improvement: make config file location configurable via CLI args

src/bin/bulkloader.rs

@@ -20,7 +20,7 @@ pub fn main() -> Result<()> {
     let _trace_sub = tracing_subscriber::fmt::try_init();
     println!("Nostr-rs-relay Bulk Loader");
     // check for a database file, or create one.
-    let settings = config::Settings::new();
+    let settings = config::Settings::new(&None);
     if !Path::new(&settings.database.data_directory).is_dir() {
         info!("Database directory does not exist");
         return Err(Error::DatabaseDirError);

src/cli.rs

@@ -10,4 +10,11 @@ pub struct CLIArgs {
         required = false,
     )]
     pub db: Option<String>,
+    #[arg(
+        short,
+        long,
+        help = "Use the <file name> as the location of the config file",
+        required = false,
+    )]
+    pub config: Option<String>,
 }

src/config.rs

@@ -155,10 +155,10 @@ pub struct Settings {
 
 impl Settings {
     #[must_use]
-    pub fn new() -> Self {
+    pub fn new(config_file_name: &Option<String>) -> Self {
         let default_settings = Self::default();
         // attempt to construct settings with file
-        let from_file = Self::new_from_default(&default_settings);
+        let from_file = Self::new_from_default(&default_settings, config_file_name);
         match from_file {
             Ok(f) => f,
             Err(e) => {
@@ -168,13 +168,19 @@ impl Settings {
         }
     }
 
-    fn new_from_default(default: &Settings) -> Result<Self, ConfigError> {
+
+    fn new_from_default(default: &Settings, config_file_name: &Option<String>) -> Result<Self, ConfigError> {
+        let default_config_file_name = "config.toml".to_string();
+        let config: &String = match config_file_name {
+            Some(value) => value,
+            None => &default_config_file_name
+        };
         let builder = Config::builder();
         let config: Config = builder
         // use defaults
             .add_source(Config::try_from(default)?)
         // override with file contents
-            .add_source(File::with_name("config.toml"))
+            .add_source(File::with_name(config))
             .build()?;
         let mut settings: Settings = config.try_deserialize()?;
         // ensure connection pool size is logical

src/main.rs

@@ -11,9 +11,14 @@ use console_subscriber::ConsoleLayer;
 
 /// Start running a Nostr relay server.
 fn main() {
-    // configure settings from config.toml
-    // replace default settings with those read from config.toml
-    let mut settings = config::Settings::new();
+    let args = CLIArgs::parse();
+
+    // get config file name from args
+    let config_file_arg = args.config;
+
+    // configure settings from the config file (defaults to config.toml)
+    // replace default settings with those read from the config file
+    let mut settings = config::Settings::new(&config_file_arg);
 
     // setup tracing
     if settings.diagnostics.tracing {
@@ -25,8 +30,6 @@ fn main() {
     }
     info!("Starting up from main");
 
-    let args = CLIArgs::parse();
-
     // get database directory from args
     let db_dir_arg = args.db;