Facilitate OPA decision correlation with business flows

[JanardhanSharma]

Context

The release of the feature Facilitate OPA decision correlation with business flows (PR) led to bug that leads to the skipper restarts. This is because an object of same reference is being shared among the different instances of opa instances.

Error log from the reported bug (for those who cannot access the bug details):

goroutine 191993 [running]:
github.com/zalando/skipper/filters/openpolicyagent.setDecisionIdInRequest(0x4004494720, {0x40067c6440?, 0x10?})
github.com/zalando/skipper/filters/openpolicyagent/evaluation.go:92 +0xe4
github.com/zalando/skipper/filters/openpolicyagent.(*OpenPolicyAgentInstance).Eval(0x40059ef400, {0x16b6bb0, 0x40044946c0}, 0x4004494720)
github.com/zalando/skipper/filters/openpolicyagent/evaluation.go:27 +0x164
github.com/zalando/skipper/filters/openpolicyagent/opaauthorizerequest.(*opaAuthorizeRequestFilter).Request(0x4002234520, {0x16ccd90, 0x40091ca100})
github.com/zalando/skipper/filters/openpolicyagent/opaauthorizerequest/opaauthorizerequest.go:131 +0x1a4
github.com/zalando/skipper/proxy.(*Proxy).applyFiltersToRequest(0x4003510500, {0x40053e9a40, 0x7, 0x10d1400?}, 0x40091ca100)
github.com/zalando/skipper/proxy/proxy.go:895 +0x248
github.com/zalando/skipper/proxy.(*Proxy).do(0x4003510500, 0x40091ca100, {0x16c8360, 0x400174d810})
github.com/zalando/skipper/proxy/proxy.go:1216 +0x5a0
github.com/zalando/skipper/proxy.(*Proxy).ServeHTTP(0x4003510500, {0x16b33f0, 0x4001d6fdc0}, 0x4003126480)
github.com/zalando/skipper/proxy/proxy.go:1610 +0x648
github.com/zalando/skipper/net.(*ForwardedHeadersHandler).ServeHTTP(0x4001426640, {0x16b33f0, 0x4001d6fdc0}, 0x4003126000)
github.com/zalando/skipper/net/headers.go:77 +0x114
github.com/zalando/skipper/net.(*HostPatchHandler).ServeHTTP(0x4004cc3920, {0x16b33f0, 0x4001d6fdc0}, 0x4003126000)
github.com/zalando/skipper/net/host.go:60 +0x84
github.com/zalando/skipper/net.(*RequestMatchHandler).ServeHTTP(0x4000f7e8d0, {0x16b33f0, 0x4001d6fdc0}, 0x4003126000)
github.com/zalando/skipper/net/request.go:20 +0xb0
net/http.serverHandler.ServeHTTP({0x40044943f0?}, {0x16b33f0?, 0x4001d6fdc0?}, 0x6?)
net/http/server.go:3137 +0xbc
net/http.(*conn).serve(0x4007109050, {0x16b6bb0, 0x4000f7ec00})
net/http/server.go:2039 +0x508
created by net/http.(*Server).Serve in goroutine 1
net/http/server.go:3285 +0x3f0

ACs

Fix the opaauhorizerequest filter restart issue.

fixes #3179

[JanardhanSharma]

@AlexanderYastrebov @mjungsbluth @szuecs If we could merge this it will be nice, I am on vacation this week, once I am back I have a feeling I will get a lot of merge conflicts :D

[AlexanderYastrebov]

Please squash all commits and add commit message describing the change (think like #3041 was never merged)

[JanardhanSharma]

Please squash all commits and add commit message describing the change (think like #3041 was never merged)

done.

[AlexanderYastrebov]

Please squash all commits and add commit message describing the change (think like #3041 was never merged)

done.

Commit message is empty, otherwise lgtm.

[AlexanderYastrebov]

👍

[JanardhanSharma]

@szuecs could you please oblige with a thumbs up

[MustafaSaber]

hi @JanardhanSharma, I think we can merge, but it would be nice to have performance tests to understand the impact before and after. Maybe in a follow up PR?

I will add my +1 once you confirm

[JanardhanSharma]

hi @JanardhanSharma, I think we can merge, but it would be nice to have performance tests to understand the impact before and after. Maybe in a follow up PR?

I will add my +1 once you confirm

Thanks @MustafaSaber. Yes I will create a subsequent ticket in the backlog for the test case as well.

[MustafaSaber]

👍