base-resolver

base-resolver is a V2 component that implements the Component Resolver FIDL protocol fuchsia.component.resolution.Resolver and exposes this protocol as a resolver capability.

The responsibility of base-resolver is to resolve URLs to packages that are located in pkgfs and are part of the “base” set of packages.

Building

The base-resolver component should be part of the core product configuration and be buildable by any fx set invocation.

Running

This component is not packaged in the traditional way. Instead, its binary and manifest are included in the Zircon Boot Image (ZBI) and are accessible via bootfs.

To launch this component, include it as a child in the component topology using the URL fuchsia-boot:///#meta/base-resolver.cm, and include its exposed resolver capability in an environment.

{% includecode gerrit_repo="fuchsia/fuchsia" gerrit_path="src/sys/base-resolver/tests/meta/integration-test.cml" region_tag="environment"}

Testing

Unit tests for base-resolver are available in the base-resolver-unittests package.

$ fx test base-resolver-unittests

Integration tests for base-resolver are available in the base-resolver-tests package.

$ fx test base-resolver-tests

pkg-cache-resolver

pkg-cache-resolver implements the Component Resolver FIDL protocol fuchsia.component.resolution.Resolver and exposes this protocol as a resolver capability.

The responsibility of pkg-cache-resolver is to resolve the URL “fuchsia-pkg-cache:///#meta/pkg-cache.cm”. It does this by:

1. Using fuchsia.boot/Arguments to determine the hash of the system_image package.
2. Reading the system_image package to determine the hash of the pkg-cache package.
3. Using an RX* handle to blobfs and the package-directory library to serve the package directory for pkg-cache directly out of blobfs.

The code for pkg-cache-resolver is in the same directory as the base-resolver because:

1. They are built into the same binary to save space in bootfs (they both build with the Rust VFS library which is large).
2. Eventually base-resolver should stop using pkgfs/packages and instead serve packages directly from blobfs (and therefore only serve base packages, whereas currently base-resolver can resolve any non-base packages exposed by pkgfs/packages). This will be implemented by changing the pkg-cache-resolver implementation to resolve any of the base packages instead of only pkg-cache, at which point the two resolvers can be merged into a single component and pkg-cache-resolver can be deleted. This is tracked at fxbug.dev/101492.

Building

The pkg-cache-resolver component should be part of the core product configuration and be buildable by any fx set invocation.

Running

This component is not packaged in the traditional way. Instead, its binary and manifest are included in the Zircon Boot Image (ZBI) and are accessible via bootfs.

To launch this component, include it as a child in the component topology using the URL fuchsia-boot:///#meta/pkg-cache-resolver.cm, and include its exposed resolver capability in an environment.

Testing

Unit tests for pkg-cache-resolver are included in the base-resolver-unittests package.

$ fx test base-resolver-unittests

Integration tests for pkg-cache-resolver are available in the base-resolver-tests package (which uses pkg-cache-resolver as a component resolver) and the base-resolver-integration-tests package, which uses RealmBuilder to fake the dependencies.

$ fx test base-resolver-tests base-resolver-integration-tests