Setup Kaggle environment on extension load (#31)

* Automatically setup kaggle environment https://github.com/andreinechaev/nvcc4jupyter/issues/29

* Update package lists before installing cuda toolkit

nvcc4jupyter/setup_env.py

@@ -0,0 +1,72 @@
+"""
+Setup steps for platforms such as Kaggle, Colab, etc. to allow our extension
+to work on them immediately after loading it.
+"""
+
+# pylint: disable=missing-function-docstring
+
+import os
+import traceback
+from subprocess import DEVNULL, STDOUT, check_call
+from typing import Optional
+
+PATH_PRIORITY_DIR = "/usr/bin/priority"
+KAGGLE_GCC_8_PATH = "/usr/bin/gcc-8"
+
+
+def print_platform(platform: str) -> None:
+    print(f'Detected platform "{platform}". Running its setup...')
+
+
+def kaggle_setup() -> None:
+    print("Updating the package lists...")
+    check_call(["/usr/bin/apt-get", "update"], stdout=DEVNULL, stderr=STDOUT)
+
+    print("Installing nvidia-cuda-toolkit, this may take a few minutes...")
+    check_call(
+        ["/usr/bin/apt-get", "install", "-y", "nvidia-cuda-toolkit"],
+        stdout=DEVNULL,
+        stderr=STDOUT,
+    )
+    os.makedirs(PATH_PRIORITY_DIR, exist_ok=True)
+
+    gcc_symlink_path = os.path.join(PATH_PRIORITY_DIR, "gcc")
+    if not os.path.exists(gcc_symlink_path):
+        os.symlink(KAGGLE_GCC_8_PATH, gcc_symlink_path)
+
+    if PATH_PRIORITY_DIR not in os.environ["PATH"].split(":"):
+        os.environ["PATH"] = f"{PATH_PRIORITY_DIR}:" + os.environ["PATH"]
+
+
+def colab_setup() -> None:
+    pass
+
+
+def setup_environment() -> None:
+    """
+    Detect the platform the extension was loaded on and run the necessary
+    steps (install dependencies, add executables to PATH, etc.) for the
+    extension to work.
+    """
+
+    if "NVCC4JUPYTER_NO_SETUP" in os.environ:
+        return
+
+    platform: Optional[str] = None
+    try:
+        if "KAGGLE_URL_BASE" in os.environ:
+            platform = "Kaggle"
+            print_platform(platform)
+            kaggle_setup()
+        elif "COLAB_RELEASE_TAG" in os.environ:
+            platform = "Colab"
+            print_platform(platform)
+            colab_setup()
+    except Exception:  # pylint: disable=broad-exception-caught
+        print(
+            f'Setup failed for detected platform "{platform}". Set the'
+            ' "NVCC4JUPYTER_NO_SETUP" environment variable to disable running'
+            " the setup on load. Please report the following error to"
+            " https://github.com/andreinechaev/nvcc4jupyter/issues:"
+            f" following error message:\n{traceback.format_exc()}"
+        )