RichLog

A RichLog is a widget which displays scrollable content that may be appended to in realtime.

Call RichLog.write with a string or Rich Renderable to write content to the end of the RichLog. Call RichLog.clear to clear the content.

Tip

See also Log which is an alternative to RichLog but specialized for simple text.

• Focusable
• Container

Example

The example below shows an application showing a RichLog with different kinds of data logged.

Outputrich_log.py

import csv
import io

from rich.syntax import Syntax
from rich.table import Table

from textual import events
from textual.app import App, ComposeResult
from textual.widgets import RichLog

CSV = """lane,swimmer,country,time
4,Joseph Schooling,Singapore,50.39
2,Michael Phelps,United States,51.14
5,Chad le Clos,South Africa,51.14
6,László Cseh,Hungary,51.14
3,Li Zhuhao,China,51.26
8,Mehdy Metella,France,51.58
7,Tom Shields,United States,51.73
1,Aleksandr Sadovnikov,Russia,51.84"""


CODE = '''\
def loop_first_last(values: Iterable[T]) -> Iterable[tuple[bool, bool, T]]:
    """Iterate and generate a tuple with a flag for first and last value."""
    iter_values = iter(values)
    try:
        previous_value = next(iter_values)
    except StopIteration:
        return
    first = True
    for value in iter_values:
        yield first, False, previous_value
        first = False
        previous_value = value
    yield first, True, previous_value\
'''


class RichLogApp(App):
    def compose(self) -> ComposeResult:
        yield RichLog(highlight=True, markup=True)

    def on_ready(self) -> None:
        """Called  when the DOM is ready."""
        text_log = self.query_one(RichLog)

        text_log.write(Syntax(CODE, "python", indent_guides=True))

        rows = iter(csv.reader(io.StringIO(CSV)))
        table = Table(*next(rows))
        for row in rows:
            table.add_row(*row)

        text_log.write(table)
        text_log.write("[bold magenta]Write text or any Rich renderable!")

    def on_key(self, event: events.Key) -> None:
        """Write Key events to log."""
        text_log = self.query_one(RichLog)
        text_log.write(event)


if __name__ == "__main__":
    app = RichLogApp()
    app.run()

Reactive Attributes

Name	Type	Default	Description
highlight	bool	False	Automatically highlight content.
markup	bool	False	Apply markup.
max_lines	int	None	Maximum number of lines in the log or None for no maximum.
min_width	int	78	Minimum width of renderables.
wrap	bool	False	Enable word wrapping.

Messages

This widget sends no messages.

Bindings

This widget has no bindings.

Component Classes

This widget has no component classes.

---

Bases: ScrollView

A widget for logging Rich renderables and text.

Parameters:

Name	Type	Description	Default
max_lines	int | None	Maximum number of lines in the log or None for no maximum.	None
min_width	int	Width to use for calls to write with no specified width.	78
wrap	bool	Enable word wrapping (default is off).	False
highlight	bool	Automatically highlight content. By default, the ReprHighlighter is used. To customize highlighting, set highlight=True and then set the highlighter attribute to an instance of Highlighter.	False
markup	bool	Apply Rich console markup.	False
auto_scroll	bool	Enable automatic scrolling to end.	True
name	str | None	The name of the text log.	None
id	str | None	The ID of the text log in the DOM.	None
classes	str | None	The CSS classes of the text log.	None
disabled	bool	Whether the text log is disabled or not.	False

auto_scroll class-attribute instance-attribute

auto_scroll: var[bool] = auto_scroll

Automatically scroll to the end on write.

highlight class-attribute instance-attribute

highlight: var[bool] = highlight

Automatically highlight content.

highlighter instance-attribute

highlighter: Highlighter = ReprHighlighter()

Rich Highlighter used to highlight content when highlight is True

lines instance-attribute

lines: list[Strip] = []

The lines currently visible in the log.

markup class-attribute instance-attribute

markup: var[bool] = markup

Apply Rich console markup.

max_lines class-attribute instance-attribute

max_lines: var[int | None] = max_lines

Maximum number of lines in the log or None for no maximum.

min_width class-attribute instance-attribute

min_width: var[int] = min_width

Minimum width of renderables.

wrap class-attribute instance-attribute

wrap: var[bool] = wrap

Enable word wrapping.

clear

clear()

Clear the text log.

Returns:

Type	Description
Self	The RichLog instance.

write

write(
    content,
    width=None,
    expand=False,
    shrink=True,
    scroll_end=None,
    animate=False,
)

Write a string or a Rich renderable to the bottom of the log.

Notes

The rendering of content will be deferred until the size of the RichLog is known. This means if you call write in compose or on_mount, the content will not be rendered immediately.

Parameters:

Name	Type	Description	Default
content	RenderableType | object	Rich renderable (or a string).	required
width	int | None	Width to render, or None to use RichLog.min_width. If specified, expand and shrink will be ignored.	None
expand	bool	Permit expanding of content to the width of the content region of the RichLog. If width is specified, then expand will be ignored.	False
shrink	bool	Permit shrinking of content to fit within the content region of the RichLog. If width is specified, then shrink will be ignored.	True
scroll_end	bool | None	Enable automatic scroll to end, or None to use self.auto_scroll.	None
animate	bool	Enable animation if the log will scroll.	False

Returns:

Type	Description
Self	The RichLog instance.