[release] linkspeed v0.1.2

Cargo.lock

@@ -20,7 +20,7 @@ checksum = "ce23b50ad8242c51a442f3ff322d56b02f08852c77e4c0b4d3fd684abc89c683"
 
 [[package]]
 name = "linkspeed"
-version = "0.1.1"
+version = "0.1.2"
 dependencies = [
  "eyre",
 ]

Cargo.toml

@@ -1,12 +1,13 @@
 [package]
 name = "linkspeed"
-version = "0.1.1"
+version = "0.1.2"
 edition = "2024"
 
 [lints.rust]
 unsafe_code = "forbid"
 
 [lints.clippy]
+redundant_closure_for_method_calls = "allow"
 similar_names = "allow"
 
 pedantic = { level = "warn", priority = -1 }

src/main.rs

@@ -6,6 +6,8 @@ mod sysfs;
 
 use std::{env, thread::sleep};
 
+use sysfs::NetdevError;
+
 use crate::{cfg::Config, measure::LinkSpeed};
 
 fn main() -> eyre::Result<()> {
@@ -19,7 +21,12 @@ fn main() -> eyre::Result<()> {
         (Some(_), Some(na)) => na,
         (Some(nc), None) => nc,
         (None, Some(na)) => na,
-        (None, None) => eyre::bail!("No network device specified"),
+        (None, None) => {
+            eyre::bail!(
+                "No network device specified. Please provide a network device name as an argument or in the config file.\n\n{}",
+                NetdevError::available_netdevs_msg()
+            );
+        }
     };
 
     let link_speed = LinkSpeed::new(&netdev_name)?;

src/sysfs.rs

@@ -3,24 +3,73 @@ use std::{
     io::{Read as _, Seek as _, SeekFrom},
 };
 
-use eyre::Context as _;
-
-pub(crate) struct Netdev {
+pub struct Netdev {
     rx_bytes: File,
     tx_bytes: File,
 }
 
+#[derive(Debug)]
+pub enum NetdevError {
+    NotFound { name: String },
+    IoError { name: String, err: std::io::Error },
+}
+
+impl NetdevError {
+    pub fn available_netdevs_msg() -> String {
+        let list = Netdev::list()
+            .unwrap_or_default()
+            .into_iter()
+            .map(|dev| format!("    {dev}"))
+            .collect::<Vec<_>>()
+            .join("\n");
+
+        format!("Available network devices:\n{list}")
+    }
+}
+
+impl std::fmt::Display for NetdevError {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            NetdevError::NotFound { name } => write!(
+                f,
+                "Netdev '{name}' not found.\n\n{}",
+                Self::available_netdevs_msg()
+            ),
+            NetdevError::IoError { name, err } => {
+                write!(f, "I/O Error occurred for netdev '{name}': {err}")
+            }
+        }
+    }
+}
+
 impl Netdev {
+    const SYS_CLASS_NET: &'static str = "/sys/class/net";
+
     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")?;
+        let rx_bytes = Self::open_netdev_stat(name, "rx_bytes")?;
+        let tx_bytes = Self::open_netdev_stat(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 open_netdev_stat(name: &str, stat: &str) -> eyre::Result<File> {
+        let sys_class_net = Self::SYS_CLASS_NET;
+        let path = format!("{sys_class_net}/{name}/statistics/{stat}");
+        match File::open(&path) {
+            Ok(file) => Ok(file),
+            Err(e) => {
+                if e.kind() == std::io::ErrorKind::NotFound {
+                    Err(eyre::eyre!(NetdevError::NotFound {
+                        name: name.to_string(),
+                    }))
+                } else {
+                    Err(eyre::eyre!(NetdevError::IoError {
+                        name: name.to_string(),
+                        err: e,
+                    }))
+                }
+            }
+        }
     }
 
     fn read_bytes(file: &mut File) -> eyre::Result<u64> {
@@ -37,4 +86,17 @@ impl Netdev {
     pub fn tx_bytes(&mut self) -> eyre::Result<u64> {
         Self::read_bytes(&mut self.tx_bytes)
     }
+
+    pub fn list() -> eyre::Result<Vec<String>> {
+        let mut entries = std::fs::read_dir(Self::SYS_CLASS_NET)?
+            .filter_map(|entry| {
+                entry
+                    .ok()
+                    .and_then(|entry| entry.file_name().into_string().ok())
+            })
+            .collect::<Vec<_>>();
+
+        entries.sort();
+        Ok(entries)
+    }
 }