dashboard-lego 0.11.2

A modular Python library for building interactive dashboards using Dash and Plotly

Dashboard Lego 🧱

A modular Python library for building interactive dashboards using Dash and Plotly.

Dashboard Lego allows you to build complex dashboards from independent, reusable "blocks" like building with LEGO bricks. This simplifies development, improves code readability, and promotes component reusability.

---

✨ Key Features

• Modular Architecture: Build dashboards from independent blocks (KPIs, charts, text)
• Reactive State Management: Built-in state manager for easy interactivity between blocks (filters, drill-down, etc.)
• Flexible Grid System: Position blocks in any configuration using a grid system based on dash-bootstrap-components
• Data Caching: Built-in caching at the data source level for improved performance
• Easy Extension: Easily create custom blocks and data sources by inheriting from base classes
• Presets & Layouts: Pre-built EDA and ML visualization blocks, plus layout presets for common dashboard patterns
• Comprehensive Testing: Full test coverage with unit, integration, and performance tests

📦 Installation

1. Clone the repository:

   git clone https://github.com/your-username/dashboard-lego.git
   cd dashboard-lego
   

2. Create a virtual environment and install dependencies: We recommend using uv for fast installation.

   # Install uv
   pip install uv
   
   # Create environment and install dependencies
   uv venv
   uv pip install -e .[dev]
   

🚀 Quick Start

Below is an example of a simple dashboard. The complete code can be found in examples/01_simple_dashboard.py.

# examples/01_simple_dashboard.py

import dash
import dash_bootstrap_components as dbc
import plotly.express as px
import pandas as pd
import plotly.graph_objects as go

from core.datasource import BaseDataSource
from core.page import DashboardPage
from blocks.kpi import KPIBlock
from blocks.chart import StaticChartBlock
from presets.layouts import one_column

# 1. Define a data source
class SalesDataSource(BaseDataSource):
    def __init__(self, file_path):
        self.file_path = file_path
        super().__init__()

    def _load_data(self, params: dict) -> pd.DataFrame:
        return pd.read_csv(self.file_path)

    def get_kpis(self) -> dict:
        if self._data is None: return {}
        return {
            "total_sales": self._data["Sales"].sum(),
            "total_units": self._data["UnitsSold"].sum()
        }

    def get_filter_options(self, filter_name: str) -> list:
        return []

    def get_summary(self) -> str:
        return ""

# 2. Define a plotting function
def plot_sales_by_fruit(df: pd.DataFrame, ctx) -> go.Figure:
    sales_by_fruit = df.groupby("Fruit")["Sales"].sum().reset_index()
    return px.bar(sales_by_fruit, x="Fruit", y="Sales", title="Sales by Fruit")

# 3. Initialize your data source and blocks
datasource = SalesDataSource(file_path="examples/sample_data.csv")
datasource.init_data()

kpi_block = KPIBlock(
    block_id="sales_kpis",
    datasource=datasource,
    kpi_definitions=[
        {"key": "total_sales", "title": "Total Sales", "color": "success"},
        {"key": "total_units", "title": "Total Units Sold", "color": "info"},
    ],
    subscribes_to="dummy_state"
)

chart_block = StaticChartBlock(
    block_id="sales_chart",
    datasource=datasource,
    title="Fruit Sales",
    chart_generator=plot_sales_by_fruit,
    subscribes_to="dummy_state"
)

# 4. Assemble the dashboard page using layout presets
dashboard_page = DashboardPage(
    title="Simple Sales Dashboard",
    blocks=one_column([kpi_block, chart_block]),  # Stack blocks vertically
    theme=dbc.themes.LUX
)

# 5. Run the application
app = dash.Dash(__name__, external_stylesheets=[dashboard_page.theme])
app.layout = dashboard_page.build_layout()
dashboard_page.register_callbacks(app)

if __name__ == "__main__":
    app.run_server(debug=True)

To run this example:

python examples/01_simple_dashboard.py

🔗 Interactivity

dashboard-lego makes it easy to link blocks together. One block can publish its state (e.g., a filter value), and other blocks can subscribe to that state and update accordingly.

This is implemented through the StateManager, which automatically creates Dash callbacks.

See the complete interactive dashboard example in examples/02_interactive_dashboard.py.

🎨 Presets and Layouts

EDA Presets

Presets are ready-to-use blocks for standard data analysis tasks (EDA) that significantly reduce boilerplate code:

• CorrelationHeatmapPreset: Automatically builds a correlation heatmap for all numeric columns in your data
• GroupedHistogramPreset: Creates an interactive histogram with dropdowns for column and grouping selection
• MissingValuesPreset: Displays a bar chart showing the percentage of missing values for each column, helping quickly assess data quality
• BoxPlotPreset: Allows comparing distributions of a numeric feature across different categories using interactive box plot charts

Example usage of presets can be found in examples/03_presets_dashboard.py.

ML Presets

Machine learning visualization presets for common ML workflows:

• MetricCardBlock: Compact display for ML metrics in a list format
• ConfusionMatrixPreset: Interactive confusion matrix visualization
• FeatureImportancePreset: Feature importance charts for model interpretation
• ROC_CurvePreset: ROC curve visualization for classification models

Layout Presets

DashboardPage supports declarative layout schemas:

• Cell: Block or (Block, { 'xs|sm|md|lg|xl': int, 'offset': int, 'align': str, 'className': str, 'style': dict, 'children': [row_specs] })
• Row: [cells] or ([cells], { 'align': str, 'justify': str, 'g': int, 'className': str, 'style': dict })

If widths are not specified, for backward compatibility, automatic equal division is set via width.

The presets/layouts.py module provides common templates: one_column, two_column_8_4, three_column_4_4_4, kpi_row_top, etc.

📊 Data Sources

Dashboard Lego supports multiple data source types:

• CSV Source: Load data from CSV files with automatic caching
• Parquet Source: High-performance columnar data loading
• SQL Source: Connect to databases via SQLAlchemy
• Custom Sources: Inherit from BaseDataSource to create your own data providers

🧪 Testing

The library is covered by comprehensive tests. To run tests:

# Make sure you have dev dependencies installed
# uv pip install -e .[dev,docs,ml,sql]

# Run tests
uv run pytest

# Run with coverage
uv run pytest --cov=dashboard_lego --cov-report=html

📚 Documentation

Building Documentation Locally

cd docs

# Build and serve locally (opens http://localhost:8000)
make serve

# Just build HTML
make html

# Clean and rebuild
make clean && make html

# Check docs build without errors
make check

Documentation Structure

• API Documentation: Automatically generated from docstrings
• User Guides: Installation, quick start, and concepts
• Examples: Check the examples/ directory for various use cases
• Contributing: See CONTRIBUTING.md for development guidelines
• Changelog: Track changes in CHANGELOG.md

Publishing Documentation

Automatic (Recommended):

• Documentation is automatically built and published to GitHub Pages when tests pass on main branch
• Available at: https://blghtr.github.io/dashboard_lego/

Note: No manual publishing needed! CI handles everything automatically.

🛠️ Development

Prerequisites

• Python 3.10+
• uv (recommended) or pip

Development Setup

# Clone and setup
[uv] pip install dashboard-lego

# Run pre-commit hooks
pre-commit install

# Run tests
uv run pytest

Code Style

• Black for code formatting
• Flake8 for linting
• MyPy for type checking
• Pre-commit hooks for automated checks

🤝 Contributing

We welcome contributions! Please see CONTRIBUTING.md for detailed information on:

• Development setup and guidelines
• Code style and standards
• Testing requirements
• Pull request process
• Creating presets and custom blocks

📄 License

This project is distributed under the MIT License. See the LICENSE file for details.

🚀 Roadmap

• Enhanced chart types and customization options
• Real-time data streaming capabilities
• Advanced theming and styling system
• Export functionality (PDF, PNG, etc.)
• Web-based dashboard builder interface
• Additional ML visualization presets
• Database connection presets
• Mobile-responsive optimizations

---

Build amazing dashboards with Dashboard Lego! 🧱✨