A Mock Battery Project

In the previous section, we saw how the Smart Battery Specification (SBS) defines a set of functions that a Smart Battery service should implement.

In this section, we are going to review how these traits are defined in Rust within the embedded-services repository, and we are going to import these structures into our own workspace as we build our mock battery. In subsequent sections we'll connect the battery into the supporting upstream EC service framwork.

Setting up for development

We are going to create a project space that contains a folder for our battery code, and the dependent repository clones.

So, start by finding a suitable location on your local computer and create the workpace:

mkdir battery_project
cd battery_project
git init

This will create a workspace root for us and establish it as a git repository (not attached).

Now, we are going to bring the embedded-batteries directory into our workspace and build the crates it exports.

(from the battery_project directory):

git submodule add https://github.com/OpenDevicePartnership/embedded-batteries

The embedded-batteries repository has the subsystem service definitions for the battery defined in both embedded-batteries and embedded-batteries-async crates. We are going to use the async variant here because this is required when attaching later to the Controller, which we will attach our battery implementation into the larger service framework.

Now, we can create our project space and start our own work. Within the battery_project directory, create a folder named mock_battery and give it this project structure:

mock_battery/
  src/ 
   - lib.rs
   - mock_battery.rs
  Cargo.toml 
  
Cargo.toml  

note there are two Cargo.toml files here. One is within the battery_project root folder and the other is at the root of mock_battery. The mock_battery.rs file resides within the mock_battery/src directory.

The contents of the battery_project/Cargo.toml file should contain:

[workspace]
resolver = "2"
members = [
    "mock_battery"
]

and the contents of the battery_project/mock_battery/Cargo.toml file should be set to:

[package]
name = "mock_battery"
version = "0.1.0"
edition = "2024"


[dependencies]
embedded-batteries-async = { path = "../embedded-batteries/embedded-batteries-async" }

This structure and the Cargo.toml definitions just define a minimal skeleton for the dependencies we will be adding to as we continue to build our mock battery implementation and work it into the larger ODP framework.

The lib.rs file is used to tell Rust which modules are part of the project. Set it's contents to:

pub mod mock_battery;

the mock_battery.rs file can be empty for now. We will define its contents in the next section.