Overview: Feature Flag Manager

The Feature Flag Manager module provides a robust solution for managing feature toggles in software systems. Its purpose is to enable developers to dynamically enable or disable specific features without requiring changes to the underlying codebase. This allows for controlled experimentation, gradual rollouts, and environment-specific feature management.

Purpose

The Feature Flag Manager serves as an administrative tool to manage feature flags across different environments (e.g., development, staging, production) and user segments. It enables developers to:

Safely test features in production without impacting end-users.
Roll out new features or updates in a phased manner.
Disable problematic features quickly without redeploying code.
Target specific user groups or regions for feature availability.

Benefits

The Feature Flag Manager offers several key benefits:

Rapid Experimentation: Developers can enable and disable features on-the-fly, allowing for quick testing and iteration.
Risk Mitigation: Features can be rolled out incrementally to a small subset of users before full deployment, reducing the risk of introducing bugs or performance issues.
Environment-Specific Control: Different environments (e.g., dev, staging, production) can have unique feature configurations, ensuring consistency across workflows.
User Segmentation: Features can be targeted based on user attributes (e.g., region, role, or ID), enabling A/B testing and personalized experiences.
Reduced Deployment Risks: Bugs or issues in new features can be quickly reverted without the need for redeployment.
Improved Collaboration: The module provides a centralized platform for managing feature toggles, fostering better collaboration among developers and admins.

Usage Scenarios

The Feature Flag Manager is ideal for the following scenarios:

Feature Testing: Developers can enable a new feature in production to test its behavior without exposing it to all users.
Phased Rollouts: New features can be rolled out gradually to specific user groups or regions, allowing for controlled adoption.
A/B Testing: Features can be toggled on and off for different segments of users to compare performance or user feedback.
Bug Fixes: If a feature introduces a bug in production, the Feature Flag Manager allows developers to disable it quickly without redeploying code.
Environment-Specific Configurations: Different environments (e.g., dev, staging, production) can have distinct feature settings to align with their specific needs.
Feature Deprecation: Developers can disable deprecated features while maintaining backward compatibility with existing systems.

By leveraging the Feature Flag Manager, developers gain the flexibility and control needed to manage features effectively throughout the software lifecycle.

# Feature Flag Manager

## Overview
The **Feature Flag Manager** is a module designed to control the enablement or disablement of specific features within a software system. This allows for dynamic management of features without requiring redeployment, making it ideal for testing, user experience optimization, and environment-specific configurations.

## Key Features

### 1. Feature Enable/Disable
- **Description**: Enables or disables specific features based on administrative control.
- **Use Case**: Quickly toggle features on or off to test functionality, roll out changes gradually, or fix issues without redeploying code.

### 2. Environment-Specific Configuration
- **Description**: Allows features to be enabled or disabled for different environments (e.g., Development, Staging, Production).
- **Use Case**: Tailor feature availability based on the environment, ensuring that certain features are only accessible in specific contexts.

### 3. User Group Targeting
- **Description**: Enable or disable features for specific user groups.
- **Use Case**: A/B testing, where different user segments can access features at varying stages of development or deployment.

### 4. Feature Rollout
- **Description**: Gradually roll out features to a subset of users before full deployment.
- **Use Case**: Risk mitigation by starting with small user groups to identify and address issues before a full rollout.

### 5. Audit Trail
- **Description**: Logs changes made to feature flags for auditing purposes.
- **Use Case**: Track who made changes, when they were made, and what the changes were, ensuring accountability and compliance.

### 6. Permission-Based Access Control
- **Description**: Restrict access to feature flags based on user roles or permissions.
- **Use Case**: Ensure that only authorized personnel can modify feature flags, enhancing security and preventing unintended changes.

### 7. Feature State Monitoring
- **Description**: Monitor the state of features in real-time.
- **Use Case**: Quickly identify if a feature is enabled or disabled across different environments or user groups.

### 8. Integration with External Systems
- **Description**: Integrate with external systems, APIs, or services to dynamically update feature states.
- **Use Case**: Automatically sync feature flag changes with other components of the system for consistent behavior.

### 9. Dependency Management
- **Description**: Manage dependencies between features to ensure proper functionality when features are toggled.
- **Use Case**: Define relationships where enabling one feature may require disabling another, or vice versa, to maintain system integrity.

### 10. Historical Data Tracking
- **Description**: Track historical states of feature flags over time.
- **Use Case**: Analyze past changes to identify patterns, issues, or the impact of specific changes on system behavior.

## Summary
The **Feature Flag Manager** provides a robust and flexible solution for managing features in a software system. With capabilities ranging from simple enable/disable operations to environment-specific configurations and user group targeting, this module empowers developers and administrators to control feature availability effectively. The inclusion of features like audit trails, permission-based access control, and historical data tracking ensures transparency, security, and comprehensive oversight.

Here’s a technical documentation for the Feature Flag Manager module with sample code implementations:

1. FastAPI Endpoint Example

This example shows a FastAPI endpoint to manage feature flags.

from fastapi import APIRouter, Depends, HTTPException
from typing import List
from pydantic import BaseModel
import os

router = APIRouter()

class FeatureFlag(BaseModel):
    name: str
    description: str
    status: bool
    environment: str
    enable_time: int
    disable_time: int
    user_id: str

# Sample configuration
_ENV_PREFIX = "FEATURE_FLAG_"
_CONFIG = {
    "development": os.getenv(f"{_ENV_PREFIX}DEVELOPMENT_ENABLED", "true").lower() in ["true", "on", "1"],
    "analytics": os.getenv(f"{_ENV_PREFIX}ANALYTICS_ENABLED", "true").lower() in ["true", "on", "1"]
}

@router.get("/feature-flags", response_model=List[FeatureFlag])
async def get_feature_flags():
    """Get all feature flags"""
    return [
        FeatureFlag(
            name="development",
            description="Enable development features",
            status=_CONFIG["development"],
            environment=os.getenv("ENVIRONMENT", "production"),
            enable_time=int(os.getenv(f"{_ENV_PREFIX}DEVELOPMENT_ENABLE_TIME", 0)),
            disable_time=int(os.getenv(f"{_ENV_PREFIX}DEVELOPMENT_DISABLE_TIME", 0)),
            user_id=os.getenv("USER_ID", "admin")
        ),
        FeatureFlag(
            name="analytics",
            description="Enable analytics features",
            status=_CONFIG["analytics"],
            environment=os.getenv("ENVIRONMENT", "production"),
            enable_time=int(os.getenv(f"{_ENV_PREFIX}ANALYTICS_ENABLE_TIME", 0)),
            disable_time=int(os.getenv(f"{_ENV_PREFIX}ANALYTICS_DISABLE_TIME", 0)),
            user_id=os.getenv("USER_ID", "admin")
        )
    ]

@router.post("/feature-flags/{name}", response_model=FeatureFlag)
async def toggle_feature_flag(name: str):
    """Toggle a feature flag"""
    if name not in _CONFIG:
        raise HTTPException(status_code=404, detail=f"Feature flag {name} not found")
    
    # Toggle the status
    new_status = not _CONFIG[name]
    _CONFIG[name] = new_status
    
    return FeatureFlag(
        name=name,
        description="Enable analytics features",
        status=new_status,
        environment=os.getenv("ENVIRONMENT", "production"),
        enable_time=int(os.getenv(f"{_ENV_PREFIX}{name.upper()}_ENABLE_TIME", 0)),
        disable_time=int(os.getenv(f"{_ENV_PREFIX}{name.upper()}_DISABLE_TIME", 0)),
        user_id=os.getenv("USER_ID", "admin")
    )

2. React UI Component Example

This example shows a simple React component to display and manage feature flags.

import React, { useState } from 'react';

interface FeatureFlag {
    name: string;
    description: string;
    status: boolean;
    environment: string;
    enableTime: number;
    disableTime: number;
    userId: string;
}

const FeatureFlagManager = () => {
    const [featureFlags, setFeatureFlags] = useState<FeatureFlag[]>([
        {
            name: 'development',
            description: 'Enable development features',
            status: true,
            environment: 'production',
            enableTime: 1625937600,
            disableTime: 0,
            userId: 'admin'
        },
        {
            name: 'analytics',
            description: 'Enable analytics features',
            status: true,
            environment: 'production',
            enableTime: 1625937600,
            disableTime: 0,
            userId: 'admin'
        }
    ]);

    const toggleFeatureFlag = async (name: string) => {
        try {
            const response = await fetch(`api/feature-flags/${name}`, { 
                method: 'POST',
                headers: {
                    'Content-Type': 'application/json',
                },
            });
            
            if (!response.ok) {
                throw new Error('Failed to toggle feature flag');
            }
            
            const updatedFlags = featureFlags.map(flag => 
                flag.name === name ? await response.json() : flag
            );
            setFeatureFlags(updatedFlags);
        } catch (error) {
            console.error('Error:', error);
        }
    };

    return (
        <div className="feature-flag-manager">
            <h1>Feature Flag Manager</h1>
            <div className="flags-container">
                {featureFlags.map(flag => (
                    <div 
                        key={flag.name}
                        className={`flag-item ${flag.status ? 'enabled' : 'disabled'}`}
                    >
                        <div className="flag-info">
                            <h3>{flag.description}</h3>
                            <p>Status: {'✓'.repeat(flag.status ? 1 : 0)}</p>
                            <p>Environment: {flag.environment}</p>
                        </div>
                        <button 
                            onClick={() => toggleFeatureFlag(flag.name)}
                            className={`toggle-button ${flag.status ? 'active' : ''}`}
                        >
                            {flag.status ? 'Disable' : 'Enable'}
                        </button>
                    </div>
                ))}
            </div>
        </div>
    );
};

export default FeatureFlagManager;

3. Pydantic Data Schema Example

This example shows the data models for feature flags.

from pydantic import BaseModel, Field
from typing import Optional

class FeatureFlagCreate(BaseModel):
    name: str = Field(..., min_length=1)
    description: str = Field(..., min_length=1)
    status: bool = True
    environment: str = "production"
    enable_time: Optional[int] = None
    disable_time: Optional[int] = None
    user_id: str = Field(..., min_length=1)

class FeatureFlagRead(BaseModel):
    name: str = Field(...)
    description: str = Field(...)
    status: bool = Field(...)
    environment: str = Field(...)
    enable_time: Optional[int] = None
    disable_time: Optional[int] = None
    user_id: str = Field(...)

Summary

This documentation provides a basic implementation of a Feature Flag Manager module with:

A FastAPI endpoint for managing feature flags.
A React UI component for displaying and toggling feature flags.
Pydantic models for validating feature flag data.

The implementation includes:

Environment-based configuration
Enable/disable timestamps
User tracking
Basic error handling
Toggle functionality

You can extend this further by adding:

More granular permissions
Historical tracking of changes
Feature flag dependencies
Webhooks for change notifications

Module Name: Feature Flag Manager

Summary

The Feature Flag Manager allows administrators to enable or disable specific features for testing, users, or environments. This module provides fine-grained control over feature availability without requiring code changes.

User Management: For managing user permissions and access levels.
Environment Configurator: For configuring environment-specific settings.
Audit Log: For tracking changes to feature flags and their impact.
API Gateway: For exposing feature flag status via APIs.

Use Cases

1. Feature Rollout

Enable a new feature in the test environment before rolling it out to production.
Example: feature.flag.enable("new_feature").

2. Beta Testing

Restrict access to a feature for a subset of users based on user roles or identifiers.
Example: if is_beta_user(user): feature.flag.enable_for_user(user, "beta-feature").

3. Feature Experimentation

Toggle features dynamically during A/B testing without redeploying code.
Example: feature.flag.toggle("experiment-feature", enabled=True).

4. Emergency Rollback

Disable a problematic feature quickly if issues arise in production.
Example: feature.flag.disable("faulty_feature").

Integration Tips

Environment Variables: Use environment variables to configure default feature flag states.
CI/CD Pipeline: Integrate the Feature Flag Manager into your CI/CD pipeline for automated feature rollouts.
Logging: Implement logging in the Feature Flag Manager to track changes and their impact on system behavior.

Configuration Options

Configuration Key	Description	Default Value	Example Value
`FEATURE_FLAG_API_KEY`	API key for authenticating feature flag requests.	N/A	”your_api_key”
`DEFAULT_FEATURE_STATE`	Default state of new features (enabled or disabled).	“disabled”
`FEATURE_FLAGS_FILE_PATH`	Path to the file storing feature flags configuration.	”./flags.json”
`ALLOWED_ENVIRONMENTS`	List of allowed environments for feature flag changes.	[“dev”, “prod”]	[” staging “]

Module Details

Name: Feature Flag Manager
Category: Admin
Summary: Manage the enablement or disablement of features in a controlled manner.
Target User: Developers and administrators.
Version: 1.0.0

Feature Flag Manager

Overview: Feature Flag Manager

Purpose

Benefits

Usage Scenarios

1. FastAPI Endpoint Example

2. React UI Component Example

3. Pydantic Data Schema Example

Summary

Module Name: Feature Flag Manager

Category

Summary

Related Modules

Use Cases

1. Feature Rollout

2. Beta Testing

3. Feature Experimentation

4. Emergency Rollback

Integration Tips

Configuration Options

Module Details