Show currently loading recordings in Recordings menu (#3307)

### What
* Closes #3192

Shows currently loading receivers in the recordings panel until they
actually receive some data.

This is a blink-and-you'll-miss-it sort of thing (especially with a good
internet connection), but take a look at the top-left of the screen:


![loading-msg](https://github.com/rerun-io/rerun/assets/1148717/20e133ed-8164-4c73-9057-82ba7bfd5d8e)


### Checklist
* [x] I have read and agree to [Contributor
Guide](https://github.com/rerun-io/rerun/blob/main/CONTRIBUTING.md) and
the [Code of
Conduct](https://github.com/rerun-io/rerun/blob/main/CODE_OF_CONDUCT.md)
* [x] I've included a screenshot or gif (if applicable)
* [x] I have tested [demo.rerun.io](https://demo.rerun.io/pr/3307) (if
applicable)

- [PR Build Summary](https://build.rerun.io/pr/3307)
- [Docs
preview](https://rerun.io/preview/44f7f8d87b7f656725e3eb7698eee8cd3947ecfb/docs)
<!--DOCS-PREVIEW-->
- [Examples
preview](https://rerun.io/preview/44f7f8d87b7f656725e3eb7698eee8cd3947ecfb/examples)
<!--EXAMPLES-PREVIEW-->
- [Recent benchmark results](https://ref.rerun.io/dev/bench/)
- [Wasm size tracking](https://ref.rerun.io/dev/sizes/)

---------

Co-authored-by: Andreas Reich <[email protected]>

crates/re_renderer/examples/framework.rs

@@ -246,7 +246,7 @@ impl<E: Example + 'static> Application<E> {
                             return;
                         }
                         Err(err) => {
-                            re_log::warn!(%err, "dropped frame");
+                            re_log::warn!("Dropped frame: {err}");
                             return;
                         }
                     };

crates/re_smart_channel/src/receive_set.rs

@@ -31,6 +31,11 @@ impl<T: Send> ReceiveSet<T> {
         rx.push(r);
     }
 
+    /// Disconnect from any channel with the given source.
+    pub fn remove(&self, source: &SmartChannelSource) {
+        self.receivers.lock().retain(|r| r.source() != source);
+    }
+
     /// List of connected receiver sources.
     ///
     /// This gets culled after calling one of the `recv` methods.

crates/re_ui/src/lib.rs

@@ -702,12 +702,13 @@ impl ReUi {
     }
 
     /// Two-column grid to be used in selection view.
+    ///
+    /// Use this when you expect the right column to have multi-line entries.
     #[allow(clippy::unused_self)]
-    pub fn selection_grid(&self, ui: &mut egui::Ui, id: &str) -> egui::Grid {
+    pub fn selection_grid(&self, _ui: &mut egui::Ui, id: &str) -> egui::Grid {
         // Spread rows a bit to make it easier to see the groupings
-        egui::Grid::new(id)
-            .num_columns(2)
-            .spacing(ui.style().spacing.item_spacing + egui::vec2(0.0, 8.0))
+        let spacing = egui::vec2(8.0, 16.0);
+        egui::Grid::new(id).num_columns(2).spacing(spacing)
     }
 
     /// Draws a shadow into the given rect with the shadow direction given from dark to light

crates/re_viewer/src/app.rs

@@ -712,9 +712,9 @@ impl App {
                 re_smart_channel::SmartMessagePayload::Msg(msg) => msg,
                 re_smart_channel::SmartMessagePayload::Quit(err) => {
                     if let Some(err) = err {
-                        re_log::warn!(%msg.source, err, "data source has left unexpectedly");
+                        re_log::warn!("Data source {} has left unexpectedly: {err}", msg.source);
                     } else {
-                        re_log::debug!(%msg.source, "data source has left");
+                        re_log::debug!("Data source {} has left", msg.source);
                     }
                     continue;
                 }

crates/re_viewer/src/app_state.rs

@@ -171,7 +171,7 @@ impl AppState {
                         // before drawing the blueprint panel.
                         ui.spacing_mut().item_spacing.y = 0.0;
 
-                        let recording_shown = recordings_panel_ui(&mut ctx, ui);
+                        let recording_shown = recordings_panel_ui(&mut ctx, rx, ui);
 
                         if recording_shown {
                             ui.add_space(4.0);

crates/re_viewer/src/store_hub.rs

@@ -108,7 +108,7 @@ impl StoreHub {
                 StoreContext {
                     blueprint,
                     recording,
-                    alternate_recordings: self.store_dbs.recordings().collect_vec(),
+                    all_recordings: self.store_dbs.recordings().collect_vec(),
                 }
             })
     }

crates/re_viewer/src/ui/recordings_panel.rs

@@ -1,15 +1,24 @@
-use re_viewer_context::{CommandSender, SystemCommand, SystemCommandSender, ViewerContext};
 use std::collections::BTreeMap;
+
 use time::macros::format_description;
 
+use re_log_types::LogMsg;
+use re_smart_channel::{ReceiveSet, SmartChannelSource};
+use re_viewer_context::{CommandSender, SystemCommand, SystemCommandSender, ViewerContext};
+
 static TIME_FORMAT_DESCRIPTION: once_cell::sync::Lazy<
     &'static [time::format_description::FormatItem<'static>],
 > = once_cell::sync::Lazy::new(|| format_description!(version = 2, "[hour]:[minute]:[second]Z"));
 
 /// Show the currently open Recordings in a selectable list.
+/// Also shows the currently loading receivers.
 ///
 /// Returns `true` if any recordings were shown.
-pub fn recordings_panel_ui(ctx: &mut ViewerContext<'_>, ui: &mut egui::Ui) -> bool {
+pub fn recordings_panel_ui(
+    ctx: &mut ViewerContext<'_>,
+    rx: &ReceiveSet<LogMsg>,
+    ui: &mut egui::Ui,
+) -> bool {
     ctx.re_ui.panel_content(ui, |re_ui, ui| {
         re_ui.panel_title_bar_with_buttons(
             ui,
@@ -26,16 +35,87 @@ pub fn recordings_panel_ui(ctx: &mut ViewerContext<'_>, ui: &mut egui::Ui) -> bo
         .auto_shrink([false, true])
         .max_height(300.)
         .show(ui, |ui| {
-            ctx.re_ui
-                .panel_content(ui, |_re_ui, ui| recording_list_ui(ctx, ui))
+            ctx.re_ui.panel_content(ui, |_re_ui, ui| {
+                let mut any_shown = false;
+                any_shown |= recording_list_ui(ctx, ui);
+
+                // Show currently loading things after.
+                // They will likely end up here as recordings soon.
+                any_shown |= loading_receivers_ui(ctx, rx, ui);
+
+                any_shown
+            })
         })
         .inner
 }
 
+fn loading_receivers_ui(
+    ctx: &mut ViewerContext<'_>,
+    rx: &ReceiveSet<LogMsg>,
+    ui: &mut egui::Ui,
+) -> bool {
+    let sources_with_stores: ahash::HashSet<SmartChannelSource> = ctx
+        .store_context
+        .all_recordings
+        .iter()
+        .filter_map(|store| store.data_source.clone())
+        .collect();
+
+    let mut any_shown = false;
+
+    for source in rx.sources() {
+        let (always_show, string) = match source.as_ref() {
+            SmartChannelSource::File(path) => (false, format!("Loading {}…", path.display())),
+
+            SmartChannelSource::RrdHttpStream { url } => (false, format!("Loading {url}…")),
+
+            SmartChannelSource::RrdWebEventListener => {
+                (false, "Waiting on Web Event Listener…".to_owned())
+            }
+
+            SmartChannelSource::Sdk => (false, "Waiting on SDK…".to_owned()),
+
+            SmartChannelSource::WsClient { ws_server_url } => {
+                (false, format!("Loading from {ws_server_url}…"))
+            }
+
+            SmartChannelSource::TcpServer { port } => {
+                // We have a TcpServer when running just `cargo rerun`
+                (true, format!("Hosting a TCP Server on port {port}"))
+            }
+        };
+
+        // Only show if we don't have a recording for this source,
+        // i.e. if this source hasn't sent anything yet.
+        // Note that usually there is a one-to-one mapping between a source and a recording,
+        // but it is possible to send multiple recordings over the same channel.
+        if always_show || !sources_with_stores.contains(&source) {
+            any_shown = true;
+            let response = ctx
+                .re_ui
+                .list_item(string)
+                .with_buttons(|re_ui, ui| {
+                    let resp = re_ui
+                        .small_icon_button(ui, &re_ui::icons::REMOVE)
+                        .on_hover_text("Disconnect from this source");
+                    if resp.clicked() {
+                        rx.remove(&source);
+                    }
+                    resp
+                })
+                .show(ui);
+            if let SmartChannelSource::TcpServer { .. } = source.as_ref() {
+                response.on_hover_text("You can connect to this viewer from a Rerun SDK");
+            }
+        }
+    }
+
+    any_shown
+}
+
 /// Draw the recording list.
 ///
 /// Returns `true` if any recordings were shown.
-#[allow(clippy::blocks_in_if_conditions)]
 fn recording_list_ui(ctx: &mut ViewerContext<'_>, ui: &mut egui::Ui) -> bool {
     let ViewerContext {
         store_context,
@@ -44,7 +124,7 @@ fn recording_list_ui(ctx: &mut ViewerContext<'_>, ui: &mut egui::Ui) -> bool {
     } = ctx;
 
     let mut store_dbs_map: BTreeMap<_, Vec<_>> = BTreeMap::new();
-    for store_db in &store_context.alternate_recordings {
+    for store_db in &store_context.all_recordings {
         let key = store_db
             .store_info()
             .map_or("<unknown>", |info| info.application_id.as_str());
@@ -133,7 +213,7 @@ fn recording_ui(
         })
         .unwrap_or("<unknown time>".to_owned());
 
-    re_ui
+    let response = re_ui
         .list_item(format!("{prefix}{name}"))
         .with_buttons(|re_ui, ui| {
             let resp = re_ui
@@ -155,7 +235,68 @@ fn recording_ui(
             ui.painter()
                 .circle(rect.center(), 4.0, color, egui::Stroke::NONE);
         })
-        .show(ui)
+        .show(ui);
+
+    response.on_hover_ui(|ui| {
+        recording_hover_ui(re_ui, ui, store_db);
+    })
+}
+
+fn recording_hover_ui(re_ui: &re_ui::ReUi, ui: &mut egui::Ui, store_db: &re_data_store::StoreDb) {
+    egui::Grid::new("recording_hover_ui")
+        .num_columns(2)
+        .show(ui, |ui| {
+            re_ui.grid_left_hand_label(ui, "Store ID");
+            ui.label(store_db.store_id().to_string());
+            ui.end_row();
+
+            if let Some(data_source) = &store_db.data_source {
+                re_ui.grid_left_hand_label(ui, "Data source");
+                ui.label(data_source_string(data_source));
+                ui.end_row();
+            }
+
+            if let Some(set_store_info) = store_db.recording_msg() {
+                let re_log_types::StoreInfo {
+                    application_id,
+                    store_id: _,
+                    is_official_example: _,
+                    started,
+                    store_source,
+                    store_kind,
+                } = &set_store_info.info;
+
+                re_ui.grid_left_hand_label(ui, "Application ID");
+                ui.label(application_id.to_string());
+                ui.end_row();
+
+                re_ui.grid_left_hand_label(ui, "Recording started");
+                ui.label(started.format());
+                ui.end_row();
+
+                re_ui.grid_left_hand_label(ui, "Source");
+                ui.label(store_source.to_string());
+                ui.end_row();
+
+                // We are in the recordings menu, we know the kind
+                if false {
+                    re_ui.grid_left_hand_label(ui, "Kind");
+                    ui.label(store_kind.to_string());
+                    ui.end_row();
+                }
+            }
+        });
+}
+
+fn data_source_string(data_source: &re_smart_channel::SmartChannelSource) -> String {
+    match data_source {
+        SmartChannelSource::File(path) => path.display().to_string(),
+        SmartChannelSource::RrdHttpStream { url } => url.clone(),
+        SmartChannelSource::RrdWebEventListener => "Web Event Listener".to_owned(),
+        SmartChannelSource::Sdk => "SDK".to_owned(),
+        SmartChannelSource::WsClient { ws_server_url } => ws_server_url.clone(),
+        SmartChannelSource::TcpServer { port } => format!("TCP Server, port {port}"),
+    }
 }
 
 fn add_button_ui(ctx: &mut ViewerContext<'_>, ui: &mut egui::Ui) {

crates/re_viewer_context/src/store_context.rs

@@ -4,5 +4,5 @@ use re_data_store::StoreDb;
 pub struct StoreContext<'a> {
     pub blueprint: &'a StoreDb,
     pub recording: Option<&'a StoreDb>,
-    pub alternate_recordings: Vec<&'a StoreDb>,
+    pub all_recordings: Vec<&'a StoreDb>,
 }

crates/re_ws_comms/src/server.rs

@@ -165,9 +165,9 @@ fn to_broadcast_stream(
                 }
                 re_smart_channel::SmartMessagePayload::Quit(err) => {
                     if let Some(err) = err {
-                        re_log::warn!(%msg.source, err, "sender has left unexpectedly");
+                        re_log::warn!("Sender {} has left unexpectedly: {err}", msg.source);
                     } else {
-                        re_log::debug!(%msg.source, "sender has left");
+                        re_log::debug!("Sender {} has left", msg.source);
                     }
                 }
             }