fix: bound direct command fetches

crates/x-media/src/site/mod.rs

@@ -516,6 +516,15 @@ pub async fn fetch_once(url: &str) -> Result<Option<Fetched>, FetchError> {
     fetch_with_attempts(url, 1).await
 }
 
+/// A small admission gate for `/test` and `/debug`, which run directly in
+/// dispatcher handlers instead of the URL worker pool.
+pub async fn acquire_command_fetch_slot() -> tokio::sync::OwnedSemaphorePermit {
+    std::sync::Arc::clone(&COMMAND_FETCH_SLOTS)
+        .acquire_owned()
+        .await
+        .expect("command fetch gate closed")
+}
+
 /// Total attempts of the retried [`fetch`] (3: the initial try plus two).
 const MAX_FETCH_ATTEMPTS: u32 = 3;
 
@@ -530,6 +539,8 @@ const MAX_FETCH_ATTEMPTS: u32 = 3;
 /// deliberately simple: the wait is bounded by the same retries.
 static FETCH_SLOTS: LazyLock<tokio::sync::Semaphore> =
     LazyLock::new(|| tokio::sync::Semaphore::new(8));
+static COMMAND_FETCH_SLOTS: LazyLock<std::sync::Arc<tokio::sync::Semaphore>> =
+    LazyLock::new(|| std::sync::Arc::new(tokio::sync::Semaphore::new(2)));
 
 async fn fetch_with_attempts(url: &str, attempts: u32) -> Result<Option<Fetched>, FetchError> {
     // Wall time of the whole fetch, retry backoff included: the ugoira encode

crates/xmedia-bot/src/handlers/commands.rs

@@ -598,11 +598,7 @@ pub(crate) async fn execute_command(
                 .await?;
                 return Ok(());
             }
-            // The ordinary link pipeline with the chat's post-send actions
+            let _command_fetch = x_media::site::acquire_command_fetch_slot().await;
-            // suppressed: the media is sent (and cached) like a normal link,
-            // but nothing is forwarded to the channel and no
-            // edit-before-forward prompt opens. Info level echoes the
-            // normalized key (never the raw URL) per the logging convention.
             log::info!("test: sending [key={}]", log_key(url));
             url_media(
                 ctx,
@@ -612,6 +608,7 @@ pub(crate) async fn execute_command(
                 PostSend::Suppressed,
             )
             .await;
+            drop(_command_fetch);
         }
         Command::Debug(arg) => {
             let url = arg.trim();
@@ -625,8 +622,7 @@ pub(crate) async fn execute_command(
                 .await?;
                 return Ok(());
             }
-            // Debug tool: report the parse result only — nothing is sent,
+            let _command_fetch = x_media::site::acquire_command_fetch_slot().await;
-            // cached or forwarded.
             log::info!("debug: parsing [key={}]", log_key(url));
             match x_media::site::fetch(url).await {
                 Ok(None) => {