CLI missing argument for targets

[aardschok]

Issue:

We have setup a publishing approach which uses targets so we only get those plugins when the target is set to X. When attempting to run pyblish publish --targets X we are notified that there is no such option as --targets.

After looking in the code we found that the publish function has the keyword argument targets but the CLI module has no integration of it.

Motivation

Update CLI to support targets

[tokejepsen]

👍

[aardschok]

When going over the amount of kwargs which needed to be set I tested a more global approach thanks to @BigRoy.

Instead following the trail of targets throughout pyblish-base and pyblish-qml I have introduced an environment variable called PYBLISH_TARGETS which is being set in our Avalon CLI.

Snippet:

if kwargs.targets:
    os.environ["PYBLISH_TARGETS"] = os.pathsep.join(kwargs.targets)

In the api module of pyblish-base I ensured the environment variable is being checked and process in the __init__ function with the following snippet:

# Register targets for current session
for t in os.environ.get("PYBLISH_TARGETS", "").split(os.pathsep):
    if t:
        register_target(t)

I did however implement a click.option for targets to be passed on the publish function to ensure that, when the flag --nogui is used, you are still able to pass on the targets.

Any thoughts on this approach?

[aardschok]

Full code can be viewed here:
https://github.com/aardschok/pyblish-base/tree/334