wip: replace dyn Error with concrete

src/init.rs

@@ -3,12 +3,14 @@ mod config;
 pub(crate) mod error;
 
 use std::env;
-use std::error as std_err;
+use anyhow::Context;
 
-pub async fn start() -> Result<(), Box<dyn std_err::Error>> {
+const WINGMATE_CONFIG_PATH: &'static str = "WINGMATE_CONFIG_PATH";
+
+pub async fn start() -> Result<(), error::WingmateInitError> {
     let mut vec_search: Vec<String> = Vec::new();
 
-    match env::var("WINGMATE_CONFIG_PATH") {
+    match env::var(WINGMATE_CONFIG_PATH) {
         Ok(paths) => {
             for p in paths.split(':') {
                 vec_search.push(String::from(p));
@@ -16,7 +18,8 @@ pub async fn start() -> Result<(), Box<dyn std_err::Error>> {
         },
         Err(e) => {
             if let env::VarError::NotUnicode(_) = e {
-                return Err(e.into());
+                return Err(e).context(format!("reading {} env var", WINGMATE_CONFIG_PATH))
+                    .map_err(|e| {error::WingmateInitError::Other { source: e }} );
             } else {
                 vec_search.push(String::from("/etc/wingmate"));
             }