feat: print config snippets of error location

src/config.rs

@@ -4,6 +4,7 @@ use std::{
     path::{Path, PathBuf},
 };
 
+use miette::{NamedSource, Result, SourceOffset};
 use serde::Deserialize;
 
 use crate::error::Error;
@@ -21,26 +22,31 @@ pub struct Config {
 
 pub fn read<P>(filename: P) -> Result<Config, Error>
 where
-    P: AsRef<Path> + AsRef<OsStr>,
+    P: AsRef<Path>,
+    P: AsRef<OsStr>,
 {
     let file_content = fs::read_to_string(&filename).map_err(|_| Error::ConfigNotFound {
         path: PathBuf::from(&filename),
     })?;
-    deserialize(&file_content)
+    deserialize(&file_content, &filename)
 }
 
 /// Deserialize config intro struct.
-/// # Errors
-///
-/// Will return `Err` if deserialization error.
-/// Possibly the error contains a position (line number) of the occurred error
-/// But this is not accurate. All the other apps that depend on toml.rs
-/// share the same faith.
-fn deserialize(content: &str) -> Result<Config, Error> {
+fn deserialize<P>(content: &str, filename: P) -> Result<Config, Error>
+where
+    P: AsRef<Path>,
+    P: AsRef<OsStr>,
+{
     match toml::from_str(content) {
         Ok(config) => Ok(config),
-        Err(e) => Err(Error::InvalidConfig {
-            message: e.to_string(),
-        }),
+        Err(e) => {
+            let (line, column) = &e.line_col().unwrap_or((0, 0));
+            let filename = Path::new(&filename);
+            Err(Error::InvalidConfig {
+                src: NamedSource::new(filename.to_string_lossy(), content.to_owned()),
+                bad_bit: SourceOffset::from_location(content, line + 1, column + 1),
+                message: e.to_string(),
+            })?
+        }
     }
 }

src/error.rs

@@ -1,6 +1,6 @@
 use std::path::PathBuf;
 
-use miette::Diagnostic;
+use miette::{Diagnostic, NamedSource, SourceOffset};
 use thiserror::Error;
 
 /// all possible errors returned by the app.
@@ -29,7 +29,13 @@ pub enum Error {
         url(docsrs),
         help("See the configuration example https://github.com/BiznetGIO/digs#usage")
     )]
-    InvalidConfig { message: String },
+    InvalidConfig {
+        #[source_code]
+        src: NamedSource,
+        #[label("{message}")]
+        bad_bit: SourceOffset,
+        message: String,
+    },
 }
 
 impl std::convert::From<std::io::Error> for Error {

src/main.rs

@@ -20,7 +20,8 @@ fn run() -> Result<()> {
         cli::RecordType::TXT => RecordType::TXT,
     };
 
-    let printer = Printer::new(domain, record_type, opts.config);
+    let config_file = opts.config;
+    let printer = Printer::new(domain, record_type, config_file);
     printer.print()?;
     Ok(())
 }

src/output.rs

@@ -10,19 +10,19 @@ use crate::{config, dns};
 pub struct Printer {
     domain: String,
     record_type: RecordType,
-    config: PathBuf,
+    config_file: PathBuf,
 }
 
 impl Printer {
     pub fn new(domain: String, record_type: RecordType, config: PathBuf) -> Self {
         Self {
             domain,
             record_type,
-            config,
+            config_file: config,
         }
     }
     pub fn print(&self) -> Result<(), Error> {
-        let config = config::read(&self.config)?;
+        let config = config::read(&self.config_file)?;
 
         for server in config.servers {
             let response = dns::query(&self.domain, self.record_type, &server.ip);