Display inactive filesystem error on hover

docs/index.md

@@ -123,6 +123,13 @@ the server's working directory in both the browser UI and in the kernel side.
 Since the kernel is usually a fully privileged process, this restriction only applies to the automatic behavior of jupyter_fsspec.
 :::
 
+### Inactive Filesystems
+
+Filesystems that are not instantiated due to an error will appear grayed out and will display an error message on hover.
+On click, there will be more information logged to the browser console.
+
+![Jupyter FSSpec Inactive Filesystem](_static/s3fs_inactive.png 'Jupyter FSSpec Inactive Filesystem')
+
 ## The `helper` module
 
 You can import the `jupyter_fsspec.helper` module into your notebooks to interact with

jupyter_fsspec/handlers.py

@@ -463,10 +463,10 @@ async def get(self):
 
         fs_instance = fs["instance"]
         response = {}
-        is_async = fs_instance.async_impl
 
         try:
             with handle_exception(self):
+                is_async = fs_instance.async_impl
                 result = (
                     await fs_instance._ls(item_path, detail=True)
                     if is_async

src/FssFilesysItem.ts

@@ -36,17 +36,24 @@ class FssFilesysItem {
 
     const fsItem = document.createElement('div');
     fsItem.classList.add('jfss-fsitem-root');
+    this.root = fsItem;
 
     if ('error' in fsInfo) {
       fsItem.classList.add('jfss-fsitem-error');
+      fsItem.dataset.errorMessage = fsInfo.error.short_traceback;
+      fsItem.addEventListener(
+        'mouseenter',
+        this.handleDisplayFSError.bind(this)
+      );
+    } else {
+      fsItem.addEventListener('mouseenter', this.handleFsysHover.bind(this));
+      fsItem.addEventListener('mouseleave', this.handleFsysHover.bind(this));
+
+      // Set the tooltip
+      this.root.title = `Root Path: ${fsInfo.path}`;
     }
-    fsItem.addEventListener('mouseenter', this.handleFsysHover.bind(this));
-    fsItem.addEventListener('mouseleave', this.handleFsysHover.bind(this));
-    fsItem.dataset.fssname = fsInfo.name;
-    this.root = fsItem;
 
-    // Set the tooltip
-    this.root.title = `Root Path: ${fsInfo.path}`;
+    fsItem.dataset.fssname = fsInfo.name;
 
     this.nameField = document.createElement('div');
     this.nameField.classList.add('jfss-fsitem-name');
@@ -176,6 +183,48 @@ class FssFilesysItem {
     }
   }
 
+  handleDisplayFSError(event: MouseEvent): void {
+    const fsItem = event.currentTarget as HTMLElement;
+    const errorMessage = fsItem.dataset.errorMessage;
+
+    const tooltip = document.createElement('div');
+    tooltip.className = 'jfss-fsitem-tooltip';
+    tooltip.textContent = `[Inactive] ${errorMessage}`;
+
+    Object.assign(tooltip.style, {
+      position: 'fixed',
+      backgroundColor: 'rgba(242, 159, 159, 0.85)',
+      color: 'rgb(77, 16, 16)',
+      padding: '4px 8px',
+      boxShadow: '0 2px 6px rgba(0,0,0,0.2)',
+      zIndex: '9999',
+      fontSize: '12px',
+      visibility: 'hidden'
+    });
+
+    document.body.appendChild(tooltip);
+
+    // Measure and position tooltip
+    const offset = 10;
+    const { clientX: x, clientY: y } = event;
+    const { width, height } = tooltip.getBoundingClientRect();
+    const maxX = window.innerWidth - width - offset;
+    const maxY = window.innerHeight - height - offset;
+
+    const left = Math.min(x + offset, maxX);
+    const top = Math.min(y + offset, maxY);
+
+    tooltip.style.left = `${left}px`;
+    tooltip.style.top = `${top}px`;
+    tooltip.style.visibility = 'visible';
+
+    const removeTooltip = () => {
+      tooltip.remove();
+      fsItem.removeEventListener('mouseleave', removeTooltip);
+    };
+    fsItem.addEventListener('mouseleave', removeTooltip);
+  }
+
   handleFsysHover(event: any) {
     if (event.type === 'mouseenter') {
       this.hovered = true;
@@ -190,10 +239,11 @@ class FssFilesysItem {
       protocol: this.filesysProtocol,
       path: this.fsInfo.path
     });
-    if (this.fsInfo.error) {
+    if ('error' in this.fsInfo) {
       this.logger.error('Inactive filesystem', {
         ...this.fsInfo.error
       });
+      return;
     }
     this.selected = true;
     this.filesysClicked.emit(this.fsInfo);

ui-tests/tests/filesystem_interaction.test.ts

@@ -192,6 +192,33 @@ test('test open jupyterFsspec with hdfs config', async ({ page }) => {
     .toHaveText('Path: myhdfs');
 });
 
+test('test filesystem error on hover', async ({ page }) => {
+  await page.route('http://localhost:8888/jupyter_fsspec/config?**', route => {
+    route.fulfill({
+      status: 200,
+      contentType: 'application/json',
+      body: JSON.stringify(hdfsConfig)
+    });
+  });
+
+  await page.goto();
+  await page.getByText('FSSpec', { exact: true }).click();
+
+  // verify filesystem item was created
+  await expect.soft(page.locator('.jfss-fsitem-root')).toBeVisible();
+
+  // filesystem details should match as expected
+  await expect.soft(page.locator('.jfss-fsitem-error')).toBeVisible();
+  await expect.soft(page.locator('.jfss-fsitem-name')).toBeVisible();
+  page.locator('.jfss-fsitem-error').hover();
+  await expect.soft(page.locator('.jfss-fsitem-tooltip')).toBeVisible();
+  await expect
+    .soft(page.locator('.jfss-fsitem-tooltip'))
+    .toContainText('[Inactive]');
+  page.mouse.move(0, 0);
+  await expect.soft(page.locator('.jfss-fsitem-tooltip')).toBeHidden();
+});
+
 test('test memory filesystem with mock config data', async ({ page }) => {
   await page.goto();
   await page.getByText('FSSpec', { exact: true }).click();