Process Dependencies

When you create a process recipe, you can pass in an array of recipes in the dependencies option (or call the .dependencies() method to create a new recipe with more dependencies). When baked, the process will use these dependencies to append to $PATH or other environment variables (the explicit env vars on the process take precedent over the env vars set by dependencies).

Dependency structure

Any directory recipe can be used as a dependency, but it will only do something useful if it follows a specific scheme.

Explicit env vars

A dependency recipe can set environment variables in its parent by creating a brioche-env.d directory:

• brioche-env.d should contain an inner env directory
• env can contain files, symlinks, or directories. Each one should be named after an environment variable to set.
  • For a file, the environment variable will be set to the contents of the file. This value will be used as a fallback if the environment variable is not set.
  • For a symlink, the environment variable will be set to an absolute path of the symlink’s target. This value will be used as a fallback if the environment variable is not set.
  • For a directory, it should only contain symlinks. The environment variable will contain absolute paths of the symlink targets concatenated together with :. Each individual symlink’s name is unused. This value will be appended to the environment variable if it’s already set.

Here’s an example structure to set some env vars:

artifact
├── brioche-env.d
│  └── env
│     ├── LIBRARY_PATH
│     │  ├── lib -> ../../../lib
│     │  └── usr_lib -> ../../../usr/lib
│     ├── PKG_CONFIG_PATH
│     │  └── lib_pkgconfig -> ../../../lib/pkgconfig
│     ├── ARTIFACT_ROOT -> ../../..
│     └── DEBUG
├── lib
│  ├── pkgconfig
│  │  └── ...
│  └── ...
└── usr
   └── lib
      └── ...

If this artifact is used as a dependency for a process, then the process would start with these environment variables set:

• $LIBRARY_PATH: /absolute/path/to/artifact/lib:/absolute/path/to/artifact/usr/lib
• $PKG_CONFIG_PATH: /absolute/path/to/artifact/lib/pkgconfig
• $ARTIFACT_ROOT: /absolute/path/to/artifact
• $DEBUG: (The literal contents of the DEBUG file)

You can use the std.setEnv() function to more easily build this directory structure:

return std.setEnv(recipe, {
  LIBRARY_PATH: {
    append: [{ path: "lib" }, { path: "usr/lib" }],
  },
  PKG_CONFIG_PATH: {
    append: [{ path: "lib/pkgconfig" }],
  },
  ARTIFACT_ROOT: { fallback: { path: "." } },
  DEBUG: { fallback: { value: "1" } },
});

If multiple dependencies set the same env vars (or two dependencies merged together with std.merge()), then the env vars will be set from all of the dependencies.

Implicit $PATH

If a dependency includes a bin/ directory, then it will be implicitly added to $PATH automatically. The dependency can add additional directories to $PATH explicitly as well (e.g. using std.setEnv), and the values will be concatenated together with :.