main: Implement exponential backoff in the feed fetcher loop

Backoff with an exponentially increasing delay when feeds can't be
fetched or parsed, with a maximum of 6h (after which retry every 6h)

src/main.rs

@@ -59,6 +59,7 @@ async fn main() -> anyhow::Result<()> {
     let handles: Vec<JoinHandle<_>> = config.feeds.clone().into_iter().map(|feed_config| {
         let state_db = Arc::clone(&state_db);
         let bcast_tx = bcast_tx.clone();
+        let mut backoff: u64 = feed_config.delay;
 
         tokio::spawn(async move {
 
@@ -80,10 +81,15 @@ async fn main() -> anyhow::Result<()> {
                 };
 
                 let feed = if feed.is_none() {
-                    debug!("Sleeping for {} seconds before refreshing this feed", feed_config.delay);
-                    sleep(Duration::from_secs(feed_config.delay)).await;
+                    backoff = max(backoff * 2, 6 * 3600);
+                    error!("Backing off for {} seconds", backoff);
+                    sleep(Duration::from_secs(backoff)).await;
                     continue;
                 } else {
+                    if backoff != feed_config.delay {
+                        debug!("Resetting exponential backoff timer");
+                        backoff = feed_config.delay;
+                    }
                     feed.unwrap()
                 };
 

src/matrix.rs

@@ -98,7 +98,7 @@ pub async fn login_and_sync<T: Clone>(
     client
         .matrix_auth()
         .login_username(username, password)
-        .initial_device_display_name("bender v0.1.3")
+        .initial_device_display_name("bender v0.1.4")
         .await?;
 
     info!("logged in as {username}");