Intermittent test failure UniterSuite.TestUniterCollectMetrics

[Tim Penhey]

http://reports.vapour.ws/releases/2884/job/run-unit-tests-win2012-amd64/attempt/899

FAIL: uniter_test.go:1434: UniterSuite.TestUniterCollectMetrics

util_test.go:988:
    c.Assert(err, jc.ErrorIsNil)
... value *errors.Err = &errors.Err{message:"", cause:(*os.LinkError)(0xc084599300), previous:(*errors.Err)(0xc084a935f0), file:"github.com/juju/juju/worker/uniter/metrics/metrics.go", line:148} ("link c:\\users\\admini~1\\appdata\\local\\temp\\tmpc4yzfj\\gogo\\tmp-juju-testagiqcb\\check-2674201130786856345\\1\\agents\\unit-u-0\\state\\spool\\metrics\\.6cc9f4fb-4d9c-4344-84fe-6dbbd39a0a75.inc-a14d0d03-361f-4f11-8018-61d4f94979b3 c:\\users\\admini~1\\appdata\\local\\temp\\tmpc4yzfj\\gogo\\tmp-juju-testagiqcb\\check-2674201130786856345\\1\\agents\\unit-u-0\\state\\spool\\metrics\\6cc9f4fb-4d9c-4344-84fe-6dbbd39a0a75: not supported by windows")
... error stack:
 link c:\users\admini~1\appdata\local\temp\tmpc4yzfj\gogo\tmp-juju-testagiqcb\check-2674201130786856345\1\agents\unit-u-0\state\spool\metrics\.6cc9f4fb-4d9c-4344-84fe-6dbbd39a0a75.inc-a14d0d03-361f-4f11-8018-61d4f94979b3 c:\users\admini~1\appdata\local\temp\tmpc4yzfj\gogo\tmp-juju-testagiqcb\check-2674201130786856345\1\agents\unit-u-0\state\spool\metrics\6cc9f4fb-4d9c-4344-84fe-6dbbd39a0a75: not supported by windows
 github.com/juju/juju/worker/uniter/metrics/metrics.go:65:
 github.com/juju/juju/worker/uniter/metrics/metrics.go:148:

[Casey Marshall (cmars)]

os.Link is used for atomically renaming files on Linux. This doesn't work on Windows, will need to add an alternative implementation for that OS.

[Casey Marshall (cmars)]

Will need a non-overwriting file move to land in utils first: http://reviews.vapour.ws/r/2188/

[Casey Marshall (cmars)]

Ready to land when master is unblocked: https://github.com/juju/juju/pull/2809