improvement: cache actual destination

src/database/globals.rs

@@ -1,20 +1,25 @@
 use crate::{database::Config, utils, Error, Result};
+use trust_dns_resolver::TokioAsyncResolver;
+use std::collections::HashMap;
 use log::error;
 use ruma::ServerName;
 use std::sync::Arc;
+use std::sync::RwLock;
 
 pub const COUNTER: &str = "c";
 
 #[derive(Clone)]
 pub struct Globals {
     pub(super) globals: sled::Tree,
+    config: Config,
     keypair: Arc<ruma::signatures::Ed25519KeyPair>,
     reqwest_client: reqwest::Client,
-    config: Config,
+    pub actual_destination_cache: Arc<RwLock<HashMap<Box<ServerName>, (String, Option<String>)>>>, // actual_destination, host
+    dns_resolver: TokioAsyncResolver,
 }
 
 impl Globals {
-    pub fn load(globals: sled::Tree, config: Config) -> Result<Self> {
+    pub async fn load(globals: sled::Tree, config: Config) -> Result<Self> {
         let bytes = &*globals
             .update_and_fetch("keypair", utils::generate_keypair)?
             .expect("utils::generate_keypair always returns Some");
@@ -51,9 +56,13 @@ impl Globals {
 
         Ok(Self {
             globals,
+            config,
             keypair: Arc::new(keypair),
             reqwest_client: reqwest::Client::new(),
-            config,
+            dns_resolver: TokioAsyncResolver::tokio_from_system_conf().await.map_err(|_| {
+                Error::bad_config("Failed to set up trust dns resolver with system config.")
+            })?,
+            actual_destination_cache: Arc::new(RwLock::new(HashMap::new())),
         })
     }
 
@@ -103,4 +112,8 @@ impl Globals {
     pub fn federation_enabled(&self) -> bool {
         self.config.federation_enabled
     }
+
+    pub fn dns_resolver(&self) -> &TokioAsyncResolver {
+        &self.dns_resolver
+    }
 }