fix: add comprehensive pipeline logging for debugging

kiosk/src/pipeline.rs

@@ -2,8 +2,6 @@ use gstreamer::prelude::*;
 use gstreamer::{self as gst, Element, Pipeline};
 use tracing::{error, info, warn};
 
-/// Create a GStreamer pipeline for an RTSP camera that outputs to a GTK4 paintable sink.
-/// Returns (pipeline, paintable_sink).
 pub fn create_camera_pipeline(name: &str, rtsp_uri: &str) -> Option<(Pipeline, Element)> {
     let pipeline_name = format!("cam-{name}");
     let pipeline = Pipeline::with_name(&pipeline_name);
@@ -13,72 +11,102 @@ pub fn create_camera_pipeline(name: &str, rtsp_uri: &str) -> Option<(Pipeline, E
         .property("latency", 300u32)
         .property_from_str("protocols", "tcp")
         .build()
+        .map_err(|e| error!("[{pipeline_name}] rtspsrc: {e}"))
         .ok()?;
 
-    let decode = gst::ElementFactory::make("decodebin").build().ok()?;
-    let convert = gst::ElementFactory::make("videoconvert").build().ok()?;
+    let decode = gst::ElementFactory::make("decodebin")
+        .build()
+        .map_err(|e| error!("[{pipeline_name}] decodebin: {e}"))
+        .ok()?;
+
+    let convert = gst::ElementFactory::make("videoconvert")
+        .build()
+        .map_err(|e| error!("[{pipeline_name}] videoconvert: {e}"))
+        .ok()?;
 
     let sink = gst::ElementFactory::make("gtk4paintablesink")
         .build()
-        .map_err(|e| {
-            error!("gtk4paintablesink not available: {e}. Install gst-plugin-gtk4");
-        })
+        .map_err(|e| error!("[{pipeline_name}] gtk4paintablesink: {e}"))
         .ok()?;
 
-    let queue = gst::ElementFactory::make("queue")
-        .property("max-size-buffers", 1u32)
-        .property_from_str("leaky", "downstream")
-        .build()
+    pipeline.add_many([&src, &decode, &convert, &sink]).ok()?;
+    gst::Element::link_many([&convert, &sink])
+        .map_err(|e| error!("[{pipeline_name}] link convert→sink failed: {e}"))
         .ok()?;
 
-    pipeline.add_many([&src, &decode, &queue, &convert, &sink]).ok()?;
-
     // rtspsrc → decodebin (dynamic pads)
     let decode_weak = decode.downgrade();
+    let pn = pipeline_name.clone();
     src.connect_pad_added(move |_src, pad| {
+        info!("[{pn}] rtspsrc pad added: {}", pad.name());
         let Some(decode) = decode_weak.upgrade() else { return };
         let sink_pad = decode.static_pad("sink").unwrap();
         if !sink_pad.is_linked() {
-            let _ = pad.link(&sink_pad);
-        }
-    });
-
-    // decodebin → queue → convert → sink (dynamic pads, video only)
-    let queue_weak = queue.downgrade();
-    let pipeline_name_clone = pipeline_name.clone();
-    decode.connect_pad_added(move |_decode, pad| {
-        let caps = pad.current_caps().unwrap_or_else(|| pad.query_caps(None));
-        let caps_str = caps.to_string();
-
-        if !caps_str.starts_with("video/") {
-            return;
-        }
-
-        info!("[{pipeline_name_clone}] decodebin video pad: {caps_str}");
-
-        let Some(queue) = queue_weak.upgrade() else { return };
-        let sink_pad = queue.static_pad("sink").unwrap();
-        if !sink_pad.is_linked() {
-            if pad.link(&sink_pad).is_err() {
-                warn!("[{pipeline_name_clone}] decodebin pad link failed");
+            match pad.link(&sink_pad) {
+                Ok(_) => info!("[{pn}] rtspsrc→decodebin linked"),
+                Err(e) => error!("[{pn}] rtspsrc→decodebin link failed: {e:?}"),
             }
         }
     });
 
-    gst::Element::link_many([&queue, &convert, &sink]).ok()?;
+    // decodebin → convert (dynamic pads, video only)
+    let convert_weak = convert.downgrade();
+    let pn2 = pipeline_name.clone();
+    decode.connect_pad_added(move |_decode, pad| {
+        let caps = pad.current_caps().unwrap_or_else(|| pad.query_caps(None));
+        let structure = caps.structure(0);
+        let media = structure.map(|s| s.name().to_string()).unwrap_or_default();
+
+        info!("[{pn2}] decodebin pad: {media}");
+
+        if !media.starts_with("video/") {
+            return;
+        }
+
+        let Some(convert) = convert_weak.upgrade() else { return };
+        let sink_pad = convert.static_pad("sink").unwrap();
+        if !sink_pad.is_linked() {
+            match pad.link(&sink_pad) {
+                Ok(_) => info!("[{pn2}] decodebin→convert linked"),
+                Err(e) => error!("[{pn2}] decodebin→convert link failed: {e:?}"),
+            }
+        }
+    });
+
+    // Watch bus for errors
+    let pn3 = pipeline_name.clone();
+    let bus = pipeline.bus().unwrap();
+    bus.add_watch_local(move |_bus, msg| {
+        use gst::MessageView;
+        match msg.view() {
+            MessageView::Error(err) => {
+                error!("[{pn3}] pipeline error: {} ({:?})", err.error(), err.debug());
+            }
+            MessageView::Warning(w) => {
+                warn!("[{pn3}] pipeline warning: {} ({:?})", w.error(), w.debug());
+            }
+            MessageView::StateChanged(sc) => {
+                if sc.src().map(|s| s.name().as_str() == pn3).unwrap_or(false) {
+                    info!("[{pn3}] state: {:?} → {:?}", sc.old(), sc.current());
+                }
+            }
+            _ => {}
+        }
+        gst::glib::ControlFlow::Continue
+    })
+    .ok()?;
 
     info!("[{pipeline_name}] pipeline created for {rtsp_uri}");
     Some((pipeline, sink))
 }
 
-/// Start a pipeline.
 pub fn play(pipeline: &Pipeline) {
-    if let Err(e) = pipeline.set_state(gst::State::Playing) {
-        error!("Failed to set pipeline to Playing: {e:?}");
+    match pipeline.set_state(gst::State::Playing) {
+        Ok(r) => info!("[{}] set_state(Playing) = {r:?}", pipeline.name()),
+        Err(e) => error!("[{}] set_state(Playing) failed: {e:?}", pipeline.name()),
     }
 }
 
-/// Stop a pipeline.
 pub fn stop(pipeline: &Pipeline) {
     let _ = pipeline.set_state(gst::State::Null);
 }