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Experimental Features#

Warning

These are experimental features of rattler-build and may change or go away completely.

Currently only build & rebuild command supports the following experimental features.

To enable them use the --experimental flag with the command. Or, use the environment variable, RATTLER_BUILD_EXPERIMENTAL=1.

Jinja functions#

load_from_file(<file_path>)#

The jinja function load_from_file allows loading from files, specifically, it allows loading from toml, json and yaml to an object to allow to fetch things directly from it. While it loads all other files as strings.

Usage#

This is useful when you have the project description in a well defined project file, such as, Cargo.toml, package.json, pyproject.toml, package.yaml, or stack.yaml. And would like to keep the recipe as simple as possible, while not worrying about keeping changes in sync, perhaps using it with CI/CD.

Or, from some other source that provides a well-defined output format.

Example against Cargo.toml inside rattler-build github repository:

recipe.yaml
context:
  name: ${{ load_from_file("Cargo.toml").package.name }}
  version: ${{ load_from_file("Cargo.toml").package.version }}
  source_url: ${{ load_from_file("Cargo.toml").package.homepage }}
  rust_toolchain: ${{ load_from_file("rust-toolchains") }}

package:
  name: ${{ name }}
  version: ${{ version }}

source:
  git: ${{ source_url }}
  tag: ${{ source_tag }}}}

requirements:
  build:
    - rust ==${{ rust_toolchain }}

build:
  script: cargo build --release -p ${{ name }}

test:
  - script: cargo test -p ${{ name }}
  - script: cargo test -p rust-test -- --test-threads=1

about:
  home: ${{ source_url }}
  repository: ${{ source_url }}
  documentation: ${{ load_from_file("Cargo.toml").package.documentation }}
  summary: ${{ load_from_file("Cargo.toml").package.description }}
  license: ${{ load_from_file("Cargo.toml").package.license }}

Git functions#

Git functions are useful for getting the latest tag and commit hash. These can be used in the context section of the recipe, to fetch version information from the git repository.

Examples 
# latest tag in the repo
git.latest_tag(<git_repo_url>)

# latest tag revision(aka, hash of tag commit) in the repo
git.latest_tag_rev(<git_repo_url>)

# latest commit revision(aka, hash of head commit) in the repo
git.head_rev(<git_repo_url>)

Usage#

These can be useful for automating minor things inside the recipe itself. Such as if the current version is the latest version, if the current hash is the latest hash, etc.

recipe.yaml
context:
  git_repo_url: "https://github.com/prefix-dev/rattler-build"
  latest_tag: ${{ git.latest_tag( git_repo_url ) }}

package:
  name: "rattler-build"
  version: ${{ latest_tag }}

source:
  git: ${{ git_repo_url }}
  tag: ${{ latest_tag }}

Though it's important to understand currently we don't guarantee caching for repo fetch for git functions this may lead to some performance issues.