first draft

Author: provinzkraut

litestar/cli/_shell_startup.py

@@ -0,0 +1,7 @@
+import os
+
+from litestar.cli._utils import _load_app_from_path, populate_repl_globals
+
+app = _load_app_from_path(os.environ["LITESTAR_APP"]).app
+new_locals, _ = populate_repl_globals(app=app)
+globals().update(new_locals)

litestar/cli/_utils.py

@@ -581,3 +581,16 @@ def isatty() -> bool:
     This is a convenience wrapper around the built in system methods.  This allows for easier testing of TTY/non-TTY modes.
     """
     return sys.stdout.isatty()
+
+
+def populate_repl_globals(app: Litestar) -> tuple[dict[str, Any], str]:
+    repl_locals = {"app": Litestar}
+    banner = "app = Litestar(...)\n\n"
+    for plugin in app.plugins.cli:
+        plugin_provided = plugin.populate_repl_namespace(app=app)
+        if plugin_provided:
+            banner += f"Plugin {type(plugin).__name__!r} provided:"
+            for name, value in plugin_provided.items():
+                repl_locals[name] = value
+                banner += f"name = {value!r}\n"
+    return repl_locals, banner

litestar/cli/commands/core.py

@@ -1,12 +1,13 @@
 from __future__ import annotations
 
+import importlib.resources
 import inspect
 import multiprocessing
 import os
 import subprocess
 import sys
 from contextlib import AbstractContextManager, ExitStack, contextmanager
-from typing import TYPE_CHECKING, Any
+from typing import TYPE_CHECKING, Any, Literal
 
 try:
     import rich_click as click
@@ -21,6 +22,7 @@
     console,
     create_ssl_files,
     isatty,
+    populate_repl_globals,
     remove_default_schema_routes,
     remove_routes_with_patterns,
     show_app_info,
@@ -365,3 +367,86 @@ def _handle_http_route(self, route: HTTPRoute) -> None:
                     branch.add(" ".join([f"[green]{path}[green]", *handler_info]))
             else:
                 branch.add(" ".join(handler_info))
+
+
+def _autoselect_repl_module() -> Literal["repl", "asyncio", "ipython"]:
+    import importlib.util
+
+    if importlib.util.find_spec("IPython"):
+        return "ipython"
+
+    if sys.version_info >= (3, 13):
+        return "asyncio"
+
+    return "repl"
+
+
+@click.command(name="shell")
+@click.option(
+    "--repl",
+    default=None,
+    type=click.Choice(("repl", "asyncio", "ipython")),
+    envvar="LITESTAR_REPL",
+    required=False,
+    help="Start a Python shell with the Litestar application and other values provided by plugins preloaded",
+)
+def shell_command(
+    app: Litestar,
+    repl: Literal["repl", "asyncio", "ipython"] | None = None,
+) -> None:  # pragma: no cover
+    if repl is None:
+        repl = _autoselect_repl_module()
+        click.secho(f"Starting Litestar shell using autoselected REPL {repl!r}", fg="blue")
+
+    if repl == "asyncio":
+        if sys.version_info < (3, 13):
+            click.secho("Litestar shell using the asyncio REPL requires Python 3.13 or greater", fg="red")
+            click.secho(
+                "To use the Litestar shell with an async REPL in this version of Python, y"
+                "ou can install Litestar with the 'ipython' extra (litestar[ipython]) "
+                "and then select ipython as the repl, either by starting he Litestar "
+                "shell with 'litestar shell --repl=ipython' or setting the "
+                "'LITESTAR_REPL=ipython' environment variable",
+                fg="blue",
+            )
+            quit(1)
+
+        # since it's currently not possible to customise e.g. the namespace of the
+        # asyncio REPL, we have to get a bit creative here
+
+        if "PYTHONSTARTUP" in os.environ:  # type: ignore[unreachable]
+            click.secho(
+                "Cannot run Litestar shell with asyncio REPL when PYTHONSTARTUP is "
+                "set. PYTHONSTARTUP is currently set to "
+                f"{os.environ['PYTHONSTARTUP']!r}. Either unset PYTHONSTARTUP or use a "
+                "different REPL ('repl' or 'ipython').",
+                fg="red",
+            )
+
+        subprocess.run(  # noqa: S603
+            [sys.executable, "-m", "asyncio"],
+            check=False,
+            env={
+                **os.environ,
+                "PYTHONSTARTUP": str(importlib.resources.files("litestar.cli").joinpath("_shell_startup")) + ".py",
+            },
+        )
+    elif repl == "repl":
+        import code
+
+        repl_locals, banner = populate_repl_globals(app=app)
+        interpreter = code.InteractiveConsole(locals=repl_locals)
+        interpreter.interact(banner=banner)
+    elif repl == "ipython":
+        import IPython
+        from traitlets.config.loader import Config
+
+        repl_locals, banner = populate_repl_globals(app=app)
+
+        config = Config()
+        config.TerminalInteractiveShell.banner2 = banner
+
+        IPython.start_ipython(argv=[], user_ns=repl_locals, config=config)  # type: ignore[no-untyped-call]
+    else:
+        click.secho(f"Unsupported REPL {repl!r}")  # type: ignore[unreachable]
+        quit(1)

litestar/cli/main.py

@@ -51,3 +51,4 @@ def litestar_group(ctx: click.Context, app_path: str | None, app_dir: Path | Non
 litestar_group.add_command(core.version_command)  # pyright: ignore
 litestar_group.add_command(sessions.sessions_group)  # pyright: ignore
 litestar_group.add_command(schema.schema_group)  # pyright: ignore
+litestar_group.add_command(core.shell_command)  # pyright: ignore

litestar/plugins/base.py

@@ -164,6 +164,12 @@ def is_debug_mode(app: Litestar):
     def server_lifespan(self, app: Litestar) -> Iterator[None]:
         yield
 
+    def populate_repl_namespace(self, app: Litestar) -> dict[str, Any]:
+        """Return a dict that will be used to populate the REPL namespace of the
+        Litestar shell.
+        """
+        return {}
+
 
 class SerializationPlugin(abc.ABC):
     """Abstract base class for plugins that extend DTO functionality"""

pyproject.toml

@@ -185,6 +185,7 @@ dev = [
   "daphne>=4.0.0",
   "opentelemetry-sdk",
   "httpx-sse",
+  "ipython",
 ]
 
 docs = [