add metrics for "I'm feeling lucky" searches

Author: syphar

src/metrics/mod.rs

@@ -69,6 +69,9 @@ metrics! {
 
         /// The number of attempted files that failed due to a memory limit
         pub(crate) html_rewrite_ooms: IntCounter,
+
+        /// the number of "I'm feeling lucky" searches for crates
+        pub(crate) im_feeling_lucky_searches: IntCounter,
     }
 
     // The Rust prometheus library treats the namespace as the "prefix" of the metric name: a

src/web/releases.rs

@@ -550,6 +550,9 @@ fn redirect_to_random_crate(req: &Request, conn: &mut PoolClient) -> IronResult<
             let mut resp = Response::with((status::Found, Redirect(url)));
             resp.headers.set(Expires(HttpDate(time::now())));
 
+            let metrics = extension!(req, crate::Metrics).clone();
+            metrics.im_feeling_lucky_searches.inc();
+
             log::debug!("finished random crate search on iteration {}", i);
             return Ok(resp);
         } else {