feat(portal): send account_slug in gateway init (#9653)

Adds the `account_slug` to the gateway's `init` message. When the
account slug is changed, the gateway's socket is disconnected using the
same mechanism as gateway deletion, which causes the gateway to
reconnect immediately and receive a new `init`.

Related: #9545

elixir/apps/api/lib/api/gateway/channel.ex

@@ -48,7 +48,10 @@ defmodule API.Gateway.Channel do
       :ok = Enum.each(relays, &Domain.Relays.subscribe_to_relay_presence/1)
       :ok = maybe_subscribe_for_relays_presence(relays, socket)
 
+      account = Domain.Accounts.fetch_account_by_id!(socket.assigns.gateway.account_id)
+
       push(socket, "init", %{
+        account_slug: account.slug,
         interface: Views.Interface.render(socket.assigns.gateway),
         relays: Views.Relay.render_many(relays, relay_credentials_expire_at),
         config: %{

elixir/apps/api/test/api/gateway/channel_test.exs

@@ -58,17 +58,23 @@ defmodule API.Gateway.ChannelTest do
       assert is_number(online_at)
     end
 
-    test "sends list of resources after join", %{
+    test "sends init message after join", %{
+      account: account,
       gateway: gateway
     } do
       assert_push "init", %{
+        account_slug: account_slug,
         interface: interface,
+        relays: relays,
         config: %{
           ipv4_masquerade_enabled: true,
           ipv6_masquerade_enabled: true
         }
       }
 
+      assert account_slug == account.slug
+      assert relays == []
+
       assert interface == %{
                ipv4: gateway.ipv4,
                ipv6: gateway.ipv6

elixir/apps/domain/lib/domain/events/hooks/accounts.ex

@@ -6,6 +6,17 @@ defmodule Domain.Events.Hooks.Accounts do
   @impl true
   def on_insert(_data), do: :ok
 
+  # Account slug changed - disconnect gateways for updated init
+
+  @impl true
+  def on_update(%{"slug" => old_slug}, %{"slug" => slug, "id" => account_id} = _data)
+      when old_slug != slug do
+    # Technically we could push a :slug_changed message to the Gateways here,
+    # but at the time of writing, disconnecting and reconnecting is safer to ensure
+    # all relevant state on the Gateway is updated correctly.
+    PubSub.Account.Gateways.disconnect(account_id)
+  end
+
   # Account disabled - disconnect clients
   @impl true
   def on_update(

elixir/apps/domain/lib/domain/gateways/presence.ex

@@ -10,6 +10,7 @@ defmodule Domain.Gateways.Presence do
     with {:ok, _} <- __MODULE__.Group.track(gateway.group_id, gateway.id),
          {:ok, _} <- __MODULE__.Account.track(gateway.account_id, gateway.id) do
       :ok = PubSub.Gateway.subscribe(gateway.id)
+      :ok = PubSub.Account.Gateways.subscribe(gateway.account_id)
     end
   end
 

elixir/apps/domain/lib/domain/pubsub.ex

@@ -84,6 +84,24 @@ defmodule Domain.PubSub do
       end
     end
 
+    defmodule Gateways do
+      def subscribe(account_id) do
+        account_id
+        |> topic()
+        |> Domain.PubSub.subscribe()
+      end
+
+      def disconnect(account_id) do
+        account_id
+        |> topic()
+        |> Domain.PubSub.broadcast("disconnect")
+      end
+
+      defp topic(account_id) do
+        Atom.to_string(__MODULE__) <> ":" <> account_id
+      end
+    end
+
     defmodule Policies do
       def subscribe(account_id) do
         account_id

elixir/apps/domain/test/domain/events/hooks/accounts_test.exs

@@ -13,10 +13,25 @@ defmodule Domain.Events.Hooks.AccountsTest do
   end
 
   describe "update/2" do
+    test "disconnects gateways if slug changes" do
+      account = Fixtures.Accounts.create_account()
+      gateway = Fixtures.Gateways.create_gateway(account: account)
+      :ok = Domain.Gateways.Presence.connect(gateway)
+
+      old_data = %{"slug" => "old"}
+      data = %{"slug" => "new", "id" => account.id}
+
+      assert :ok == on_update(old_data, data)
+
+      assert_receive "disconnect"
+    end
+
     test "sends :config_changed if config changes" do
       account = Fixtures.Accounts.create_account()
+      gateway = Fixtures.Gateways.create_gateway(account: account)
 
       :ok = Domain.PubSub.Account.subscribe(account.id)
+      :ok = Domain.Gateways.Presence.connect(gateway)
 
       old_data = %{
         "id" => account.id,
@@ -33,6 +48,7 @@ defmodule Domain.Events.Hooks.AccountsTest do
 
       assert :ok == on_update(old_data, data)
       assert_receive :config_changed
+      refute_receive "disconnect"
     end
 
     test "does not send :config_changed if config does not change" do