Has anybody written any Rust application against the Ledger API?

I would be interested how you included the whole tree of .proto files.

This is my starting point and it only explains how single .proto files can be used:

hyperium/tonic/blob/debcafe08cd64f03bff2fee0eaa1521e47794a8a/examples/helloworld-tutorial.md

# Getting Started

This tutorial is meant to be an introduction to Tonic and assumes that you have basic [Rust] experience as well as an understanding of what [protocol buffers] are. If you don't, feel free to read up on the pages linked in this paragraph and come back to this tutorial once you feel you are ready!

[rust]: https://www.rust-lang.org/
[protocol buffers]: https://developers.google.com/protocol-buffers/docs/overview

## Prerequisites

To run the sample code and walk through the tutorial, the only prerequisite is Rust itself.
[rustup] is a convenient tool to install it, if you haven't already.

[rustup]: https://rustup.rs

## Project Setup

For this tutorial, we will start by creating a new Rust project with Cargo:

```shell
$ cargo new helloworld-tonic

Not sure of whether you can pass a directory and have it walk recursively (although that’s probably a nice contribution to make to the project, if they don’t) but it looks like you can use tonic_build::configure() to add more files (see the examples here).

Thank you!

Yes, this is the build.rs which does the job:

fn main() -> Result<(), Box<dyn std::error::Error>> {
    tonic_build::configure()
        .build_server(false)
        .compile(
            &[ // the list of protos
                "com/daml/ledger/api/v1/admin/config_management_service.proto",
                "com/daml/ledger/api/v1/admin/package_management_service.proto",
                "com/daml/ledger/api/v1/admin/participant_pruning_service.proto",
                "com/daml/ledger/api/v1/admin/party_management_service.proto",
                "com/daml/ledger/api/v1/testing/reset_service.proto",
                "com/daml/ledger/api/v1/testing/time_service.proto",
                "com/daml/ledger/api/v1/active_contracts_service.proto",
                "com/daml/ledger/api/v1/command_completion_service.proto",
                "com/daml/ledger/api/v1/command_service.proto",
                "com/daml/ledger/api/v1/command_submission_service.proto",
                "com/daml/ledger/api/v1/commands.proto",
                "com/daml/ledger/api/v1/completion.proto",
                "com/daml/ledger/api/v1/event.proto",
                "com/daml/ledger/api/v1/experimental_features.proto",
                "com/daml/ledger/api/v1/ledger_configuration_service.proto",
                "com/daml/ledger/api/v1/ledger_identity_service.proto",
                "com/daml/ledger/api/v1/ledger_offset.proto",
                "com/daml/ledger/api/v1/package_service.proto",
                "com/daml/ledger/api/v1/transaction.proto",
                "com/daml/ledger/api/v1/transaction_filter.proto",
                "com/daml/ledger/api/v1/transaction_service.proto",
                "com/daml/ledger/api/v1/value.proto",
                "com/daml/ledger/api/v1/version_service.proto",
            ],
            &["."], // specify the root location to search proto dependencies
        )?;
    Ok(())
}