Previously, we were inconsistent on how we handled argument validation
in the CLI. Many commands used cobra.Command's Args property to
provide a validator if they took arguments, but commands which did not
rarely used cobra.NoArgs to indicate this.
This change does two things:
1. Introduce `cmdutil.ArgsFunc` which works like `cmdutil.RunFunc`, it
wraps an existing cobra type and lets us control the behavior when an
arguments validator fails.
2. Ensure every command sets the Args property with an instance of
cmdutil.ArgsFunc. The cmdutil package defines wrapers for all the
cobra validators we are using, to prevent us from having to spell out
`cmduitl.ArgsFunc(...)` everywhere.
Fixes#588
This change introduces an abstraction for a `backend` which manages
the implementation of some CLI commands. As part of defining the
interface, we introduce a new local backend implementation that just
uses data local to the machine.
This will let us share argument parsing and some display information
between the local case and the pulumi.com case in the CLI. We can
continue to refine this interface over time (e.g. today we have the
implementation of the Destroy/Update/Preview actually writing output
but instead they should be returning strongly typed data that the CLI
knows how to display and is unified across Pulumi.com deploys and
local deploys).
But this is a good first step.
We now encrypt secrets at rest based on a key derived from a user
suplied passphrase.
The system is designed in a way such that we should be able to have a
different decrypter (either using a local key or some remote service
in the Pulumi.com case in the future).
Care is taken to ensure that we do not leak decrypted secrets into the
"info" section of the checkpoint file (since we currently store the
config there).
In addtion, secrets are "pay for play", a passphrase is only needed
when dealing with a value that's encrypted. If secure config values
are not used, `pulumi` will never prompt you for a
passphrase. Otherwise, we only prompt if we know we are going to need
to decrypt the value. For example, `pulumi config <key>` only prompts
if `<key>` is encrypted and `pulumi deploy` and friends only prompt if
you are targeting a stack that has secure configuration assoicated
with it.
Secure values show up as unecrypted config values inside the language
hosts and providers.
Previously we used the word "Environment" as the term for a deployment
target, but since then we've started to use the term Stack. Adopt this
across the CLI.
From a user's point of view, there are a few changes:
1. The `env` verb has been renamed to `stack`
2. The `-e` and `--env` options to commands which operate on an
environment now take `-s` or `--stack` instead.
3. Becase of (2), the commands that used `-s` to display a summary now
only support passing the full option name (`--summary`).
On the local file system, we still store checkpoint data in the `env`
sub-folder under `.pulumi` (so we can reuse existing checkpoint files
that were written to the old folder)
