Handle error at first trace request

CHANGELOG.md

@@ -1,7 +1,7 @@
 ## Current
 
 ### Features
-- [#3013](https://github.com/poanetwork/blockscout/pull/3013) - Raw trace of transaction on-demand
+- [#3013](https://github.com/poanetwork/blockscout/pull/3013), [#3026](https://github.com/poanetwork/blockscout/pull/3026) - Raw trace of transaction on-demand
 - [#3000](https://github.com/poanetwork/blockscout/pull/3000) - Get rid of storing of internal transactions for simple coin transfers
 - [#2875](https://github.com/poanetwork/blockscout/pull/2875) - Save contract code from Parity genesis file
 - [#2834](https://github.com/poanetwork/blockscout/pull/2834) - always redirect to checksummed hash

apps/block_scout_web/lib/block_scout_web/controllers/transaction_raw_trace_controller.ex

@@ -35,7 +35,7 @@ defmodule BlockScoutWeb.TransactionRawTraceController do
         if first_trace_exists do
           internal_transactions
         else
-          {:ok, first_trace_params} =
+          response =
             Chain.fetch_first_trace(
               [
                 %{
@@ -48,6 +48,8 @@ defmodule BlockScoutWeb.TransactionRawTraceController do
               json_rpc_named_arguments
             )
 
+          case response do
+            {:ok, first_trace_params} ->
               InternalTransactions.run_insert_only(first_trace_params, %{
                 timeout: :infinity,
                 timestamps: Import.timestamps(),
@@ -55,6 +57,10 @@ defmodule BlockScoutWeb.TransactionRawTraceController do
               })
 
               Chain.all_transaction_to_internal_transactions(hash)
+
+            {:error, _} ->
+              internal_transactions
+          end
         end
 
       render(

apps/ethereum_jsonrpc/lib/ethereum_jsonrpc/parity.ex

@@ -2,7 +2,7 @@ defmodule EthereumJSONRPC.Parity do
   @moduledoc """
   Ethereum JSONRPC methods that are only supported by [Parity](https://wiki.parity.io/).
   """
-
+  require Logger
   import EthereumJSONRPC, only: [id_to_params: 1, integer_to_quantity: 1, json_rpc: 2, request: 1]
 
   alias EthereumJSONRPC.Parity.{FetchedBeneficiaries, Traces}
@@ -53,17 +53,33 @@ defmodule EthereumJSONRPC.Parity do
   def fetch_first_trace(transactions_params, json_rpc_named_arguments) when is_list(transactions_params) do
     id_to_params = id_to_params(transactions_params)
 
-    with {:ok, responses} <-
+    trace_replay_transaction_response =
       id_to_params
       |> trace_replay_transaction_requests()
-           |> json_rpc(json_rpc_named_arguments) do
-      {:ok, [first_trace]} = trace_replay_transaction_responses_to_first_trace_params(responses, id_to_params)
+      |> json_rpc(json_rpc_named_arguments)
 
+    case trace_replay_transaction_response do
+      {:ok, responses} ->
+        case trace_replay_transaction_responses_to_first_trace_params(responses, id_to_params) do
+          {:ok, [first_trace]} ->
             %{block_hash: block_hash} =
               transactions_params
               |> Enum.at(0)
 
-      {:ok, [%{first_trace: first_trace, block_hash: block_hash, json_rpc_named_arguments: json_rpc_named_arguments}]}
+            {:ok,
+             [%{first_trace: first_trace, block_hash: block_hash, json_rpc_named_arguments: json_rpc_named_arguments}]}
+
+          {:error, error} ->
+            Logger.error(inspect(error))
+            {:error, error}
+        end
+
+      {:error, :econnrefused} ->
+        {:error, :econnrefused}
+
+      {:error, [error]} ->
+        Logger.error(inspect(error))
+        {:error, error}
     end
   end
 

apps/explorer/lib/explorer/chain.ex

@@ -4070,10 +4070,13 @@ defmodule Explorer.Chain do
   Fetches the first trace from the Parity trace URL.
   """
   def fetch_first_trace(transactions_params, json_rpc_named_arguments) do
-    {:ok, [%{first_trace: first_trace, block_hash: block_hash, json_rpc_named_arguments: json_rpc_named_arguments}]} =
-      EthereumJSONRPC.fetch_first_trace(transactions_params, json_rpc_named_arguments)
-
+    case EthereumJSONRPC.fetch_first_trace(transactions_params, json_rpc_named_arguments) do
+      {:ok, [%{first_trace: first_trace, block_hash: block_hash, json_rpc_named_arguments: json_rpc_named_arguments}]} ->
         format_tx_first_trace(first_trace, block_hash, json_rpc_named_arguments)
+
+      {:error, error} ->
+        {:error, error}
+    end
   end
 
   defp format_tx_first_trace(first_trace, block_hash, json_rpc_named_arguments) do