refactor: use log::Level's deserialiser, and link example TOML

lychee-bin/src/main.rs

@@ -64,7 +64,7 @@ use std::path::PathBuf;
 use std::sync::Arc;
 
 use anyhow::{Context, Error, Result, bail};
-use clap::Parser;
+use clap::{Parser, crate_version};
 use commands::{CommandParams, generate};
 use formatters::{get_stats_formatter, log::init_logging};
 use http::HeaderMap;
@@ -266,7 +266,12 @@ fn run_main() -> Result<i32> {
     let opts = match load_config() {
         Ok(opts) => opts,
         Err(e) => {
-            error!("Error while loading config: {e}");
+            error!(
+                "Error while loading config: {}\n\
+                See: https://github.com/lycheeverse/lychee/blob/lychee-v{}/lychee.example.toml",
+                e,
+                crate_version!()
+            );
             exit(ExitCode::ConfigFile as i32);
         }
     };

lychee-bin/src/verbosity.rs

@@ -1,6 +1,7 @@
 use log::Level;
 use log::LevelFilter;
 use serde::Deserialize;
+use std::str::FromStr;
 
 /// Control the verbosity of the CLI output
 ///
@@ -98,19 +99,21 @@ impl<'de> Deserialize<'de> for Verbosity {
     where
         D: serde::Deserializer<'de>,
     {
-        let s = String::deserialize(deserializer)?;
-        let level = match s.to_lowercase().as_str() {
-            "error" => Level::Error,
-            "warn" | "warning" => Level::Warn,
-            "info" => Level::Info,
-            "debug" => Level::Debug,
-            "trace" => Level::Trace,
-            level => {
-                return Err(serde::de::Error::custom(format!(
-                    "invalid log level `{level}`"
-                )));
-            }
+        let custom_error = || {
+            use serde::de::Error;
+            D::Error::custom(
+                r#"invalid verbosity value, expected one of "error", "warn", "info", "debug", or "trace""#,
+            )
         };
+
+        let level = String::deserialize(deserializer).map_err(|_| custom_error())?;
+        let level = if level.eq_ignore_ascii_case("warning") {
+            "warn"
+        } else {
+            &level
+        };
+        let level = log::Level::from_str(level).map_err(|_| custom_error())?;
+
         Ok(Verbosity {
             verbose: level_value(level) as u8,
             quiet: 0,