From 18fd154ab0649f74cf2013097ea9dcf28283c38a Mon Sep 17 00:00:00 2001
From: Jun Kurihara <junkurihara@users.noreply.github.com>
Date: Sun, 2 Nov 2025 23:51:22 +0900
Subject: [PATCH] feat: support realtime config+block+allow files reloading

---
 proxy-bin/Cargo.toml                  |  2 +-
 proxy-bin/src/config/target_config.rs | 47 ++++++++++++++++++++++++++-
 proxy-bin/src/main.rs                 |  5 +--
 3 files changed, 50 insertions(+), 4 deletions(-)

diff --git a/proxy-bin/Cargo.toml b/proxy-bin/Cargo.toml
index 8617d09..ac2db92 100644
--- a/proxy-bin/Cargo.toml
+++ b/proxy-bin/Cargo.toml
@@ -39,7 +39,7 @@ toml = { version = "0.9.8", default-features = false, features = [
   "parse",
   "serde",
 ] }
-hot_reload = { version = "0.3.4", features = ["file-reloader"] }
+hot_reload = { version = "0.3.5", features = ["file-reloader"] }
 
 # logging
 tracing = { version = "0.1.41" }
diff --git a/proxy-bin/src/config/target_config.rs b/proxy-bin/src/config/target_config.rs
index 0a28b88..275e702 100644
--- a/proxy-bin/src/config/target_config.rs
+++ b/proxy-bin/src/config/target_config.rs
@@ -1,9 +1,15 @@
 use super::{toml::ConfigToml, utils_dns_proto::parse_proto_sockaddr_str, utils_verifier::*};
 use crate::{constants::*, error::*, log::*};
+use async_trait::async_trait;
 use doh_auth_proxy_lib::{
   AuthenticationConfig, NextHopRelayConfig, ProxyConfig, QueryManipulationConfig, SubseqRelayConfig, TokenConfig,
 };
-use std::{env, path::PathBuf, sync::Arc};
+use hot_reload::AsyncFileLoad;
+use std::{
+  env,
+  path::{Path, PathBuf},
+  sync::Arc,
+};
 use tokio::time::Duration;
 
 pub type ConfigReloader = hot_reload::file_reloader::FileReloader<TargetConfig>;
@@ -25,6 +31,45 @@ impl TryFrom<&PathBuf> for TargetConfig {
   }
 }
 
+#[async_trait]
+impl AsyncFileLoad for TargetConfig {
+  type Error = String;
+
+  async fn async_load_from<T>(path: T) -> Result<Self, Self::Error>
+  where
+    T: AsRef<Path> + Send,
+  {
+    let config_str = tokio::fs::read_to_string(path)
+      .await
+      .map_err(|e| format!("Failed to read config file: {}", e))?;
+    let config_toml: ConfigToml = toml::from_str(&config_str).map_err(|e| format!("Failed to parse toml: {}", e))?;
+    let query_manipulation_config: Option<QueryManipulationConfig> = (&config_toml)
+      .try_into()
+      .map_err(|e| format!("Failed to parse query manipulation config: {}", e))?;
+    Ok(Self {
+      config_toml,
+      query_manipulation_config: query_manipulation_config.map(Arc::new),
+    })
+  }
+
+  fn dependent_paths(&self) -> Vec<PathBuf> {
+    let mut paths = Vec::new();
+
+    let Some(plugins) = &self.config_toml.plugins else {
+      return paths;
+    };
+
+    if let Some(blocked_file) = &plugins.domains_blocked_file {
+      paths.push(PathBuf::from(blocked_file));
+    }
+    if let Some(overridden_file) = &plugins.domains_overridden_file {
+      paths.push(PathBuf::from(overridden_file));
+    }
+
+    paths
+  }
+}
+
 impl TargetConfig {
   /// build new target config by loading query manipulation plugin configs
   pub fn new(config_file: &PathBuf) -> anyhow::Result<Self> {
diff --git a/proxy-bin/src/main.rs b/proxy-bin/src/main.rs
index c2eb308..f562b6d 100644
--- a/proxy-bin/src/main.rs
+++ b/proxy-bin/src/main.rs
@@ -35,14 +35,15 @@ fn main() {
         std::process::exit(1);
       }
     } else {
-      let reloader_config = ReloaderConfig::polling(CONFIG_WATCH_DELAY_SECS);
+      // With config file watcher in hybrid mode
+      let reloader_config = ReloaderConfig::hybrid(CONFIG_WATCH_DELAY_SECS);
       let (config_service, config_rx) =
         ReloaderService::<ConfigReloader, TargetConfig, String>::new(&parsed_opts.config_file_path, reloader_config)
           .await
           .unwrap();
 
       tokio::select! {
-        Err(e) = config_service.start() => {
+        Err(e) = config_service.start_with_realtime() => {
           error!("config reloader service exited: {e}");
           std::process::exit(1);
         }