[feat] config file. also: extreme over-engineering

Cargo.lock

@@ -2,6 +2,31 @@
 # It is not intended for manual editing.
 version = 4
 
+[[package]]
+name = "eyre"
+version = "0.6.12"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7cd915d99f24784cdc19fd37ef22b97e3ff0ae756c7e492e9fbfe897d61e2aec"
+dependencies = [
+ "indenter",
+ "once_cell",
+]
+
+[[package]]
+name = "indenter"
+version = "0.3.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ce23b50ad8242c51a442f3ff322d56b02f08852c77e4c0b4d3fd684abc89c683"
+
 [[package]]
 name = "linkspeed"
 version = "0.1.0"
+dependencies = [
+ "eyre",
+]
+
+[[package]]
+name = "once_cell"
+version = "1.21.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d75b0bedcc4fe52caa0e03d9f1151a323e4aa5e2d78ba3580400cd3c9e2bc4bc"

Cargo.toml

@@ -3,11 +3,32 @@ name = "linkspeed"
 version = "0.1.0"
 edition = "2024"
 
+[lints.rust]
+unsafe_code = "forbid"
+
+[lints.clippy]
+similar_names = "allow"
+
+pedantic = { level = "warn", priority = -1 }
+todo = "warn"
+unwrap_used = "warn"
+
 [dependencies]
+eyre = "0.6"
 
 [profile.release]
-lto = true
-debug = false
-strip = true
+debug = true
+debug-assertions = true
+overflow-checks = true
+strip = false
+lto = false
 panic = "unwind"
 codegen-units = 1
+
+[profile.release-lto]
+inherits = "release"
+lto = true
+debug = false
+debug-assertions = false
+overflow-checks = false
+strip = true

rustfmt.toml

@@ -0,0 +1,3 @@
+group_imports = "StdExternalCrate"
+imports_granularity = "Crate"
+imports_layout = "HorizontalVertical"

src/cfg.rs

@@ -0,0 +1,64 @@
+use std::{
+    env,
+    fs::File,
+    io::{BufRead as _, BufReader},
+    path::PathBuf,
+    time::Duration,
+};
+
+use eyre::ContextCompat as _;
+
+pub(crate) struct Config {
+    pub(crate) netdev: Option<String>,
+    pub(crate) interval: Duration,
+}
+
+impl Config {
+    const CONFIG_FILE: &'static str = ".config/pfs/linkspeed";
+
+    pub(crate) fn from_file() -> eyre::Result<Self> {
+        let config_file = PathBuf::from(env::var("HOME")?).join(Self::CONFIG_FILE);
+
+        let mut config = Self::default();
+
+        if let Ok(file) = File::open(&config_file) {
+            let file = BufReader::new(file);
+
+            for line in file.lines() {
+                let line = line?;
+
+                match &line {
+                    line if line.starts_with("netdev") => {
+                        config.netdev = Some(Self::read_config_value(line)?.to_string());
+                    }
+                    line if line.starts_with("interval") => {
+                        let interval = Self::read_config_value(line)?.parse::<f64>()?;
+                        config.interval = Duration::from_secs_f64(interval);
+                    }
+                    _ => {}
+                }
+            }
+        }
+
+        Ok(config)
+    }
+
+    fn read_config_value(line: &str) -> eyre::Result<&str> {
+        let val = line
+            .split('=')
+            .nth(1)
+            .wrap_err("failed to parse value".to_string())?
+            .trim();
+
+        Ok(val)
+    }
+}
+
+impl Default for Config {
+    fn default() -> Self {
+        Config {
+            netdev: None,
+            interval: Duration::from_secs(1),
+        }
+    }
+}

src/macros.rs

@@ -0,0 +1,57 @@
+mod byte_conversion {
+    #[macro_export]
+    macro_rules! kbit {
+        ($bytes:expr) => {
+            kbyte!($bytes) * 8.0
+        };
+    }
+
+    #[macro_export]
+    macro_rules! mbit {
+        ($bytes:expr) => {
+            mbyte!($bytes) * 8.0
+        };
+    }
+
+    #[macro_export]
+    macro_rules! gbit {
+        ($bytes:expr) => {
+            gbyte!($bytes) * 8.0
+        };
+    }
+
+    #[macro_export]
+    macro_rules! tbit {
+        ($bytes:expr) => {
+            tbyte!($bytes) * 8.0
+        };
+    }
+
+    #[macro_export]
+    macro_rules! kbyte {
+        ($bytes:expr) => {
+            $bytes / 1024.0
+        };
+    }
+
+    #[macro_export]
+    macro_rules! mbyte {
+        ($bytes:expr) => {
+            kbyte!($bytes) / 1024.0
+        };
+    }
+
+    #[macro_export]
+    macro_rules! gbyte {
+        ($bytes:expr) => {
+            mbyte!($bytes) / 1024.0
+        };
+    }
+
+    #[macro_export]
+    macro_rules! tbyte {
+        ($bytes:expr) => {
+            gbyte!($bytes) / 1024.0
+        };
+    }
+}

src/main.rs

@@ -1,92 +1,38 @@
-use std::{
-    env,
-    fs::File,
-    io::{self, Read, Seek, SeekFrom},
-    thread::sleep,
-    time::{Duration, Instant},
-};
+mod cfg;
+mod macros;
+mod math;
+mod measure;
+mod sysfs;
 
-struct LinkSpeed {
-    rx: File,
-    tx: File,
-    rx_bytes: u64,
-    tx_bytes: u64,
-    time: Instant,
-}
+use std::{env, thread::sleep};
 
-impl LinkSpeed {
-    pub fn new(dev: String) -> io::Result<Self> {
-        let rx_bytes_file = File::open(format!("/sys/class/net/{dev}/statistics/rx_bytes"))?;
-        let tx_bytes_file = File::open(format!("/sys/class/net/{dev}/statistics/tx_bytes"))?;
+use crate::{cfg::Config, measure::LinkSpeed};
 
-        Ok(Self {
-            rx: rx_bytes_file,
-            tx: tx_bytes_file,
-            rx_bytes: 0,
-            tx_bytes: 0,
-            time: Instant::now(),
-        })
-    }
+fn main() -> eyre::Result<()> {
+    let config = Config::from_file()?;
 
-    fn read_bytes(file: &mut File) -> io::Result<u64> {
-        file.seek(SeekFrom::Start(0))?;
-        let mut buf = String::new();
-        file.read_to_string(&mut buf)?;
-        Ok(buf.trim().parse().unwrap_or(0))
-    }
+    let arg_netdev = env::args().nth(1);
 
-    fn update(&mut self) -> io::Result<(u64, u64)> {
-        let rx_bytes = Self::read_bytes(&mut self.rx)?;
-        let tx_bytes = Self::read_bytes(&mut self.tx)?;
+    // prefer given argument over the config file
+    #[allow(clippy::match_same_arms)]
+    let netdev_name = match (config.netdev, arg_netdev) {
+        (Some(_), Some(na)) => na,
+        (Some(nc), None) => nc,
+        (None, Some(na)) => na,
+        (None, None) => eyre::bail!("No network device specified"),
+    };
 
-        let mut rx_diff = rx_bytes - self.rx_bytes;
-        let mut tx_diff = tx_bytes - self.tx_bytes;
+    let link_speed = LinkSpeed::new(&netdev_name)?;
 
-        if self.rx_bytes == 0 {
-            self.rx_bytes = rx_bytes;
-            rx_diff = 0;
-        }
-
-        if self.tx_bytes == 0 {
-            self.tx_bytes = tx_bytes;
-            tx_diff = 0;
-        }
-
-        self.rx_bytes = rx_bytes;
-        self.tx_bytes = tx_bytes;
-
-        Ok((rx_diff, tx_diff))
-    }
-
-    pub fn get_measurement(&mut self) -> (f64, f64) {
-        let elapsed = self.time.elapsed().as_secs_f64();
-        let (rx, tx) = self.update().unwrap();
-        let rx_speed = rx as f64 / elapsed;
-        let tx_speed = tx as f64 / elapsed;
-        self.time = Instant::now();
-        (rx_speed, tx_speed)
-    }
-}
-
-impl Iterator for LinkSpeed {
-    type Item = (f64, f64);
-
-    fn next(&mut self) -> Option<Self::Item> {
-        Some(self.get_measurement())
-    }
-}
-
-fn main() {
-    let netdev_name = env::args().nth(1).expect("No network device provided");
-
-    let link_speed = LinkSpeed::new(netdev_name).expect("Failed to create LinkSpeed object");
-
-    link_speed.for_each(|(rx_speed, tx_speed)| {
+    link_speed.for_each(|measurement| {
         println!(
             "RX: {:.0} MBit/s, TX: {:.0} MBit/s",
-            rx_speed / 1024.0 / 1024.0 * 8.0,
-            tx_speed / 1024.0 / 1024.0 * 8.0
+            mbit!(measurement.rx),
+            mbit!(measurement.tx)
         );
-        sleep(Duration::from_millis(1000));
+
+        sleep(config.interval);
     });
+
+    Ok(())
 }

src/math.rs

@@ -0,0 +1,10 @@
+pub(crate) fn safe_u64_to_f64(value: u64) -> eyre::Result<f64> {
+    const MAX_SAFE_INT: u64 = 1 << 53;
+
+    if value < MAX_SAFE_INT {
+        #[allow(clippy::cast_precision_loss)]
+        Ok(value as f64)
+    } else {
+        eyre::bail!("Value {value} exceeds maximum safe integer, potential precision loss")
+    }
+}

src/measure.rs

@@ -0,0 +1,82 @@
+use std::time::Instant;
+
+use crate::{math::safe_u64_to_f64, sysfs::Netdev};
+
+pub(crate) struct LinkSpeed {
+    netdev: Netdev,
+    rx_bytes: u64,
+    tx_bytes: u64,
+    time: Instant,
+}
+
+pub(crate) struct MeasurementSpeed {
+    pub(crate) rx: f64,
+    pub(crate) tx: f64,
+}
+struct MeasurementDiff {
+    rx: u64,
+    tx: u64,
+}
+
+impl LinkSpeed {
+    pub fn new(name: &str) -> eyre::Result<Self> {
+        let netdev = Netdev::from_name(name)?;
+
+        Ok(Self {
+            netdev,
+            rx_bytes: 0,
+            tx_bytes: 0,
+            time: Instant::now(),
+        })
+    }
+
+    fn update(&mut self) -> eyre::Result<MeasurementDiff> {
+        let rx_bytes = self.netdev.rx_bytes()?;
+        let tx_bytes = self.netdev.tx_bytes()?;
+
+        let mut rx_diff = rx_bytes - self.rx_bytes;
+        let mut tx_diff = tx_bytes - self.tx_bytes;
+
+        if self.rx_bytes == 0 {
+            self.rx_bytes = rx_bytes;
+            rx_diff = 0;
+        }
+
+        if self.tx_bytes == 0 {
+            self.tx_bytes = tx_bytes;
+            tx_diff = 0;
+        }
+
+        self.rx_bytes = rx_bytes;
+        self.tx_bytes = tx_bytes;
+
+        Ok(MeasurementDiff {
+            rx: rx_diff,
+            tx: tx_diff,
+        })
+    }
+
+    pub fn get_measurement(&mut self) -> eyre::Result<MeasurementSpeed> {
+        let elapsed = self.time.elapsed().as_secs_f64();
+        let diff = self.update()?;
+        let rx_speed = safe_u64_to_f64(diff.rx)? / elapsed;
+        let tx_speed = safe_u64_to_f64(diff.tx)? / elapsed;
+        self.time = Instant::now();
+        Ok(MeasurementSpeed {
+            rx: rx_speed,
+            tx: tx_speed,
+        })
+    }
+}
+
+impl Iterator for LinkSpeed {
+    type Item = MeasurementSpeed;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        let measurement = self.get_measurement();
+        match measurement {
+            Ok(measurement) => Some(measurement),
+            Err(e) => panic!("Error getting measurement: {e}"),
+        }
+    }
+}

src/sysfs.rs

@@ -0,0 +1,40 @@
+use std::{
+    fs::File,
+    io::{Read as _, Seek as _, SeekFrom},
+};
+
+use eyre::Context as _;
+
+pub(crate) struct Netdev {
+    rx_bytes: File,
+    tx_bytes: File,
+}
+
+impl Netdev {
+    pub fn from_name(name: &str) -> eyre::Result<Self> {
+        let rx_bytes = Self::open_netdev(name, "rx_bytes")?;
+        let tx_bytes = Self::open_netdev(name, "tx_bytes")?;
+
+        Ok(Self { rx_bytes, tx_bytes })
+    }
+
+    fn open_netdev(dev: &str, stat: &str) -> eyre::Result<File> {
+        let path = format!("/sys/class/net/{dev}/statistics/{stat}");
+        File::open(&path).wrap_err(format!("Failed to open netdev '{dev}'"))
+    }
+
+    fn read_bytes(file: &mut File) -> eyre::Result<u64> {
+        file.seek(SeekFrom::Start(0))?;
+        let mut buf = String::new();
+        file.read_to_string(&mut buf)?;
+        Ok(buf.trim().parse().unwrap_or(0))
+    }
+
+    pub fn rx_bytes(&mut self) -> eyre::Result<u64> {
+        Self::read_bytes(&mut self.rx_bytes)
+    }
+
+    pub fn tx_bytes(&mut self) -> eyre::Result<u64> {
+        Self::read_bytes(&mut self.tx_bytes)
+    }
+}