use a FuturesOrdered wait group

src/domain/acme/manager.rs

@@ -80,26 +80,27 @@ where
         where Self: 'mgr;
 
     fn sync_domain(&self, domain: domain::Name) -> Self::SyncDomainFuture<'_> {
-        // if there's an existing cert, and its expiry (determined by the soonest value of
-        // not_after amongst its parts) is later than 30 days from now, then we consider it to be
-        // synced.
-        if let Ok(cert) = self.store.get_certificate(domain.as_str()) {
-            let thirty_days = openssl::asn1::Asn1Time::days_from_now(30)
-                .expect("parsed thirty days from now as Asn1Time");
-
-            let soonest_not_after = cert[1..]
-                .into_iter()
-                .map(|cert_part| cert_part.not_after())
-                .fold(cert[0].not_after(), |a, b| if a < b { a } else { b });
-
-            if thirty_days < soonest_not_after {
-                return Box::pin(future::ready(Ok(())));
-            }
-        }
-
-        println!("fetching a new certificate for domain {}", domain.as_str());
-
         Box::pin(async move {
+            // if there's an existing cert, and its expiry (determined by the soonest value of
+            // not_after amongst its parts) is later than 30 days from now, then we consider it to be
+            // synced.
+            if let Ok(cert) = self.store.get_certificate(domain.as_str()) {
+                let thirty_days = openssl::asn1::Asn1Time::days_from_now(30)
+                    .expect("parsed thirty days from now as Asn1Time");
+
+                let cert_with_soonest_not_after = cert
+                    .into_iter()
+                    .reduce(|a, b| if a.not_after() < b.not_after() { a } else { b })
+                    .ok_or(error::Unexpected::from(
+                        "expected there to be more than one cert",
+                    ))?;
+
+                if thirty_days < cert_with_soonest_not_after.not_after() {
+                    return Ok(());
+                }
+            }
+
+            println!("fetching a new certificate for domain {}", domain.as_str());
             let mut builder = acme2::OrderBuilder::new(self.account.clone());
             builder.add_dns_identifier(domain.as_str().to_string());
             let order = builder.build().await.map_unexpected()?;

src/main.rs

@@ -1,6 +1,7 @@
 #![feature(result_option_inspect)]
 
 use clap::Parser;
+use futures::stream::futures_unordered::FuturesUnordered;
 use futures::stream::StreamExt;
 use signal_hook_tokio::Signals;
 use tokio::select;
@@ -58,6 +59,8 @@ struct Cli {
 fn main() {
     let config = Cli::parse();
 
+    let mut wait_group = FuturesUnordered::new();
+
     let tokio_runtime = std::sync::Arc::new(
         tokio::runtime::Builder::new_multi_thread()
             .enable_all()
@@ -123,7 +126,7 @@ fn main() {
         domain_acme_manager.clone(),
     );
 
-    let origin_syncer_handler = {
+    wait_group.push({
         let manager = manager.clone();
         let canceller = canceller.clone();
 
@@ -152,7 +155,7 @@ fn main() {
                     });
             }
         })
-    };
+    });
 
     let service = domiply::service::new(
         manager,
@@ -176,7 +179,7 @@ fn main() {
             async move { Ok::<_, Infallible>(service) }
         });
 
-    let server_handler = {
+    wait_group.push({
         let http_domain = config.http_domain.clone();
 
         tokio_runtime.spawn(async move {
@@ -193,7 +196,7 @@ fn main() {
                 panic!("server error: {}", e);
             };
         })
-    };
+    });
 
     // if there's an acme manager then it means that https is enabled, and we should ensure that
     // the http domain for domiply itself has a valid certificate.
@@ -201,19 +204,17 @@ fn main() {
         let domain = domiply::domain::Name::from_str(&config.http_domain)
             .expect("--http-domain parses as a domain");
 
-        tokio_runtime.spawn(async move {
+        wait_group.push(tokio_runtime.spawn(async move {
             _ = domain_acme_manager
                 .sync_domain(domain.clone())
                 .await
                 .inspect_err(|err| {
-                    println!("Error while getting cert for {}: {err}", domain.as_str())
+                    panic!("Error while getting cert for {}: {err}", domain.as_str())
                 });
-        });
+        }));
     }
 
-    tokio_runtime
-        .block_on(async { futures::try_join!(origin_syncer_handler, server_handler) })
-        .unwrap();
+    tokio_runtime.block_on(async { while let Some(_) = wait_group.next().await {} });
 
     println!("Graceful shutdown complete");
 }