Index

Hydra is a powerful configuration framework for Python applications, focused on modularity.

The generic config layout consists of multiple groups, each containing multiple options, and a root config, composing the resulting config object by choosing one option in each group:

conf/
    group1/
        option1.yaml
        option2.yaml
    group2/
        option1.yaml
        option2.yaml
    config.yaml

Example:

composed configcommandconfig.yamlgroup1/option2.yamlgroup2/option1.yaml

group1:
    field1: value1
    field2: value2
group2:
    key: "option one in group two"

python3 main.py

defaults:
    - group1: option2
    - group2: option1

field1: value1
field2: value2

key: "option one in group two"

You can also override single parameters or the entire options on group level via command line arguments:

composed configcommandconfig.yamlgroup1/option2.yamlgroup2/option2.yaml

group1:
    field1: other value
    field2: value2
group2:
    key: "option two in group two"

python3 main.py group2=option2 group1.field1="other value"

defaults:
    - group1: option2
    - group2: option1

field1: value1
field2: value2

key: "option two in group two"

Read Hydra docs for a more detailed introduction into its features.