add commandline arg to specify a conduwuit config file

Signed-off-by: strawberry <strawberry@puppygock.gay>

DIFFERENCES.md

@@ -79,4 +79,5 @@
 - Make `CONDUIT_CONFIG` optional, relevant for container users that configure only by environment variables and no longer need to set `CONDUIT_CONFIG` to an empty string.
 - Config option to change Conduit's behaviour of homeserver key fetching (`query_trusted_key_servers_first`). This option sets whether conduwuit will query trusted notary key servers first before the individual homeserver(s), or vice versa.
 - Implement database flush and cleanup Conduit operations when using RocksDB
-- Implement legacy Matrix `/v1/` media endpoints that some clients and servers may still call
+- Implement legacy Matrix `/v1/` media endpoints that some clients and servers may still call
+- Commandline argument to specify the path to a config file

src/main.rs

@@ -53,13 +53,18 @@ use tracing_subscriber::{prelude::*, EnvFilter};
 #[global_allocator]
 static GLOBAL: Jemalloc = Jemalloc;
 
-#[derive(Parser)]
+#[derive(Parser, Debug)]
 #[clap(version, about, long_about = None)]
-struct Args;
+struct Args {
+	#[arg(short, long)]
+	/// Optional argument to the path of a conduwuit config TOML file
+	config: Option<String>,
+}
 
 #[tokio::main]
 async fn main() {
-	Args::parse();
+	let args = Args::parse();
+
 	// Initialize config
 	let raw_config = if Env::var("CONDUIT_CONFIG").is_some() {
 		Figment::new()
@@ -71,6 +76,16 @@ async fn main() {
 				.nested(),
 			)
 			.merge(Env::prefixed("CONDUIT_").global())
+	} else if args.config.is_some() {
+		Figment::new()
+			.merge(
+				Toml::file(args.config.expect(
+					"conduwuit config commandline argument was specified, but appears to be invalid. This should be \
+					 set to the path of a valid TOML file.",
+				))
+				.nested(),
+			)
+			.merge(Env::prefixed("CONDUIT_").global())
 	} else {
 		Figment::new().merge(Env::prefixed("CONDUIT_").global())
 	};