datasette plugins --requirements, closes #2133

datasette/cli.py

@@ -223,15 +223,23 @@ pm.hook.publish_subcommand(publish=publish)
 
 @cli.command()
 @click.option("--all", help="Include built-in default plugins", is_flag=True)
+@click.option(
+    "--requirements", help="Output requirements.txt of installed plugins", is_flag=True
+)
 @click.option(
     "--plugins-dir",
     type=click.Path(exists=True, file_okay=False, dir_okay=True),
     help="Path to directory containing custom plugins",
 )
-def plugins(all, plugins_dir):
+def plugins(all, requirements, plugins_dir):
     """List currently installed plugins"""
     app = Datasette([], plugins_dir=plugins_dir)
-    click.echo(json.dumps(app._plugins(all=all), indent=4))
+    if requirements:
+        for plugin in app._plugins():
+            if plugin["version"]:
+                click.echo("{}=={}".format(plugin["name"], plugin["version"]))
+    else:
+        click.echo(json.dumps(app._plugins(all=all), indent=4))
 
 
 @cli.command()

docs/cli-reference.rst

@@ -282,6 +282,7 @@ Output JSON showing all currently installed plugins, their versions, whether the
 
     Options:
       --all                    Include built-in default plugins
+      --requirements           Output requirements.txt of installed plugins
       --plugins-dir DIRECTORY  Path to directory containing custom plugins
       --help                   Show this message and exit.
 

docs/plugins.rst

@@ -90,7 +90,12 @@ You can see a list of installed plugins by navigating to the ``/-/plugins`` page
 
 You can also use the ``datasette plugins`` command::
 
-    $ datasette plugins
+    datasette plugins
+
+Which outputs:
+
+.. code-block:: json
+
     [
         {
             "name": "datasette_json_html",
@@ -107,7 +112,8 @@ You can also use the ``datasette plugins`` command::
     cog.out("\n")
     result = CliRunner().invoke(cli.cli, ["plugins", "--all"])
     # cog.out() with text containing newlines was unindenting for some reason
-    cog.outl("If you run ``datasette plugins --all`` it will include default plugins that ship as part of Datasette::\n")
+    cog.outl("If you run ``datasette plugins --all`` it will include default plugins that ship as part of Datasette:\n")
+    cog.outl(".. code-block:: json\n")
     plugins = [p for p in json.loads(result.output) if p["name"].startswith("datasette.")]
     indented = textwrap.indent(json.dumps(plugins, indent=4), "    ")
     for line in indented.split("\n"):
@@ -115,7 +121,9 @@ You can also use the ``datasette plugins`` command::
     cog.out("\n\n")
 .. ]]]
 
-If you run ``datasette plugins --all`` it will include default plugins that ship as part of Datasette::
+If you run ``datasette plugins --all`` it will include default plugins that ship as part of Datasette:
+
+.. code-block:: json
 
     [
         {
@@ -236,6 +244,22 @@ If you run ``datasette plugins --all`` it will include default plugins that ship
 
 You can add the ``--plugins-dir=`` option to include any plugins found in that directory.
 
+Add ``--requirements`` to output a list of installed plugins that can then be installed in another Datasette instance using ``datasette install -r requirements.txt``::
+
+    datasette plugins --requirements
+
+The output will look something like this::
+
+    datasette-codespaces==0.1.1
+    datasette-graphql==2.2
+    datasette-json-html==1.0.1
+    datasette-pretty-json==0.2.2
+    datasette-x-forwarded-host==0.1
+
+To write that to a ``requirements.txt`` file, run this::
+
+    datasette plugins --requirements > requirements.txt
+
 .. _plugins_configuration:
 
 Plugin configuration
@@ -390,7 +414,7 @@ Any values embedded in ``metadata.yaml`` will be visible to anyone who views the
 
 If you are publishing your data using the :ref:`datasette publish <cli_publish>` family of commands, you can use the ``--plugin-secret`` option to set these secrets at publish time. For example, using Heroku you might run the following command::
 
-    $ datasette publish heroku my_database.db \
+    datasette publish heroku my_database.db \
         --name my-heroku-app-demo \
         --install=datasette-auth-github \
         --plugin-secret datasette-auth-github client_id your_client_id \

tests/test_cli.py

@@ -108,6 +108,9 @@ def test_plugins_cli(app_client):
     assert set(names).issuperset({p["name"] for p in EXPECTED_PLUGINS})
     # And the following too:
     assert set(names).issuperset(DEFAULT_PLUGINS)
+    # --requirements should be empty because there are no installed non-plugins-dir plugins
+    result3 = runner.invoke(cli, ["plugins", "--requirements"])
+    assert result3.output == ""
 
 
 def test_metadata_yaml():