🚦Slider warning messages when requests encounter problems

frontend/common/SliderServerClient.js

@@ -3,6 +3,7 @@
 import { pack, unpack } from "./MsgPack.js"
 import immer from "../imports/immer.js"
 import _ from "../imports/lodash.js"
+import { open_pluto_popup } from "../components/Popup.js"
 
 const assert_response_ok = (/** @type {Response} */ r) => (r.ok ? r : Promise.reject(r))
 
@@ -39,6 +40,23 @@
         ])
     )
 
+const sliders_error = (e, previously_set) => {
+    const el = previously_set ? document.querySelector(`bond[def=${previously_set.values().next().value}]`) : null
+    if (e.status === 503) {
+        open_pluto_popup({
+            type: "warn",
+            body: "Sliders are still starting, check back later for interactivity!",
+            source_element: el,
+        })
+    } else {
+        open_pluto_popup({
+            type: "warn",
+            body: "Error connecting to slider server!",
+            source_element: el,
+        })
+    }
+}
+
 export const slider_server_actions = ({ setStatePromise, launch_params, actions, get_original_state, get_current_state, apply_notebook_patches }) => {
     setStatePromise(
         immer((state) => {
@@ -53,30 +71,33 @@
 
     notebookfile_hash.then((x) => console.log("Notebook file hash:", x))
 
-    const bond_connections = notebookfile_hash
-        .then((hash) => fetch(trailingslash(launch_params.slider_server_url) + "bondconnections/" + hash))
-        .then(assert_response_ok)
-        .then((r) => r.arrayBuffer())
-        .then((b) => unpack(new Uint8Array(b)))
-
-    bond_connections.then((x) => {
-        console.log("Bond connections:", x)
-        setStatePromise(
-            immer((state) => {
-                state.slider_server.connecting = false
-                state.slider_server.interactive = Object.keys(x).length > 0
-            })
-        )
-    })
+    let bond_connections = null
 
     const mybonds = {}
     const bonds_to_set = {
         current: new Set(),
     }
     const request_bond_response = debounced_promises(async () => {
+        if (!bond_connections) {
+            const bond_connections_res = await notebookfile_hash.then((hash) =>
+                fetch(trailingslash(launch_params.slider_server_url) + "bondconnections/" + hash)
+            )
+            if (bond_connections_res.ok) {
+                bond_connections = await bond_connections_res.arrayBuffer().then((x) => unpack(new Uint8Array(x)))
+
+                console.log("Bond connections:", bond_connections)
+                setStatePromise(
+                    immer((state) => {
+                        state.slider_server.connecting = false
+                        state.slider_server.interactive = Object.keys(bond_connections).length > 0
+                    })
+                )
+            }
+        }
+
         const base = trailingslash(launch_params.slider_server_url)
         const hash = await notebookfile_hash
-        const graph = await bond_connections
+        const graph = bond_connections || {}
 
         // compute dependencies and update cell running statuses
         const dep_graph = get_current_state().cell_dependencies
@@ -92,6 +113,7 @@
             const to_send = new Set(bonds_to_set.current)
             bonds_to_set.current.forEach((varname) => (graph[varname] ?? []).forEach((x) => to_send.add(x)))
             console.debug("Requesting bonds", bonds_to_set.current, to_send)
+            const previously_set = new Set(bonds_to_set.current)
             bonds_to_set.current = new Set()
 
             const mybonds_filtered = Object.fromEntries(
@@ -129,16 +151,25 @@
                         ids_of_cells_that_ran.forEach((id) => {
                             state.cell_results[id] = original.cell_results[id]
                         })
-                        running_cells.forEach((id) => {
-                            state.cell_results[id].queued = false
-                            state.cell_results[id].running = false
-                        })
                     })(get_current_state())
                 )
             } catch (e) {
                 console.error(unpacked, e)
+
+                if (previously_set.size === 1) {
+                    sliders_error(e, previously_set)
+                }
             }
         }
+
+        await setStatePromise(
+            immer((state) => {
+                running_cells.forEach((id) => {
+                    state.notebook.cell_results[id].queued = false
+                    state.notebook.cell_results[id].running = false
+                })
+            })
+        )
     })
 
     return {