fix: Rework initialization of the `RollupL1ReorgMonitor` and fix `read_system_config` for fallback cases (#11275)

* Fix init in RollupL1ReorgMonitor

* Update PULL_REQUEST_TEMPLATE

* Fix init in RollupL1ReorgMonitor

* Update PULL_REQUEST_TEMPLATE

* Fix read_system_config function for fallback cases

* Update rollup_l1_reorg_monitor.ex

Co-authored-by: Victor Baranov <baranov.viktor.27@gmail.com>

---------

Co-authored-by: POA <33550681+poa@users.noreply.github.com>
Co-authored-by: Victor Baranov <baranov.viktor.27@gmail.com>

PULL_REQUEST_TEMPLATE.md

@@ -27,6 +27,6 @@
 - [ ] If I added new functionality, I added tests covering it.
 - [ ] If I fixed a bug, I added a regression test to prevent the bug from silently reappearing again.
 - [ ] I checked whether I should update the docs and did so by submitting a PR to [docs repository](https://github.com/blockscout/docs).
-- [ ] If I added/changed/removed ENV var, I submitted a PR to [docs repository](https://github.com/blockscout/docs) to update the list of [env vars](https://github.com/blockscout/docs/blob/master/for-developers/information-and-settings/env-variables.md) and I updated the version to `master` in the Version column. If I removed variable, I added it to [Deprecated ENV Variables](https://github.com/blockscout/docs/blob/master/for-developers/information-and-settings/env-variables/deprecated-env-variables/README.md) page. After merging docs PR, changes will be reflected in these [pages](https://docs.blockscout.com/for-developers/information-and-settings/env-variables).
+- [ ] If I added/changed/removed ENV var, I submitted a PR to [docs repository](https://github.com/blockscout/docs) to update the list of [env vars](https://github.com/blockscout/docs/blob/master/setup/env-variables/README.md) and I updated the version to `master` in the Version column. If I removed variable, I added it to [Deprecated ENV Variables](https://github.com/blockscout/docs/blob/master/setup/env-variables/deprecated-env-variables/README.md) page. After merging docs PR, changes will be reflected in these [pages](https://docs.blockscout.com/setup/env-variables).
 - [ ] If I added new DB indices, I checked, that they are not redundant, with PGHero or other tools.
 - [ ] If I added/removed chain type, I modified the Github CI matrix and PR labels accordingly.

apps/indexer/lib/indexer/fetcher/optimism.ex

@@ -20,6 +20,7 @@ defmodule Indexer.Fetcher.Optimism do
   alias EthereumJSONRPC.Block.ByNumber
   alias EthereumJSONRPC.Contract
   alias Explorer.Repo
+  alias Indexer.Fetcher.RollupL1ReorgMonitor
   alias Indexer.Helper
 
   @fetcher_name :optimism
@@ -238,8 +239,7 @@ defmodule Indexer.Fetcher.Optimism do
     optimism_l1_rpc = l1_rpc_url()
 
     with {:system_config_valid, true} <- {:system_config_valid, Helper.address_correct?(system_config)},
-         {:reorg_monitor_started, true} <-
-           {:reorg_monitor_started, !is_nil(Process.whereis(Indexer.Fetcher.RollupL1ReorgMonitor))},
+         _ <- RollupL1ReorgMonitor.wait_for_start(caller),
          {:rpc_l1_undefined, false} <- {:rpc_l1_undefined, is_nil(optimism_l1_rpc)},
          json_rpc_named_arguments = json_rpc_named_arguments(optimism_l1_rpc),
          {optimism_portal, start_block_l1} <- read_system_config(system_config, json_rpc_named_arguments),
@@ -275,13 +275,6 @@ defmodule Indexer.Fetcher.Optimism do
          stop: false
        }}
     else
-      {:reorg_monitor_started, false} ->
-        Logger.error(
-          "Cannot start this process as reorg monitor in Indexer.Fetcher.RollupL1ReorgMonitor is not started."
-        )
-
-        {:stop, :normal, %{}}
-
       {:rpc_l1_undefined, true} ->
         Logger.error("L1 RPC URL is not defined.")
         {:stop, :normal, %{}}
@@ -353,23 +346,46 @@ defmodule Indexer.Fetcher.Optimism do
 
     error_message = &"Cannot call public getters of SystemConfig. Error: #{inspect(&1)}"
 
-    case Helper.repeated_call(
-           &json_rpc/2,
-           [requests, json_rpc_named_arguments],
-           error_message,
-           Helper.finite_retries_number()
-         ) do
-      {:ok, responses} ->
-        "0x000000000000000000000000" <> optimism_portal = Enum.at(responses, 0).result
-        start_block = quantity_to_integer(Enum.at(responses, 1).result)
-        {"0x" <> optimism_portal, start_block}
+    env = Application.get_all_env(:indexer)[__MODULE__]
+    fallback_start_block = env[:start_block_l1]
+
+    {optimism_portal, start_block} =
+      case Helper.repeated_call(
+             &json_rpc/2,
+             [requests, json_rpc_named_arguments],
+             error_message,
+             Helper.finite_retries_number()
+           ) do
+        {:ok, responses} ->
+          optimism_portal_result = Map.get(Enum.at(responses, 0), :result)
+
+          optimism_portal =
+            with {:nil_result, true, _} <- {:nil_result, is_nil(optimism_portal_result), optimism_portal_result},
+                 {:fallback_defined, true} <- {:fallback_defined, Helper.address_correct?(env[:portal])} do
+              env[:portal]
+            else
+              {:nil_result, false, portal} ->
+                "0x000000000000000000000000" <> optimism_portal = portal
+                "0x" <> optimism_portal
+
+              {:fallback_defined, false} ->
+                nil
+            end
+
+          start_block =
+            responses
+            |> Enum.at(1)
+            |> Map.get(:result, fallback_start_block)
+            |> quantity_to_integer()
+
+          {optimism_portal, start_block}
 
-      _ ->
-        env = Application.get_all_env(:indexer)[__MODULE__]
+        _ ->
+          {env[:portal], fallback_start_block}
+      end
 
-        if Helper.address_correct?(env[:portal]) and not is_nil(env[:start_block_l1]) do
-          {env[:portal], env[:start_block_l1]}
-        end
+    if Helper.address_correct?(optimism_portal) and !is_nil(start_block) do
+      {String.downcase(optimism_portal), start_block}
     end
   end
 

apps/indexer/lib/indexer/fetcher/optimism/transaction_batch.ex

@@ -102,8 +102,7 @@ defmodule Indexer.Fetcher.Optimism.TransactionBatch do
            {:system_config_valid, Helper.address_correct?(system_config)},
          {:genesis_block_l2_invalid, false} <-
            {:genesis_block_l2_invalid, is_nil(env[:genesis_block_l2]) or env[:genesis_block_l2] < 0},
-         {:reorg_monitor_started, true} <-
-           {:reorg_monitor_started, !is_nil(Process.whereis(RollupL1ReorgMonitor))},
+         _ <- RollupL1ReorgMonitor.wait_for_start(__MODULE__),
          {:rpc_l1_undefined, false} <- {:rpc_l1_undefined, is_nil(optimism_l1_rpc)},
          json_rpc_named_arguments = Optimism.json_rpc_named_arguments(optimism_l1_rpc),
          {:system_config_read, {start_block_l1, batch_inbox, batch_submitter}} <-
@@ -160,13 +159,6 @@ defmodule Indexer.Fetcher.Optimism.TransactionBatch do
         Logger.error("L2 genesis block number is undefined or invalid.")
         {:stop, :normal, state}
 
-      {:reorg_monitor_started, false} ->
-        Logger.error(
-          "Cannot start this process as reorg monitor in Indexer.Fetcher.RollupL1ReorgMonitor is not started."
-        )
-
-        {:stop, :normal, state}
-
       {:rpc_l1_undefined, true} ->
         Logger.error("L1 RPC URL is not defined.")
         {:stop, :normal, state}
@@ -1447,25 +1439,51 @@ defmodule Indexer.Fetcher.Optimism.TransactionBatch do
 
     error_message = &"Cannot call public getters of SystemConfig. Error: #{inspect(&1)}"
 
-    case Helper.repeated_call(
-           &json_rpc/2,
-           [requests, json_rpc_named_arguments],
-           error_message,
-           Helper.finite_retries_number()
-         ) do
-      {:ok, responses} ->
-        start_block = quantity_to_integer(Enum.at(responses, 0).result)
-        "0x000000000000000000000000" <> batch_inbox = Enum.at(responses, 1).result
-        "0x000000000000000000000000" <> batch_submitter = Enum.at(responses, 2).result
-        {start_block, String.downcase("0x" <> batch_inbox), String.downcase("0x" <> batch_submitter)}
+    env = Application.get_all_env(:indexer)[__MODULE__]
+    fallback_start_block = Application.get_all_env(:indexer)[Indexer.Fetcher.Optimism][:start_block_l1]
+
+    {start_block, batch_inbox, batch_submitter} =
+      case Helper.repeated_call(
+             &json_rpc/2,
+             [requests, json_rpc_named_arguments],
+             error_message,
+             Helper.finite_retries_number()
+           ) do
+        {:ok, responses} ->
+          start_block =
+            responses
+            |> Enum.at(0)
+            |> Map.get(:result, fallback_start_block)
+            |> quantity_to_integer()
+
+          inbox_result = Map.get(Enum.at(responses, 1), :result)
+          submitter_result = Map.get(Enum.at(responses, 2), :result)
+
+          {batch_inbox, batch_submitter} =
+            with {:nil_result, true, _, _} <-
+                   {:nil_result, is_nil(inbox_result) or is_nil(submitter_result), inbox_result, submitter_result},
+                 {:fallback_defined, true} <-
+                   {:fallback_defined,
+                    Helper.address_correct?(env[:inbox]) and Helper.address_correct?(env[:submitter])} do
+              {env[:inbox], env[:submitter]}
+            else
+              {:nil_result, false, inbox, submitter} ->
+                "0x000000000000000000000000" <> batch_inbox = inbox
+                "0x000000000000000000000000" <> batch_submitter = submitter
+                {"0x" <> batch_inbox, "0x" <> batch_submitter}
+
+              {:fallback_defined, false} ->
+                {nil, nil}
+            end
 
-      _ ->
-        start_block = Application.get_all_env(:indexer)[Indexer.Fetcher.Optimism][:start_block_l1]
-        env = Application.get_all_env(:indexer)[__MODULE__]
+          {start_block, batch_inbox, batch_submitter}
 
-        if not is_nil(start_block) and Helper.address_correct?(env[:inbox]) and Helper.address_correct?(env[:submitter]) do
-          {start_block, String.downcase(env[:inbox]), String.downcase(env[:submitter])}
-        end
+        _ ->
+          {fallback_start_block, env[:inbox], env[:submitter]}
+      end
+
+    if !is_nil(start_block) and Helper.address_correct?(batch_inbox) and Helper.address_correct?(batch_submitter) do
+      {start_block, String.downcase(batch_inbox), String.downcase(batch_submitter)}
     end
   end
 

apps/indexer/lib/indexer/fetcher/polygon_zkevm/bridge_l1.ex

@@ -57,7 +57,7 @@ defmodule Indexer.Fetcher.PolygonZkevm.BridgeL1 do
     env_l2 = Application.get_all_env(:indexer)[Indexer.Fetcher.PolygonZkevm.BridgeL2]
 
     with {:start_block_undefined, false} <- {:start_block_undefined, is_nil(env[:start_block])},
-         {:reorg_monitor_started, true} <- {:reorg_monitor_started, !is_nil(Process.whereis(RollupL1ReorgMonitor))},
+         _ <- RollupL1ReorgMonitor.wait_for_start(__MODULE__),
          rpc = env[:rpc],
          {:rpc_undefined, false} <- {:rpc_undefined, is_nil(rpc)},
          {:rollup_network_id_l1_is_valid, true} <-
@@ -101,10 +101,6 @@ defmodule Indexer.Fetcher.PolygonZkevm.BridgeL1 do
         # the process shouldn't start if the start block is not defined
         {:stop, :normal, %{}}
 
-      {:reorg_monitor_started, false} ->
-        Logger.error("Cannot start this process as Indexer.Fetcher.RollupL1ReorgMonitor is not started.")
-        {:stop, :normal, %{}}
-
       {:rpc_undefined, true} ->
         Logger.error("L1 RPC URL is not defined.")
         {:stop, :normal, %{}}

apps/indexer/lib/indexer/fetcher/rollup_l1_reorg_monitor.ex

@@ -16,6 +16,7 @@ defmodule Indexer.Fetcher.RollupL1ReorgMonitor do
   alias Indexer.Helper
 
   @fetcher_name :rollup_l1_reorg_monitor
+  @start_recheck_period_seconds 3
 
   @modules_can_use_reorg_monitor (case Application.compile_env(:explorer, :chain_type) do
                                     :optimism ->
@@ -67,6 +68,11 @@ defmodule Indexer.Fetcher.RollupL1ReorgMonitor do
     GenServer.start_link(__MODULE__, args, Keyword.put_new(gen_server_options, :name, __MODULE__))
   end
 
+  @impl GenServer
+  def init(_args) do
+    {:ok, %{}, {:continue, :ok}}
+  end
+
   @doc """
     This function initializes L1 blocks reorg monitor for the current rollup
     defined by CHAIN_TYPE. If the current chain is not a rollup, the module just doesn't start.
@@ -84,10 +90,10 @@ defmodule Indexer.Fetcher.RollupL1ReorgMonitor do
 
     ## Returns
     - `{:ok, state}` with the determined parameters for the monitor loop if at least one rollup module is launched.
-    - `:ignore` if the monitor is not needed.
+    - `{:stop, :normal, %{}}` if the monitor is not needed.
   """
   @impl GenServer
-  def init(_args) do
+  def handle_continue(:ok, _state) do
     Logger.metadata(fetcher: @fetcher_name)
 
     modules_using_reorg_monitor =
@@ -96,7 +102,7 @@ defmodule Indexer.Fetcher.RollupL1ReorgMonitor do
 
     if Enum.empty?(modules_using_reorg_monitor) do
       # don't start reorg monitor as there is no module which would use it
-      :ignore
+      {:stop, :normal, %{}}
     else
       l1_rpc = Enum.at(modules_using_reorg_monitor, 0).l1_rpc_url()
 
@@ -106,7 +112,7 @@ defmodule Indexer.Fetcher.RollupL1ReorgMonitor do
 
       Process.send(self(), :reorg_monitor, [])
 
-      {:ok,
+      {:noreply,
        %{
          block_check_interval: block_check_interval,
          json_rpc_named_arguments: json_rpc_named_arguments,
@@ -155,4 +161,34 @@ defmodule Indexer.Fetcher.RollupL1ReorgMonitor do
 
     {:noreply, %{state | prev_latest: latest}}
   end
+
+  @doc """
+    Infinitely waits for the module to be initialized and started.
+
+    ## Parameters
+    - `waiting_module`: The module which called this function.
+
+    ## Returns
+    - nothing
+  """
+  @spec wait_for_start(module()) :: any()
+  def wait_for_start(waiting_module) do
+    state =
+      try do
+        __MODULE__
+        |> Process.whereis()
+        |> :sys.get_state()
+      catch
+        :exit, _ -> %{}
+      end
+
+    if map_size(state) == 0 do
+      Logger.warning(
+        "#{waiting_module} waits for #{__MODULE__} to start. Rechecking in #{@start_recheck_period_seconds} second(s)..."
+      )
+
+      :timer.sleep(@start_recheck_period_seconds * 1_000)
+      wait_for_start(waiting_module)
+    end
+  end
 end

apps/indexer/lib/indexer/fetcher/scroll/batch.ex

@@ -78,7 +78,7 @@ defmodule Indexer.Fetcher.Scroll.Batch do
     env = Application.get_all_env(:indexer)[__MODULE__]
 
     with {:start_block_undefined, false} <- {:start_block_undefined, is_nil(env[:start_block])},
-         {:reorg_monitor_started, true} <- {:reorg_monitor_started, !is_nil(Process.whereis(RollupL1ReorgMonitor))},
+         _ <- RollupL1ReorgMonitor.wait_for_start(__MODULE__),
          rpc = l1_rpc_url(),
          {:rpc_undefined, false} <- {:rpc_undefined, is_nil(rpc)},
          {:scroll_chain_contract_address_is_valid, true} <-
@@ -114,10 +114,6 @@ defmodule Indexer.Fetcher.Scroll.Batch do
         # the process shouldn't start if the start block is not defined
         {:stop, :normal, %{}}
 
-      {:reorg_monitor_started, false} ->
-        Logger.error("Cannot start this process as Indexer.Fetcher.RollupL1ReorgMonitor is not started.")
-        {:stop, :normal, %{}}
-
       {:rpc_undefined, true} ->
         Logger.error("L1 RPC URL is not defined.")
         {:stop, :normal, %{}}

apps/indexer/lib/indexer/fetcher/scroll/bridge_l1.ex

@@ -69,7 +69,7 @@ defmodule Indexer.Fetcher.Scroll.BridgeL1 do
     env = Application.get_all_env(:indexer)[__MODULE__]
 
     with {:start_block_undefined, false} <- {:start_block_undefined, is_nil(env[:start_block])},
-         {:reorg_monitor_started, true} <- {:reorg_monitor_started, !is_nil(Process.whereis(RollupL1ReorgMonitor))},
+         _ <- RollupL1ReorgMonitor.wait_for_start(__MODULE__),
          rpc = l1_rpc_url(),
          {:rpc_undefined, false} <- {:rpc_undefined, is_nil(rpc)},
          {:messenger_contract_address_is_valid, true} <-
@@ -104,10 +104,6 @@ defmodule Indexer.Fetcher.Scroll.BridgeL1 do
         # the process shouldn't start if the start block is not defined
         {:stop, :normal, %{}}
 
-      {:reorg_monitor_started, false} ->
-        Logger.error("Cannot start this process as Indexer.Fetcher.RollupL1ReorgMonitor is not started.")
-        {:stop, :normal, %{}}
-
       {:rpc_undefined, true} ->
         Logger.error("L1 RPC URL is not defined.")
         {:stop, :normal, %{}}

apps/indexer/lib/indexer/fetcher/shibarium/l1.ex

@@ -112,7 +112,7 @@ defmodule Indexer.Fetcher.Shibarium.L1 do
     env = Application.get_all_env(:indexer)[__MODULE__]
 
     with {:start_block_undefined, false} <- {:start_block_undefined, is_nil(env[:start_block])},
-         {:reorg_monitor_started, true} <- {:reorg_monitor_started, !is_nil(Process.whereis(RollupL1ReorgMonitor))},
+         _ <- RollupL1ReorgMonitor.wait_for_start(__MODULE__),
          rpc = env[:rpc],
          {:rpc_undefined, false} <- {:rpc_undefined, is_nil(rpc)},
          {:deposit_manager_address_is_valid, true} <-
@@ -164,10 +164,6 @@ defmodule Indexer.Fetcher.Shibarium.L1 do
         # the process shouldn't start if the start block is not defined
         {:stop, :normal, %{}}
 
-      {:reorg_monitor_started, false} ->
-        Logger.error("Cannot start this process as Indexer.Fetcher.RollupL1ReorgMonitor is not started.")
-        {:stop, :normal, %{}}
-
       {:rpc_undefined, true} ->
         Logger.error("L1 RPC URL is not defined.")
         {:stop, :normal, %{}}