add prometheus metrics

src/bot.rs

@@ -1,6 +1,5 @@
 use crate::{
-    gitea::{GiteaAPI, WebhookType},
-    open_router::OpenRouterClient,
+    gitea::{GiteaAPI, WebhookType}, metrics, open_router::OpenRouterClient,
 };
 use serde::Deserialize;
 use std::{collections::HashSet, sync::Arc};
@@ -87,10 +86,12 @@ impl Bot {
             info!(queued = rx.len(), active = tasks.len(), "Webhook received");
             let permit = sem.clone().acquire_owned().await?;
             let self_clone = self.clone();
+            metrics::increment_task_active();
 
             tasks.spawn(async move {
                 self_clone.exec(wb).await;
                 drop(permit);
+                metrics::decrement_task_active();
             });
         }
 
@@ -102,6 +103,8 @@ impl Bot {
 
     #[instrument(skip(self, webhook), fields(repo, pr))]
     pub async fn exec(&self, webhook: WebhookType) {
+        let event_type_str = webhook.event_type_str();
+
         match &webhook {
             WebhookType::Review(p) => {
                 tracing::Span::current().record("repo", &p.repository.full_name);
@@ -121,8 +124,12 @@ impl Bot {
         .await;
 
         match exec_result {
-            Ok(_) => info!("Task completed"),
+            Ok(_) => {
+                metrics::task_completed(event_type_str);
+                info!("Task completed");
+            }
             Err(err) => {
+                metrics::task_failed(event_type_str);
                 error!(%err, "Task error");
                 sentry_anyhow::capture_anyhow(&err);
             }