With file persistence in docker.

Author: mikeckennedy

.gitignore

@@ -206,4 +206,5 @@ marimo/_static/
 marimo/_lsp/
 __marimo__/
 
-.idea/
+.idea/
+/code/08-reproducibility/math_research/data/run-count.txt

code/08-reproducibility/compose.yaml

@@ -15,6 +15,8 @@ services:
     container_name: math_research
     image: math_research
     working_dir: /app
+    volumes:
+      - ./math_research/data:/data
     ports:
       - "9000:9000"
     platform: linux/amd64

code/08-reproducibility/math_research/src/math-research.ipynb

@@ -12,20 +12,20 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 7,
    "id": "f7f8b7ff-2950-4c93-b874-2f99d53bb669",
    "metadata": {
     "ExecuteTime": {
-     "end_time": "2025-07-23T16:35:41.612096Z",
-     "start_time": "2025-07-23T16:35:41.608392Z"
+     "end_time": "2025-08-02T01:13:40.632240Z",
+     "start_time": "2025-08-02T01:13:40.628063Z"
     }
    },
-   "outputs": [],
    "source": [
     "# Import our math utility functions.\n",
     "import mathf\n",
     "from pathlib import Path"
-   ]
+   ],
+   "outputs": [],
+   "execution_count": 2
   },
   {
    "cell_type": "markdown",
@@ -111,23 +111,19 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 19,
    "id": "5deaf5a6",
-   "metadata": {},
-   "outputs": [
-    {
-     "name": "stdout",
-     "output_type": "stream",
-     "text": [
-      "This is run 10\n"
-     ]
+   "metadata": {
+    "ExecuteTime": {
+     "end_time": "2025-08-02T01:14:53.816909Z",
+     "start_time": "2025-08-02T01:14:53.792645Z"
     }
-   ],
+   },
    "source": [
     "# Let's just show that we can read/write data persistently.\n",
     "file = Path('/data/run-count.txt')\n",
     "if not file.parent.exists():\n",
     "    file = Path('../data/run-count.txt')\n",
+    "    file.parent.mkdir(parents=True, exist_ok=True)\n",
     "\n",
     "if file.exists():\n",
     "    with open(file, 'r', encoding='utf-8') as f:\n",
@@ -141,7 +137,30 @@
     "    f.write(str(run_count))\n",
     "\n",
     "print(f'This is run {run_count}')"
-   ]
+   ],
+   "outputs": [
+    {
+     "ename": "IsADirectoryError",
+     "evalue": "[Errno 21] Is a directory: '../data/run-count.txt'",
+     "output_type": "error",
+     "traceback": [
+      "\u001B[31m---------------------------------------------------------------------------\u001B[39m",
+      "\u001B[31mIsADirectoryError\u001B[39m                         Traceback (most recent call last)",
+      "\u001B[36mCell\u001B[39m\u001B[36m \u001B[39m\u001B[32mIn[6]\u001B[39m\u001B[32m, line 8\u001B[39m\n\u001B[32m      5\u001B[39m     file.parent.mkdir(parents=\u001B[38;5;28;01mTrue\u001B[39;00m, exist_ok=\u001B[38;5;28;01mTrue\u001B[39;00m)\n\u001B[32m      7\u001B[39m \u001B[38;5;28;01mif\u001B[39;00m file.exists():\n\u001B[32m----> \u001B[39m\u001B[32m8\u001B[39m     \u001B[38;5;28;01mwith\u001B[39;00m \u001B[38;5;28;43mopen\u001B[39;49m\u001B[43m(\u001B[49m\u001B[43mfile\u001B[49m\u001B[43m,\u001B[49m\u001B[43m \u001B[49m\u001B[33;43m'\u001B[39;49m\u001B[33;43mr\u001B[39;49m\u001B[33;43m'\u001B[39;49m\u001B[43m,\u001B[49m\u001B[43m \u001B[49m\u001B[43mencoding\u001B[49m\u001B[43m=\u001B[49m\u001B[33;43m'\u001B[39;49m\u001B[33;43mutf-8\u001B[39;49m\u001B[33;43m'\u001B[39;49m\u001B[43m)\u001B[49m \u001B[38;5;28;01mas\u001B[39;00m f:\n\u001B[32m      9\u001B[39m         run_count = \u001B[38;5;28mint\u001B[39m(f.read())\n\u001B[32m     10\u001B[39m \u001B[38;5;28;01melse\u001B[39;00m:\n",
+      "\u001B[36mFile \u001B[39m\u001B[32m~/github/courses/just-enough-python-datasci/just-enough-data-sci-course/venv/lib/python3.13/site-packages/IPython/core/interactiveshell.py:343\u001B[39m, in \u001B[36m_modified_open\u001B[39m\u001B[34m(file, *args, **kwargs)\u001B[39m\n\u001B[32m    336\u001B[39m \u001B[38;5;28;01mif\u001B[39;00m file \u001B[38;5;129;01min\u001B[39;00m {\u001B[32m0\u001B[39m, \u001B[32m1\u001B[39m, \u001B[32m2\u001B[39m}:\n\u001B[32m    337\u001B[39m     \u001B[38;5;28;01mraise\u001B[39;00m \u001B[38;5;167;01mValueError\u001B[39;00m(\n\u001B[32m    338\u001B[39m         \u001B[33mf\u001B[39m\u001B[33m\"\u001B[39m\u001B[33mIPython won\u001B[39m\u001B[33m'\u001B[39m\u001B[33mt let you open fd=\u001B[39m\u001B[38;5;132;01m{\u001B[39;00mfile\u001B[38;5;132;01m}\u001B[39;00m\u001B[33m by default \u001B[39m\u001B[33m\"\u001B[39m\n\u001B[32m    339\u001B[39m         \u001B[33m\"\u001B[39m\u001B[33mas it is likely to crash IPython. If you know what you are doing, \u001B[39m\u001B[33m\"\u001B[39m\n\u001B[32m    340\u001B[39m         \u001B[33m\"\u001B[39m\u001B[33myou can use builtins\u001B[39m\u001B[33m'\u001B[39m\u001B[33m open.\u001B[39m\u001B[33m\"\u001B[39m\n\u001B[32m    341\u001B[39m     )\n\u001B[32m--> \u001B[39m\u001B[32m343\u001B[39m \u001B[38;5;28;01mreturn\u001B[39;00m \u001B[43mio_open\u001B[49m\u001B[43m(\u001B[49m\u001B[43mfile\u001B[49m\u001B[43m,\u001B[49m\u001B[43m \u001B[49m\u001B[43m*\u001B[49m\u001B[43margs\u001B[49m\u001B[43m,\u001B[49m\u001B[43m \u001B[49m\u001B[43m*\u001B[49m\u001B[43m*\u001B[49m\u001B[43mkwargs\u001B[49m\u001B[43m)\u001B[49m\n",
+      "\u001B[31mIsADirectoryError\u001B[39m: [Errno 21] Is a directory: '../data/run-count.txt'"
+     ]
+    }
+   ],
+   "execution_count": 6
+  },
+  {
+   "metadata": {},
+   "cell_type": "code",
+   "outputs": [],
+   "execution_count": null,
+   "source": "",
+   "id": "2e12bad509461386"
   }
  ],
  "metadata": {