fix: heath check should check the conn managed by Tenants.Connect (#699)

* fix: heath check should check the conn managed by Tenants.Connect

* fix: dialyzer warnings

Author: chasers

lib/realtime/tenants.ex

@@ -5,8 +5,7 @@ defmodule Realtime.Tenants do
 
   require Logger
   alias Realtime.Repo.Replica
-  alias Realtime.Api
-  alias Realtime.{Api.Tenant, PostgresCdc, UsersCounter}
+  alias Realtime.{Api.Tenant, UsersCounter, Tenants}
 
   @doc """
   Gets a list of connected tenant `external_id` strings in the cluster or a node.
@@ -23,21 +22,20 @@ defmodule Realtime.Tenants do
   end
 
   @doc """
-  Gets the database connection pid of the SubscriptionManager `manager` and the
-  Postgrex connection pool `subs_pool`.
-
-  When this function returns `:wait` the  database connection tree is starting and the
-  caller should not try to start the database connection tree again.
+  Gets the database connection pid managed by the Tenants.Connect process.
 
   ## Examples
 
-      iex> get_manager_conn(Extensions.PostgresCdcRls, "not_started_external_id")
-      {:error, nil}
+      iex> get_health_conn(%Tenant{external_id: "not_found_tenant"})
+      {:error, :tenant_database_unavailable}
   """
 
-  @spec get_manager_conn(:atom, %Tenant{}) :: {:error, :wait | nil} | {:ok, pid(), pid()}
-  def get_manager_conn(module, %Tenant{external_id: external_id}) do
-    module.get_manager_conn(external_id)
+  @spec get_health_conn(%Tenant{}) :: {:error, term()} | {:ok, pid()}
+  def get_health_conn(%Tenant{external_id: external_id}) do
+    case Tenants.Connect.get_status(external_id) do
+      {:ok, conn} -> {:ok, conn}
+      {:error, reason} -> {:error, reason}
+    end
   end
 
   @doc """
@@ -60,19 +58,15 @@ defmodule Realtime.Tenants do
            | %{connected_cluster: pos_integer, db_connected: false, healthy: false}}
           | {:ok, %{connected_cluster: non_neg_integer, db_connected: true, healthy: true}}
   def health_check(external_id) when is_binary(external_id) do
-    with %Tenant{} = tenant <- Api.get_tenant_by_external_id(external_id),
-         {:ok, module} <- PostgresCdc.driver(tenant.postgres_cdc_default),
-         {:error, _} <- get_manager_conn(module, tenant),
+    with %Tenant{} = tenant <- Tenants.Cache.get_tenant_by_external_id(external_id),
+         {:error, _} <- get_health_conn(tenant),
          connected_cluster when connected_cluster > 0 <- UsersCounter.tenant_users(external_id) do
       {:error, %{healthy: false, db_connected: false, connected_cluster: connected_cluster}}
     else
       nil ->
         {:error, :tenant_not_found}
 
-      {:error, _mod} ->
-        {:error, "Bad value for tenant field `postgres_cdc_default`"}
-
-      {:ok, _manager, _subs_pool} ->
+      {:ok, _health_conn} ->
         connected_cluster = UsersCounter.tenant_users(external_id)
 
         {:ok, %{healthy: true, db_connected: true, connected_cluster: connected_cluster}}

lib/realtime/tenants/connect.ex

@@ -17,9 +17,23 @@ defmodule Realtime.Tenants.Connect do
   @spec lookup_or_start_connection(binary()) :: {:ok, DBConnection.t()} | {:error, term()}
   def lookup_or_start_connection(tenant_id) do
     case get_status(tenant_id) do
-      :undefined -> call_external_node(tenant_id)
       {:ok, conn} -> {:ok, conn}
-      _ -> {:error, :tenant_database_unavailable}
+      {:error, :tenant_database_unavailable} -> call_external_node(tenant_id)
+      {:error, :initializing} -> {:error, :tenant_database_unavailable}
+    end
+  end
+
+  @doc """
+  Returns the database connection pid from :syn if it exists.
+  """
+
+  @spec get_status(binary()) ::
+          {:ok, DBConnection.t()} | {:error, :tenant_database_unavailable | :initializing}
+  def get_status(tenant_id) do
+    case :syn.lookup(__MODULE__, tenant_id) do
+      {_, %{conn: conn}} when not is_nil(conn) -> {:ok, conn}
+      {_, %{conn: nil}} -> {:error, :initializing}
+      _error -> {:error, :tenant_database_unavailable}
     end
   end
 
@@ -74,13 +88,6 @@ defmodule Realtime.Tenants.Connect do
 
   ## Private functions
 
-  defp get_status(tenant_id) do
-    case :syn.lookup(__MODULE__, tenant_id) do
-      {_, %{conn: conn}} when not is_nil(conn) -> {:ok, conn}
-      error -> error
-    end
-  end
-
   defp call_external_node(tenant_id) do
     with tenant <- Tenants.Cache.get_tenant_by_external_id(tenant_id),
          {:ok, node} <- Realtime.Nodes.get_node_for_tenant(tenant) do

lib/realtime_web/controllers/tenant_controller.ex

@@ -261,11 +261,6 @@ defmodule RealtimeWeb.TenantController do
         conn
         |> put_status(404)
         |> render("not_found.json", tenant: nil)
-
-      {:error, message} when is_binary(message) ->
-        conn
-        |> put_status(422)
-        |> json(%{errors: [message]})
     end
   end
 end

mix.exs

@@ -4,7 +4,7 @@ defmodule Realtime.MixProject do
   def project do
     [
       app: :realtime,
-      version: "2.25.0",
+      version: "2.25.1",
       elixir: "~> 1.14.0",
       elixirc_paths: elixirc_paths(Mix.env()),
       start_permanent: Mix.env() == :prod,

test/realtime_web/controllers/tenant_controller_test.exs

@@ -211,10 +211,11 @@ defmodule RealtimeWeb.TenantControllerTest do
         UsersCounter.add(self(), ext_id)
 
         # Fake a db connection
-        {:ok, mod} = PostgresCdc.driver(tenant.postgres_cdc_default)
-        :syn.add_node_to_scopes([mod])
-        :syn.register(mod, ext_id, self(), %{region: nil, manager: nil, subs_pool: nil})
-        mod.update_meta(ext_id, self(), self())
+        :syn.register(Realtime.Tenants.Connect, ext_id, self(), %{conn: nil})
+
+        :syn.update_registry(Realtime.Tenants.Connect, ext_id, fn _pid, meta ->
+          %{meta | conn: conn}
+        end)
 
         conn = get(conn, Routes.tenant_path(conn, :health, ext_id))
         data = json_response(conn, 200)["data"]