feat: add env variable to disable rich CLI output (#2654)

* feat: add env variable to disable rich CLI output

* lint: fix mypy

Author: Lancetnik

docs/docs/en/getting-started/cli.md

@@ -132,8 +132,33 @@ You can pass any custom flags for logging configuration, it's `--log-level` or `
 
 ### Event Loop
 
-FastStream is built on [anyio](https://github.com/agronholm/anyio) and supports using any event loop implementation (for example, [asyncio](https://docs.python.org/3/library/asyncio-eventloop.html),  [uvloop](https://github.com/MagicStack/uvloop), [winloop](https://github.com/Vizonex/Winloop), and [rloop](https://github.com/gi0baro/rloop)). By default, FastStream uses behavior from anyio: use uvloop (on Unix) if it exists, with fallback to asyncio. You can set event loop factory explicitly via the `--loop` option.
+**FastStream** is built on [anyio](https://github.com/agronholm/anyio) and supports using any event loop implementation (for example, [asyncio](https://docs.python.org/3/library/asyncio-eventloop.html),  [uvloop](https://github.com/MagicStack/uvloop), [winloop](https://github.com/Vizonex/Winloop), and [rloop](https://github.com/gi0baro/rloop)). By default, **FastStream** uses behavior from anyio: use uvloop (on Unix) if it exists, with fallback to asyncio.
+
+You can set the event loop factory explicitly via the `--loop` option in the CLI:
 
 ```shell
 faststream run main:app --loop=uvloop:new_event_loop
 ```
+
+Alternatively, you can specify the event loop implementation using the `FASTSTREAM_LOOP` environment variable. For example:
+
+```shell
+FASTSTREAM_LOOP=uvloop:new_event_loop faststream run main:app
+```
+
+This lets you control the event loop used by **FastStream** either via command-line flags or by setting an environment variable, according to your deployment or development needs.
+
+### Rich Output Mode
+
+**FastStream** CLI uses [Typer](https://typer.tiangolo.com/){.external-link target="_blank"} rich formatting for its help and error messages. You can control this behavior with the `FASTSTREAM_CLI_RICH_MODE` environment variable:
+
+```shell
+# available values: rich, markdown, or none
+FASTSTREAM_CLI_RICH_MODE=none faststream run main:app
+```
+
+- `rich` *(default)* – use Typer's rich markup styling.
+- `markdown` – render CLI output using markdown-compatible formatting.
+- `none` – disable rich formatting and use plain-text output.
+
+This is useful when working in terminals that do not support ANSI styling or when copying CLI output into plain-text environments.

faststream/_internal/cli/main.py

@@ -1,9 +1,10 @@
 import logging
+import os
 import sys
 import warnings
 from contextlib import suppress
 from pathlib import Path
-from typing import TYPE_CHECKING, Any, cast
+from typing import TYPE_CHECKING, Any, Literal, cast
 
 import anyio
 import typer
@@ -37,7 +38,18 @@
 if TYPE_CHECKING:
     from faststream._internal.broker import BrokerUsecase
 
-cli = typer.Typer(pretty_exceptions_short=True)
+rich_mode = os.getenv("FASTSTREAM_CLI_RICH_MODE", "rich")
+if rich_mode == "none":
+    rich_markup_mode: Literal["markdown", "rich"] | None = None
+elif rich_mode in {"md", "markdown"}:
+    rich_markup_mode = "markdown"
+elif rich_mode == "rich":
+    rich_markup_mode = "rich"
+else:
+    msg = f"Invalid rich mode: {rich_mode}"
+    raise ValueError(msg)
+
+cli = typer.Typer(pretty_exceptions_short=True, rich_markup_mode=rich_markup_mode)
 cli.add_typer(docs_app, name="docs", help="Documentations commands")