experiments

Signed-off-by: Marc-Antoine Perennou <[email protected]>

examples/t.rs

@@ -0,0 +1,122 @@
+use lapin::{
+    message::DeliveryResult, options::*, publisher_confirm::Confirmation, types::FieldTable,
+    BasicProperties, Connection, ConnectionProperties,
+};
+use tracing::info;
+
+fn main() {
+    if std::env::var("RUST_LOG").is_err() {
+        std::env::set_var("RUST_LOG", "info");
+    }
+
+    tracing_subscriber::fmt::init();
+
+    let addr = std::env::var("AMQP_ADDR").unwrap_or_else(|_| "amqp://127.0.0.1:5672/%2f".into());
+    let recovery_config = lapin::experimental::RecoveryConfig {
+        auto_recover_channels: true,
+    };
+
+    async_global_executor::block_on(async {
+        let conn = Connection::connect(
+            &addr,
+            ConnectionProperties::default().with_experimental_recovery_config(recovery_config),
+        )
+        .await
+        .expect("connection error");
+
+        info!("CONNECTED");
+
+        {
+            let channel1 = conn.create_channel().await.expect("create_channel");
+            let channel2 = conn.create_channel().await.expect("create_channel");
+            channel1
+                .confirm_select(ConfirmSelectOptions::default())
+                .await
+                .expect("confirm_select");
+            channel1
+                .queue_declare(
+                    "recover-test",
+                    QueueDeclareOptions::default(),
+                    FieldTable::default(),
+                )
+                .await
+                .expect("queue_declare");
+
+            info!("will consume");
+            let channel = channel2.clone();
+            channel2
+                .basic_consume(
+                    "recover-test",
+                    "my_consumer",
+                    BasicConsumeOptions::default(),
+                    FieldTable::default(),
+                )
+                .await
+                .expect("basic_consume")
+                .set_delegate(move |delivery: DeliveryResult| {
+                    let channel = channel.clone();
+                    async move {
+                        info!(message=?delivery, "received message");
+                        if let Ok(Some(delivery)) = delivery {
+                            delivery
+                                .ack(BasicAckOptions::default())
+                                .await
+                                .expect("basic_ack");
+                            if &delivery.data[..] == b"after" {
+                                channel
+                                    .basic_cancel("my_consumer", BasicCancelOptions::default())
+                                    .await
+                                    .expect("basic_cancel");
+                            }
+                        }
+                    }
+                });
+
+            info!("will publish");
+            let confirm = channel1
+                .basic_publish(
+                    "",
+                    "recover-test",
+                    BasicPublishOptions::default(),
+                    b"before",
+                    BasicProperties::default(),
+                )
+                .await
+                .expect("basic_publish")
+                .await
+                .expect("publisher-confirms");
+            assert_eq!(confirm, Confirmation::Ack(None));
+
+            info!("before fail");
+            assert!(channel1
+                .queue_declare(
+                    "fake queue",
+                    QueueDeclareOptions {
+                        passive: true,
+                        ..QueueDeclareOptions::default()
+                    },
+                    FieldTable::default(),
+                )
+                .await
+                .is_err());
+            info!("after fail");
+
+            info!("publish after");
+            let confirm = channel1
+                .basic_publish(
+                    "",
+                    "recover-test",
+                    BasicPublishOptions::default(),
+                    b"after",
+                    BasicProperties::default(),
+                )
+                .await
+                .expect("basic_publish")
+                .await
+                .expect("publisher-confirms");
+            assert_eq!(confirm, Confirmation::Ack(None));
+        }
+
+        conn.run().expect("conn.run");
+    });
+}

src/acknowledgement.rs

@@ -62,6 +62,10 @@ impl Acknowledgements {
     pub(crate) fn on_channel_error(&self, error: Error) {
         self.0.lock().on_channel_error(error);
     }
+
+    pub(crate) fn reset(&self) {
+        self.0.lock().reset();
+    }
 }
 
 impl fmt::Debug for Acknowledgements {
@@ -174,4 +178,9 @@ impl Inner {
             }
         }
     }
+
+    fn reset(&mut self) {
+        // FIXME(recovery): handle pendings ??
+        self.delivery_tag = IdSequence::new(false);
+    }
 }

src/channel.rs

@@ -86,6 +86,7 @@ impl fmt::Debug for Channel {
 }
 
 impl Channel {
+    #[allow(clippy::too_many_arguments)]
     pub(crate) fn new(
         channel_id: ChannelId,
         configuration: Configuration,
@@ -579,13 +580,20 @@ impl Channel {
     }
 
     fn on_channel_close_ok_sent(&self, error: Option<Error>) {
-        self.set_closed(
-            error
-                .clone()
-                .unwrap_or(Error::InvalidChannelState(ChannelState::Closing)),
-        );
-        if let Some(error) = error {
-            self.error_handler.on_error(error);
+        match (self.recovery_config.auto_recover_channels, error) {
+            (true, Some(error)) if error.is_amqp_soft_error() => {
+                self.status.set_reconnecting(error)
+            }
+            (_, error) => {
+                self.set_closed(
+                    error
+                        .clone()
+                        .unwrap_or(Error::InvalidChannelState(ChannelState::Closing)),
+                );
+                if let Some(error) = error {
+                    self.error_handler.on_error(error);
+                }
+            }
         }
     }
 
@@ -868,6 +876,15 @@ impl Channel {
         resolver: PromiseResolver<Channel>,
         channel: Channel,
     ) -> Result<()> {
+        if self.recovery_config.auto_recover_channels {
+            self.status.update_recovery_context(|ctx| {
+                ctx.set_expected_replies(self.frames.take_expected_replies(self.id));
+            });
+            self.acknowledgements.reset();
+            if !self.status.confirm() {
+                self.status.finalize_recovery();
+            }
+        }
         self.set_state(ChannelState::Connected);
         resolver.resolve(channel);
         Ok(())
@@ -907,8 +924,19 @@ impl Channel {
         self.set_closing(error.clone().ok());
         let error = error.map_err(|error| info!(channel=%self.id, ?method, code_to_error=%error, "Channel closed with a non-error code")).ok();
         let channel = self.clone();
-        self.internal_rpc
-            .register_internal_future(async move { channel.channel_close_ok(error).await });
+        self.internal_rpc.register_internal_future(async move {
+            channel.channel_close_ok(error).await?;
+            if channel.recovery_config.auto_recover_channels {
+                let ch = channel.clone();
+                channel.channel_open(ch).await?;
+                if channel.status.confirm() {
+                    channel
+                        .confirm_select(ConfirmSelectOptions::default())
+                        .await?;
+                }
+            }
+            Ok(())
+        });
         Ok(())
     }
 

src/channel_recovery_context.rs

@@ -0,0 +1,33 @@
+use crate::{
+    frames::{ExpectedReply, Frames},
+    Error,
+};
+
+use std::collections::VecDeque;
+
+pub(crate) struct ChannelRecoveryContext {
+    pub(crate) cause: Error,
+    expected_replies: Option<VecDeque<ExpectedReply>>,
+}
+
+impl ChannelRecoveryContext {
+    pub(crate) fn new(cause: Error) -> Self {
+        Self {
+            cause,
+            expected_replies: None,
+        }
+    }
+
+    pub(crate) fn set_expected_replies(
+        &mut self,
+        expected_replies: Option<VecDeque<ExpectedReply>>,
+    ) {
+        self.expected_replies = expected_replies;
+    }
+
+    pub(crate) fn finalize_recovery(self) {
+        if let Some(replies) = self.expected_replies {
+            Frames::cancel_expected_replies(replies, self.cause);
+        }
+    }
+}

src/channel_status.rs

@@ -1,7 +1,8 @@
 use crate::{
     channel_receiver_state::{ChannelReceiverStates, DeliveryCause},
+    channel_recovery_context::ChannelRecoveryContext,
     types::{ChannelId, Identifier, PayloadSize},
-    Result,
+    Error, Result,
 };
 use parking_lot::Mutex;
 use std::{fmt, sync::Arc};
@@ -12,7 +13,7 @@ pub struct ChannelStatus(Arc<Mutex<Inner>>);
 
 impl ChannelStatus {
     pub fn initializing(&self) -> bool {
-        self.0.lock().state == ChannelState::Initial
+        [ChannelState::Initial, ChannelState::Reconnecting].contains(&self.0.lock().state)
     }
 
     pub fn closing(&self) -> bool {
@@ -23,6 +24,17 @@ impl ChannelStatus {
         self.0.lock().state == ChannelState::Connected
     }
 
+    pub(crate) fn update_recovery_context<F: Fn(&mut ChannelRecoveryContext)>(&self, apply: F) {
+        let mut inner = self.0.lock();
+        if let Some(context) = inner.recovery_context.as_mut() {
+            apply(context);
+        }
+    }
+
+    pub(crate) fn finalize_recovery(&self) {
+        self.0.lock().finalize_recovery();
+    }
+
     pub(crate) fn can_receive_messages(&self) -> bool {
         [ChannelState::Closing, ChannelState::Connected].contains(&self.0.lock().state)
     }
@@ -32,8 +44,10 @@ impl ChannelStatus {
     }
 
     pub(crate) fn set_confirm(&self) {
-        self.0.lock().confirm = true;
+        let mut inner = self.0.lock();
+        inner.confirm = true;
         trace!("Publisher confirms activated");
+        inner.finalize_recovery();
     }
 
     pub fn state(&self) -> ChannelState {
@@ -44,6 +58,12 @@ impl ChannelStatus {
         self.0.lock().state = state;
     }
 
+    pub(crate) fn set_reconnecting(&self, error: Error) {
+        let mut inner = self.0.lock();
+        inner.state = ChannelState::Reconnecting;
+        inner.recovery_context = Some(ChannelRecoveryContext::new(error));
+    }
+
     pub(crate) fn auto_close(&self, id: ChannelId) -> bool {
         id != 0 && self.0.lock().state == ChannelState::Connected
     }
@@ -116,6 +136,7 @@ impl ChannelStatus {
 pub enum ChannelState {
     #[default]
     Initial,
+    Reconnecting,
     Connected,
     Closing,
     Closed,
@@ -141,6 +162,7 @@ struct Inner {
     send_flow: bool,
     state: ChannelState,
     receiver_state: ChannelReceiverStates,
+    recovery_context: Option<ChannelRecoveryContext>,
 }
 
 impl Default for Inner {
@@ -150,6 +172,15 @@ impl Default for Inner {
             send_flow: true,
             state: ChannelState::default(),
             receiver_state: ChannelReceiverStates::default(),
+            recovery_context: None,
+        }
+    }
+}
+
+impl Inner {
+    pub(crate) fn finalize_recovery(&mut self) {
+        if let Some(ctx) = self.recovery_context.take() {
+            ctx.finalize_recovery();
         }
     }
 }

src/frames.rs

@@ -87,8 +87,21 @@ impl Frames {
         self.inner.lock().drop_pending(error);
     }
 
+    pub(crate) fn take_expected_replies(
+        &self,
+        channel_id: ChannelId,
+    ) -> Option<VecDeque<ExpectedReply>> {
+        self.inner.lock().expected_replies.remove(&channel_id)
+    }
+
     pub(crate) fn clear_expected_replies(&self, channel_id: ChannelId, error: Error) {
-        self.inner.lock().clear_expected_replies(channel_id, error);
+        if let Some(replies) = self.take_expected_replies(channel_id) {
+            Self::cancel_expected_replies(replies, error)
+        }
+    }
+
+    pub(crate) fn cancel_expected_replies(replies: VecDeque<ExpectedReply>, error: Error) {
+        Inner::cancel_expected_replies(replies, error)
     }
 
     pub(crate) fn poison(&self) -> Option<Error> {
@@ -265,12 +278,6 @@ impl Inner {
         None
     }
 
-    fn clear_expected_replies(&mut self, channel_id: ChannelId, error: Error) {
-        if let Some(replies) = self.expected_replies.remove(&channel_id) {
-            Self::cancel_expected_replies(replies, error);
-        }
-    }
-
     fn cancel_expected_replies(replies: VecDeque<ExpectedReply>, error: Error) {
         for ExpectedReply(reply, cancel) in replies {
             match reply {

src/lib.rs

@@ -136,6 +136,7 @@ mod buffer;
 mod channel;
 mod channel_closer;
 mod channel_receiver_state;
+mod channel_recovery_context;
 mod channel_status;
 mod channels;
 mod configuration;