From 89a1fc95e2dbcedab0ca66b852370fd0babd123d Mon Sep 17 00:00:00 2001
From: Francesco Noacco <francesco.noacco@secomind.com>
Date: Tue, 22 Aug 2023 15:26:02 +0200
Subject: [PATCH] refactor(trigger_engine): port query to xandra
 feat(trigger_engine): tag connection_error log

Signed-off-by: Francesco Noacco <francesco.noacco@secomind.com>
---
 .../lib/astarte_trigger_engine/application.ex |  2 +-
 .../lib/astarte_trigger_engine/config.ex      |  8 +--
 .../astarte_trigger_engine/events_consumer.ex | 59 +++++++++++++------
 3 files changed, 43 insertions(+), 26 deletions(-)

diff --git a/apps/astarte_trigger_engine/lib/astarte_trigger_engine/application.ex b/apps/astarte_trigger_engine/lib/astarte_trigger_engine/application.ex
index 4d0f64ae5..6db695a2c 100644
--- a/apps/astarte_trigger_engine/lib/astarte_trigger_engine/application.ex
+++ b/apps/astarte_trigger_engine/lib/astarte_trigger_engine/application.ex
@@ -1,7 +1,7 @@
 #
 # This file is part of Astarte.
 #
-# Copyright 2023 SECO Mind Srl
+# Copyright 2017-2023 SECO Mind Srl
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
diff --git a/apps/astarte_trigger_engine/lib/astarte_trigger_engine/config.ex b/apps/astarte_trigger_engine/lib/astarte_trigger_engine/config.ex
index 66ac386b7..ed7e149fb 100644
--- a/apps/astarte_trigger_engine/lib/astarte_trigger_engine/config.ex
+++ b/apps/astarte_trigger_engine/lib/astarte_trigger_engine/config.ex
@@ -1,7 +1,7 @@
 #
 # This file is part of Astarte.
 #
-# Copyright 2023 SECO Mind Srl
+# Copyright 2017-2023 SECO Mind Srl
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -200,15 +200,9 @@ defmodule Astarte.TriggerEngine.Config do
   defdelegate xandra_nodes, to: DataAccessConfig
   defdelegate xandra_nodes!, to: DataAccessConfig
 
-  @doc "A list of {host, port} values of accessible Cassandra nodes in a CQEx compliant format"
-  defdelegate cqex_nodes, to: DataAccessConfig
-  defdelegate cqex_nodes!, to: DataAccessConfig
-
   def xandra_options! do
     DataAccessConfig.xandra_options!()
     |> Keyword.put(:name, :xandra)
     |> Keyword.drop([:autodiscovery])
   end
-
-  defdelegate cqex_options!, to: DataAccessConfig
 end
diff --git a/apps/astarte_trigger_engine/lib/astarte_trigger_engine/events_consumer.ex b/apps/astarte_trigger_engine/lib/astarte_trigger_engine/events_consumer.ex
index 2e0034cd1..a7b293377 100644
--- a/apps/astarte_trigger_engine/lib/astarte_trigger_engine/events_consumer.ex
+++ b/apps/astarte_trigger_engine/lib/astarte_trigger_engine/events_consumer.ex
@@ -1,7 +1,7 @@
 #
 # This file is part of Astarte.
 #
-# Copyright 2017-2018 Ispirata Srl
+# Copyright 2017-2023 SECO Mind Srl
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -19,9 +19,6 @@
 defmodule Astarte.TriggerEngine.EventsConsumer do
   alias Astarte.Core.Triggers.SimpleEvents.SimpleEvent
   alias Astarte.Core.Triggers.Trigger
-  alias Astarte.DataAccess.Database
-  alias CQEx.Query, as: DatabaseQuery
-  alias CQEx.Result, as: DatabaseResult
   require Logger
 
   defmodule Behaviour do
@@ -248,27 +245,53 @@ defmodule Astarte.TriggerEngine.EventsConsumer do
   end
 
   defp retrieve_trigger_configuration(realm_name, trigger_id) do
-    query =
-      DatabaseQuery.new()
-      |> DatabaseQuery.statement(
-        "SELECT value FROM kv_store WHERE group='triggers' AND key=:trigger_id;"
-      )
-      |> DatabaseQuery.put(:trigger_id, trigger_id)
+    statement =
+      "SELECT value FROM #{realm_name}.kv_store WHERE group='triggers' AND key=:trigger_id;"
 
-    with {:ok, client} <- Database.connect(realm: realm_name),
-         {:ok, result} <- DatabaseQuery.call(client, query),
-         [value: trigger_data] <- DatabaseResult.head(result),
-         trigger <- Trigger.decode(trigger_data),
-         {:ok, action} <- Jason.decode(trigger.action) do
+    params = %{"trigger_id" => trigger_id}
+
+    with :ok <- check_realm_name_ok(realm_name),
+         {:ok, prepared} <- Xandra.Cluster.prepare(:xandra, statement),
+         {:ok, result} <- Xandra.Cluster.execute(:xandra, prepared, params),
+         {:ok, action} <- parse_trigger_data(result) do
       {:ok, action}
     else
-      {:error, :database_connection_error} ->
-        Logger.warn("Database connection error.")
+      {:error, error = %Xandra.Error{}} ->
+        Logger.warning("Database error: #{Exception.message(error)}", tag: "database_error")
+
+        {:error, :database_error}
+
+      {:error, error = %Xandra.ConnectionError{}} ->
+        Logger.warning("Database connection error while #{Exception.message(error)}",
+          tag: "database_connection_error"
+        )
+
         {:error, :database_connection_error}
 
       error ->
-        Logger.warn("Error while processing event: #{inspect(error)}")
+        error
+    end
+  end
+
+  defp parse_trigger_data(xandra_page) do
+    with %{"value" => trigger_data} <-
+           Enum.at(xandra_page, 0, {:error, :invalid_query_result, xandra_page}),
+         trigger = Trigger.decode(trigger_data),
+         {:ok, action} <- Jason.decode(trigger.action) do
+      {:ok, action}
+    else
+      error ->
+        Logger.warning("Error while processing event: #{inspect(error)}")
         {:error, :trigger_not_found}
     end
   end
+
+  defp check_realm_name_ok(realm_name) do
+    if Astarte.Core.Realm.valid_name?(realm_name) do
+      :ok
+    else
+      Logger.warning("Invalid realm name: #{realm_name}")
+      {:error, :invalid_realm_name}
+    end
+  end
 end