BM-658: Add proper error handling for eth value string parsing failure (#411)

- Addresses silent failure on parsing highlighted in
#321 (comment)

Author: willemolding

Diff for: crates/broker/src/bin/broker.rs

@@ -33,11 +33,18 @@ async fn main() -> Result<()> {
         CustomRetryPolicy,
     );
     let client = RpcClient::builder().layer(retry_layer).http(args.rpc_url.clone());
-
     let balance_alerts_layer = BalanceAlertLayer::new(BalanceAlertConfig {
         watch_address: wallet.default_signer().address(),
-        warn_threshold: config.market.balance_warn_threshold.and_then(|s| parse_ether(&s).ok()),
-        error_threshold: config.market.balance_error_threshold.and_then(|s| parse_ether(&s).ok()),
+        warn_threshold: config
+            .market
+            .balance_warn_threshold
+            .map(|s| parse_ether(&s))
+            .transpose()?,
+        error_threshold: config
+            .market
+            .balance_error_threshold
+            .map(|s| parse_ether(&s))
+            .transpose()?,
     });
 
     let provider = ProviderBuilder::new()

Diff for: crates/broker/src/order_monitor.rs

@@ -78,12 +78,14 @@ where
                     .market
                     .stake_balance_warn_threshold
                     .as_ref()
-                    .and_then(|s| parse_ether(s).ok()),
+                    .map(|s| parse_ether(s))
+                    .transpose()?,
                 &config
                     .market
                     .stake_balance_error_threshold
                     .as_ref()
-                    .and_then(|s| parse_ether(s).ok()),
+                    .map(|s| parse_ether(s))
+                    .transpose()?,
             );
         }