✨add CodecFactoryOptionsMutators for codecfactory

[Chaunceyctx]

What does this do, and why do we need it?

we have a production scenario:

the struct corresponding to crd declared in the v1 version of the controller includes field A. However, when we upgrade the v1 controller to v2, field A is removed from the struct, like:

v1 struct:

type Work struct {
	Workload WorkloadTemplate `json:"workload,omitempty"`
}

type WorkloadTemplate struct {
	field1 []byte `json:"field1,omitempty"`
        field2 []byte `json:"field2,omitempty"`
}

v2 struct:

type Work struct {
	Workload WorkloadTemplate `json:"workload,omitempty"`
}

type WorkloadTemplate struct {
	field1 []byte `json:"field1,omitempty"`
        field2 []byte `json:"field2,omitempty"`

+      field3 []byte `json:"field3,omitempty"`
or
        field2 rename to field22  []byte `json:"field22,omitempty"`
}

So we want the controller to realize this error during data deserialization, so we need to switch the corresponding serializer to strict mode.

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[k8s-ci-robot]

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[Chaunceyctx]

/ping gently @vincepri @sbueringer PTAL, thanks a lot :)

[Chaunceyctx]

/ping gently @troy0820

[sbueringer]

What is the user-facing difference in impact between configuring strict here vs. using client.WithFieldValdation to set FieldValidation in the Options structs?

Is it that the latter only affects Create/Update/patch?

[Chaunceyctx]

What is the user-facing difference in impact between configuring strict here vs. using client.WithFieldValdation to set FieldValidation in the Options structs?

Is it that the latter only affects Create/Update/patch?

@sbueringer thanks a lot for feedback :) Yes, FieldValidation will be used in CreateOptions/UpdateOptions/PatchOptions. And these Options will tell apiserver how to select mode of decodeSerializer(strict or not strict), like: https://github.com/kubernetes/kubernetes/blob/6746df77f2376c6bc1fd0de767d2a94e6bd6cec1/staging/src/k8s.io/apiserver/pkg/endpoints/handlers/update.go#L109

So client also need to know how to select mode of decodeSerializer and use strict mode of decodeSerializer to avoid the aforementioned issue.

I will address failed ci job.

[alvaroaleman]

That seems like a pretty big footgun though, because you became unable to tolerate any skew between the CRD and the controller, even for backwards-compatible changes?

[Chaunceyctx]

@alvaroaleman thanks for your comment :). IMO, these options can be true or false which depends on the user's use case. For my scenario described above, I have deployed a workload similar to StatefulSet and used ControllerRevision to record the workload.spec. If the workload.spec changes (some fields have been dropped in the v2 workload controller), it will lead to rolling update of the workload, impacting production. Therefore, I need to explicitly use the strict deserializer and any field added/dropped should not be permitted. For other scenarios, it's not necessary to set these options.

[alvaroaleman]

Yeah but this is a cache-wide setting, using errors in the cache deserialization as a marker just seems like a very brittle approach

[Chaunceyctx]

It makes sense. I will find other approaches to implement it like ByObject field:)

[sbueringer]

/ok-to-test

[Chaunceyctx]

@sbueringer excuse me, could you give me some hints to address this failed ci job? I am a noob for go-apidiff tool

[Chaunceyctx]

/retest

[Chaunceyctx]

@sbueringer excuse me, could you give me some hints to address this failed ci job? I am a noob for go-apidiff tool

fields added need to be comparable. @sbueringer PTAL again, thanks a lot :)

[troy0820]

Do we need to add any tests for this @sbueringer ?

[alvaroaleman]

What is the point of CodecFactoryPretty, when would someone want this?

[Chaunceyctx]

"strict" and "pretty" are both options of Codecfactory, so for the sake of completeness, I added these two variables together. But I indeed didn't think of practical scenarios for "pretty".

[alvaroaleman]

That seems like a pretty big footgun though, because you became unable to tolerate any skew between the CRD and the controller, even for backwards-compatible changes?

[k8s-ci-robot]

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[Chaunceyctx]

I have changed the implementation so that the strict mode of codec is restricted to a specific GroupVersionKind (GVK) instead of applying to the cache-level. @alvaroaleman PTAL, thank you so much :)

[k8s-ci-robot]

@Chaunceyctx: The following test failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Required	Rerun command
pull-controller-runtime-apidiff	330bbcc	link	false	/test pull-controller-runtime-apidiff

Full PR test history. Your PR dashboard. Please help us cut down on flakes by linking to an open issue when you hit one in your PR.

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