From c4ac0d0570151381a12de436804bbe31704735e0 Mon Sep 17 00:00:00 2001
From: strct <dev@strct.cc>
Date: Sat, 10 Oct 2020 15:57:23 +0200
Subject: [PATCH] matrix-sdk: example: retry autojoin

---
 matrix_sdk/examples/autojoin.rs | 23 ++++++++++++++++++-----
 1 file changed, 18 insertions(+), 5 deletions(-)

diff --git a/matrix_sdk/examples/autojoin.rs b/matrix_sdk/examples/autojoin.rs
index 2af9a61b..ca757244 100644
--- a/matrix_sdk/examples/autojoin.rs
+++ b/matrix_sdk/examples/autojoin.rs
@@ -1,4 +1,5 @@
 use std::{env, process::exit};
+use tokio::time::{delay_for, Duration};
 
 use matrix_sdk::{
     self,
@@ -32,11 +33,23 @@ impl EventEmitter for AutoJoinBot {
 
         if let SyncRoom::Invited(room) = room {
             let room = room.read().await;
-            println!("Autojoining room {}", room.display_name());
-            self.client
-                .join_room_by_id(&room.room_id)
-                .await
-                .expect("Can't join room");
+            println!("Autojoining room {}", room.room_id);
+            let mut delay = 2;
+            while let Err(err) = self.client.join_room_by_id(&room.room_id).await {
+                // retry autojoin due to synapse sending invites, before the invited user can join
+                // for more information see https://github.com/matrix-org/synapse/issues/4345
+                eprintln!(
+                    "Failed to join room {} ({:?}), retrying in {}s",
+                    room.room_id, err, delay
+                );
+                delay_for(Duration::from_secs(delay)).await;
+                delay *= 2;
+                if delay > 3600 {
+                    eprintln!("Can't join room {} ({:?})", room.room_id, err);
+                    break;
+                }
+            }
+            println!("Successfully joined room {}", room.room_id);
         }
     }
 }