refactor(runner): use custom error types with thiserror and miette

Cargo.lock

@@ -770,6 +770,7 @@ dependencies = [
  "miette",
  "rustls",
  "serde",
+ "thiserror",
  "tokio",
  "tokio-rustls",
  "toml",

runner/Cargo.toml

@@ -9,13 +9,14 @@ clap.workspace = true
 common.workspace = true
 miette.workspace = true
 rustls.workspace = true
+serde.workspace = true
+thiserror.workspace = true
 tokio-rustls.workspace = true
 tokio.workspace = true
-tracing.workspace = true
-tracing-subscriber.workspace = true
-uuid.workspace = true
-serde.workspace = true
 toml.workspace = true
+tracing-subscriber.workspace = true
+tracing.workspace = true
+uuid.workspace = true
 
 [lints]
 workspace = true

runner/src/config.rs

@@ -1,6 +1,5 @@
-use crate::args::Args;
+use crate::{args::Args, error};
 use common::KeyExchangeMode;
-use miette::{Context, IntoDiagnostic, miette};
 use serde::Deserialize;
 use std::{fs::read_to_string, net::SocketAddr, path::PathBuf};
 
@@ -23,16 +22,9 @@ pub struct Config {
 ///
 /// # Errors
 /// Returns an error if the file cannot be read or parsed.
-pub fn load_from_file(path: &PathBuf) -> miette::Result<Config> {
-    let content = read_to_string(path)
-        .into_diagnostic()
-        .context(format!("failed to read config file: {}", path.display()))?;
-    let config = toml::from_str::<Config>(&content)
-        .into_diagnostic()
-        .context(format!(
-            "failed to parse TOML config from file {}",
-            path.display()
-        ))?;
+pub fn load_from_file(path: &PathBuf) -> error::Result<Config> {
+    let content = read_to_string(path).map_err(error::Error::Io)?;
+    let config = toml::from_str::<Config>(&content).map_err(error::Error::Toml)?;
     Ok(config)
 }
 
@@ -40,7 +32,7 @@ pub fn load_from_file(path: &PathBuf) -> miette::Result<Config> {
 ///
 /// # Errors
 /// Never returns an error, but returns Result for consistency.
-pub fn load_from_cli(args: &Args) -> miette::Result<Config> {
+pub fn load_from_cli(args: &Args) -> error::Result<Config> {
     Ok(Config {
         benchmarks: vec![BenchmarkConfig {
             mode: args.mode.to_string(),
@@ -50,7 +42,7 @@ pub fn load_from_cli(args: &Args) -> miette::Result<Config> {
             concurrency: args.concurrency,
             server: args
                 .server
-                .ok_or_else(|| miette!("--server is required when not using --config"))?,
+                .ok_or_else(|| error::Error::config("--server ir required"))?,
         }],
     })
 }

runner/src/error.rs

@@ -0,0 +1,72 @@
+//! Error types for the benchmark runner.
+
+use miette::Diagnostic;
+use thiserror::Error;
+
+/// Result type using the runner's custom error type.
+pub type Result<T> = std::result::Result<T, Error>;
+
+/// Errors that can occur during benchmark execution.
+#[derive(Debug, Error, Diagnostic)]
+pub enum Error {
+    /// TLS configuration or handshake failure.
+    #[error(transparent)]
+    #[diagnostic(code(runner::tls_error))]
+    TlsConfig(#[from] rustls::Error),
+
+    /// File or network I/O error.
+    #[error(transparent)]
+    #[diagnostic(code(runner::io_error))]
+    Io(#[from] std::io::Error),
+
+    /// TOML configuration file parse error.
+    #[error(transparent)]
+    #[diagnostic(code(runner::toml_error))]
+    Toml(#[from] toml::de::Error),
+
+    /// Invalid key exchange mode string.
+    #[error("Invalid mode: {0}")]
+    #[diagnostic(code(runner::invalid_mode))]
+    InvalidMode(String),
+
+    /// Configuration validation or missing required fields.
+    #[error("Config error: {0}")]
+    #[diagnostic(code(runner::config_error))]
+    Config(String),
+
+    /// Network connection failure.
+    #[error("Network error: {0}")]
+    #[diagnostic(code(runner::network_error))]
+    Network(String),
+
+    /// Protocol-level error (malformed requests, unexpected responses).
+    #[error("Protocol error: {0}")]
+    #[diagnostic(code(runner::protocol_error))]
+    Protocol(String),
+}
+
+impl Error {
+    /// Create an invalid mode error.
+    #[inline]
+    pub fn invalid_mode(error: impl Into<String>) -> Self {
+        Self::InvalidMode(error.into())
+    }
+
+    /// Create a config error.
+    #[inline]
+    pub fn config(error: impl Into<String>) -> Self {
+        Self::Config(error.into())
+    }
+
+    /// Create a network error.
+    #[inline]
+    pub fn network(error: impl Into<String>) -> Self {
+        Self::Network(error.into())
+    }
+
+    /// Create a protocol error.
+    #[inline]
+    pub fn protocol(error: impl Into<String>) -> Self {
+        Self::Protocol(error.into())
+    }
+}

runner/src/lib.rs

@@ -1,2 +1,3 @@
 pub mod args;
 pub mod config;
+pub mod error;