From dec2b0ee8149bc92bbd51430c25d61a9836031c1 Mon Sep 17 00:00:00 2001
From: Jamil <jamilbk@users.noreply.github.com>
Date: Wed, 5 Feb 2025 05:41:19 -0800
Subject: [PATCH] fix(portal): Only configure Sentry.LoggerHandler once (#8025)

The applications within our umbrella are all joined into a single Erlang
cluster, and logger configuration is applied already to the entire
umbrella.

As such, registering the Sentry log handler in each application's
startup routine triggers duplicate handlers to be registered for the
cluster, resulting in warnings like this in GCP:

```
Event dropped due to being a duplicate of a previously-captured event.
```

As such, we can move the log handler configuration to the top-level
`:logger` key, under the `:logger` subkey for configuring a single
handler. We then load this handler config in the `domain` app only and
it applies to the entire cluster.
---
 elixir/apps/api/lib/api/application.ex       |  2 --
 elixir/apps/domain/lib/domain/application.ex |  2 +-
 elixir/apps/web/lib/web/application.ex       |  2 --
 elixir/config/config.exs                     | 33 +++++++-------------
 4 files changed, 12 insertions(+), 27 deletions(-)

diff --git a/elixir/apps/api/lib/api/application.ex b/elixir/apps/api/lib/api/application.ex
index aebac738b..e83082974 100644
--- a/elixir/apps/api/lib/api/application.ex
+++ b/elixir/apps/api/lib/api/application.ex
@@ -6,8 +6,6 @@ defmodule API.Application do
     _ = :opentelemetry_cowboy.setup()
     _ = OpentelemetryPhoenix.setup(adapter: :cowboy2)
 
-    Logger.add_handlers(:api)
-
     children = [
       API.Endpoint
     ]
diff --git a/elixir/apps/domain/lib/domain/application.ex b/elixir/apps/domain/lib/domain/application.ex
index 81f80691d..47fcf608e 100644
--- a/elixir/apps/domain/lib/domain/application.ex
+++ b/elixir/apps/domain/lib/domain/application.ex
@@ -8,7 +8,7 @@ defmodule Domain.Application do
     _ = OpentelemetryLoggerMetadata.setup()
     _ = OpentelemetryEcto.setup([:domain, :repo])
 
-    Logger.add_handlers(:domain)
+    Logger.add_handlers(:logger)
 
     # Can be uncommented when this bug is fixed: https://github.com/open-telemetry/opentelemetry-erlang-contrib/issues/327
     # _ = OpentelemetryFinch.setup()
diff --git a/elixir/apps/web/lib/web/application.ex b/elixir/apps/web/lib/web/application.ex
index 74535e9f6..c0d740891 100644
--- a/elixir/apps/web/lib/web/application.ex
+++ b/elixir/apps/web/lib/web/application.ex
@@ -7,8 +7,6 @@ defmodule Web.Application do
     _ = :opentelemetry_cowboy.setup()
     _ = OpentelemetryPhoenix.setup(adapter: :cowboy2)
 
-    Logger.add_handlers(:web)
-
     children = [
       Web.Endpoint
     ]
diff --git a/elixir/config/config.exs b/elixir/config/config.exs
index 6cc0de03d..92aa222f5 100644
--- a/elixir/config/config.exs
+++ b/elixir/config/config.exs
@@ -12,17 +12,6 @@ import Config
 ##### Domain ##################
 ###############################
 
-config :domain, :logger, [
-  {:handler, :domain, Sentry.LoggerHandler,
-   %{
-     config: %{
-       level: :warning,
-       metadata: :all,
-       capture_log_messages: true
-     }
-   }}
-]
-
 config :domain, ecto_repos: [Domain.Repo]
 config :domain, generators: [binary_id: true, context_app: :domain]
 
@@ -128,17 +117,6 @@ config :domain, web_external_url: "http://localhost:13000"
 ##### Web #####################
 ###############################
 
-config :web, :logger, [
-  {:handler, :web, Sentry.LoggerHandler,
-   %{
-     config: %{
-       level: :warning,
-       metadata: :all,
-       capture_log_messages: true
-     }
-   }}
-]
-
 config :web, ecto_repos: [Domain.Repo]
 config :web, generators: [binary_id: true, context_app: :domain]
 config :web, client_handler: "firezone-fd0020211111://"
@@ -254,6 +232,17 @@ config :logger, :default_formatter,
   format: "$time $metadata[$level] $message\n",
   metadata: :all
 
+config :logger, :logger, [
+  {:handler, :sentry, Sentry.LoggerHandler,
+   %{
+     config: %{
+       level: :warning,
+       metadata: :all,
+       capture_log_messages: true
+     }
+   }}
+]
+
 # Use Jason for JSON parsing in Phoenix
 config :phoenix, :json_library, Jason