feat: allow specifying config path via command flag

Cargo.lock

@@ -426,6 +426,7 @@ dependencies = [
  "threadpool",
  "tikv-jemallocator",
  "tokio",
+ "toml_edit 0.22.12",
  "tower",
  "tower-http",
  "tracing",
@@ -1818,12 +1819,11 @@ checksum = "5b40af805b3121feab8a3c29f04d8ad262fa8e0561883e7653e024ae4479e6de"
 
 [[package]]
 name = "proc-macro-crate"
-version = "2.0.2"
+version = "2.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b00f26d3400549137f92511a46ac1cd8ce37cb5598a96d382381458b992a5d24"
+checksum = "7e8366a6159044a37876a2b9817124296703c586a5c92e2c53751fa06d8d43e8"
 dependencies = [
- "toml_datetime",
- "toml_edit",
+ "toml_edit 0.20.2",
 ]
 
 [[package]]
@@ -2871,14 +2871,14 @@ dependencies = [
  "serde",
  "serde_spanned",
  "toml_datetime",
- "toml_edit",
+ "toml_edit 0.20.2",
 ]
 
 [[package]]
 name = "toml_datetime"
-version = "0.6.3"
+version = "0.6.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7cda73e2f1397b1262d6dfdcef8aafae14d1de7748d66822d3bfeeb6d03e5e4b"
+checksum = "3550f4e9685620ac18a50ed434eb3aec30db8ba93b0287467bca5826ea25baf1"
 dependencies = [
  "serde",
 ]
@@ -2893,7 +2893,18 @@ dependencies = [
  "serde",
  "serde_spanned",
  "toml_datetime",
- "winnow",
+ "winnow 0.5.40",
+]
+
+[[package]]
+name = "toml_edit"
+version = "0.22.12"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d3328d4f68a705b2a4498da1d580585d39a6510f98318a2cec3018a7ec61ddef"
+dependencies = [
+ "indexmap 2.2.5",
+ "toml_datetime",
+ "winnow 0.6.6",
 ]
 
 [[package]]
@@ -3437,6 +3448,15 @@ dependencies = [
  "memchr",
 ]
 
+[[package]]
+name = "winnow"
+version = "0.6.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f0c976aaaa0e1f90dbb21e9587cdaf1d9679a1cde8875c0d6bd83ab96a208352"
+dependencies = [
+ "memchr",
+]
+
 [[package]]
 name = "winreg"
 version = "0.50.0"

Cargo.toml

@@ -106,6 +106,8 @@ clap = { version = "4.3.0", default-features = false, features = ["std", "derive
 futures-util = { version = "0.3.28", default-features = false }
 # Used for reading the configuration from conduit.toml & environment variables
 figment = { version = "0.10.8", features = ["env", "toml"] }
+# Used to generate the default config file
+toml_edit = "0.22"
 
 # Validating urls in config
 url = { version = "2", features = ["serde"] }

nix/pkgs/default/default.nix

@@ -54,6 +54,7 @@ let
       include = [
         "Cargo.lock"
         "Cargo.toml"
+        "conduit-example.toml"
         "src"
       ];
     };

src/clap.rs

@@ -1,6 +1,6 @@
 //! Integration with `clap`
 
-use clap::Parser;
+use clap::{Parser, Subcommand};
 
 /// Returns the current version of the crate with extra info if supplied
 ///
@@ -19,7 +19,20 @@ fn version() -> String {
 /// Command line arguments
 #[derive(Parser)]
 #[clap(about, version = version())]
-pub struct Args {}
+pub struct Args {
+    #[command(subcommand)]
+    pub command: Option<Commands>,
+
+    /// Path to the config file
+    #[arg(short, long, value_name = "PATH")]
+    pub config: Option<String>,
+}
+
+#[derive(Subcommand)]
+pub enum Commands {
+    /// Generates a default config file
+    GenerateConfig,
+}
 
 /// Parse command line arguments into structured data
 pub fn parse() -> Args {

src/lib.rs

@@ -3,7 +3,7 @@ pub mod clap;
 mod config;
 mod database;
 mod service;
-mod utils;
+pub mod utils;
 
 // Not async due to services() being used in many closures, and async closures are not stable as of writing
 // This is the case for every other occurence of sync Mutex/RwLock, except for database related ones, where

src/main.rs

@@ -7,7 +7,11 @@ use axum::{
     Router,
 };
 use axum_server::{bind, bind_rustls, tls_rustls::RustlsConfig, Handle as ServerHandle};
-use conduit::api::{client_server, server_server};
+use conduit::{
+    api::{client_server, server_server},
+    clap::Commands,
+    utils::random_string,
+};
 use figment::{
     providers::{Env, Format, Toml},
     Figment,
@@ -23,7 +27,12 @@ use ruma::api::{
     },
     IncomingRequest,
 };
-use tokio::signal;
+use tokio::{
+    fs::{try_exists, File},
+    io::AsyncWriteExt,
+    signal,
+};
+use toml_edit::DocumentMut;
 use tower::ServiceBuilder;
 use tower_http::{
     cors::{self, CorsLayer},
@@ -44,23 +53,46 @@ static GLOBAL: Jemalloc = Jemalloc;
 
 #[tokio::main]
 async fn main() {
-    clap::parse();
+    let cli = clap::parse();
 
+    let path = cli.config.unwrap_or_else(|| {
+        Env::var("CONDUIT_CONFIG")
+            .expect("The config path must either be set via the -c/--config flag or the CONDUIT_CONFIG env var. Example: /etc/conduit.toml")
+    });
+
+    match cli.command {
+        Some(Commands::GenerateConfig) => {
+            let toml = include_str!("../conduit-example.toml");
+            let mut doc = toml.parse::<DocumentMut>().expect("invalid doc");
+            doc["global"]["registration_token"] = toml_edit::value(random_string(64));
+
+            if let Ok(true) = try_exists(path.clone()).await {
+                panic!("Error: file '{}' already exists", path);
+                // Any possible error should be caught on creation
+            } else {
+                match File::create(path).await {
+                    Ok(mut file) => match file.write(&doc.to_string().into_bytes()).await {
+                        Err(e) => panic!("Error writing config file: {e}"),
+                        Ok(_) => {
+                            println!("Successfully generated config file");
+                        }
+                    },
+                    Err(e) => panic!("Error creating config file: {e}"),
+                }
+            }
+        }
+        None => {
             // Initialize config
-    let raw_config =
-        Figment::new()
-            .merge(
-                Toml::file(Env::var("CONDUIT_CONFIG").expect(
-                    "The CONDUIT_CONFIG env var needs to be set. Example: /etc/conduit.toml",
-                ))
-                .nested(),
-            )
+            let raw_config = Figment::new()
+                .merge(Toml::file(path).nested())
                 .merge(Env::prefixed("CONDUIT_").global());
 
             let config = match raw_config.extract::<Config>() {
                 Ok(s) => s,
                 Err(e) => {
-            eprintln!("It looks like your config is invalid. The following error occurred: {e}");
+                    eprintln!(
+                        "It looks like your config is invalid. The following error occurred: {e}"
+                    );
                     std::process::exit(1);
                 }
             };
@@ -68,7 +100,9 @@ async fn main() {
             config.warn_deprecated();
 
             if config.allow_jaeger {
-        opentelemetry::global::set_text_map_propagator(opentelemetry_jaeger::Propagator::new());
+                opentelemetry::global::set_text_map_propagator(
+                    opentelemetry_jaeger::Propagator::new(),
+                );
                 let tracer = opentelemetry_jaeger::new_agent_pipeline()
                     .with_auto_split_batch(true)
                     .with_service_name("conduit")
@@ -123,7 +157,8 @@ async fn main() {
             // * https://www.freedesktop.org/software/systemd/man/systemd.exec.html#id-1.12.2.1.17.6
             // * https://github.com/systemd/systemd/commit/0abf94923b4a95a7d89bc526efc84e7ca2b71741
             #[cfg(unix)]
-    maximize_fd_limit().expect("should be able to increase the soft limit to the hard limit");
+            maximize_fd_limit()
+                .expect("should be able to increase the soft limit to the hard limit");
 
             info!("Loading database");
             if let Err(error) = KeyValueDatabase::load_or_create(config).await {
@@ -139,6 +174,8 @@ async fn main() {
             if config.allow_jaeger {
                 opentelemetry::global::shutdown_tracer_provider();
             }
+        }
+    }
 }
 
 async fn run_server() -> io::Result<()> {