Merge ac5954bd31 into c435a80030

datasette/cli.py

@@ -477,6 +477,11 @@ def uninstall(packages, yes):
     is_flag=True,
     help="Create database files if they do not exist",
 )
+@click.option(
+    "--create-wal",
+    is_flag=True,
+    help="Create database files if they do not exist, in WAL mode",
+)
 @click.option(
     "--crossdb",
     is_flag=True,
@@ -532,6 +537,7 @@ def serve(
     pdb,
     open_browser,
     create,
+    create_wal,
     crossdb,
     nolock,
     ssl_keyfile,
@@ -618,12 +624,14 @@ def serve(
     elif len(directories) == 1:
         kwargs["config_dir"] = pathlib.Path(directories[0])
 
-    # Verify list of files, create if needed (and --create)
+    # Verify list of files, create if needed (and --create / --create-wal)
     for file in file_paths:
         if not pathlib.Path(file).exists():
-            if create:
+            if create or create_wal:
                 conn = sqlite3.connect(file)
                 conn.execute("vacuum")
+                if create_wal:
+                    conn.execute("pragma journal_mode=wal")
                 conn.close()
             else:
                 raise click.ClickException(

docs/cli-reference.rst

@@ -132,6 +132,8 @@ Use ``--internal PATH`` or the ``DATASETTE_INTERNAL`` environment variable to pe
       --pdb                           Launch debugger on any errors
       -o, --open                      Open Datasette in your web browser
       --create                        Create database files if they do not exist
+      --create-wal                    Create database files if they do not exist, in
+                                      WAL mode
       --crossdb                       Enable cross-database joins using the /_memory
                                       database
       --nolock                        Ignore locking, open locked files in read-only

tests/test_cli.py

@@ -171,6 +171,7 @@ def test_metadata_yaml():
         nolock=False,
         open_browser=False,
         create=False,
+        create_wal=False,
         ssl_keyfile=None,
         ssl_certfile=None,
         return_instance=True,
@@ -462,6 +463,37 @@ def test_serve_create(tmpdir):
     assert db_path.exists()
 
 
+def test_serve_create_wal(tmpdir):
+    runner = CliRunner()
+    db_path = tmpdir / "does_not_exist_yet.db"
+    assert not db_path.exists()
+    result = runner.invoke(
+        cli, [str(db_path), "--create-wal", "--get", "/-/databases.json"]
+    )
+    assert result.exit_code == 0, result.output
+    assert db_path.exists()
+    # The new database should be in WAL mode
+    conn = sqlite3.connect(str(db_path))
+    try:
+        assert conn.execute("pragma journal_mode").fetchone()[0] == "wal"
+    finally:
+        conn.close()
+
+
+def test_serve_create_does_not_set_wal(tmpdir):
+    runner = CliRunner()
+    db_path = tmpdir / "does_not_exist_yet.db"
+    result = runner.invoke(
+        cli, [str(db_path), "--create", "--get", "/-/databases.json"]
+    )
+    assert result.exit_code == 0, result.output
+    conn = sqlite3.connect(str(db_path))
+    try:
+        assert conn.execute("pragma journal_mode").fetchone()[0] != "wal"
+    finally:
+        conn.close()
+
+
 @pytest.mark.parametrize("argument", ("-c", "--config"))
 @pytest.mark.parametrize("format_", ("json", "yaml"))
 def test_serve_config(tmpdir, argument, format_):