From c418b689078878cc079801d37cbedebba2730f04 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jonatan=20K=C5=82osko?= <jonatanklosko@gmail.com>
Date: Fri, 29 Nov 2024 18:22:29 +0800
Subject: [PATCH] Add env vars for logger configuration

---
 README.md              | 10 +++++++---
 config/dev.exs         |  6 ++++--
 lib/livebook.ex        |  8 ++++++--
 lib/livebook/config.ex | 29 +++++++++++++++++++++--------
 4 files changed, 38 insertions(+), 15 deletions(-)

diff --git a/README.md b/README.md
index 17e56f6ac74a..3711c7ea4586 100644
--- a/README.md
+++ b/README.md
@@ -220,9 +220,6 @@ The following environment variables can be used to configure Livebook on boot:
     configuration. Defaults to "livebook" under the default user data
     directory.
 
-  * `LIVEBOOK_DEBUG` - enables verbose logging, when set to "true". Disabled
-    by default.
-
   * `LIVEBOOK_DEFAULT_RUNTIME` - sets the runtime type that is used by default
     when none is started explicitly for the given notebook. Must be either
     "standalone" (Standalone), "attached:NODE:COOKIE" (Attached node)
@@ -261,6 +258,13 @@ The following environment variables can be used to configure Livebook on boot:
   * `LIVEBOOK_IP` - sets the ip address to start the web application on.
     Must be a valid IPv4 or IPv6 address.
 
+  * `LIVEBOOK_LOG_LEVEL` - sets the logger level, allowing for more verbose
+    logging, either of: error, warning, notice, info, debug. Defaults to warning.
+
+  * `LIVEBOOK_LOG_METADATA` - a comma-separated list of metadata keys that should
+    be included in the log messages. Currently the only Livebook-spcecific key is
+    users (attached to evaluation logs). By default includes only request_id.
+
   * `LIVEBOOK_NODE` - sets the node name for running Livebook in a cluster.
     Note that Livebook always runs using long names distribution, so the
     node host name must use a fully qualified domain name (FQDN) or an IP
diff --git a/config/dev.exs b/config/dev.exs
index 4049d77b5645..59348b447ddd 100644
--- a/config/dev.exs
+++ b/config/dev.exs
@@ -61,8 +61,10 @@ config :livebook, LivebookWeb.Endpoint,
     web_console_logger: true
   ]
 
-# Do not include metadata nor timestamps in development logs
-config :logger, :console, format: "[$level] $message\n"
+# Do not include timestamps in development logs
+config :logger, :console,
+  format: "$metadata[$level] $message\n",
+  metadata: []
 
 # Include HEEx debug annotations as HTML comments in rendered markup
 config :phoenix_live_view, :debug_heex_annotations, true
diff --git a/lib/livebook.ex b/lib/livebook.ex
index ac085cf0de11..188d298c2fae 100644
--- a/lib/livebook.ex
+++ b/lib/livebook.ex
@@ -97,8 +97,12 @@ defmodule Livebook do
         Livebook.Config.secret!("LIVEBOOK_SECRET_KEY_BASE") ||
           Livebook.Utils.random_secret_key_base()
 
-    if Livebook.Config.debug!("LIVEBOOK_DEBUG") do
-      config :logger, level: :debug
+    if level = Livebook.Config.log_level!("LIVEBOOK_LOG_LEVEL") do
+      config :logger, level: level
+    end
+
+    if metadata = Livebook.Config.log_metadata!("LIVEBOOK_LOG_METADATA") do
+      config :logger, :console, metadata: metadata
     end
 
     if port = Livebook.Config.port!("LIVEBOOK_PORT") do
diff --git a/lib/livebook/config.ex b/lib/livebook/config.ex
index 9a8b9e97c2f8..a5c8e392a41b 100644
--- a/lib/livebook/config.ex
+++ b/lib/livebook/config.ex
@@ -444,18 +444,31 @@ defmodule Livebook.Config do
   end
 
   @doc """
-  Parses and validates debug mode from env.
-  """
-  def debug!(env) do
-    if debug = System.get_env(env) do
-      cond do
-        debug in ["1", "true"] -> true
-        debug in ["0", "false"] -> false
-        true -> abort!("expected #{env} to be a boolean, got: #{inspect(debug)}")
+  Parses and validates log level from env.
+  """
+  def log_level!(env) do
+    levels = ~w(error warning notice info debug)
+
+    if level = System.get_env(env) do
+      if level in levels do
+        String.to_atom(level)
+      else
+        abort!("expected #{env} to be one of #{Enum.join(levels, ", ")}, got: #{inspect(levels)}")
       end
     end
   end
 
+  @doc """
+  Parses and validates log metadata keys from env.
+  """
+  def log_metadata!(env) do
+    if metadata = System.get_env(env) do
+      for item <- String.split(metadata, ","),
+          key = String.trim(item),
+          do: String.to_atom(key)
+    end
+  end
+
   @doc """
   Parses and validates the port from env.
   """