Add some error chaining to log more on auth failure

src/controllers/util.rs

@@ -42,11 +42,12 @@ impl<'a> UserAuthenticationExt for dyn Request + 'a {
                         user_id: token.user_id,
                         token_id: Some(token.id),
                     })
-                    // Convert a NotFound (or other database error) into Unauthorized
-                    .map_err(|_| Box::new(Unauthorized) as Box<dyn AppError>)
+                    .chain_error(|| internal("invalid token"))
+                    .chain_error(|| Box::new(Unauthorized) as Box<dyn AppError>)
             } else {
                 // Unable to authenticate the user
-                Err(Box::new(Unauthorized))
+                Err(internal("no cookie session or auth header found"))
+                    .chain_error(|| Box::new(Unauthorized) as Box<dyn AppError>)
             }
         }
     }

src/middleware/block_traffic.rs

@@ -47,6 +47,8 @@ impl Handler for BlockTraffic {
             .iter()
             .any(|value| self.blocked_values.iter().any(|v| v == value));
         if has_blocked_value {
+            let cause = format!("blocked due to contents of header {}", self.header_name);
+            super::log_request::add_custom_metadata(req, "cause", cause);
             let body = format!(
                 "We are unable to process your request at this time. \
                  This usually means that you are in violation of our crawler \

src/middleware/require_user_agent.rs

@@ -24,6 +24,7 @@ impl Handler for RequireUserAgent {
         let has_user_agent = request_header(req, "User-Agent") != "";
         let is_download = req.path().ends_with("download");
         if !has_user_agent && !is_download {
+            super::log_request::add_custom_metadata(req, "cause", "no user agent");
             let body = format!(
                 include_str!("no_user_agent_message.txt"),
                 request_header(req, "X-Request-Id"),