From 0f7c71a86f8963740eb3cf51efa0c521e62cb591 Mon Sep 17 00:00:00 2001
From: Simon Willison <swillison@gmail.com>
Date: Sat, 7 Jan 2023 15:48:08 -0800
Subject: [PATCH] What to do if extensions will not load, refs #1979

---
 docs/installation.rst | 57 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 57 insertions(+)

diff --git a/docs/installation.rst b/docs/installation.rst
index a4757736..121f2ef5 100644
--- a/docs/installation.rst
+++ b/docs/installation.rst
@@ -230,3 +230,60 @@ Some plugins such as `datasette-ripgrep <https://datasette.io/plugins/datasette-
         pip install datasette-ripgrep'
 
     docker commit $(docker ps -lq) datasette-with-ripgrep
+
+.. _installation_extensions:
+
+A note about extensions
+=======================
+
+SQLite supports extensions, such as :ref:`spatialite` for geospatial operations.
+
+These can be loaded using the ``--load-extension`` argument, like so::
+
+    datasette --load-extension=/usr/local/lib/mod_spatialite.dylib
+
+Some Python installations do not include support for SQLite extensions. If this is the case you will see the following error when you attempt to load an extension:
+
+    Your Python installation does not have the ability to load SQLite extensions.
+
+In some cases you may see the following error message instead::
+
+    AttributeError: 'sqlite3.Connection' object has no attribute 'enable_load_extension'
+
+On macOS the easiest fix for this is to install Datasette using Homebrew::
+
+    brew install datasette
+
+Use ``which datasette`` to confirm that ``datasette`` will run that version. The output should look something like this::
+
+    /usr/local/opt/datasette/bin/datasette
+
+If you get a different location here such as ``/Library/Frameworks/Python.framework/Versions/3.10/bin/datasette`` you can run the following command to cause ``datasette`` to execute the Homebrew version instead::
+
+    alias datasette=$(echo $(brew --prefix datasette)/bin/datasette)
+
+You can undo this operation using::
+
+    unalias datasette
+
+If you need to run SQLite with extension support for other Python code, you can do so by install Python itself using Homebrew::
+
+    brew install python
+
+Then executing Python using::
+
+    /usr/local/opt/python@3/libexec/bin/python
+
+A more convenient way to work with this version of Python may be to use it to create a virtual environment::
+
+    /usr/local/opt/python@3/libexec/bin/python -m venv datasette-venv
+
+Then activate it like this::
+
+    source datasette-venv/bin/activate
+
+Now running ``python`` and ``pip`` will work against a version of Python 3 that includes support for SQLite extensions::
+
+    pip install datasette
+    which datasette
+    datasette --version