environs/bootstrap: bootstrap major.minor.patch

environs/bootstrap: bootstrap major.minor.patch

Bootstrap tools selection is changed so that it
will select tools with the same major, minor and
patch level as the current (CLI) tools if possible.
If there are no such tools, the most recent tools
with matching major/minor are chosen as before and
a warning will be logged.

This change allows us to change bootstrap behaviour
even within a minor release series (except of course
for existing releases).

The most recent tools with matching major/minor will
be set in agent-version, which causes the machine
agent to immediately upgrade.

Fixes lp:1247232

https://code.launchpad.net/~axwalk/juju-core/lp1247232-bootstrap-majorminorpatch/+merge/216278

(do not edit description out of merge proposal)

[axw, 2014-04-17 09:33:31]

Please take a look.

[jameinel, 2014-04-17 09:45:47]

I'd really like to see this tested live, though I'm not sure it will be easy to
set up the test (you'll have to populate a couple versions of the tools, and
then bootstrap with an old version of them).

We'll also certainly want to let CI know about it right away, since it will
change how they do some of their testing.

Mostly, though, LGTM.

https://codereview.appspot.com/88840043/diff/1/environs/bootstrap/bootstrap.go
File environs/bootstrap/bootstrap.go (right):

https://codereview.appspot.com/88840043/diff/1/environs/bootstrap/bootstrap.g...
environs/bootstrap/bootstrap.go:72: // We should only ever bootstrap the exact
same version as the client,
This whole chunk of code seems quite localized, is it possible to just pull it
into a helper function to keep the units of work focused?

[axw, 2014-04-17 09:46:24]

Please take a look.

[axw, 2014-04-17 10:11:22]

On 2014/04/17 09:45:47, jameinel wrote:
> I'd really like to see this tested live, though I'm not sure it will be easy
to
> set up the test (you'll have to populate a couple versions of the tools, and
> then bootstrap with an old version of them).

I did test it live by applying the patch to 1.17.6. It successfully bootstrapped
with 1.17.6, and then immediately upgraded to 1.17.7.

> We'll also certainly want to let CI know about it right away, since it will
> change how they do some of their testing.
> 
> Mostly, though, LGTM.
> 
> https://codereview.appspot.com/88840043/diff/1/environs/bootstrap/bootstrap.go
> File environs/bootstrap/bootstrap.go (right):
> 
>
https://codereview.appspot.com/88840043/diff/1/environs/bootstrap/bootstrap.g...
> environs/bootstrap/bootstrap.go:72: // We should only ever bootstrap the exact
> same version as the client,
> This whole chunk of code seems quite localized, is it possible to just pull it
> into a helper function to keep the units of work focused?

I pulled out a little bit, but half of it is specific to the context.

[axw, 2014-04-17 10:14:21]

Please take a look.