Merge pull request #12 from flokli/machine-id

src/system: use /etc/machine-id as machine identifier

Cargo.nix

@@ -1734,6 +1734,11 @@ rec {
             packageId = "tracing-subscriber";
             features = [ "env-filter" ];
           }
+          {
+            name = "uuid";
+            packageId = "uuid";
+            features = [ "v4" ];
+          }
           {
             name = "wry";
             packageId = "wry";
@@ -7363,6 +7368,47 @@ rec {
         features = { };
         resolvedDefaultFeatures = [ "default" ];
       };
+      "uuid" = rec {
+        crateName = "uuid";
+        version = "1.10.0";
+        edition = "2018";
+        sha256 = "0503gvp08dh5mnm3f0ffqgisj6x3mbs53dmnn1lm19pga43a1pw1";
+        authors = [
+          "Ashley Mannix<ashleymannix@live.com.au>"
+          "Dylan DPC<dylan.dpc@gmail.com>"
+          "Hunar Roop Kahlon<hunar.roop@gmail.com>"
+        ];
+        dependencies = [
+          {
+            name = "getrandom";
+            packageId = "getrandom 0.2.15";
+            optional = true;
+          }
+        ];
+        features = {
+          "arbitrary" = [ "dep:arbitrary" ];
+          "atomic" = [ "dep:atomic" ];
+          "borsh" = [ "dep:borsh" "dep:borsh-derive" ];
+          "bytemuck" = [ "dep:bytemuck" ];
+          "default" = [ "std" ];
+          "fast-rng" = [ "rng" "dep:rand" ];
+          "js" = [ "dep:wasm-bindgen" "getrandom?/js" ];
+          "macro-diagnostics" = [ "dep:uuid-macro-internal" ];
+          "md5" = [ "dep:md-5" ];
+          "rng" = [ "dep:getrandom" ];
+          "serde" = [ "dep:serde" ];
+          "sha1" = [ "dep:sha1_smol" ];
+          "slog" = [ "dep:slog" ];
+          "v1" = [ "atomic" ];
+          "v3" = [ "md5" ];
+          "v4" = [ "rng" ];
+          "v5" = [ "sha1" ];
+          "v6" = [ "atomic" ];
+          "v7" = [ "rng" ];
+          "zerocopy" = [ "dep:zerocopy" ];
+        };
+        resolvedDefaultFeatures = [ "default" "rng" "std" "v4" ];
+      };
       "valuable" = rec {
         crateName = "valuable";
         version = "0.1.0";

Cargo.toml

@@ -14,6 +14,7 @@ tao = "0.28.1"
 thiserror = "1.0.62"
 tracing = "0.1.40"
 tracing-subscriber = { version = "0.3.18", features = ["env-filter"] }
+uuid = { version = "1.10.0", features = ["v4"] }
 wry = "0.41.0"
 
 # FUTUREWORK: Somehow rustc wants to link this against zlib.

src/main.rs

@@ -31,9 +31,7 @@ fn main() -> color_eyre::eyre::Result<()> {
 
     let cli = Cli::parse();
 
-    debug!("Acquiring the CPU serial number...");
-    let serial = system::get_cpu_serial().context("getting cpu serial")?;
-    debug!(%serial, "got CPU serial number");
+    let machine_id = system::get_machine_id().context("getting machine id")?;
 
     debug!("Loading the config");
     let config = Config::load(cli.default_config_path.map(|p| PathBuf::from(p)))
@@ -44,7 +42,7 @@ fn main() -> color_eyre::eyre::Result<()> {
     let (sender, receiver) = channel();
 
     let listener = mqtt::Listener {
-        id: config.id.unwrap_or(serial),
+        id: config.id.unwrap_or(machine_id),
         host: config.host,
         port: config.port,
         sender,

src/system.rs

@@ -1,31 +1,17 @@
-use std::{
-    fs::File,
-    io::{BufRead, BufReader},
-};
+use tracing::{instrument, warn};
 
-use crate::common::Error;
+const MACHINE_ID_PATH: &'static str = "/etc/machine-id";
 
-#[cfg(debug_assertions)]
-const CPU_INFO_PATH: &'static str = "./cpuinfo";
-
-#[cfg(not(debug_assertions))]
-const CPU_INFO_PATH: &'static str = "/proc/cpuinfo";
-
-pub(crate) fn get_cpu_serial() -> Result<String, Error> {
-    let file =
-        File::open(CPU_INFO_PATH).map_err(|e| Error::FileIoError(CPU_INFO_PATH.into(), e))?;
-    let reader = BufReader::new(file);
-    let mut lines = reader.lines();
-
-    while let Some(Ok(line)) = lines.next() {
-        if line.starts_with("Serial") {
-            let (_, serial) = line
-                .split_once(':')
-                .ok_or(Error::ParsingError(CPU_INFO_PATH.into()))?;
-
-            return Ok(serial.trim().to_string());
-        }
+/// Returns the system machine id
+/// (https://www.freedesktop.org/software/systemd/man/latest/machine-id.html)
+/// Falls back to a random uuid if the file doesn't exist, or another error
+/// occurs during retrieval. It logs a warning in this case.
+#[instrument(ret, err)]
+pub(crate) fn get_machine_id() -> std::io::Result<String> {
+    if let Ok(machine_id) = std::fs::read_to_string(MACHINE_ID_PATH) {
+        Ok(machine_id.trim().to_string())
+    } else {
+        warn!("unable to read machine id, setting a random one");
+        Ok(uuid::Uuid::new_v4().to_string())
     }
-
-    Err(Error::ParsingError(CPU_INFO_PATH.into()))
 }