Add projector for host checks selection (#1542)

* Add host selection projector

* Update host read model and add migration

* Add host selected checks view

* Use host_details_updated view and event

lib/trento/application/projectors/cluster_projector.ex

@@ -89,9 +89,6 @@ defmodule Trento.ClusterProjector do
       changeset =
         ClusterReadModel
         |> Repo.get(id)
-        # TODO: couldn't make it work with Ecto.Multi
-        # With following line when we receive an empty list of selected checks, the readmodel does not get updated
-        # %ClusterReadModel{id: id}
         |> ClusterReadModel.changeset(%{
           selected_checks: checks
         })

lib/trento/application/projectors/host_projector.ex

@@ -16,6 +16,7 @@ defmodule Trento.HostProjector do
     HeartbeatFailed,
     HeartbeatSucceded,
     HostAddedToCluster,
+    HostChecksSelected,
     HostDetailsUpdated,
     HostRegistered,
     ProviderUpdated
@@ -84,6 +85,23 @@ defmodule Trento.HostProjector do
     end
   )
 
+  project(
+    %HostChecksSelected{
+      host_id: id,
+      checks: checks
+    },
+    fn multi ->
+      changeset =
+        HostReadModel
+        |> Repo.get(id)
+        |> HostReadModel.changeset(%{
+          selected_checks: checks
+        })
+
+      Ecto.Multi.update(multi, :host, changeset)
+    end
+  )
+
   project(
     %HeartbeatSucceded{host_id: id},
     fn multi ->
@@ -228,5 +246,21 @@ defmodule Trento.HostProjector do
     })
   end
 
+  def after_update(
+        %HostChecksSelected{host_id: host_id, checks: checks},
+        _,
+        _
+      ) do
+    host = %HostReadModel{id: host_id, selected_checks: checks}
+
+    message =
+      HostView.render(
+        "host_details_updated.json",
+        %{host: host}
+      )
+
+    TrentoWeb.Endpoint.broadcast("monitoring:hosts", "host_details_updated", message)
+  end
+
   def after_update(_, _, _), do: :ok
 end

lib/trento/application/read_models/host_read_model.ex

@@ -21,7 +21,7 @@ defmodule Trento.HostReadModel do
     field :agent_version, :string
     field :cluster_id, Ecto.UUID
     field :heartbeat, Ecto.Enum, values: [:critical, :passing, :unknown]
-
+    field :selected_checks, {:array, :string}, default: []
     field :provider, Ecto.Enum, values: Provider.values()
     field :provider_data, :map
 

priv/repo/migrations/20230616114036_add_selected_checks_to_hosts.exs

@@ -0,0 +1,9 @@
+defmodule Trento.Repo.Migrations.AddSelectedChecksToHosts do
+  use Ecto.Migration
+
+  def change do
+    alter table(:hosts) do
+      add :selected_checks, {:array, :string}, default: []
+    end
+  end
+end

test/trento/application/projectors/host_projector_test.exs

@@ -24,6 +24,7 @@ defmodule Trento.HostProjectorTest do
     HeartbeatFailed,
     HeartbeatSucceded,
     HostAddedToCluster,
+    HostChecksSelected,
     HostDetailsUpdated,
     ProviderUpdated
   }
@@ -166,6 +167,28 @@ defmodule Trento.HostProjectorTest do
                      1000
   end
 
+  test "should update the selected_checks field when event is received" do
+    %{id: host_id} = insert(:host)
+
+    cases = [
+      %{checks: [Faker.StarWars.character(), Faker.StarWars.character()]},
+      %{checks: []}
+    ]
+
+    Enum.each(cases, fn %{checks: checks} ->
+      event = %HostChecksSelected{host_id: host_id, checks: checks}
+
+      ProjectorTestHelper.project(HostProjector, event, "host_projector")
+      host_projection = Repo.get!(HostReadModel, event.host_id)
+
+      assert event.checks == host_projection.selected_checks
+
+      assert_broadcast "host_details_updated",
+                       %{selected_checks: ^checks, id: ^host_id},
+                       1000
+    end)
+  end
+
   test "should update the heartbeat field to passing status when HeartbeatSucceded is received",
        %{host_id: host_id} do
     event = %HeartbeatSucceded{