local: use sudo internally

local: use sudo internally

The local provider has been updated to do several things:
- use environs/cloudinit to bootstrap
- rely on the terminationworker to cleanup
- prevent bootstrap if the user is root (forcing good practice)
- use sudo internally, in bootstrap/destroy

Bootstrap now generates a script, a la manual bootstrap,
and executes it with "sudo bash". Destroy works by repeating
the "juju destroy-environment" command under sudo, which is
necessary to destroy any leftover containers.

https://code.launchpad.net/~axwalk/juju-core/local-provider-environs-cloudinit/+merge/202791

(do not edit description out of merge proposal)

[axw, 2014-01-23 05:50:25]

Please take a look.

[Michael Nelson, 2014-01-23 10:54:28]

https://codereview.appspot.com/55880043/diff/1/provider/local/environ.go
File provider/local/environ.go (right):

https://codereview.appspot.com/55880043/diff/1/provider/local/environ.go#newc...
provider/local/environ.go:402: cmd := exec.Command("sudo",
append([]string{juju}, os.Args[1:]...)...)
Not a review, just a question: If I'm using /home/me/golang/bin/juju
destroy-environment (whether via PATH or explicitly), I think "sudo juju ..."
won't necessarily use the same binary - at least, I was caught by that recently.
It might be better to get the actual binary name instead of []string{juju}?

[axw, 2014-01-23 11:02:24]

https://codereview.appspot.com/55880043/diff/1/provider/local/environ.go
File provider/local/environ.go (right):

https://codereview.appspot.com/55880043/diff/1/provider/local/environ.go#newc...
provider/local/environ.go:402: cmd := exec.Command("sudo",
append([]string{juju}, os.Args[1:]...)...)
On 2014/01/23 10:54:28, Michael Nelson wrote:
> Not a review, just a question: If I'm using /home/me/golang/bin/juju
> destroy-environment (whether via PATH or explicitly), I think "sudo juju ..."
> won't necessarily use the same binary - at least, I was caught by that
recently.

Right, this is one of the problems with using sudo externally: the environment
isn't (by default) propagated through sudo. People have had to work around this
by either using "sudo -E ..." or "sudo `which juju` ...".

> It might be better to get the actual binary name instead of []string{juju}?

This is the point of the exec.LookPath above. See:
http://golang.org/pkg/os/exec/#LookPath

[Michael Nelson, 2014-01-23 11:06:36]

On Thu, Jan 23, 2014 at 12:02 PM,  <axwalk@gmail.com> wrote:
>
> This is the point of the exec.LookPath above. See:
> http://golang.org/pkg/os/exec/#LookPath
>

Excellent, thanks.

[axw, 2014-01-23 22:29:59]

Please take a look.

[thumper, 2014-01-23 23:33:50]

LGTM - looks awesome!

https://codereview.appspot.com/55880043/diff/20001/provider/local/export_test.go
File provider/local/export_test.go (right):

https://codereview.appspot.com/55880043/diff/20001/provider/local/export_test...
provider/local/export_test.go:14: FinishBootstrap = &finishBootstrap
nice...