Wire up authenticating httpstorage

Wire up authenticating httpstorage

There are two things happening here:
 - httpstorage authentication changes
 - wiring up to null provider/localstorage worker.

The httpstorage authentication mechanism has
changed to use an auth key (randomly generated
as part of the boilerplate), rather than client
certificates. This gives us more options for
using the storage, since now you don't need the
client to share the CA key.

Also, when serving HTTPS, HTTP is *also* provided,
but only for non-modifying operations. This allows
wget et al. to fetch files from the storage without
bypassing certificate validation. The HTTP interface
disallows modifying operations if there is an HTTPS
interface backing it. To get an HTTPS URL, a HEAD
request may be performed on the HTTP interface.

https://code.launchpad.net/~axwalk/juju-core/null-provider-storage-auth/+merge/187964

(do not edit description out of merge proposal)

[axw, 2013-09-27 02:50:33]

Please take a look.

[axw, 2013-09-27 02:59:53]

Please take a look.

[thumper, 2013-10-02 05:07:25]

LGTM, few comments

https://codereview.appspot.com/14011044/diff/4001/environs/httpstorage/backen...
File environs/httpstorage/backend.go (right):

https://codereview.appspot.com/14011044/diff/4001/environs/httpstorage/backen...
environs/httpstorage/backend.go:78: http.Error(w, "method HEAD is not
supported", http.StatusMethodNotAllowed)
shouldn't we return here?  So as not to change the header to 200 OK?

https://codereview.appspot.com/14011044/diff/4001/provider/null/environ.go
File provider/null/environ.go (right):

https://codereview.appspot.com/14011044/diff/4001/provider/null/environ.go#ne...
provider/null/environ.go:150: return
httpstorage.Client(e.envConfig().storageAddr())
If this is an error condition, shouldn't we log an error (which the users now
see) and return nil rather than http storage?

[axw1, 2013-10-02 05:47:24]

https://codereview.appspot.com/14011044/diff/4001/environs/httpstorage/backen...
File environs/httpstorage/backend.go (right):

https://codereview.appspot.com/14011044/diff/4001/environs/httpstorage/backen...
environs/httpstorage/backend.go:78: http.Error(w, "method HEAD is not
supported", http.StatusMethodNotAllowed)
On 2013/10/02 05:07:25, thumper wrote:
> shouldn't we return here?  So as not to change the header to 200 OK?

It doesn't actually change in practice, as the first header wins. But this was
an oversight and I've fixed it. I added a test while I was at it. Thanks.

https://codereview.appspot.com/14011044/diff/4001/provider/null/environ.go
File provider/null/environ.go (right):

https://codereview.appspot.com/14011044/diff/4001/provider/null/environ.go#ne...
provider/null/environ.go:150: return
httpstorage.Client(e.envConfig().storageAddr())
On 2013/10/02 05:07:25, thumper wrote:
> If this is an error condition, shouldn't we log an error (which the users now
> see) and return nil rather than http storage?

Done.