chore: Include previous status to failed metric (#735)

* chore: Include previous status to failed metric

* chore: Improvements

Author: zeljkoX

src/metrics/mod.rs

@@ -138,9 +138,12 @@ lazy_static! {
     };
 
     // Counter for failed transactions (Failed, Expired, Canceled statuses).
+    // Labels: relayer_id, network_type, failure_reason, previous_status.
+    // Note: `previous_status` label added to track the pipeline stage before the failure
+    // (e.g. "pending", "sent", "submitted"), enabling pre- vs post-submission attribution.
     pub static ref TRANSACTIONS_FAILED: CounterVec = {
         let opts = Opts::new("transactions_failed_total", "Total number of failed transactions");
-        let counter_vec = CounterVec::new(opts, &["relayer_id", "network_type", "failure_reason"]).unwrap();
+        let counter_vec = CounterVec::new(opts, &["relayer_id", "network_type", "failure_reason", "previous_status"]).unwrap();
         REGISTRY.register(Box::new(counter_vec.clone())).unwrap();
         counter_vec
     };

src/repositories/transaction/transaction_redis.rs

@@ -694,6 +694,7 @@ impl RedisTransactionRepository {
         let is_final = is_final_state(new_status);
 
         if !was_final && is_final {
+            let previous_status = format!("{old_status:?}").to_lowercase();
             let meta = updated_tx.metadata.as_ref();
             let had_insufficient_fee = meta.is_some_and(|m| m.insufficient_fee_retries > 0);
             let had_try_again_later = meta.is_some_and(|m| m.try_again_later_retries > 0);
@@ -772,17 +773,32 @@ impl RedisTransactionRepository {
                         })
                         .unwrap_or("failed");
                     TRANSACTIONS_FAILED
-                        .with_label_values(&[relayer_id, &network_type, failure_reason])
+                        .with_label_values(&[
+                            relayer_id,
+                            &network_type,
+                            failure_reason,
+                            &previous_status,
+                        ])
                         .inc();
                 }
                 TransactionStatus::Expired => {
                     TRANSACTIONS_FAILED
-                        .with_label_values(&[relayer_id, &network_type, "expired"])
+                        .with_label_values(&[
+                            relayer_id,
+                            &network_type,
+                            "expired",
+                            &previous_status,
+                        ])
                         .inc();
                 }
                 TransactionStatus::Canceled => {
                     TRANSACTIONS_FAILED
-                        .with_label_values(&[relayer_id, &network_type, "canceled"])
+                        .with_label_values(&[
+                            relayer_id,
+                            &network_type,
+                            "canceled",
+                            &previous_status,
+                        ])
                         .inc();
                 }
                 _ => {}