util/log: add GC of old log files

[petermattis]

GC old log files, controlled by the MaxFilesPerSeverity setting (default
20).

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This change is 

[petermattis]

Review status: 0 of 3 files reviewed at latest revision, 1 unresolved discussion.

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pkg/util/log/file.go, line 45 at r1 (raw file):

// MaxFilesPerSeverity is the maximum number of log files per severity.
var MaxFilesPerSeverity = 20

Should this be MaxSizePerSeverity? With the current settings, we could conceivably have 20 10MB log files per severity for a total of 1000MB of log files. That's quite a bit, though not horrific if the user a 1TB+ size disk.

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Comments from Reviewable

[bdarnell]

Reviewed 3 of 3 files at r1.
Review status: all files reviewed at latest revision, 2 unresolved discussions, all commit checks successful.

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pkg/util/log/clog_test.go, line 540 at r1 (raw file):

	MaxSize = 1 // ensure rotation on every log write

	for i := 0; i < 100; i++ {

s/100/MaxFilesPerSeverity*10/

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pkg/util/log/file.go, line 45 at r1 (raw file):

Previously, petermattis (Peter Mattis) wrote…

Should this be MaxSizePerSeverity? With the current settings, we could conceivably have 20 10MB log files per severity for a total of 1000MB of log files. That's quite a bit, though not horrific if the user a 1TB+ size disk.

Yeah, limiting by size would be better, I think.

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Comments from Reviewable

[petermattis]

Review status: 0 of 3 files reviewed at latest revision, 2 unresolved discussions.

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pkg/util/log/clog_test.go, line 540 at r1 (raw file):

Previously, bdarnell (Ben Darnell) wrote…

s/100/MaxFilesPerSeverity*10/

Done.

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pkg/util/log/file.go, line 45 at r1 (raw file):

Previously, bdarnell (Ben Darnell) wrote…

Yeah, limiting by size would be better, I think.

Done.

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Comments from Reviewable