Fix oomparser regex for kernels 5.0 and higher

[kgtw]

#2418 introduced new regex for 5.0 kernels and higher, the regex had a typo and wasn't resolving the correct container names.

Fixes: #2813

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[k8s-ci-robot]

Hi @kgtw. Thanks for your PR.

I'm waiting for a google member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

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[kgtw]

@googlebot I signed it!

[iwankgb]

@kgtw would you be able to provide a unit test to save us from regression?

[kgtw]

Hi @iwankgb - Thanks for the speedy review!

I believe the updated unit-test on L84 should cover regressions, it was previously validating the bad regex.

[iwankgb]

@kgtw will the regexp work for pre-5.0 messages too?

[kgtw]

The regex being changed is only for >=5.0 kernels.

OOM messages on kernels lower than 5.0 have a different format and are handled by a different regex pattern and the legacy test cases L33-L59

The existing functionality of getContainerName() has not changed, where it will try to parse the 5.0 regex, failing that it will fallback to legacy parsing.

cadvisor/utils/oomparser/oomparser.go

Lines 73 to 89 in dcbeba1

	func getContainerName(line string, currentOomInstance *OomInstance) (bool, error) {
	parsedLine := containerRegexp.FindStringSubmatch(line)
	if parsedLine == nil {
	// Fall back to the legacy format if it isn't found here.
	return false, getLegacyContainerName(line, currentOomInstance)
	}
	currentOomInstance.ContainerName = parsedLine[6]
	currentOomInstance.VictimContainerName = parsedLine[5]
	currentOomInstance.Constraint = parsedLine[1]
	pid, err := strconv.Atoi(parsedLine[8])
	if err != nil {
	return false, err
	}
	currentOomInstance.Pid = pid
	currentOomInstance.ProcessName = parsedLine[7]
	return true, nil
	}

[iwankgb]

Thank you, sir!
@bobbypage you are still the only person that has power to LGTM it.

[iwankgb]

/ok-to-test

[bobbypage]

thanks!