Support private charms from charm store

[Greg Lutostanski]

We should support non-public charms. Such as those that are not granted read access to everyone, but only logged in users. Not sure on how this might work, but should be possible I would hope.

[Martin Hilton (martin-hilton)]

There are two way we can do this, the first, and easiest, would be to delegate to charm pull to do the actual fetching for us. Otherwise we need to create a python implementation of the "bakery" authentication protocol and use that when we fetch the charm.

It should be noted that the charm pull command only (currently) supports a somewhat convoluted login mechanism based around Ubuntu SSO OAuth tokens, which might be fiddly to set up for codetree uses.

[Tom Haddon (mthaddon)]

Note that we're currently seeing the following from codetree when "charm" is installed:

2017-03-13 14:49:29 [INFO] Building resource tree

Error: version is not a valid subcommand

usage: /usr/bin/charm subcommand

  Available subcommands are:
    Error: version is not a valid subcommand

usage: /usr/bin/charm subcommand

  Available subcommands are:
    create
    get
    getall
    list
    promulgate
    proof
    review
    review-queue
    search
    subscribers
    unpromulgate
    update
create
    get
    getall
    list
    promulgate
    proof
    review
    review-queue
    search
    subscribers
    unpromulgate
    update

[Tom Haddon (mthaddon)]

I should mention that the previous comment is with charm version 1.0.0-0ubuntu2 (in trusty)

[Tom Haddon (mthaddon)]

I think the best option here is to find out if codetree really needs a more recent version of charm-tools than is in trusty, or if we can support the stock trusty version as well. If we can support that, let's do so. If we can't, let's update codetree to fail gracefully if you don't have a recent enough version of charm-tools installed (i.e. fall back to using the non charm-tools way of grabbing charms from the charmstore). It should also give a user-friendly warning message that this is the case.

We can then install a more recent version of charm-tools (likely using the classic snap) in places where we need to use private charms.

[Tom Haddon (mthaddon)]

This is now supported via charm show/charm pull commands.