Major Description
Provide the dag number, which is a unique number, for each dag running within an application in the TezInputContext, TezOutputContext, TezProcessorContext.
When containers are re-used, or for external services, this can be used to generate intermediate data to a dag specific directory instead of an application specific directory, where it becomes difficult to differentiate between different dags.
The DAG name does provide this - but is not suitable for use in a directory name. Hashing the name is an option, but can lead to collisions.
Generating data into a dag specific directory will eventually only be usable when we move away from the default MR handler, or enhance it to support an additional parameter.