Updates schema for simplified calling convention

[mpeck]

This removes the enforcing and execution fields from the command schema and adds a requirement for rules. In order to support version 2 to some extent I added a new module, Spanner.Config.Upgrader that attempts to upgrade version 2 bundles to version 3. It will abort with an error if the bundle it is trying to upgrade contains a once command.

This also changes the validator's return signature a bit. It will return {:ok, config} like before in the success case but now will also return {:warning, config, warnings} if the bundle was upgraded. warnings of course contains a list of warning messages encountered during the upgrade. The failure case changed a bit as well, now we return {:error, errors, warnings}, errors containing the list of errors and warnings containing the list of warnings in the case of an attempted upgrade.

Since the return signature changed we will also need to update cog and cogctl at merge.

resolves operable/cog#623

[kevsmith]

Is this ready for review? I wasn't sure if there were changes pending based on our conversation this morning.

[mpeck]

Hey @kevsmith, sorry I missed your message. This is ready for review now. I implemented the bits that we talked about this morning.

[vanstee]

This seemed a little weird. Are we running v2 configs through the v3 schema after upgrading?

[kevsmith]

The plan @mpeck and I discussed on Friday was to auto-convert v2 compliant configs if the commands are already multi calling convention since converting a non-enforcing command is simply generating a rule when command is foo:bar allow.

[mpeck]

Good point, we should just need the 3 here.

[vanstee]

@mpeck Looks good. Do we end up showing the warnings to users in cogctl?

[vanstee]

Ah found the warnings that are emitted for the question above.

[kevsmith]

I think the following would be a bit clearer:

@current_config_version 3
@old_config_version @current_config_version - 1

def validate(%{"cog_bundle_version" => @current_config_version}) do
. . .
end
def validate(%{"cog_bundle_version" => @old_config_version}=config) do
  case try_convert(config) do
    {:ok, converted} ->
      validate(converted)
    {:error, errors} ->
      {:error, errors, []}
  end
end
def validate(_) do
  {:error, "Not a valid command config"}
end

[kevsmith]

Why not put the N-1 version number explicitly here? Makes the intent much more obvious, imo.

[mpeck]

There are two things that we could error on here. 1) If an old bundle version is specified and 2) if no bundle version is specified. To me it felt cleaner for the upgrader to contain that logic. Then we don't have error messaging for the same basic thing spread over multiple modules. But I'm not super passionate about that. If you think it's clearer to have it here I can move those bits.

[kevsmith]

Modulo my question on the latest round of commits I'm +1 to merge