b2luigi - bringing batch 2 luigi!
b2luigi is a helper package for
luigi for scheduling large luigi workflows on a batch system.
It is as simple as
import b2luigi class MyTask(b2luigi.Task): def output(self): return b2luigi.LocalTarget("output_file.txt") def run(self): with self.output().open("w") as f: f.write("This is a test\n") if __name__ == "__main__": b2luigi.process(MyTask(), batch=True)
Jump right into it with out Quick Start.
If you have never worked with
luigi before, you may want to have a look into the luigi documentation.
But you can learn most of the nice features also from this documentation!
The API of
b2luigi is still under construction.
Please remember this when using the package in production!
Why not use the already created batch tasks?¶
Luigi already contains a large set of tasks for scheduling and monitoring batch jobs . But for thousands of tasks in very large projects with different task-defining libraries, you have some problems:
- You want to run many (many many!) batch jobs in parallel In other luigi batch implementations, for every running batch job you also need a running task that monitors it. On most of the systems, the maximal number of processes is limited per user, so you will not be able to run more batch jobs than this. But what do you do if you have thousands of tasks to do?
- You have already a large set of luigi tasks in your project
In other implementations you either have to override a
workfunction (and you are not allowed to touch the
runfunction) or they can only run an external command, which you need to define. The first approach plays not well when mixing non-batch and batch task libraries and the second has problems when you need to pass complex arguments to the external command (via command line).
- You do not know which batch system you will run on Currently, the batch tasks are mostly defined for a specific batch system. But what if you want to switch from AWS to Azure? From LSF to SGE?
b2luigi, which tries to solve all this (but was heavily inspired by the previous implementations):
- You can run as many tasks as your batch system can handle in parallel! There will only be a single process running on your submission machine.
- No need to rewrite your tasks! Just call them with
b2luigi.process(.., batch=True)or with
python file.py --batchand you are ready to go!
- Switching the batch system is just a single change in a config file or one line in python. In the future, there will even be an automatic discovery of the batch system to use.
Is this the only thing I can do with b2luigi?¶
b2luigi should help you with large luigi projects, we have also included some helper functionalities for
luigi tasks and task handling.
b2luigi task is a super-hero version of
luigi task, with simpler handling for output and input files.
Also, we give you working examples and best-practices for better data management and how to accomplish your goals,
that we have learned with time.
Why are you still talking, lets use it!¶
Have a look into the Quick Start.
If you find any bugs or want to improve the documentation, please send me a pull request.
This project is in beta. Please be extra cautious when using in production mode. You can help me by working with one of the todo items described in Development and TODOs.
- Quick Start
- Batch Processing
- Belle II specific examples
- API Documentation
- Run Modes
- Development and TODOs
b2luigi stands for multiple things at the same time:
- It brings batch to (2) luigi.
- It helps you with the bread and butter work in luigi (e.g. proper data management)
- It was developed for the Belle II experiment.
- Main developer
- Michael Eliachevitch (meliache)
- Original author
- Nils Braun (nils-braun)
- Features, fixing, help and testing
- Stolen ideas