flagswift 1.1.3

Official Python SDK for FlagSwift feature flags

FlagSwift Python SDK

Official Python client for FlagSwift feature flags.

Installation

pip install flagswift

Quick Start

from flagswift import FlagSwift

# Initialize the client
flags = FlagSwift(api_key='sk_live_your_api_key_here')

# Check if a feature is enabled
if flags.is_enabled('new-feature'):
    # Use new feature
    print("New feature is enabled!")
else:
    # Use old feature
    print("Using old feature")

Usage Examples

Basic Feature Flag Check

from flagswift import FlagSwift

flags = FlagSwift(
    api_key='sk_live_your_api_key_here',
    environment='production'
)

# Simple check
if flags.is_enabled('dark-mode'):
    enable_dark_mode()

User Targeting

# Check flag for specific user
user_id = 'user-123'

if flags.is_enabled('beta-feature', user_id=user_id):
    show_beta_feature()
else:
    show_standard_feature()

Multiple User Identifiers

# Check flag with multiple identifiers (email, user_id, etc.)
identifiers = ['[e-mail]', 'user-123']

if flags.is_enabled('premium-feature', user_id=identifiers):
    show_premium_feature()

Django Integration

# settings.py
from flagswift import FlagSwift

FLAGSWIFT = FlagSwift(
    api_key='sk_live_your_api_key_here',
    environment='production'
)

# views.py
from django.conf import settings

def my_view(request):
    user_id = str(request.user.id)

    if settings.FLAGSWIFT.is_enabled('new-dashboard', user_id=user_id):
        return render(request, 'new_dashboard.html')
    else:
        return render(request, 'old_dashboard.html')

FastAPI Integration

from fastapi import FastAPI, Depends
from flagswift import FlagSwift

app = FastAPI()

# Initialize FlagSwift
flags = FlagSwift(
    api_key='sk_live_your_api_key_here',
    environment='production'
)

@app.get("/feature")
async def get_feature(user_id: str):
    if flags.is_enabled('new-api', user_id=user_id):
        return {"version": "v2", "features": ["new", "improved"]}
    else:
        return {"version": "v1", "features": ["standard"]}

Flask Integration

from flask import Flask, request
from flagswift import FlagSwift

app = Flask(__name__)

flags = FlagSwift(
    api_key='sk_live_your_api_key_here',
    environment='production'
)

@app.route('/api/data')
def get_data():
    user_id = request.headers.get('X-User-ID')

    if flags.is_enabled('new-algorithm', user_id=user_id):
        return use_new_algorithm()
    else:
        return use_old_algorithm()

Advanced Features

Configuration Object

from flagswift import FlagSwift, FlagSwiftConfig

config = FlagSwiftConfig(
    api_key='sk_live_your_api_key_here',
    environment='staging',
    base_url='https://flagswift.com',
    timeout=10,
    cache_timeout=300,  # 5 minutes
    max_retries=3,
    failsafe_fallbacks={
        'critical-feature': True,  # Always enabled if API fails
        'experimental-feature': False  # Always disabled if API fails
    },
    global_identifier='system-service-id'  # Default user for all checks
)

flags = FlagSwift.from_config(config)

Kill Switch

Immediately disable features in production:

# Activate kill switch (disables flags immediately)
flags.activate_kill_switch(
    flags=['problematic-feature'],
    environments=['production']
)

# Deactivate kill switch (restores previous state)
flags.deactivate_kill_switch(
    flags=['problematic-feature'],
    environments=['production']
)

# Check kill switch status
if flags.is_kill_switch_enabled():
    print("Kill switch is active!")

Refresh Flags

# Force refresh from server
flags.refresh()

# Refresh with specific user context
flags.refresh(user_id='user-123')

Get All Flags

# Get all flags and their states
all_flags = flags.get_all_flags()
print(all_flags)
# {'feature-1': True, 'feature-2': False, ...}

Get Flag Configuration

# Get detailed flag configuration
config = flags.get_flag_config('my-feature')
print(config)
# {
#   'enabled': True,
#   'rolloutPercentage': 50,
#   'targeting': {'enabled': True, 'users': ['user-1', 'user-2']}
# }

SDK Status

# Get SDK status
status = flags.get_status()
print(status)
# {
#   'initialized': True,
#   'flag_count': 10,
#   'environment': 'production',
#   'kill_switch_active': False,
#   'cache_valid': True
# }

ML Model A/B Testing Example

from flagswift import FlagSwift

flags = FlagSwift(api_key='sk_live_your_key')

def predict(data, user_id):
    if flags.is_enabled('new-ml-model', user_id=user_id):
        # Use new model
        return new_model.predict(data)
    else:
        # Use stable model
        return stable_model.predict(data)

Error Handling

from flagswift import FlagSwift, FlagSwiftError, AuthenticationError, NetworkError

try:
    flags = FlagSwift(api_key='sk_live_your_key')
    flags.initialize()

except AuthenticationError:
    print("Invalid API key")
except NetworkError:
    print("Network error - using fallback values")
except FlagSwiftError as e:
    print(f"FlagSwift error: {e}")

Best Practices

1. Initialize Once

# ✅ Good: Initialize once at application startup
flags = FlagSwift(api_key='sk_live_your_key')

# ❌ Bad: Don't create new instances for each check
def check_feature():
    flags = FlagSwift(api_key='sk_live_your_key')  # Don't do this!
    return flags.is_enabled('feature')

2. Use Failsafe Fallbacks

# Always provide fallbacks for critical features
flags = FlagSwift(
    api_key='sk_live_your_key',
    failsafe_fallbacks={
        'payment-processing': True,  # Critical: always enabled
        'experimental-ui': False      # Experimental: always disabled
    }
)

3. Cache Strategy

# For high-traffic APIs, use longer cache
flags = FlagSwift(
    api_key='sk_live_your_key',
    cache_timeout=600  # 10 minutes
)

# For real-time updates, use shorter cache or manual refresh
flags = FlagSwift(
    api_key='sk_live_your_key',
    cache_timeout=30  # 30 seconds
)

Configuration Options

Option	Type	Default	Description
api_key	str	Required	Your FlagSwift server API key
environment	str	'production'	Environment name
base_url	str	'https://flagswift.com'	FlagSwift API URL
timeout	int	5	Request timeout (seconds)
cache_timeout	int	300	Cache validity (seconds)
max_retries	int	3	Maximum retry attempts
failsafe_fallbacks	dict	{}	Default values when API fails
kill_switch_fallbacks	dict	{}	Values during kill switch
global_identifier	str/list	None	Default user identifier

API Reference

FlagSwift Class

Methods

• is_enabled(flag_name, user_id=None) - Check if flag is enabled
• get_all_flags() - Get all flags
• get_flag_config(flag_name) - Get flag configuration
• refresh(user_id=None) - Force refresh from server
• activate_kill_switch(flags, environments=None) - Activate kill switch
• deactivate_kill_switch(flags, environments=None) - Deactivate kill switch
• is_kill_switch_enabled() - Check kill switch status
• get_status() - Get SDK status

Testing with Postman

You can test your FlagSwift integration using the same backend server from your Node.js example. The Python SDK makes the same API calls to /api/flags/server.

Support

• 📧 Email: [e-mail]
• 📚 Docs: https://flagswift.com/docs

License

MIT License - see LICENSE file for details