New --setting to replace --config, closes #992

datasette/cli.py

@@ -2,6 +2,7 @@
 import uvicorn
 import click
 from click import formatting
+from click.types import CompositeParamType
 from click_default_group import DefaultGroup
 import json
 import os
@@ -29,6 +30,7 @@
 
 
 class Config(click.ParamType):
+    # This will be removed in Datasette 1.0 in favour of class Setting
     name = "config"
 
     def convert(self, config, param, ctx):
@@ -63,6 +65,39 @@ def convert(self, config, param, ctx):
             self.fail("Invalid option")
 
 
+class Setting(CompositeParamType):
+    name = "setting"
+    arity = 2
+
+    def convert(self, config, param, ctx):
+        name, value = config
+        if name not in DEFAULT_CONFIG:
+            self.fail(
+                f"{name} is not a valid option (--help-config to see all)",
+                param,
+                ctx,
+            )
+            return
+        # Type checking
+        default = DEFAULT_CONFIG[name]
+        if isinstance(default, bool):
+            try:
+                return name, value_as_boolean(value)
+            except ValueAsBooleanError:
+                self.fail(f'"{name}" should be on/off/true/false/1/0', param, ctx)
+                return
+        elif isinstance(default, int):
+            if not value.isdigit():
+                self.fail(f'"{name}" should be an integer', param, ctx)
+                return
+            return name, int(value)
+        elif isinstance(default, str):
+            return name, value
+        else:
+            # Should never happen:
+            self.fail("Invalid option")
+
+
 @click.group(cls=DefaultGroup, default="serve", default_if_no_args=True)
 @click.version_option(version=__version__)
 def cli():
@@ -330,7 +365,14 @@ def uninstall(packages, yes):
 @click.option(
     "--config",
     type=Config(),
-    help="Set config option using configname:value docs.datasette.io/en/stable/config.html",
+    help="Deprecated: set config option using configname:value. Use --setting instead.",
+    multiple=True,
+)
+@click.option(
+    "--setting",
+    "settings",
+    type=Setting(),
+    help="Setting, see docs.datasette.io/en/stable/config.html",
     multiple=True,
 )
 @click.option(
@@ -372,6 +414,7 @@ def serve(
     static,
     memory,
     config,
+    settings,
     secret,
     root,
     get,
@@ -410,6 +453,15 @@ def serve(
     if metadata:
         metadata_data = parse_metadata(metadata.read())
 
+    combined_config = {}
+    if config:
+        click.echo(
+            "--config name:value will be deprecated in Datasette 1.0, use --setting name value instead",
+            err=True,
+        )
+        combined_config.update(config)
+    combined_config.update(settings)
+
     kwargs = dict(
         immutables=immutable,
         cache_headers=not reload,
@@ -420,7 +472,7 @@ def serve(
         template_dir=template_dir,
         plugins_dir=plugins_dir,
         static_mounts=static,
-        config=dict(config),
+        config=combined_config,
         memory=memory,
         secret=secret,
         version_note=version_note,

docs/datasette-serve-help.txt

@@ -25,9 +25,10 @@ Options:
   --plugins-dir DIRECTORY   Path to directory containing custom plugins
   --static MOUNT:DIRECTORY  Serve static files from this directory at /MOUNT/...
   --memory                  Make :memory: database available
-  --config CONFIG           Set config option using configname:value
-                            docs.datasette.io/en/stable/config.html
+  --config CONFIG           Deprecated: set config option using configname:value. Use
+                            --setting instead.
 
+  --setting SETTING...      Setting, see docs.datasette.io/en/stable/config.html
   --secret TEXT             Secret used for signing secure values, such as signed
                             cookies
 

tests/test_cli.py

@@ -4,6 +4,7 @@
     TestClient as _TestClient,
     EXPECTED_PLUGINS,
 )
+import asyncio
 from datasette.plugins import DEFAULT_PLUGINS
 from datasette.cli import cli, serve
 from datasette.version import __version__
@@ -17,6 +18,13 @@
 from unittest import mock
 
 
+@pytest.fixture
+def ensure_eventloop():
+    # Workaround for "Event loop is closed" error
+    if asyncio.get_event_loop().is_closed():
+        asyncio.set_event_loop(asyncio.new_event_loop())
+
+
 def test_inspect_cli(app_client):
     runner = CliRunner()
     result = runner.invoke(cli, ["inspect", "fixtures.db"])
@@ -115,6 +123,7 @@ def test_metadata_yaml():
         static=[],
         memory=False,
         config=[],
+        settings=[],
         secret=None,
         root=False,
         version_note=None,
@@ -163,3 +172,30 @@ def test_version():
     runner = CliRunner()
     result = runner.invoke(cli, ["--version"])
     assert result.output == f"cli, version {__version__}\n"
+
+
+def test_setting(ensure_eventloop):
+    runner = CliRunner()
+    result = runner.invoke(
+        cli, ["--setting", "default_page_size", "5", "--get", "/-/config.json"]
+    )
+    assert result.exit_code == 0, result.output
+    assert json.loads(result.output)["default_page_size"] == 5
+
+
+def test_setting_type_validation(ensure_eventloop):
+    runner = CliRunner(mix_stderr=False)
+    result = runner.invoke(cli, ["--setting", "default_page_size", "dog"])
+    assert result.exit_code == 2
+    assert '"default_page_size" should be an integer' in result.stderr
+
+
+def test_config_deprecated(ensure_eventloop):
+    # The --config option should show a deprecation message
+    runner = CliRunner(mix_stderr=False)
+    result = runner.invoke(
+        cli, ["--config", "allow_download:off", "--get", "/-/config.json"]
+    )
+    assert result.exit_code == 0
+    assert not json.loads(result.output)["allow_download"]
+    assert "will be deprecated in" in result.stderr