Let query module return errors

src/bin/indexrs.rs

@@ -89,12 +89,8 @@ fn run_server(config: &Config) {
         scope.spawn(|| rpc::serve(config.rpc_addr(), &query, chan));
         loop {
             thread::sleep(poll_delay);
-            query.update_mempool();
-            let current_tip = daemon
-                .getbestblockhash()
-                .expect("failed to get latest blockhash");
-
-            if tip == current_tip {
+            query.update_mempool().unwrap();
+            if tip == daemon.getbestblockhash().unwrap() {
                 continue;
             }
             tip = index.update(&store, &daemon);

src/query.rs

@@ -11,6 +11,8 @@ use mempool::Tracker;
 use store::Store;
 use types::HashPrefix;
 
+error_chain!{}
+
 pub struct FundingOutput {
     pub txn_id: Sha256dHash,
     pub height: i32,
@@ -207,11 +209,11 @@ impl<'a> Query<'a> {
         Some((merkle, pos))
     }
 
-    pub fn update_mempool(&self) {
+    pub fn update_mempool(&self) -> Result<()> {
         self.tracker
             .write()
             .unwrap()
             .update(self.daemon)
-            .expect("failed to update mempool")
+            .chain_err(|| "failed to update mempool")
     }
 }