e2e: pretty-print objects

[pohly]

What would you like to be added?

There is no good pretty-printing for Kubernetes API objects, which affects debugging. All of the following options have drawbacks:

• fmt.Sprintf("%+v") (single line, no clear distinction between fields)
• obj.String() (auto-generated, single line, does not omit empty fields)

What we want is probably:

• multi-line
• omitting empty fields as defined by the type

In other words, YAML?

/cc @tallclair

Why is this needed?

For example for

kubernetes/test/e2e/framework/pod/wait.go

Lines 77 to 82 in 619f1cf

	func TimeoutError(msg string, observedObjects ...interface{}) *timeoutError {
	return &timeoutError{
	msg: msg,
	observedObjects: observedObjects,
	}
	}

:

			err := e2epod.WaitForPodNameRunningInNamespace(f.ClientSet, pod.Name, pod.Namespace)
			framework.ExpectNoError(err, "start pod with inline resource claim")

=>

    Aug 17 09:55:26.691: INFO: Unexpected error: start pod with inline resource claim: 
        <*pod.timeoutError | 0xc004274e40>: {
            msg: "timed out while waiting for pod dra-5838/tester-1 to be running",
            observedObjects: [
                <*v1.Pod | 0xc002123800>{
                    TypeMeta: {Kind: "", APIVersion: ""},
                    ObjectMeta: {
                        Name: "tester-1",
                        GenerateName: "",
                        Namespace: "dra-5838",
                        SelfLink: "",
                        UID: "c3a4dfa5-5297-44e0-acdc-bdfb82035b80",
                        ResourceVersion: "379",
                        Generation: 0,
                        CreationTimestamp: {
                            Time: {
                                wall: 0,
                                ext: 63796319426,
                                loc: {
                                    name: "Local",
                                    zone: [
                                        {name: "LMT", offset: 3208, isDST: false},
                                        {name: "CEST", offset: 7200, isDST: true},
                                        {name: "CET", offset: 3600, isDST: false},
                                        {name: "CEST", offset: 7200, isDST: true},
                                        {name: "CET", offset: 3600, isDST: false},
                                        {name: "CEMT", offset: 10800, isDST: true},
                                        {name: "CEMT", offset: 10800, isDST: true},
                                        {name: "CEST", offset: 7200, isDST: true},
                                        {name: "CET", offset: 3600, isDST: false},
                                    ],
                                    tx: [
                                        {
                                            when: -576460752303423488,
                                            index: 0,
                                            isstd: false,
                                            isutc: false,
                                        },
                                        {when: -2422054408, index: 2, isstd: false, isutc: false},
                                        {when: -1693706400, index: 1, isstd: false, isutc: false},
                                        {when: -1680483600, index: 2, isstd: true, isutc: false},
                                        {when: -1663455600, index: 3, isstd: true, isutc: false},
                                        {when: -1650150000, index: 4, isstd: false, isutc: false},
                                        {when: -1632006000, index: 3, isstd: true, isutc: false},
                                        {when: -1618700400, index: 4, isstd: true, isutc: true},
                                        {when: -938905200, index: 3, isstd: true, isutc: true},
                                        {when: -857257200, index: 4, isstd: false, isutc: false},
                                        {when: -844556400, index: 3, isstd: false, isutc: false},
                                        {when: -828226800, index: 4, isstd: false, isutc: false},
                                        {when: -812502000, index: 3, isstd: false, isutc: false},
                                        {when: -796777200, index: 4, isstd: false, isutc: false},
                                        {when: -781052400, index: 3, isstd: false, isutc: false},
                                        {when: -776563200, index: 5, isstd: false, isutc: false},
                                        {when: -765936000, index: 1, isstd: false, isutc: false},
                                        {when: -761180400, index: 4, isstd: false, isutc: false},
                                        {when: -757386000, index: 2, isstd: false, isutc: false},
                                        {when: -748479600, index: 3, isstd: false, isutc: false},
                                        {when: -733273200, index: 4, isstd: false, isutc: false},
                                        {when: -717631200, index: 3, isstd: false, isutc: false},
                                        {when: -714610800, index: 6, isstd: false, isutc: false},
                                        {w...

    Gomega truncated this representation as it exceeds 'format.MaxLength'.
    Consider having the object provide a custom 'GomegaStringer' representation
    or adjust the parameters in Gomega's 'format' package.

    Learn more here: https://onsi.github.io/gomega/#adjusting-output

[pohly]

/sig testing

[aojea]

CreationTimestamp is 🙃 🥇

[spiffxp]

/triage accepted
/priority important-longterm

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/lifecycle stale

[pohly]

I believe that gomega/format.Object together with the YAML formatter from 5a01a52 is the right way forward. It will automatically switch over to YAML when applicable. This is enabled for all of the in-tree E2E suites.

However, tests must explicitly call it. I'd like to do a bit more work before closing this issue:

• update guidelines (writing-good-e2e-tests.md: polling, contexts and failure messages community#7021)
• investigate whether log messages emitted through klog can use it automatically

[pohly]

/remove-lifecycle stale
/assign

[pohly]

klog cannot use it by default because it must not depend on YAML. But JSON is now the default, which is close enough for me.

/close

[k8s-ci-robot]

@pohly: Closing this issue.

In response to this:

klog cannot use it by default because it must not depend on YAML. But JSON is now the default, which is close enough for me.

/close

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