When env variable is set, any config file will be ignored and the default settings will be used (#4594)

* do not panic when no config file found use defaults

* formatting

* implement env variable

* ermove commented code

* remove redundant comment

* remove redundant space

* simplify check logic

* format

* returns and messages

* correct mistake

crates/utils/src/settings/mod.rs

@@ -13,8 +13,17 @@ use structs::{DatabaseConnection, PictrsConfig, PictrsImageMode, Settings};
 static DEFAULT_CONFIG_FILE: &str = "config/config.hjson";
 
 pub static SETTINGS: Lazy<Settings> = Lazy::new(|| {
-  Settings::init().expect("Failed to load settings file, see documentation (https://join-lemmy.org/docs/en/administration/configuration.html)")
+  if env::var("LEMMY_INITIALIZE_WITH_DEFAULT_SETTINGS").is_ok() {
+    println!(
+      "LEMMY_INITIALIZE_WITH_DEFAULT_SETTINGS was set, any configuration file has been ignored."
+    );
+    println!("Use with other environment variables to configure this instance further; e.g. LEMMY_DATABASE_URL.");
+    Settings::default()
+  } else {
+    Settings::init().expect("Failed to load settings file, see documentation (https://join-lemmy.org/docs/en/administration/configuration.html).")
+  }
 });
+
 static WEBFINGER_REGEX: Lazy<Regex> = Lazy::new(|| {
   Regex::new(&format!(
     "^acct:([a-zA-Z0-9_]{{3,}})@{}$",
@@ -30,9 +39,7 @@ impl Settings {
   /// `lemmy_db_schema/src/lib.rs::get_database_url_from_env()`
   /// Warning: Only call this once.
   pub(crate) fn init() -> Result<Self, LemmyError> {
-    // Read the config file
     let config = from_str::<Settings>(&Self::read_config_file()?)?;
-
     if config.hostname == "unset" {
       Err(anyhow!("Hostname variable is not set!").into())
     } else {