proxy: store role not found in cache (#6439)

## Problem

There are a lot of responses with 404 role not found error, which are
not getting cached in proxy.

## Summary of changes

If there was returned an empty secret but with the project_id, store it
in cache.

proxy/src/console/provider/mock.rs

@@ -150,12 +150,10 @@ impl super::Api for Api {
         &self,
         _ctx: &mut RequestMonitoring,
         user_info: &ComputeUserInfo,
-    ) -> Result<Option<CachedRoleSecret>, GetAuthInfoError> {
-        Ok(self
-            .do_get_auth_info(user_info)
-            .await?
-            .secret
-            .map(CachedRoleSecret::new_uncached))
+    ) -> Result<CachedRoleSecret, GetAuthInfoError> {
+        Ok(CachedRoleSecret::new_uncached(
+            self.do_get_auth_info(user_info).await?.secret,
+        ))
     }
 
     async fn get_allowed_ips(

proxy/src/console/provider/neon.rs

@@ -86,9 +86,14 @@ impl Api {
                 },
             };
 
-            let secret = scram::ServerSecret::parse(&body.role_secret)
-                .map(AuthSecret::Scram)
-                .ok_or(GetAuthInfoError::BadSecret)?;
+            let secret = if body.role_secret.is_empty() {
+                None
+            } else {
+                let secret = scram::ServerSecret::parse(&body.role_secret)
+                    .map(AuthSecret::Scram)
+                    .ok_or(GetAuthInfoError::BadSecret)?;
+                Some(secret)
+            };
             let allowed_ips = body
                 .allowed_ips
                 .into_iter()
@@ -97,7 +102,7 @@ impl Api {
                 .collect_vec();
             ALLOWED_IPS_NUMBER.observe(allowed_ips.len() as f64);
             Ok(AuthInfo {
-                secret: Some(secret),
+                secret,
                 allowed_ips,
                 project_id: body.project_id.map(SmolStr::from),
             })
@@ -172,19 +177,20 @@ impl super::Api for Api {
         &self,
         ctx: &mut RequestMonitoring,
         user_info: &ComputeUserInfo,
-    ) -> Result<Option<CachedRoleSecret>, GetAuthInfoError> {
+    ) -> Result<CachedRoleSecret, GetAuthInfoError> {
         let ep = &user_info.endpoint;
         let user = &user_info.user;
         if let Some(role_secret) = self.caches.project_info.get_role_secret(ep, user) {
-            return Ok(Some(role_secret));
+            return Ok(role_secret);
         }
         let auth_info = self.do_get_auth_info(ctx, user_info).await?;
         if let Some(project_id) = auth_info.project_id {
-            if let Some(secret) = &auth_info.secret {
-                self.caches
-                    .project_info
-                    .insert_role_secret(&project_id, ep, user, secret.clone())
-            }
+            self.caches.project_info.insert_role_secret(
+                &project_id,
+                ep,
+                user,
+                auth_info.secret.clone(),
+            );
             self.caches.project_info.insert_allowed_ips(
                 &project_id,
                 ep,
@@ -192,7 +198,7 @@ impl super::Api for Api {
             );
         }
         // When we just got a secret, we don't need to invalidate it.
-        Ok(auth_info.secret.map(Cached::new_uncached))
+        Ok(Cached::new_uncached(auth_info.secret))
     }
 
     async fn get_allowed_ips(
@@ -214,11 +220,12 @@ impl super::Api for Api {
         let allowed_ips = Arc::new(auth_info.allowed_ips);
         let user = &user_info.user;
         if let Some(project_id) = auth_info.project_id {
-            if let Some(secret) = &auth_info.secret {
-                self.caches
-                    .project_info
-                    .insert_role_secret(&project_id, ep, user, secret.clone())
-            }
+            self.caches.project_info.insert_role_secret(
+                &project_id,
+                ep,
+                user,
+                auth_info.secret.clone(),
+            );
             self.caches
                 .project_info
                 .insert_allowed_ips(&project_id, ep, allowed_ips.clone());