flask-debugtoolbar-extrapanels

A collection of extra panels for Flask-DebugToolbar.

Panels

SignalsPanel

Displays all Blinker signals fired during a request, including the built-in Flask signals and any custom signals you register.

The panel shows:

• Signal name
• Sender
• Keyword arguments
• Time fired

Built-in Flask signals tracked automatically:

• request_started
• request_finished
• request_tearing_down
• got_request_exception
• template_rendered
• before_render_template
• appcontext_pushed
• appcontext_popped
• appcontext_tearing_down
• message_flashed

Installation

pip install flask-debugtoolbar-extrapanels

Or with uv:

uv add flask-debugtoolbar-extrapanels

Requirements

• Python >= 3.10
• flask-debugtoolbar >= 0.16.0

Usage

Add flask_debugtoolbar_extrapanels.SignalsPanel to the DEBUG_TB_PANELS list in your Flask app config:

from flask import Flask
from flask_debugtoolbar import DebugToolbarExtension

app = Flask(__name__)
app.config["SECRET_KEY"] = "dev-secret-key"
app.config["DEBUG"] = True
app.config["DEBUG_TB_ENABLED"] = True
app.config["DEBUG_TB_PANELS"] = [
    "flask_debugtoolbar.panels.versions.VersionDebugPanel",
    "flask_debugtoolbar.panels.timer.TimerDebugPanel",
    "flask_debugtoolbar.panels.headers.HeaderDebugPanel",
    "flask_debugtoolbar.panels.request_vars.RequestVarsDebugPanel",
    "flask_debugtoolbar.panels.config_vars.ConfigVarsDebugPanel",
    "flask_debugtoolbar.panels.template.TemplateDebugPanel",
    "flask_debugtoolbar.panels.logger.LoggingPanel",
    "flask_debugtoolbar.panels.route_list.RouteListDebugPanel",
    "flask_debugtoolbar_extrapanels.SignalsPanel",
]

toolbar = DebugToolbarExtension(app)

Watching custom signals

Use SignalsPanel.watch() to register any Blinker NamedSignal before the first request:

from blinker import signal
from flask_debugtoolbar_extrapanels import SignalsPanel

my_signal = signal("my-custom-signal")
SignalsPanel.watch("my_custom_signal", my_signal)

After registration, every time my_signal fires during a request it will appear in the Signals panel.

Running the example app

git clone https://github.com/mariofix/flask-debugtoolbar-extrapanels.git
cd flask-debugtoolbar-extrapanels
pip install flask-debugtoolbar
pip install -e .
python example_app.py

Open http://localhost:5000/ in your browser. The debug toolbar will appear with a Signals tab.

• Visit /flash to trigger message_flashed
• Visit /custom to trigger a custom Blinker signal

Development

Setup

git clone https://github.com/mariofix/flask-debugtoolbar-extrapanels.git
cd flask-debugtoolbar-extrapanels
uv sync --group dev

Running tests

uv run pytest

License

See LICENSE.