Use custom conda environment in Jupyter Notebook when user wants to use it (#2050)

* Modify the custom Python kernel

- to activate the custom environment
- for the respective Jupyter Notebook and Jupyter Console

Signed-off-by: Ayaz Salikhov <mathbunnyru@gmail.com>

* Add DL3059 to hadolint ignore list

Signed-off-by: Ayaz Salikhov <mathbunnyru@gmail.com>

* Move hadolint ignore to a single line

* Use python heredoc

* Remove unused print

* Fix style

* Do not hardcode CONDA_DIR

* Update custom_environment.dockerfile

* Use indent=1

* Implement activate_notebook_custom_env.py as a separate script

* Do not call Python manually

---------

Signed-off-by: Ayaz Salikhov <mathbunnyru@gmail.com>
Co-authored-by: Olivier Benz <olivier.benz@b-data.ch>

images/minimal-notebook/setup-scripts/activate_notebook_custom_env.py

@@ -0,0 +1,24 @@
+#!/usr/bin/env python3
+# Copyright (c) Jupyter Development Team.
+# Distributed under the terms of the Modified BSD License.
+import json
+import os
+import sys
+from pathlib import Path
+
+env_name = sys.argv[1]
+CONDA_DIR = os.environ["CONDA_DIR"]
+
+file = Path.home() / f".local/share/jupyter/kernels/{env_name}/kernel.json"
+content = json.loads(file.read_text())
+content["env"] = {
+    "XML_CATALOG_FILES": "",
+    "PATH": f"{CONDA_DIR}/envs/{env_name}/bin:$PATH",
+    "CONDA_PREFIX": f"{CONDA_DIR}/envs/{env_name}",
+    "CONDA_PROMPT_MODIFIER": f"({env_name}) ",
+    "CONDA_SHLVL": "2",
+    "CONDA_DEFAULT_ENV": env_name,
+    "CONDA_PREFIX_1": CONDA_DIR,
+}
+
+file.write_text(json.dumps(content, indent=1))