Templates¶

In modularized projects, there is often a need to have a certain common configuration for all or some modules. Typical examples could be a testing framework used in all modules or a Kotlin language version.

Amper offers a way to extract whole sections or their parts into reusable template files. These files are named <name>.module-template.yaml and have the same structure as module.yaml files.

A templates is applied to a module.yaml file by it to the apply: section:

module.yaml

product: jvm/app

apply: 
  - ../common.module-template.yaml

../common.module-template.yaml

test-dependencies:
  - org.jetbrains.kotlin:kotlin-test:1.8.10

settings:
  kotlin:
    languageVersion: 1.8

Sections in the template can also have @platform-qualifiers.

Note

Template files can't have product: and apply: sections (they can't be recursive).

Templates are applied one by one, using the same rules as platform-specific dependencies and settings:

Scalar values (strings, numbers etc.) are overridden.
Mappings and lists are appended.

Settings and dependencies from the module.yaml file are applied last. The position of the apply: section doesn't matter, the module.yaml file content always has precedence E.g.

common.module-template.yaml

dependencies:
  - ../shared

settings:
  kotlin:
    languageVersion: 1.8
  compose: enabled

module.yaml

product: jvm/app

apply:
  - ./common.module-template.yaml

dependencies:
  - ../jvm-util

settings:
  kotlin:
    languageVersion: 1.9
  jvm:
    release: 8

After applying the template the resulting effective module is:

module.yaml

product: jvm/app

dependencies:  # lists appended
  - ../shared
  - ../jvm-util

settings:  # objects merged
  kotlin:
    languageVersion: 1.9  # module.yaml overwrites value
  compose: enabled        # from the template
  jvm:
    release: 8   # from the module.yaml