add user_count in systemlog

src/cache.rs

@@ -1,4 +1,5 @@
-use crate::api::CurrentUser;
+use crate::api::{Api, CurrentUser};
+use crate::db_conn::Db;
 use crate::models::{Comment, Post, User};
 use crate::rds_conn::RdsConn;
 use crate::rds_models::{clear_all, init, BlockedUsers};
@@ -10,6 +11,9 @@ use futures_util::stream::StreamExt;
 use rocket::futures::future;
 use std::collections::HashMap;
 
+const KEY_USER_COUNT: &str = "hole_v2:cache:user_count";
+const USER_COUNT_EXPIRE_TIME: usize = 5 * 60;
+
 const INSTANCE_EXPIRE_TIME: usize = 60 * 60;
 
 const MIN_LENGTH: isize = 200;
@@ -363,3 +367,16 @@ impl BlockDictCache {
         self.rconn.del(&self.key).await
     }
 }
+
+pub async fn cached_user_count(db: &Db, rconn: &mut RdsConn) -> Api<i64> {
+    let cnt: Option<i64> = rconn.get(KEY_USER_COUNT).await?;
+    if let Some(x) = cnt {
+        Ok(x)
+    } else {
+        let x = User::get_count(db).await?;
+        rconn
+            .set_ex(KEY_USER_COUNT, x, USER_COUNT_EXPIRE_TIME)
+            .await?;
+        Ok(x)
+    }
+}