CLI: add --no-profile option

[un-def]

Disables default profile loading. Mutually exclusive with --profile.

Supported by the following commands:

• dstack apply (run configurations only)
• dstack preset create|apply
• dstack offer

[peterschmidt85]

Look good to me from UX point of view

But also think of supporting NO_DSTACK_PROFILE=1 for consistency?

[un-def]

But also think of supporting NO_DSTACK_PROFILE=1 for consistency?

A bit tricky in terms of precedence, I landed on:

--no-profile > --profile=name > DSTACK_NO_PROFILE=1 > DSTACK_PROFILE=name

That is,

dstack offer → default profile loaded
DSTACK_NO_PROFILE=1 dstack offer → no profile loaded
DSTACK_NO_PROFILE=1 DSTACK_PROFILE=my-profile dstack offer → no profile loaded
DSTACK_NO_PROFILE=1 dstack offer --profile my-profile → my-profile loaded
DSTACK_NO_PROFILE=1 DSTACK_PROFILE=other-profile dstack offer --profile my-profile → my-profile loaded
DSTACK_PROFILE=my-profile dstack offer --no-profile → no profile loaded

[peterschmidt85]

A bit tricky in terms of precedence, I landed on:

Can be made mutually exclusive?

[un-def]

Can be made mutually exclusive?

--profile and --no-profile are mutually exclusive, DSTACK_PROFILE and DSTACK_NO_PROFILE are not – unlike the command line, it's possible that the process environment is not in user's full control, e.g., they can set but cannot unset a variable, so, I'd rather not make them mutually exclusive unless there is a strong reason to do so.