feat: wip healthcheck service for paths

dap-lib/src/doh_client/doh_client_healthcheck.rs

@@ -0,0 +1,34 @@
+use super::DoHClient;
+use crate::{error::*, log::*};
+use std::sync::Arc;
+use tokio::sync::Notify;
+
+impl DoHClient {
+  /// Start health check service
+  pub async fn start_healthcheck_service(&self, term_notify: Option<Arc<Notify>>) -> Result<()> {
+    info!("Start periodic path health check service with cache purge");
+    match term_notify {
+      Some(term) => {
+        tokio::select! {
+          _ = self.healthcheck_service() => {
+            warn!("Health check service got down.");
+          }
+          _ = term.notified() => {
+            info!("Health check service receives term signal");
+          }
+        }
+      }
+      None => {
+        self.healthcheck_service().await?;
+        warn!("Health check service got down.");
+      }
+    }
+    Ok(())
+  }
+
+  /// Health check service periodically checks the health of the path and purge the cache
+  async fn healthcheck_service(&self) -> Result<()> {
+    //TODO:
+    Ok(())
+  }
+}

dap-lib/src/doh_client/doh_client_main.rs

@@ -99,9 +99,6 @@ impl DoHClient {
     // cache
     let cache = Arc::new(Cache::new(globals.proxy_config.max_cache_size));
 
-    // TODO: 3. spawn healthcheck for every possible path? too many?
-    // TODO: 4. cache purge service, simultaneously with healthcheck?
-    // TODO: 5. implement query plugins
     Ok(Self {
       http_client,
       auth_client,
@@ -128,6 +125,7 @@ impl DoHClient {
       DapError::InvalidDnsQuery
     })?;
 
+    //TODO:TODO:TODO:!
     // // Process query plugins, e.g., domain filtering, cloaking, etc.
     // if let Some(query_plugins) = context.query_plugins.clone() {
     //   let execution_result = query_plugins.execute(&query_msg, &req.0[0], context.min_ttl)?;

dap-lib/src/lib.rs

@@ -79,6 +79,10 @@ pub async fn entrypoint(
   // build doh_client
   let doh_client = Arc::new(DoHClient::new(globals.clone(), http_client.inner(), authenticator).await?);
 
+  // TODO: 3. spawn healthcheck for every possible path? too many?
+  // TODO: 4. cache purge service, simultaneously with healthcheck?
+  // TODO: 5. implement query plugins
+
   // spawn endpoint ip update service with bootstrap dns resolver and doh_client
   let doh_client_clone = doh_client.clone();
   let term_notify_clone = term_notify;