Log tokens that gave errors interacting with their functions

apps/explorer/config/config.exs

@@ -11,7 +11,7 @@ config :ecto, json_library: Jason
 config :explorer,
   ecto_repos: [Explorer.Repo],
   coin: System.get_env("COIN") || "POA",
-  token_functions_reader_retry: 3
+  token_functions_reader_max_retries: 3
 
 config :explorer, Explorer.Integrations.EctoLogger, query_time_ms_threshold: 2_000
 

apps/explorer/config/dev.exs

@@ -13,6 +13,11 @@ config :logger, :explorer,
   level: :debug,
   path: Path.absname("logs/dev/explorer.log")
 
+config :logger, :reading_token_functions,
+  level: :debug,
+  path: Path.absname("logs/dev/explorer/tokens/reading_functions.log"),
+  metadata_filter: [fetcher: :token_functions]
+
 import_config "dev.secret.exs"
 
 variant =

apps/explorer/config/prod.exs

@@ -14,6 +14,12 @@ config :logger, :explorer,
   path: Path.absname("logs/prod/explorer.log"),
   rotate: %{max_bytes: 52_428_800, keep: 19}
 
+config :logger, :reading_token_functions,
+  level: :debug,
+  path: Path.absname("logs/prod/explorer/tokens/reading_functions.log"),
+  metadata_filter: [fetcher: :token_functions],
+  rotate: %{max_bytes: 52_428_800, keep: 19}
+
 variant =
   if is_nil(System.get_env("ETHEREUM_JSONRPC_VARIANT")) do
     "parity"

apps/explorer/lib/explorer/token/functions_reader.ex

@@ -3,6 +3,8 @@ defmodule Explorer.Token.FunctionsReader do
   Reads Token's fields using Smart Contract functions from the blockchain.
   """
 
+  require Logger
+
   alias Explorer.Chain.Hash
   alias Explorer.SmartContract.Reader
 
@@ -92,7 +94,7 @@ defmodule Explorer.Token.FunctionsReader do
     decimals: 18
   }
 
-  It will retry to fetch each function in the Smart Contract according to :token_fetcher_retry
+  It will retry to fetch each function in the Smart Contract according to :token_functions_reader_max_retries
   configured in the application env case one of them raised error.
   """
   @spec get_functions_of(Hash.t()) :: Map.t()
@@ -110,39 +112,65 @@ defmodule Explorer.Token.FunctionsReader do
   end
 
   defp fetch_functions_from_contract(contract_address_hash, contract_functions) do
-    retry = Application.get_env(:explorer, :token_functions_reader_retry)
+    max_retries = Application.get_env(:explorer, :token_functions_reader_max_retries)
+    functions_fetched = %{}
+
+    fetch_functions_from_contract(contract_address_hash, contract_functions, max_retries, functions_fetched)
+  end
 
-    fetch_functions_from_contract(contract_address_hash, contract_functions, retry)
+  defp fetch_functions_from_contract(contract_address_hash, contract_functions, retries_left, functions_fetched)
+       when retries_left == 0 do
+    contract_functions_result = Reader.query_contract(contract_address_hash, @contract_abi, contract_functions)
+
+    Map.merge(functions_fetched, contract_functions_result)
   end
 
-  defp fetch_functions_from_contract(contract_address_hash, contract_functions, retry, result \\ %{}) do
+  defp fetch_functions_from_contract(contract_address_hash, contract_functions, retries_left, functions_fetched)
+       when retries_left > 0 do
     contract_functions_result = Reader.query_contract(contract_address_hash, @contract_abi, contract_functions)
 
-    contract_functions_with_errors = contract_functions_with_errors(contract_functions_result)
+    functions_with_errors =
+      Enum.filter(contract_functions_result, fn function ->
+        case function do
+          {_, {:error, _}} -> true
+          {_, {:ok, _}} -> false
+        end
+      end)
+
+    if Enum.any?(functions_with_errors) do
+      log_functions_with_errors(contract_address_hash, functions_with_errors, retries_left)
+
+      contract_functions_with_errors =
+        Map.take(
+          contract_functions,
+          Enum.map(functions_with_errors, fn {function, _} -> function end)
+        )
 
-    if Enum.any?(contract_functions_with_errors) && retry > 0 do
       fetch_functions_from_contract(
         contract_address_hash,
         contract_functions_with_errors,
-        retry - 1,
-        Map.merge(result, contract_functions_result)
+        retries_left - 1,
+        Map.merge(functions_fetched, contract_functions_result)
       )
     else
-      Map.merge(result, contract_functions_result)
+      Map.merge(functions_fetched, contract_functions_result)
     end
   end
 
-  defp contract_functions_with_errors(contract_functions) do
-    contract_functions
-    |> Enum.filter(fn function ->
-      case function do
-        {_, {:error, _}} -> true
-        {_, {:ok, _}} -> false
-      end
-    end)
-    |> Enum.reduce(%{}, fn {name, _error}, acc ->
-      Map.put(acc, name, [])
+  defp log_functions_with_errors(contract_address_hash, functions_with_errors, retries_left) do
+    error_messages =
+      Enum.map(functions_with_errors, fn {function, {:error, error_message}} ->
+        "function: #{function} - error: #{error_message} \n"
       end)
+
+    Logger.debug(
+      [
+        "<Token contract hash: #{contract_address_hash}> error while fetching metadata: \n",
+        error_messages,
+        "Retries left: #{retries_left}"
+      ],
+      fetcher: :token_functions
+    )
   end
 
   defp format_contract_functions_result(contract_functions, contract_address_hash) do

config/config.exs

@@ -25,7 +25,8 @@ config :logger,
     {LoggerFileBackend, :explorer},
     # only :indexer, but all levels
     {LoggerFileBackend, :indexer},
-    {LoggerFileBackend, :indexer_token_balances}
+    {LoggerFileBackend, :indexer_token_balances},
+    {LoggerFileBackend, :reading_token_functions}
   ]
 
 config :logger, :console,