add server.remove_good_host(..)

we'll use this later in gc jobs to clean up any hosts that have been
consistently down or whatever

src/lib.rs

@@ -53,7 +53,17 @@ impl RelayServer {
         let hosts_copy = hosts.iter().collect::<Vec<_>>();
         let serialized_hosts = serde_ipld_dagcbor::to_vec(&hosts_copy)?;
         drop(hosts);
+        self.db.insert("hosts", serialized_hosts)?;
+        Ok(())
+    }
 
+    pub async fn remove_good_host(&self, host: String) -> Result<()> {
+        tracing::debug!(%host, "dropping known-good host");
+        let mut hosts = self.known_good_hosts.lock().await;
+        hosts.remove(&host);
+        let hosts_copy = hosts.iter().collect::<Vec<_>>();
+        let serialized_hosts = serde_ipld_dagcbor::to_vec(&hosts_copy)?;
+        drop(hosts);
         self.db.insert("hosts", serialized_hosts)?;
         Ok(())
     }