fix: increase max packet size for built-in bridge

crates/common/tedge_config/src/tedge_config_cli/tedge_config.rs

@@ -769,6 +769,9 @@ define_tedge_config! {
 
         bridge: {
             #[tedge_config(default(value = false))]
+            #[tedge_config(example = "false")]
+            #[tedge_config(note = "After changing this value, run `tedge reconnect <cloud>` to apply the changes")]
+            /// Enables the built-in bridge when running tedge-mapper
             built_in: bool,
 
             reconnect_policy: {

crates/extensions/tedge_mqtt_bridge/src/lib.rs

@@ -57,6 +57,8 @@ use crate::topics::matches_ignore_dollar_prefix;
 use crate::topics::TopicConverter;
 pub use config::*;
 
+const MAX_PACKET_SIZE: usize = 268435455; // maximum allowed MQTT payload size
+
 pub struct MqttBridgeActorBuilder {}
 
 impl MqttBridgeActorBuilder {
@@ -90,6 +92,7 @@ impl MqttBridgeActorBuilder {
         if let Some(tls_config) = local_tls_config {
             local_config.set_transport(Transport::tls_with_config(tls_config.into()));
         }
+        local_config.set_max_packet_size(MAX_PACKET_SIZE, MAX_PACKET_SIZE);
         local_config.set_manual_acks(true);
         local_config.set_last_will(LastWill::new(
             &health_topic.name,
@@ -102,6 +105,7 @@ impl MqttBridgeActorBuilder {
         let reconnect_policy = tedge_config.mqtt.bridge.reconnect_policy.clone();
 
         cloud_config.set_manual_acks(true);
+        cloud_config.set_max_packet_size(MAX_PACKET_SIZE, MAX_PACKET_SIZE);
 
         let (local_client, local_event_loop) = AsyncClient::new(local_config, 10);
         let (cloud_client, cloud_event_loop) = AsyncClient::new(cloud_config, 10);
@@ -377,28 +381,16 @@ async fn half_bridge(
 
             // Keep track of packet IDs so we can acknowledge messages
             Event::Outgoing(Outgoing::Publish(pkid)) => {
-                if pkid == 0 {
-                    // Messages with pkid 0 (meaning QoS=0) should not be added to the hashmap
-                    // as multiple messages with the pkid=0 can be received
-                    match companion_bridge_half.recv().await {
-                        // A message was forwarded by the other bridge half, note the packet id
-                        Some(Some((topic, msg))) => {
-                            loop_breaker.forward_on_topic(topic, &msg);
-                        }
-
-                        // A healthcheck message was published, ignore this packet id
-                        Some(None) => {}
-
-                        // The other bridge half has disconnected, break the loop and shut down the bridge
-                        None => break,
-                    }
-                } else if let hash_map::Entry::Vacant(e) = forward_pkid_to_received_msg.entry(pkid)
-                {
+                if let hash_map::Entry::Vacant(e) = forward_pkid_to_received_msg.entry(pkid) {
                     match companion_bridge_half.recv().await {
                         // A message was forwarded by the other bridge half, note the packet id
                         Some(Some((topic, msg))) => {
                             loop_breaker.forward_on_topic(topic, &msg);
-                            e.insert(msg);
+                            if pkid != 0 {
+                                // Messages with pkid 0 (meaning QoS=0) should not be added to the hashmap
+                                // as multiple messages with the pkid=0 can be received
+                                e.insert(msg);
+                            }
                         }
 
                         // A healthcheck message was published, ignore this packet id

crates/extensions/tedge_mqtt_bridge/tests/bridge.rs

@@ -29,18 +29,17 @@ use tokio::time::timeout;
 use tracing::info;
 use tracing::warn;
 
-const DEFAULT_TIMEOUT: Duration = Duration::from_secs(3);
+const DEFAULT_TIMEOUT: Duration = Duration::from_secs(10);
 
 fn new_broker_and_client(name: &str, port: u16) -> (AsyncClient, EventLoop) {
     let mut broker = Broker::new(get_rumqttd_config(port));
     std::thread::Builder::new()
         .name(format!("{name} broker"))
         .spawn(move || broker.start().unwrap())
         .unwrap();
-    AsyncClient::new(
-        MqttOptions::new(format!("{name}-test-client"), "127.0.0.1", port),
-        10,
-    )
+    let mut client_opts = MqttOptions::new(format!("{name}-test-client"), "127.0.0.1", port);
+    client_opts.set_max_packet_size(268435455, 268435455);
+    AsyncClient::new(client_opts, 10)
 }
 
 async fn start_mqtt_bridge(local_port: u16, cloud_port: u16, rules: BridgeConfig) {
@@ -117,6 +116,46 @@ async fn bridge_many_messages() {
     next_received_message(&mut local).await.unwrap();
 }
 
+#[tokio::test]
+async fn bridge_forwards_large_messages() {
+    std::env::set_var("RUST_LOG", "tedge_mqtt_bridge=debug,rumqttc=trace,info");
+    let _ = env_logger::try_init();
+    let local_broker_port = free_port().await;
+    let cloud_broker_port = free_port().await;
+    let (local, mut ev_local) = new_broker_and_client("local", local_broker_port);
+    let (cloud, mut ev_cloud) = new_broker_and_client("cloud", cloud_broker_port);
+
+    let mut rules = BridgeConfig::new();
+    rules.forward_from_local("s/us", "c8y/", "").unwrap();
+    rules.forward_from_remote("s/ds", "c8y/", "").unwrap();
+
+    start_mqtt_bridge(local_broker_port, cloud_broker_port, rules).await;
+
+    local.subscribe(HEALTH, QoS::AtLeastOnce).await.unwrap();
+
+    wait_until_health_status_is("up", &mut ev_local)
+        .await
+        .unwrap();
+
+    local.unsubscribe(HEALTH).await.unwrap();
+    cloud.subscribe("s/us", QoS::AtLeastOnce).await.unwrap();
+    await_subscription(&mut ev_cloud).await;
+
+    let _poll_local = EventPoller::run_in_bg(ev_local);
+
+    let payload = std::iter::repeat(b'a')
+        .take(25 * 1024 * 1024)
+        .collect::<Vec<u8>>();
+
+    local
+        .publish("c8y/s/us", QoS::AtLeastOnce, false, payload.clone())
+        .await
+        .unwrap();
+
+    let msg = next_received_message(&mut ev_cloud).await.unwrap();
+    assert_eq!(msg.payload, payload);
+}
+
 #[tokio::test]
 async fn bridge_disconnect_while_sending() {
     std::env::set_var("RUST_LOG", "tedge_mqtt_bridge=info");