element_manager

Reviewed on: 2021-01-21

element_manager is a component that implements the fuchsia.element.Manager protocol. element_manager is not intended to be used on its own, but instead composed into a session as a child.

element_manager launches all elements proposed using Manager in a collection.

Use this if you want to use tools such as ffx session add, but don't want to write your own implementation of fuchsia.element.Manager.

Building

To add this project to your build, append --with //src/session/bin/element_manager to the fx set invocation.

Running

To include element_manager in a session, add the following to the session's component manifest.

Once available, session manifests should instead include element_manager.shard.cml. Related monorail issue: https://fxbug.dev/42147096.

{
    children: [
        {
            name: "element_manager",
            url: "fuchsia-pkg://fuchsia.com/element_manager#meta/element_manager.cm",
            startup: "eager",
        },
    ],
    capabilities: [
        { protocol: "fuchsia.element.Manager" },
    ],
    offer: [
        {
            protocol: [ "fuchsia.logger.LogSink" ],
            from: "parent",
            to: [ "#element_manager" ],
        },
        {
            storage: "data",
            from: "parent",
            to: "#element_manager",
        },
    ],
    expose: [
        {
            protocol: "fuchsia.element.Manager",
            from: "#element_manager",
        },
    ],
}

Testing

Unit tests for element_manager are available in the element_manager_tests package.

$ fx test element_manager_tests

Source layout

The entrypoint is located in src/main.rs. Unit tests are co-located with the code.

Element annotations

element_manager writes annotations in the namespace “element_manager”.