feat(hostd): varlink interfaced host controller to manage machine configuration and boot mgmt

hostd/.gitignore

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+/target

hostd/Cargo.toml

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+[package]
+name = "hostd"
+version.workspace = true
+edition.workspace = true
+
+[dependencies]
+anyhow.workspace = true
+varlink = "11.0.1"
+internal = { path = "../internal" }

hostd/src/main.rs

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+use anyhow::Result;
+
+use internal::ipc::patagia::io_patagia_hostd;
+use internal::ipc::systemd::io_systemd_hostname::{self, VarlinkClientInterface};
+
+const LISTEN_ADDRESS: &str = "unix:/tmp/patagia/io.patagia.hostd";
+const SYSTEMD_ADDRESS: &str = "unix:/run/systemd/io.systemd.Hostname";
+
+struct PatagiaHostd;
+
+impl io_patagia_hostd::VarlinkInterface for PatagiaHostd {
+    fn apply(
+        &self,
+        call: &mut dyn io_patagia_hostd::Call_Apply,
+        machine: io_patagia_hostd::Machine,
+    ) -> varlink::Result<()> {
+        // FIXME: Do something useful
+        println!("Applying machine config: {:#?}", machine);
+        call.reply()
+    }
+
+    fn describe(&self, call: &mut dyn io_patagia_hostd::Call_Describe) -> varlink::Result<()> {
+        // Connect to systemd.Hostname
+        let conn = varlink::Connection::with_address(SYSTEMD_ADDRESS).unwrap();
+        let mut sd = io_systemd_hostname::VarlinkClient::new(conn);
+
+        let machine = io_patagia_hostd::Machine {
+            machineId: sd.describe().call().unwrap().MachineID,
+            nodeLabels: None,
+            patagiaAgent: None,
+        };
+        call.reply(machine)
+    }
+}
+
+fn main() -> Result<()> {
+    let hostd = PatagiaHostd;
+    let hostd_iface = io_patagia_hostd::new(Box::new(hostd));
+
+    let svc = varlink::VarlinkService::new(
+        "io.patagia.hostd",
+        "Host controller for patagia",
+        "0.1",
+        "https://patagia.dev",
+        vec![Box::new(hostd_iface)],
+    );
+
+    let addr_path = std::path::Path::new(LISTEN_ADDRESS.strip_prefix("unix:").unwrap())
+        .parent()
+        .unwrap();
+
+    std::fs::create_dir_all(addr_path)?;
+
+    println!("Varlink Listening on {}", LISTEN_ADDRESS);
+
+    varlink::listen(
+        svc,
+        LISTEN_ADDRESS,
+        &varlink::ListenConfig {
+            // Listen forever (0 = forever)
+            idle_timeout: 0,
+            ..Default::default()
+        },
+    )?;
+
+    Ok(())
+}