--log-http consumes the Request Body, making it invalid

[Harwayne]

In what area(s)?

What version of Knative Client?

Version: v20190819-local-dccaf36
Build Date: 2019-08-19 22:55:23
Git Revision: dccaf36
Support:

• Serving: v0.8.0 v0.7.1
• API(s): v1alpha1

Expected Behavior

I expect that adding the --log-http flag to a command makes no difference to the request the server sees.

Actual Behavior

Adding the --log-http flag will send empty bodies in all requests (with incorrect content-length headers to boot).

Expected Cause

client/pkg/util/logging_http_transport.go

Line 51 in dccaf36

reqCopy := *r

Copies the request. Importantly, Request's Body is an interface and therefore a pass by reference. Body can only be read once, so

client/pkg/util/logging_http_transport.go

Line 65 in dccaf36

reqBytes, _ := httputil.DumpRequestOut(&reqCopy, true)

drains the body for both r and reqCopy. It then sets a copy for reqCopy.

Steps to Reproduce the Problem

Logs:

 ./kn service create --log-http foo --image foo.bar 
===== REQUEST =====
GET /apis/serving.knative.dev/v1alpha1/namespaces/default/services/foo HTTP/1.1
Host: 35.222.62.54
User-Agent: kn/v0.0.0 (linux/amd64) kubernetes/$Format
Accept: application/json, */*
Authorization: *******************************************************************************************************************************************                                                
Accept-Encoding: gzip


===== RESPONSE =====
HTTP/2.0 404 Not Found
Content-Length: 232
Audit-Id: a032637e-a483-4232-abfd-2ed69beae461
Content-Type: application/json
Date: Mon, 19 Aug 2019 22:56:35 GMT

{"kind":"Status","apiVersion":"v1","metadata":{},"status":"Failure","message":"services.serving.knative.dev \"foo\" not found","reason":"NotFound","details":{"name":"foo","group":"serving.knative.dev","kind":"services"},"code":404}

 * * * * * *
===== REQUEST =====
POST /apis/serving.knative.dev/v1alpha1/namespaces/default/services HTTP/1.1
Host: 35.222.62.54
User-Agent: kn/v0.0.0 (linux/amd64) kubernetes/$Format
Content-Length: 298
Accept: application/json, */*
Authorization: *******************************************************************************************************************************************                                                
Content-Type: application/json
Accept-Encoding: gzip

{"kind":"Service","apiVersion":"serving.knative.dev/v1alpha1","metadata":{"name":"foo","namespace":"default","creationTimestamp":null},"spec":{"template":{"metadata":{"name":"foo-wtltm-1","creationTimestamp":null},"spec":{"containers":[{"name":"","image":"foo.bar","resources":{}}]}}},"status":{}}

===== RESPONSE =====
HTTP/2.0 500 Internal Server Error
Content-Length: 156
Audit-Id: ea98f490-abaf-47f3-a445-150a9c2d120b
Content-Type: application/json
Date: Mon, 19 Aug 2019 22:56:35 GMT

{"kind":"Status","apiVersion":"v1","metadata":{},"status":"Failure","message":"request declared a Content-Length of 298 but only wrote 0 bytes","code":500}                                               

 * * * * * *

This was followed by an unrelated panic:

panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x48 pc=0x116bb94]

goroutine 1 [running]:
knative.dev/client/pkg/errors.isCRDError(0x7f748f7b1208, 0xc000264120, 0xc000264120)
        /usr/local/google/home/harwayne/go-mod/github.com/knative/client/pkg/errors/factory.go:25 +0x74                                                                                                   
knative.dev/client/pkg/errors.GetError(0x15986c0, 0xc000264120, 0xc0003e2000, 0x15986c0)
        /usr/local/google/home/harwayne/go-mod/github.com/knative/client/pkg/errors/factory.go:44 +0x8f                                                                                                   
knative.dev/client/pkg/serving/v1alpha1.(*knClient).CreateService(0xc000310260, 0xc0001eae00, 0x915503, 0xc0002a8280)                                                                                     
        /usr/local/google/home/harwayne/go-mod/github.com/knative/client/pkg/serving/v1alpha1/client.go:174 +0x84                                                                                         
knative.dev/client/pkg/kn/commands/service.createService(0x15e6800, 0xc000310260, 0xc0001eae00, 0x13dd649, 0x7, 0x1599000, 0xc000010018, 0x0, 0x0)                                                        
        /usr/local/google/home/harwayne/go-mod/github.com/knative/client/pkg/kn/commands/service/service_create.go:136 +0x4b                                                                              
knative.dev/client/pkg/kn/commands/service.NewServiceCreateCommand.func1(0xc0002a8c80, 0xc0002a2ac0, 0x1, 0x4, 0x0, 0x0)                                                                                  
        /usr/local/google/home/harwayne/go-mod/github.com/knative/client/pkg/kn/commands/service/service_create.go:100 +0x6e2                                                                             
github.com/spf13/cobra.(*Command).execute(0xc0002a8c80, 0xc0002a2a80, 0x4, 0x4, 0xc0002a8c80, 0xc0002a2a80)                                                                                               
        /usr/local/google/home/harwayne/go-mod/github.com/knative/client/vendor/github.com/spf13/cobra/command.go:762 +0x465                                                                              
github.com/spf13/cobra.(*Command).ExecuteC(0xc0002a8280, 0x15bc74fbd460474b, 0x206aa20, 0x51cddf)
        /usr/local/google/home/harwayne/go-mod/github.com/knative/client/vendor/github.com/spf13/cobra/command.go:852 +0x2ec                                                                              
github.com/spf13/cobra.(*Command).Execute(...)
        /usr/local/google/home/harwayne/go-mod/github.com/knative/client/vendor/github.com/spf13/cobra/command.go:800                                                                                     
main.main()
        /usr/local/google/home/harwayne/go-mod/github.com/knative/client/cmd/kn/main.go:36 +0xb6