soft-deps 0.1.1

Quick Start

Why use soft-deps?

• For library authors: Provide optional features without forcing users to install heavy dependencies

• For users: Get full IDE support and autocomplete even for optional dependencies

• For teams: Graceful degradation with clear error messages instead of cryptic import failures

When to use soft-deps?

Use soft-deps when your library has optional features that depend on external packages:

• Data science libraries with optional visualization (matplotlib, plotly)

• Web frameworks with optional database drivers (psycopg2, pymongo)

• CLI tools with optional cloud integrations (boto3, google-cloud)

• Any library where you want some features to work without heavy dependencies

How it works:

Library authors use the soft-deps pattern in their code:

# your_library.py
from soft_deps.api import MissingDependency

# Try to import optional dependency
try:
    import pandas as pd
except ImportError:
    # Create helpful proxy if missing
    pd = MissingDependency("pandas", "pip install pandas")

def export_to_excel(data):
    """Export data to Excel file (requires pandas)."""
    # IDE gets full autocomplete here even if pandas not installed
    # Error only occurs when this line actually executes
    return pd.DataFrame(data).to_excel("output.xlsx")

Users get seamless experience regardless of what’s installed:

# user_script.py
from your_library import export_to_excel

# This imports successfully even without pandas installed
# IDE provides full autocomplete and type hints

try:
    export_to_excel({"col1": [1, 2, 3]})
except ImportError as e:
    print(e)  # "You didn't install pandas. To use DataFrame, pip install pandas"

The difference:

# ❌ Traditional approach - breaks immediately
import pandas as pd  # ImportError if not installed

# ❌ Lazy imports - no IDE support
def export_data():
    import pandas as pd  # IDE can't help with autocomplete

# ✅ soft-deps - best of both worlds
try:
    import pandas as pd
except ImportError:
    pd = MissingDependency("pandas", "pip install pandas")
# IDE gets full support, graceful errors when actually used

Install

soft_deps is released on PyPI, so all you need is to:

$ pip install soft-deps

To upgrade to latest version:

$ pip install --upgrade soft-deps