slashes for legacy behavior
r.pathPrefix += "/"
}
return r
}
// RequestURI overwrites existing path and parameters with the value of the provided server relative
// URI. Some parameters (those in specialParameters) cannot be overwritten.
func (r *Request) RequestURI(uri string) *Request {
if r.err != nil {
return r
}
locator, err := url.Parse(uri)
if err != nil {
r.err = err
return r
}
r.pathPrefix = locator.Path
if len(locator.Query()) > 0 {
if r.params == nil {
r.params = make(url.Values)
}
for k, v := range locator.Query() {
r.params[k] = v
}
}
return r
}
const (
// A constant that clients can use to refer in a field selector to the object name field.
// Will be automatically emitted as the correct name for the API version.
nodeUnschedulable = "spec.unschedulable"
objectNameField = "metadata.name"
podHost = "spec.nodeName"
podStatus = "status.phase"
secretType = "type"
eventReason = "reason"
eventSource = "source"
eventType = "type"
eventInvolvedKind = "involvedObject.kind"
eventInvolvedNamespace = "involvedObject.namespace"
eventInvolvedName = "involvedObject.name"
eventInvolvedUID = "involvedObject.uid"
eventInvolvedAPIVersion = "involvedObject.apiVersion"
eventInvolvedResourceVersion = "involvedObject.resourceVersion"
eventInvolvedFieldPath = "involvedObject.fieldPath"
)
type clientFieldNameToAPIVersionFieldName map[string]string
func (c clientFieldNameToAPIVersionFieldName) filterField(field, value string) (newField, newValue string, err error) {
newFieldName, ok := c[field]
if !ok {
return "", "", fmt.Errorf("%v - %v - no field mapping defined", field, value)
}
return newFieldName, value, nil
}
type resourceTypeToFieldMapping map[string]clientFieldNameToAPIVersionFieldName
func (r resourceTypeToFieldMapping) filterField(resourceType, field, value string) (newField, newValue string, err error) {
fMapping, ok := r[resourceType]
if !ok {
return "", "", fmt.Errorf("%v - %v - %v - no field mapping defined", resourceType, field, value)
}
return fMapping.filterField(field, value)
}
type versionToResourceToFieldMapping map[schema.GroupVersion]resourceTypeToFieldMapping
// filterField transforms the given field/value selector for the given groupVersion and resource
func (v versionToResourceToFieldMapping) filterField(groupVersion *schema.GroupVersion, resourceType, field, value string) (newField, newValue string, err error) {
rMapping, ok := v[*groupVersion]
if !ok {
// no groupVersion overrides registered, default to identity mapping
return field, value, nil
}
newField, newValue, err = rMapping.filterField(resourceType, field, value)
if err != nil {
// no groupVersionResource overrides registered, default to identity mapping
return field, value, nil
}
return newField, newValue, nil
}
var fieldMappings = versionToResourceToFieldMapping{
v1.SchemeGroupVersion: resourceTypeToFieldMapping{
"nodes": clientFieldNameToAPIVersionFieldName{
objectNameField: objectNameField,
nodeUnschedulable: nodeUnschedulable,
},
"pods": clientFieldNameToAPIVersionFieldName{
objectNameField: objectNameField,
podHost: podHost,
podStatus: podStatus,
},
"secrets": clientFieldNameToAPIVersionFieldName{
secretType: secretType,
},
"serviceAccounts": clientFieldNameToAPIVersionFieldName{
objectNameField: objectNameField,
},
"endpoints": clientFieldNameToAPIVersionFieldName{
objectNameField: objectNameField,
},
"events": clientFieldNameToAPIVersionFieldName{
objectNameField: objectNameField,
eventReason: eventReason,
eventSource: eventSource,
eventType: eventType,
eventInvolvedKind: eventInvolvedKind,
eventInvolvedNamespace: eventInvolvedNamespace,
eventInvolvedName: eventInvolvedName,
eventInvolvedUID: eventInvolvedUID,
eventInvolvedAPIVersion: eventInvolvedAPIVersion,
eventInvolvedResourceVersion: eventInvolvedResourceVersion,
eventInvolvedFieldPath: eventInvolvedFieldPath,
},
},
}
// FieldsSelectorParam adds the given selector as a query parameter with the name paramName.
func (r *Request) FieldsSelectorParam(s fields.Selector) *Request {
if r.err != nil {
return r
}
if s == nil {
return r
}
if s.Empty() {
return r
}
s2, err := s.Transform(func(field, value string) (newField, newValue string, err error) {
return fieldMappings.filterField(r.content.GroupVersion, r.resource, field, value)
})
if err != nil {
r.err = err
return r
}
return r.setParam(metav1.FieldSelectorQueryParam(r.content.GroupVersion.String()), s2.String())
}
// LabelsSelectorParam adds the given selector as a query parameter
func (r *Request) LabelsSelectorParam(s labels.Selector) *Request {
if r.err != nil {
return r
}
if s == nil {
return r
}
if s.Empty() {
return r
}
return r.setParam(metav1.LabelSelectorQueryParam(r.content.GroupVersion.String()), s.String())
}
// UintParam creates a query parameter with the given value.
func (r *Request) UintParam(paramName string, u uint64) *Request {
if r.err != nil {
return r
}
return r.setParam(paramName, strconv.FormatUint(u, 10))
}
// Param creates a query parameter with the given string value.
func (r *Request) Param(paramName, s string) *Request {
if r.err != nil {
return r
}
return r.setParam(paramName, s)
}
// VersionedParams will take the provided object, serialize it to a map[string][]string using the
// implicit RESTClient API version and the default parameter codec, and then add those as parameters
// to the request. Use this to provide versioned query parameters from client libraries.
func (r *Request) VersionedParams(obj runtime.Object, codec runtime.ParameterCodec) *Request {
if r.err != nil {
return r
}
params, err := codec.EncodeParameters(obj, *r.content.GroupVersion)
if err != nil {
r.err = err
return r
}
for k, v := range params {
for _, value := range v {
// TODO: Move it to setParam method, once we get rid of
// FieldSelectorParam & LabelSelectorParam methods.
if k == metav1.LabelSelectorQueryParam(r.content.GroupVersion.String()) && value == "" {
// Don't set an empty selector for backward compatibility.
// Since there is no way to get the difference between empty
// and unspecified string, we don't set it to avoid having
// labelSelector= param in every request.
continue
}
if k == metav1.FieldSelectorQueryParam(r.content.GroupVersion.String()) {
if len(value) == 0 {
// Don't set an empty selector for backward compatibility.
// Since there is no way to get the difference between empty
// and unspecified string, we don't set it to avoid having
// fieldSelector= param in every request.
continue
}
// TODO: Filtering should be handled somewhere else.
selector, err := fields.ParseSelector(value)
if err != nil {
r.err = fmt.Errorf("unparsable field selector: %v", err)
return r
}
filteredSelector, err := selector.Transform(
func(field, value string) (newField, newValue string, err error) {
return fieldMappings.filterField(r.content.GroupVersion, r.resource, field, value)
})
if err != nil {
r.err = fmt.Errorf("untransformable field selector: %v", err)
return r
}
value = filteredSelector.String()
}
r.setParam(k, value)
}
}
return r
}
func (r *Request) setParam(paramName, value string) *Request {
if specialParams.Has(paramName) {
r.err = fmt.Errorf("must set %v through the corresponding function, not directly.", paramName)
return r
}
if r.params == nil {
r.params = make(url.Values)
}
r.params[paramName] = append(r.params[paramName], value)
return r
}
func (r *Request) SetHeader(key, value string) *Request {
if r.headers == nil {
r.headers = http.Header{}
}
r.headers.Set(key, value)
return r
}
// Timeout makes the request use the given duration as a timeout. Sets the "timeout"
// parameter.
func (r *Request) Timeout(d time.Duration) *Request {
if r.err != nil {
return r
}
r.timeout = d
return r
}
// Body makes the request use obj as the body. Optional.
// If obj is a string, try to read a file of that name.
// If obj is a []byte, send it directly.
// If obj is an io.Reader, use it directly.
// If obj is a runtime.Object, marshal it correctly, and set Content-Type header.
// If obj is a runtime.Object and nil, do nothing.
// Otherwise, set an error.
func (r *Request) Body(obj interface{}) *Request {
if r.err != nil {
return r
}
switch t := obj.(type) {
case string:
data, err := ioutil.ReadFile(t)
if err != nil {
r.err = err
return r
}
glogBody("Request Body", data)
r.body = bytes.NewReader(data)
case []byte:
glogBody("Request Body", t)
r.body = bytes.NewReader(t)
case io.Reader:
r.body = t
case runtime.Object:
// callers may pass typed interface pointers, therefore we must check nil with reflection
if reflect.ValueOf(t).IsNil() {
return r
}
data, err := runtime.Encode(r.serializers.Encoder, t)
if err != nil {
r.err = err
return r
}
glogBody("Request Body", data)
r.body = bytes.NewReader(data)
r.SetHeader("Content-Type", r.content.ContentType)
default:
r.err = fmt.Errorf("unknown type used for body: %+v", obj)
}
return r
}
// Context adds a context to the request. Contexts are only used for
// timeouts, deadlines, and cancellations.
func (r *Request) Context(ctx context.Context) *Request {
r.ctx = ctx
return r
}
// URL returns the current working URL.
func (r *Request) URL() *url.URL {
p := r.pathPrefix
if r.namespaceSet && len(r.namespace) > 0 {
p = path.Join(p, "namespaces", r.namespace)
}
if len(r.resource) != 0 {
p = path.Join(p, strings.ToLower(r.resource))
}
// Join trims trailing slashes, so preserve r.pathPrefix's trailing slash for backwards compatibility if nothing was changed
if len(r.resourceName) != 0 || len(r.subpath) != 0 || len(r.subresource) != 0 {
p = path.Join(p, r.resourceName, r.subresource, r.subpath)
}
finalURL := &url.URL{}
if r.baseURL != nil {
*finalURL = *r.baseURL
}
finalURL.Path = p
query := url.Values{}
for key, values := range r.params {
for _, value := range values {
query.Add(key, value)
}
}
// timeout is handled specially here.
if r.timeout != 0 {
query.Set("timeout", r.timeout.String())
}
finalURL.RawQuery = query.Encode()
return finalURL
}
// finalURLTemplate is similar to URL(), but will make all specific parameter values equal
// - instead of name or namespace, "{name}" and "{namespace}" will be used, and all query
// parameters will be reset. This creates a copy of the request so as not to change the
// underyling object. This means some useful request info (like the types of field
// selectors in use) will be lost.
// TODO: preserve field selector keys
func (r Request) finalURLTemplate() url.URL {
if len(r.resourceName) != 0 {
r.resourceName = "{name}"
}
if r.namespaceSet && len(r.namespace) != 0 {
r.namespace = "{namespace}"
}
newParams := url.Values{}
v := []string{"{value}"}
for k := range r.params {
newParams[k] = v
}
r.params = newParams
url := r.URL()
return *url
}
func (r *Request) tryThrottle() {
now := time.Now()
if r.throttle != nil {
r.throttle.Accept()
}
if latency := time.Since(now); latency > longThrottleLatency {
glog.V(4).Infof("Throttling request took %v, request: %s:%s", latency, r.verb, r.URL().String())
}
}
// Watch attempts to begin watching the requested location.
// Returns a watch.Interface, or an error.
func (r *Request) Watch() (watch.Interface, error) {
// We specifically don't want to rate limit watches, so we
// don't use r.throttle here.
if r.err != nil {
return nil, r.err
}
if r.serializers.Framer == nil {
return nil, fmt.Errorf("watching resources is not possible with this client (content-type: %s)", r.content.ContentType)
}
url := r.URL().String()
req, err := http.NewRequest(r.verb, url, r.body)
if err != nil {
return nil, err
}
if r.ctx != nil {
req = req.WithContext(r.ctx)
}
req.Header = r.headers
client := r.client
if client == nil {
client = http.DefaultClient
}
r.backoffMgr.Sleep(r.backoffMgr.CalculateBackoff(r.URL()))
resp, err := client.Do(req)
updateURLMetrics(r, resp, err)
if r.baseURL != nil {
if err != nil {
r.backoffMgr.UpdateBackoff(r.baseURL, err, 0)
} else {
r.backoffMgr.UpdateBackoff(r.baseURL, err, resp.StatusCode)
}
}
if err != nil {
// The watch stream mechanism handles many common partial data errors, so closed
// connections can be retried in many cases.
if net.IsProbableEOF(err) {
return watch.NewEmptyWatch(), nil
}
return nil, err
}
if resp.StatusCode != http.StatusOK {
defer resp.Body.Close()
if result := r.transformResponse(resp, req); result.err != nil {
return nil, result.err
}
return nil, fmt.Errorf("for request '%+v', got status: %v", url, resp.StatusCode)
}
framer := r.serializers.Framer.NewFrameReader(resp.Body)
decoder := streaming.NewDecoder(framer, r.serializers.StreamingSerializer)
return watch.NewStreamWatcher(restclientwatch.NewDecoder(decoder, r.serializers.Decoder)), nil
}
// updateURLMetrics is a convenience function for pushing metrics.
// It also handles corner cases for incomplete/invalid request data.
func updateURLMetrics(req *Request, resp *http.Response, err error) {
url := "none"
if req.baseURL != nil {
url = req.baseURL.Host
}
// Errors can be arbitrary strings. Unbound label cardinality is not suitable for a metric
// system so we just report them as `<error>`.
if err != nil {
metrics.RequestResult.Increment("<error>", req.verb, url)
} else {
//Metrics for failure codes
metrics.RequestResult.Increment(strconv.Itoa(resp.StatusCode), req.verb, url)
}
}
// Stream formats and executes the request, and offers streaming of the response.
// Returns io.ReadCloser which could be used for streaming of the response, or an error
// Any non-2xx http status code causes an error. If we get a non-2xx code, we try to convert the body into an APIStatus object.
// If we can, we return that as an error. Otherwise, we create an error that lists the http status and the content of the response.
func (r *Request) Stream() (io.ReadCloser, error) {
if r.err != nil {
return nil, r.err
}
r.tryThrottle()
url := r.URL().String()
req, err := http.NewRequest(r.verb, url, nil)
if err != nil {
return nil, err
}
if r.ctx != nil {
req = req.WithContext(r.ctx)
}
req.Header = r.headers
client := r.client
if client == nil {
client = http.DefaultClient
}
r.backoffMgr.Sleep(r.backoffMgr.CalculateBackoff(r.URL()))
resp, err := client.Do(req)
updateURLMetrics(r, resp, err)
if r.baseURL != nil {
if err != nil {
r.backoffMgr.UpdateBackoff(r.URL(), err, 0)
} else {
r.backoffMgr.UpdateBackoff(r.URL(), err, resp.StatusCode)
}
}
if err != nil {
return nil, err
}
switch {
case (resp.StatusCode >= 200) && (resp.StatusCode < 300):
return resp.Body, nil
default:
// ensure we close the body before returning the error
defer resp.Body.Close()
result := r.transformResponse(resp, req)
err := result.Error()
if err == nil {
err = fmt.Errorf("%d while accessing %v: %s", result.statusCode, url, string(result.body))
}
return nil, err
}
}
// request connects to the server and invokes the provided function when a server response is
// received. It handles retry behavior and up front validation of requests. It will invoke
// fn at most once. It will return an error if a problem occurred prior to connecting to the
// server - the provided function is responsible for handling server errors.
func (r *Request) request(fn func(*http.Request, *http.Response)) error {
//Metrics for total request latency
start := time.Now()
defer func() {
metrics.RequestLatency.Observe(r.verb, r.finalURLTemplate(), time.Since(start))
}()
if r.err != nil {
glog.V(4).Infof("Error in request: %v", r.err)
return r.err
}
// TODO: added to catch programmer errors (invoking operations with an object with an empty namespace)
if (r.verb == "GET" || r.verb == "PUT" || r.verb == "DELETE") && r.namespaceSet && len(r.resourceName) > 0 && len(r.namespace) == 0 {
return fmt.Errorf("an empty namespace may not be set when a resource name is provided")
}
if (r.verb == "POST") && r.namespaceSet && len(r.namespace) == 0 {
return fmt.Errorf("an empty namespace may not be set during creation")
}
client := r.client
if client == nil {
client = http.DefaultClient
}
// Right now we make about ten retry attempts if we get a Retry-After response.
// TODO: Change to a timeout based approach.
maxRetries := 10
retries := 0
for {
url := r.URL().String()
req, err := http.NewRequest(r.verb, url, r.body)
if err != nil {
return err
}
if r.ctx != nil {
req = req.WithContext(r.ctx)
}
req.Header = r.headers
r.backoffMgr.Sleep(r.backoffMgr.CalculateBackoff(r.URL()))
if retries > 0 {
// We are retrying the request that we already send to apiserver
// at least once before.
// This request should also be throttled with the client-internal throttler.
r.tryThrottle()
}
resp, err := client.Do(req)
updateURLMetrics(r, resp, err)
if err != nil {
r.backoffMgr.UpdateBackoff(r.URL(), err, 0)
} else {
r.backoffMgr.UpdateBackoff(r.URL(), err, resp.StatusCode)
}
if err != nil {
// "Connection reset by peer" is usually a transient error.
// Thus in case of "GET" operations, we simply retry it.
// We are not automatically retrying "write" operations, as
// they are not idempotent.
if !net.IsConnectionReset(err) || r.verb != "GET" {
return err
}
// For the purpose of retry, we set the artificial "retry-after" response.
// TODO: Should we clean the original response if it exists?
resp = &http.Response{
StatusCode: http.StatusInternalServerError,
Header: http.Header{"Retry-After": []string{"1"}},
Body: ioutil.NopCloser(bytes.NewReader([]byte{})),
}
}
done := func() bool {
// Ensure the response body is fully read and closed
// before we reconnect, so that we reuse the same TCP
// connection.
defer func() {
const maxBodySlurpSize = 2 << 10
if resp.ContentLength <= maxBodySlurpSize {
io.Copy(ioutil.Discard, &io.LimitedReader{R: resp.Body, N: maxBodySlurpSize})
}
resp.Body.Close()
}()
retries++
if seconds, wait := checkWait(resp); wait && retries < maxRetries {
if seeker, ok := r.body.(io.Seeker); ok && r.body != nil {
_, err := seeker.Seek(0, 0)
if err != nil {
glog.V(4).Infof("Could not retry request, can't Seek() back to beginning of body for %T", r.body)
fn(req, resp)
return true
}
}
glog.V(4).Infof("Got a Retry-After %s response for attempt %d to %v", seconds, retries, url)
r.backoffMgr.Sleep(time.Duration(seconds) * time.Second)
return false
}
fn(req, resp)
return true
}()
if done {
return nil
}
}
}
// Do formats and executes the request. Returns a Result object for easy response
// processing.
//
// Error type:
// * If the request can't be constructed, or an error happened earlier while building its
// arguments: *RequestConstructionError
// * If the server responds with a status: *errors.StatusError or *errors.UnexpectedObjectError
// * http.Client.Do errors are returned directly.
func (r *Request) Do() Result {
r.tryThrottle()
var result Result
err := r.request(func(req *http.Request, resp *http.Response) {
result = r.transformResponse(resp, req)
})
if err != nil {
return Result{err: err}
}
return result
}
// DoRaw executes the request but does not process the response body.
func (r *Request) DoRaw() ([]byte, error) {
r.tryThrottle()
var result Result
err := r.request(func(req *http.Request, resp *http.Response) {
result.body, result.err = ioutil.ReadAll(resp.Body)
glogBody("Response Body", result.body)
if resp.StatusCode < http.StatusOK || resp.StatusCode > http.StatusPartialContent {
result.err = r.transformUnstructuredResponseError(resp, req, result.body)
}
})
if err != nil {
return nil, err
}
return result.body, result.err
}
// transformResponse converts an API response into a structured API object
func (r *Request) transformResponse(resp *http.Response, req *http.Request) Result {
var body []byte
if resp.Body != nil {
if data, err := ioutil.ReadAll(resp.Body); err == nil {
body = data
}
}
glogBody("Response Body", body)
// verify the content type is accurate
contentType := resp.Header.Get("Content-Type")
decoder := r.serializers.Decoder
if len(contentType) > 0 && (decoder == nil || (len(r.content.ContentType) > 0 && contentType != r.content.ContentType)) {
mediaType, params, err := mime.ParseMediaType(contentType)
if err != nil {
return Result{err: errors.NewInternalError(err)}
}
decoder, err = r.serializers.RenegotiatedDecoder(mediaType, params)
if err != nil {
// if we fail to negotiate a decoder, treat this as an unstructured error
switch {
case resp.StatusCode == http.StatusSwitchingProtocols:
// no-op, we've been upgraded
case resp.StatusCode < http.StatusOK || resp.StatusCode > http.StatusPartialContent:
return Result{err: r.transformUnstructuredResponseError(resp, req, body)}
}
return Result{
body: body,
contentType: contentType,
statusCode: resp.StatusCode,
}
}
}
switch {
case resp.StatusCode == http.StatusSwitchingProtocols:
// no-op, we've been upgraded
case resp.StatusCode < http.StatusOK || resp.StatusCode > http.StatusPartialContent:
// calculate an unstructured error from the response which the Result object may use if the caller
// did not return a structured error.
retryAfter, _ := retryAfterSeconds(resp)
err := r.newUnstructuredResponseError(body, isTextResponse(resp), resp.StatusCode, req.Method, retryAfter)
return Result{
body: body,
contentType: contentType,
statusCode: resp.StatusCode,
decoder: decoder,
err: err,
}
}
return Result{
body: body,
contentType: contentType,
statusCode: resp.StatusCode,
decoder: decoder,
}
}
// glogBody logs a body output that could be either JSON or protobuf. It explicitly guards against
// allocating a new string for the body output unless necessary. Uses a simple heuristic to determine
// whether the body is printable.
func glogBody(prefix string, body []byte) {
if glog.V(8) {
if bytes.IndexFunc(body, func(r rune) bool {
return r < 0x0a
}) != -1 {
glog.Infof("%s:\n%s", prefix, hex.Dump(body))
} else {
glog.Infof("%s: %s", prefix, string(body))
}
}
}
// maxUnstructuredResponseTextBytes is an upper bound on how much output to include in the unstructured error.
const maxUnstructuredResponseTextBytes = 2048
// transformUnstructuredResponseError handles an error from the server that is not in a structured form.
// It is expected to transform any response that is not recognizable as a clear server sent error from the