improve error formatting

src/main.rs

@@ -171,7 +171,7 @@ impl Resources {
         let (etag, last_modified, events) =
             self.worker_fetch(&cal_id, &cal_opts, etag, last_modified)
             .map_err(|e| {
-                let msg = format!("{:?}", e);
+                let msg = format!("{}", e);
                 println!("[{}] {}", cal_id, msg);
                 let _ = diesel::update(calendars)
                     .filter(schema::calendars::dsl::id.eq(cal_id.clone()))
@@ -211,7 +211,7 @@ impl Resources {
         let mut done = false;
         while ! done {
             done = self.worker_job(&db)
-                .map_err(|e| println!("{:?}", e))
+                .map_err(|e| println!("{}", e))
                 .unwrap_or(false);
         }
         Ok(())
@@ -251,6 +251,18 @@ impl From<std::io::Error> for Error {
     }
 }
 
+impl std::fmt::Display for Error {
+    fn fmt(&self, fmt: &mut std::fmt::Formatter) -> Result<(), std::fmt::Error> {
+        match self {
+            Error::DbConnection(e) => e.fmt(fmt),
+            Error::Db(e) => e.fmt(fmt),
+            Error::Http(e) => e.fmt(fmt),
+            Error::Io(e) => e.fmt(fmt),
+            Error::Message(e) => e.fmt(fmt),
+        }
+    }
+}
+
 fn main() {
     let config_file = read_to_string("config.yaml")
         .expect("config.yaml");
@@ -267,7 +279,7 @@ fn main() {
         let workers: Vec<_> = (0..cpus)
             .map(|_| s.spawn(|_| {
                 res.worker_loop()
-                    .map_err(|e| println!("{:?}", e))
+                    .map_err(|e| println!("{}", e))
             }))
             .collect();
         for worker in workers.into_iter() {