Write ssh auth keys file to user home

Write ssh auth keys file to user home

The ssh auth keys file was being read and written
from the home of the current user. This is not what
we want, because the current user is root and we want
to write the file to ~ubuntu. A username parameter
was added to the ssh util methods. The file's ownership
was also changed to the specified user.

The existing utils.NormalizePath method had to be altered
to account for the more complete user home expansion, since
it previously just knew about ~/foo and now needs to know
about ~user/foo also.

https://code.launchpad.net/~wallyworld/juju-core/auth-keys-user/+merge/199932

(do not edit description out of merge proposal)

[wallyworld, 2013-12-23 05:23:35]

Please take a look.

[axw, 2013-12-23 05:45:16]

LGTM

https://codereview.appspot.com/40650049/diff/1/utils/file.go
File utils/file.go (right):

https://codereview.appspot.com/40650049/diff/1/utils/file.go#newcode45
utils/file.go:45: var userHomePathRegexp =
regexp.MustCompile("(~(?P<user>[^/]*))/(?P<path>.*)")
Pedant alert: this doesn't handle plain old "~" or "~user". Include the "/"
inside <path>, if you think we should care.

https://codereview.appspot.com/40650049/diff/1/utils/file_test.go
File utils/file_test.go (right):

https://codereview.appspot.com/40650049/diff/1/utils/file_test.go#newcode58
utils/file_test.go:58: err:  "invalid user bob: user: unknown user bob",
I sure hope nobody has a user called bob on their machine ;)
At my previous job, all build machines had a "bob" (the builder) account.

[wallyworld, 2013-12-23 05:57:21]

Please take a look.

https://codereview.appspot.com/40650049/diff/1/utils/file_test.go
File utils/file_test.go (right):

https://codereview.appspot.com/40650049/diff/1/utils/file_test.go#newcode58
utils/file_test.go:58: err:  "invalid user bob: user: unknown user bob",
On 2013/12/23 05:45:17, axw wrote:
> I sure hope nobody has a user called bob on their machine ;)
> At my previous job, all build machines had a "bob" (the builder) account.

Changed invalid user to something !bob :-)