About Hera
Hera is a Python library that allows you to construct and submit Argo Workflows. Anything you can write in YAML for Argo Workflows you can express in Hera! It is designed to be intuitive and easy to use, while also providing a powerful interface to the underlying Argo API.
Hera acts as a domain-specific-language on top of Argo, so it is primarily a way to define Workflows. In previous Argo Workflows surveys such as 2021, a better Python DSL has been highly requested to overcome the YAML barrier to adoption. In the 2022 survey results we can infer from the job roles for people using Argo Workflows that the DevOps Engineers are likely more comfortable using YAML than ML Engineers.
- DevOps Engineers: 41%
- Software Engineer: 20%
- Architects: 20%
- Data Engineer / Data Scientist / ML Engineer: 13%
We hope by providing a more intuitive Python definition language, Data and ML users of Argo Workflows will increase.
Feature Parity
A natural concern about an abstraction layer on top of another technology is whether it can function the same as the original lower layer. In this case, Hera generates a library of model classes using Argo’s OpenAPI spec which are wrapped up by Hera’s feature-rich classes, while the model classes are available as a fallback mechanism. You can check out the extensive “upstream” examples that contain side-by-side Python and YAML definitions for Workflows in the Argo examples folder on GitHub. Our CI/CD runs through the Argo examples folder to check that we are able to reproduce them using Hera Workflows written by hand (note: we have not yet written Hera Workflows for all the examples).
If you are a new user of Argo, we encourage you to become familiar with Argo’s Core Concepts, which provide a foundation of understanding when working with Hera. Working through the Argo Walk Through will also help you understand key concepts before moving to Python.
Context Managers
You will notice many classes in Hera implement the context manager interface. This was designed to mirror the YAML syntax of Argo, helping existing users come to Hera from YAML, and for users new to both Argo and Hera, who will be able to interpret and understand most of the existing YAML documentation and resources online from familiar naming and functionality in Hera. Read more in the user guides section!
Orchestrating Scripts
A natural extension of a Python DSL for Argo is tighter integration with Python scripts. This is where Hera improves the developer experience through its tailored classes and syntactic sugar to enable developers to easily orchestrate Python functions. Check out Hello World to get started!
If you want an introductory tour of Hera, check out the Hera Tour!