From 79a2e45e4986d4a75d2067179171670b12ca0ee1 Mon Sep 17 00:00:00 2001
From: Alexander Hess <alexander@webartifex.biz>
Date: Mon, 15 Jul 2024 09:53:59 +0200
Subject: [PATCH] Add tasks to install and remove kernels

---
 tasks.py | 73 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 73 insertions(+)
 create mode 100644 tasks.py

diff --git a/tasks.py b/tasks.py
new file mode 100644
index 0000000..de08af5
--- /dev/null
+++ b/tasks.py
@@ -0,0 +1,73 @@
+"""Maintenance tasks for the project."""
+
+import json
+import os
+import sys
+import tempfile
+import tomllib
+
+import invoke
+
+try:
+    from jupyter_client import kernelspec
+except ImportError:
+    raise RuntimeError('Install the "ipykernel" package first') from None
+
+
+def _ensure_venv():
+    # Source: https://stackoverflow.com/questions/1871549/how-to-determine-if-python-is-running-inside-a-virtualenv  # pylint:disable=C0301
+    if sys.prefix == sys.base_prefix:
+        raise RuntimeError("Run this command in an activated `virtualenv`")
+
+
+def _get_pyproject_name():
+    with open("pyproject.toml", "rb") as fp:
+        data = tomllib.load(fp)
+
+    try:
+        project_name = data["tool"]["poetry"]["name"]
+    except KeyError:
+        raise RuntimeError('"pyproject.toml" seems to be malformed') from None
+
+    return project_name
+
+
+@invoke.task
+def install_kernel(_c):
+    """Install the activated `virtualenv` as a `jupyter kernel`.
+    This helper task
+    """
+    _ensure_venv()
+    project_name = _get_pyproject_name()
+
+    with tempfile.TemporaryDirectory() as tmpdir:
+        spec = {
+            "argv": [
+                sys.prefix + "/bin/python",
+                "-m",
+                "ipykernel_launcher",
+                "-f",
+                "{connection_file}",
+            ],
+            "display_name": project_name,
+            "env": {"PATH": os.environ["PATH"]},
+            "interrupt_mode": "signal",
+            "language": "python",
+            "metadata": {"debugger": True},
+        }
+
+        with open(os.path.join(tmpdir, "kernel.json"), "w", encoding="utf-8") as fp:
+            json.dump(spec, fp, indent=4)
+
+        manager = kernelspec.KernelSpecManager()
+        manager.install_kernel_spec(tmpdir, kernel_name=project_name, user=True)
+
+
+@invoke.task
+def remove_kernel(_c):
+    """Remove the `jupyter kernel` corresponding to the activated `virtualenv`."""
+    _ensure_venv()
+    project_name = _get_pyproject_name()
+
+    manager = kernelspec.KernelSpecManager()
+    manager.remove_kernel_spec(project_name)