General: Environment variables groups

[iLLiCiTiT]

Brief description

Give ability to set different environment variables when are prepared on artist machine and on farm.

Description

Added one more dictionary level to environment variables dictionary which is called environment group. Default group is "standard" but is not used until environment data values use it. This gives ability to not change current settings but just extend their usage.

The environment variable group level does NOT apply on general environment variables. General environments are set in start.py before openpype cli is used.

The new dictionary level can be used before platform specific level. Example:

{
    "ENV_KEY": {
        "farm": {
            "windows": "WINDOWS",
            "linux": "LINUX",
            "darwin": "MACOS"
        }
    }
}

It won't work if the order is swapped. This will NOT work and the key will be skipped:

{
    "ENV_KEY": {
        "windows": {
            "farm": "WINDOWS"
        }
    }
}

It is also NOT possible to combine them at the same level. Only platform specific value will be used:

{
    # The key won't be set at all on Linux and MacOs
    "ENV_KEY": {
        "windows": "WINDOWS",
        "farm": "FARM"
}

New parsing function also keeps empty strings. Not sure if it's ok but there is no way how to "unset" environment variable value right now which should be possible, or?

Changes

• implemented new function parse_environments which parse environmet variables data for passed context
  • context is defined by environemnt group ("standard" is default) and platform name
• the function is used when application and tool environments are used and when project specific environments are used
• command extractenvironment can have specified envgroup value
• deadline global job specify envgroup value to "farm"

[kalisp]

It solves customer's use case for not having particular env var returned when called from farm.