datasette install / datasette uninstall commands, closes #925

datasette/cli.py

@@ -231,6 +231,31 @@ def package(
         call(args)
 
 
+@cli.command()
+@click.argument("packages", nargs=-1, required=True)
+def install(packages):
+    "Install Python packages - e.g. Datasette plugins - into the same environment as Datasett"
+    from pip._internal.cli.main import main
+
+    try:
+        main(["install"] + list(packages))
+    except SystemExit as e:
+        pass
+
+
+@cli.command()
+@click.argument("packages", nargs=-1, required=True)
+@click.option("-y", "--yes", is_flag=True, help="Don't ask for confirmation")
+def uninstall(packages, yes):
+    "Uninstall Python packages (e.g. plugins) from the Datasette environment"
+    from pip._internal.cli.main import main
+
+    try:
+        main(["uninstall"] + list(packages) + (["-y"] if yes else []))
+    except SystemExit as e:
+        pass
+
+
 @cli.command()
 @click.argument("files", type=click.Path(exists=True), nargs=-1)
 @click.option(

docs/plugins.rst

@@ -35,10 +35,26 @@ Installing plugins
 
 If a plugin has been packaged for distribution using setuptools you can use the plugin by installing it alongside Datasette in the same virtual environment or Docker container.
 
+You can install plugins using the ``datasette install`` command::
+
+    datasette install datasette-vega
+
+You can uninstall plugins with ``datasette uninstall``::
+
+    datasette uninstall datasette-vega
+
+These ommands are thin wrappers around ``pip install`` and ``pip uninstall``, which ensure they run ``pip`` in the same virtual environment as Datasette itself.
+
+One-off plugins using --plugins-dir
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
 You can also define one-off per-project plugins by saving them as ``plugin_name.py`` functions in a ``plugins/`` folder and then passing that folder to ``datasette`` using the ``--plugins-dir`` option::
 
     datasette mydb.db --plugins-dir=plugins/
 
+Deploying plugins using datasette publish
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
 The ``datasette publish`` and ``datasette package`` commands both take an optional ``--install`` argument. You can use this one or more times to tell Datasette to ``pip install`` specific plugins as part of the process::
 
     datasette publish cloudrun mydb.db --install=datasette-vega

tests/test_cli.py

@@ -12,6 +12,7 @@ import json
 import pathlib
 import pytest
 import textwrap
+from unittest import mock
 
 
 def test_inspect_cli(app_client):
@@ -107,3 +108,19 @@ def test_metadata_yaml():
     client.ds = ds
     response = client.get("/-/metadata.json")
     assert {"title": "Hello from YAML"} == response.json
+
+
+@mock.patch("pip._internal.cli.main.main")
+def test_install(main):
+    runner = CliRunner()
+    runner.invoke(cli, ["install", "datasette-mock-plugin", "datasette-mock-plugin2"])
+    main.assert_called_once_with(
+        ["install", "datasette-mock-plugin", "datasette-mock-plugin2"]
+    )
+
+
+@mock.patch("pip._internal.cli.main.main")
+def test_uninstall(main):
+    runner = CliRunner()
+    runner.invoke(cli, ["uninstall", "datasette-mock-plugin", "-y"])
+    main.assert_called_once_with(["uninstall", "datasette-mock-plugin", "-y"])