Fix Bokeh in Colab

.gitignore

@@ -9,3 +9,10 @@ build/
 tensorboard_logs/
 examples/_test*
 .mypy_cache/
+
+# OS / editor cruft
+.DS_Store
+Thumbs.db
+*.swp
+*.swo
+.idea/

examples/bokeh_colab.ipynb

@@ -0,0 +1,76 @@
+{
+ "cells": [
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": "# livelossplot + Bokeh in Colab (issue #109 verification)\n\nOpen in Colab: <a href=\"https://colab.research.google.com/github/stared/livelossplot/blob/i109-bokeh-colab/examples/bokeh_colab.ipynb\" target=\"_parent\"><img src=\"https://colab.research.google.com/assets/colab-badge.svg\"/></a>\n\nInstalls livelossplot from the `i109-bokeh-colab` branch on GitHub (not PyPI), so the in-progress Colab fix for `BokehPlot` is exercised."
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": "!pip install --quiet --upgrade git+https://github.com/stared/livelossplot.git@i109-bokeh-colab"
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "import sys\n",
+    "import livelossplot\n",
+    "print('livelossplot:', livelossplot.__version__)\n",
+    "print('running in Colab:', 'google.colab' in sys.modules)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "from time import sleep\n",
+    "import numpy as np\n",
+    "\n",
+    "from livelossplot import PlotLosses\n",
+    "from livelossplot.outputs import BokehPlot\n",
+    "\n",
+    "plotlosses = PlotLosses(outputs=[BokehPlot()])\n",
+    "\n",
+    "for i in range(10):\n",
+    "    plotlosses.update({\n",
+    "        'acc': 1 - np.random.rand() / (i + 2.),\n",
+    "        'val_acc': 1 - np.random.rand() / (i + 0.5),\n",
+    "        'loss': 1. / (i + 2.),\n",
+    "        'val_loss': 1. / (i + 0.5),\n",
+    "    })\n",
+    "    plotlosses.send()\n",
+    "    sleep(0.5)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## What you should see\n",
+    "\n",
+    "Two Bokeh panels (Accuracy, Loss) that **redraw with growing data lines** every ~0.5s. Before this fix, the panels rendered as empty skeletons and never updated (issue #109).\n",
+    "\n",
+    "If something still looks broken, please paste the failure into the issue."
+   ]
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "Python 3",
+   "language": "python",
+   "name": "python3"
+  },
+  "language_info": {
+   "name": "python"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 5
+}

livelossplot/outputs/bokeh_plot.py

@@ -1,3 +1,4 @@
+import sys
 from typing import List, Dict, Tuple
 
 from livelossplot.main_logger import MainLogger, LogItem
@@ -28,11 +29,17 @@ def __init__(
         self.skip_first = skip_first  # think about it
         self.figures = {}
         self.is_notebook = False
+        self.is_colab = 'google.colab' in sys.modules
         self.output_file = output_file
         self.colors = palettes.Category10[10]
+        self._colab_handle = None
 
     def send(self, logger: MainLogger) -> None:
         """Draw figures with metrics and show"""
+        if self.is_colab:
+            self._send_colab(logger)
+            return
+
         log_groups = logger.grouped_log_history()
         new_grid_plot = False
         for idx, (group_name, group_logs) in enumerate(log_groups.items(), start=1):
@@ -48,6 +55,46 @@ def send(self, logger: MainLogger) -> None:
         else:
             self.plotting.save(self.grid)
 
+    def _send_colab(self, logger: MainLogger) -> None:
+        """Colab actively blocks Jupyter Comms, so push_notebook is dead there.
+        Render Bokeh into a complete HTML doc and embed it via <iframe srcdoc>:
+        the iframe is a self-contained browser context, so BokehJS finds its
+        sibling JSON-data element correctly (no DOM fragmentation from Colab's
+        output handling). Updates via display_id atomically replace the iframe
+        wrapper, browser rebuilds the inner document — no flicker."""
+        import html as html_lib
+
+        from bokeh.embed import file_html
+        from bokeh.resources import CDN
+        from IPython.display import HTML, display
+
+        log_groups = logger.grouped_log_history()
+        self.figures = {}
+        for group_name, group_logs in log_groups.items():
+            fig = self.plotting.figure(title=group_name)
+            self.figures[group_name] = self._draw_metric_subplot(fig, group_logs)
+        rows, row = [], []
+        for idx, fig in enumerate(self.figures.values(), start=1):
+            row.append(fig)
+            if idx % self.max_cols == 0:
+                rows.append(row)
+                row = []
+        if row:
+            rows.append(row)
+        grid = self.plotting.gridplot(rows, sizing_mode='scale_width', width=self.plot_width, height=self.plot_height)
+        bokeh_doc = file_html(grid, CDN, 'livelossplot')
+        iframe_height = self.plot_height * len(rows) + 60
+        iframe_html = (
+            f'<iframe srcdoc="{html_lib.escape(bokeh_doc, quote=True)}" '
+            f'style="width: 100%; height: {iframe_height}px; border: none;" '
+            f'sandbox="allow-scripts allow-same-origin"></iframe>'
+        )
+        payload = HTML(iframe_html)
+        if self._colab_handle is None:
+            self._colab_handle = display(payload, display_id=True)
+        else:
+            self._colab_handle.update(payload)
+
     def _draw_metric_subplot(self, fig, group_logs: Dict[str, List[LogItem]]):
         """
         Args:
@@ -101,6 +148,8 @@ def _set_output_mode(self, mode: str):
         """Set notebook or script mode"""
         self.is_notebook = mode == 'notebook'
         if self.is_notebook:
+            # Bokeh auto-detects Colab in recent versions; passing
+            # notebook_type='colab' explicitly raises in Bokeh 3.x.
             self.io.output_notebook()
         else:
             self.io.output_file(self.output_file)