What is the correct way to get the unique Execution ID of a workflow within a task? And what is the correct way to determine if a task is running locally or remotely? - It seems the plugins do this slightly different e.g. the spark plugin vs the mlflow plugin?

The unique Id for a task is task execution Id. It should be available- it is the combination of exec Id, node Id and task name with retry attempt

Is the best way to grab this just from the

FLYTE_INTERNAL_EXECUTION_ID

env var?

No they are part of the context