# Fapilog v3 Product Requirements Document (PRD)

## Goals and Background Context

### Goals

- **Immediate Developer Productivity**: Create a logging library that works perfectly out of the box with zero configuration - `pip install fapilog` → productive immediately
- **Progressive Enhancement Philosophy**: Built-in core features provide complete logging solution, plugins enable enterprise superpowers
- **Revolutionary Async Performance**: Achieve 500K-2M events/second throughput with zero-copy operations and parallel processing
- **Plugin Ecosystem Power**: Enterprise compliance, advanced sinks, and specialized processing available through simple plugin installation
- **Universal Adoption**: Serve individual developers (zero config), startups (basic config), enterprises (plugin ecosystem) with the same core library
- **Native FastAPI Support**: Provide seamless integration with FastAPI for request-aware logging, middleware injection, lifecycle management, and observability
- **Developer-First Design**: Prioritize simplicity and immediate value, with enterprise complexity hidden behind optional plugins
- **Production Excellence**: Built-in features are production-ready; plugins add enterprise capabilities without core complexity

### Background Context

Fapilog v2 demonstrated architectural excellence, but v3 represents a fundamental shift in philosophy: **developer-first simplicity with plugin-based enterprise power**. Instead of a complex enterprise-first approach, v3 provides immediate value with built-in features while enabling unlimited extensibility through plugins.

**Core Philosophy**:

- **Built-in Features**: Complete logging solution (stdout, file, JSON, filtering, correlation) - works immediately after installation
- **Plugin Ecosystem**: Enterprise features (Splunk, compliance, PII redaction, alerting) available as optional plugins
- **FastAPI Integration**: Seamless integration with popular async web frameworks such as FastAPI for request-aware logging
- **Zero Configuration**: Default settings provide production-ready logging without any setup
- **Progressive Enhancement**: Start simple, add power as needed through plugin installation

This approach ensures fapilog competes with simple libraries for ease of use while providing enterprise capabilities that exceed complex enterprise solutions.

### Built-in vs Plugin Feature Strategy

**Core Library (Built-in) - Works immediately after `pip install fapilog`:**

| Category          | Built-in Features                           | Purpose                       |
| ----------------- | ------------------------------------------- | ----------------------------- |
| **Sinks**         | stdout, stderr, file, null                  | Essential output destinations |
| **Processors**    | filter, throttle, format, dedupe            | Core processing capabilities  |
| **Enrichers**     | timestamp, correlation, context, hostname   | Essential context enrichment  |
| **Formatters**    | simple, json, logfmt, minimal               | Standard output formats       |
| **Performance**   | Async pipeline, batching, zero-copy         | Revolutionary throughput      |
| **Configuration** | Zero-config defaults, environment variables | Immediate productivity        |
| **Integrations**  | FastAPI middleware, lifecycle, DI           | Framework compatibility       |

**Important**: The core library is a **pure Python logging library with no REST API or HTTP endpoints**. Web-based features (plugin marketplace discovery) leverage existing GitHub Pages infrastructure rather than requiring API servers.

**Plugin Ecosystem (Optional) - Enhanced capabilities via plugin installation:**

| Category                   | Plugin Examples                                  | Purpose                         |
| -------------------------- | ------------------------------------------------ | ------------------------------- |
| **Enterprise Sinks**       | splunk, elasticsearch, datadog, loki, kafka      | Advanced output destinations    |
| **Enterprise Processing**  | pii-redaction, encryption, compression, alerting | Advanced processing             |
| **Enterprise Enrichment**  | user-context, geo-location, performance-metrics  | Advanced context                |
| **Enterprise Compliance**  | pci-dss, hipaa, sox, gdpr, audit-trails          | Regulatory requirements         |
| **Enterprise Integration** | siem, apm, observability platforms               | Platform integration            |
| **Enterprise Features**    | advanced-compression, sharding, caching          | Performance optimization        |
| **Integrations**           | request-logger, otel-formatter, tracing          | HTTP access logs, OTEL, tracing |

**Progressive Enhancement Examples:**

```python
# Level 1: Zero configuration - works immediately
logger = await AsyncLogger.create()
logger.info("Hello World!")

# Level 2: Basic customization - still built-in features
logger = await AsyncLogger.create(UniversalSettings(
    sinks=["file"], formatter="json", level="DEBUG"
))

# Level 3: Enterprise power - plugin ecosystem
logger = await AsyncLogger.create(UniversalSettings(
    sinks=["file", "splunk-sink", "datadog-sink"],
    processors=["pii-redaction", "encryption", "filter"],
    compliance_standards=["pci-dss", "hipaa"]
))
```

### Built-in Security Model

**Core Library Security (Built-in) - Production-ready security without plugins:**

| Security Layer             | Built-in Protection                              | Purpose                           |
| -------------------------- | ------------------------------------------------ | --------------------------------- |
| **Input Validation**       | Pydantic LogEvent validation, type safety        | Prevent malicious data injection  |
| **File Security**          | Safe path handling, permission validation        | Secure file sink operations       |
| **Memory Safety**          | Zero-copy operations, bounded queues             | Prevent memory exhaustion attacks |
| **Error Isolation**        | Exception containment, graceful degradation      | Prevent cascade failures          |
| **Configuration Security** | Environment variable validation, secure defaults | Secure configuration handling     |
| **Async Safety**           | Proper async context isolation, thread safety    | Prevent race conditions           |

**Security Assumptions for Built-in Features:**

- **No PII by Default**: Built-in processors do not automatically redact PII (use `pii-redaction` plugin for sensitive data)
- **Local File Access**: File sink assumes secure local filesystem permissions
- **No Encryption**: Built-in features store logs in plaintext (use `encryption` plugin for sensitive environments)
- **Basic Validation**: LogEvent validation prevents injection but does not classify data sensitivity
- **No Audit Trails**: Built-in features do not maintain compliance audit logs (use compliance plugins)

**Plugin Security Enhancement:**

```python
# Built-in security - basic validation and safe operations
logger = await AsyncLogger.create()  # Safe defaults, no PII handling

# Plugin security - enterprise data protection
logger = await AsyncLogger.create(UniversalSettings(
    processors=["pii-redaction", "encryption", "audit-trail"],
    compliance_standards=["hipaa", "pci-dss"],
    security_validation=True
))
```

### Change Log

| Date       | Version | Description                                                                    | Author   |
| ---------- | ------- | ------------------------------------------------------------------------------ | -------- |
| 2024-01-XX | 1.0     | Initial PRD creation based on v2 excellence preservation and v3 migration plan | PM Agent |

## Requirements

### Functional

**FR1:** Create AsyncSmartCache with race-condition-free caching in pure async-first context
**FR2:** Build comprehensive metrics collection system with async-first patterns and zero-copy operations
**FR3:** Implement processor performance monitoring with async-first design and real-time health monitoring
**FR4:** Create background cleanup management with enhanced async patterns and zero-copy operations
**FR5:** Build async lock management with centralized async lock management and zero-copy operations
**FR6:** Implement batch management system with revolutionary async batch management and zero-copy operations
**FR7:** Create comprehensive error handling hierarchy with enhanced async patterns and zero-copy error operations
**FR8:** Build component factory pattern with revolutionary async component factory and zero-copy operations
**FR9:** Create container isolation excellence with perfect isolation and zero global state in async context
**FR10** Distribution and packaging policy
**FR11:** Implement built-in core features (stdout, file, JSON, filtering, correlation) for immediate productivity
**FR12:** Create universal plugin ecosystem with developer-friendly and enterprise-ready plugins  
**FR13:** Create plugin marketplace infrastructure for community-driven ecosystem growth
**FR14:** Implement enterprise compliance plugins with PCI-DSS, HIPAA, SOX compliance support (optional)
**FR15:** Create enterprise observability plugins with canonical log formats and correlation (optional)
**FR16:** Implement enterprise platform integration plugins with SIEM, Splunk, ELK support (optional)
**FR17:** Establish future alerting plugins foundation with event categories and severity levels (optional)
**FR18:** Achieve 500K-2M events/second throughput with parallel processing and zero-copy operations
**FR19:** Implement async-first pipeline with parallel enrichment, processing, and sink delivery
**FR20:** Create comprehensive async testing framework with plugin testing utilities
**FR21:** Implement async configuration with plugin configuration validation and marketplace integration
**FR22:** Implement built-in security model with input validation, safe file operations, and memory safety (no PII/encryption - plugins only)
**FR23:** Implement FastAPI middleware for logger injection and correlation ID propagation
**FR24:** Create request/response logger plugin compatible with FastAPI
**FR25:** Provide FastAPI-compatible logger lifecycle hooks
**FR26:** Create optional exception handler integration for FastAPI
**FR27:** Add Depends-based logger DI for FastAPI endpoints
**FR28:** Provide test fixture for verifying FastAPI log behavior
**FR20:** Establish community contribution framework with plugin development guidelines and CI/CD pipeline

### Non Functional

**NFR1:** Performance targets: 500K-2M events/second throughput with zero-copy operations
**NFR2:** Latency requirements: <1ms per event with parallel processing
**NFR3:** Memory efficiency: 80% memory reduction with zero-copy operations
**NFR4:** Type safety: 100% async type coverage with comprehensive async typing
**NFR5:** Testing coverage: 90%+ test coverage with async testing framework
**NFR6:** Documentation quality: Comprehensive async examples and enterprise deployment guides
**NFR7:** Plugin ecosystem: 100+ community plugins by v3.1 with mix of developer and enterprise
**NFR8:** Community adoption: 1000+ individual developers, 50+ contributors by v3.1
**NFR9:** Enterprise compliance: PCI-DSS, HIPAA, SOX compliance validation passing
**NFR10:** Enterprise platform integration: SIEM, Splunk, ELK integration working
**NFR11:** Container isolation: Perfect isolation with zero global state and async patterns
**NFR12:** Plugin performance: Plugin performance within 10% of core performance
**NFR13:** Enterprise compliance performance: Enterprise compliance performance within 20% of core performance
**NFR14:** Linear scalability: Async tasks vs. diminishing returns with threads
**NFR15:** Zero-copy operations: Memory views and efficient serialization throughout pipeline
**NFR16:** FastAPI integration must not introduce blocking calls or global state
**NFR17:** FastAPI logger middleware must initialize within 1ms per request
**NFR18:** Middleware must propagate correlation_id across all async operations

## User Interface Design Goals

### Overall UX Vision

The fapilog v3 library will provide **immediate productivity with zero configuration** while enabling **unlimited enterprise power through plugins**. The core experience should feel effortless for individual developers (`pip install fapilog` → productive immediately), while the plugin ecosystem provides enterprise capabilities that exceed complex enterprise solutions.

**UX Philosophy**:

- **Zero friction onboarding** - Works perfectly out of the box with no setup
- **Progressive enhancement** - Built-in features handle most use cases, plugins add enterprise power
- **Async-first throughout** - All operations use modern async/await patterns for optimal performance
- **Type-safe development** - Comprehensive type annotations for excellent IDE support

### Key Interaction Paradigms

- **Async-first patterns**: All operations use async/await for optimal performance
- **Context managers**: Automatic resource management with async context managers
- **Plugin ecosystem**: Simple plugin interface for custom sinks, processors, and enrichers
- **Configuration-driven**: YAML/JSON configuration with environment variable support
- **Type-safe**: Comprehensive type annotations for better IDE support

### Core Screens and Views

- **Basic logging interface**: Zero-configuration async logger - works immediately after installation
- **Built-in feature configuration**: Simple YAML/JSON configuration for built-in sinks, processors, enrichers
- **Plugin marketplace**: GitHub Pages-based discovery for community and enterprise plugins
- **Progressive enhancement examples**: Clear documentation showing built-in → plugin progression
- **Plugin development interface**: Simple tools and templates for creating custom plugins
- **Enterprise compliance plugins**: Optional plugin-based compliance validation and audit trails (not core library)

### Accessibility: WCAG AA

The library will support WCAG AA accessibility standards for any web-based interfaces (plugin marketplace, documentation, etc.).

### Branding

The library will maintain the existing fapilog branding while emphasizing the async-first, performance-focused, and enterprise-ready nature of v3.

### Target Device and Platforms: Cross-Platform

The library will support all Python platforms including web applications, desktop applications, mobile applications, and server-side deployments.

## Technical Assumptions

### Repository Structure: Monorepo

The project will use a monorepo structure to maintain all related components (core library, plugins, documentation, tools) in a single repository for easier development and versioning.

### Service Architecture: Monolith

The core library will be a monolithic architecture with clear separation of concerns through the plugin system. This provides the best balance of simplicity, performance, and maintainability.

### Testing Requirements: Full Testing Pyramid

The project will implement a comprehensive testing pyramid including unit tests, integration tests, performance tests, and enterprise compliance tests. All tests will be async-first to match the library architecture.

### Additional Technical Assumptions and Requests

- **Async-first throughout**: All components must be designed for async operation from the ground up
- **Zero-copy operations**: Memory efficiency through zero-copy serialization and processing
- **Plugin architecture**: Extensible plugin system for sinks, processors, enrichers, and future alerting
- **Enterprise compliance**: Built-in support for PCI-DSS, HIPAA, SOX compliance
- **Performance optimization**: Parallel processing, connection pooling, and adaptive systems
- **Container isolation**: Perfect isolation between logging instances with zero global state
- **Type safety**: Comprehensive async type annotations throughout the codebase
- **Documentation excellence**: Comprehensive async examples and enterprise deployment guides

## Epic List

**Epic 1: Foundation & Core Architecture** - Create async-first base architecture recreating v2 excellence patterns
**Epic 2: Performance Revolution** - Implement zero-copy operations and parallel processing for revolutionary throughput
**Epic 3: Plugin Ecosystem Foundation** - Create universal plugin architecture and marketplace infrastructure
**Epic 4: Enterprise Compliance & Observability** - Implement enterprise compliance and observability standards
**Epic 5: Developer Experience & Documentation** - Create comprehensive async documentation and developer experience
**Epic 6: Testing & Quality Assurance** - Build comprehensive async testing framework with enterprise compliance testing
**Epic 7: Community & Ecosystem Growth** - Establish community contribution framework and plugin marketplace
**Epic 8: Production Excellence** - Implement production-ready features with monitoring and deployment tools
**Epic 9: FastAPI Integration Layer** - Provide native FastAPI integration tools for enhanced developer productivity and observability

## Epic 1: Foundation & Core Architecture

**Epic Goal**: Create async-first base architecture that recreates and enhances the 9 critical architectural patterns from v2 excellence while achieving revolutionary performance improvements through pure async patterns and zero-copy operations.

**Integration Requirements**: All components must be async-first with perfect container isolation, zero global state, and comprehensive type safety.

### Story 1.1: Async Container Architecture

As a developer,
I want an async-first container with perfect isolation and zero global state,
so that I can create multiple isolated logging instances without any shared state or race conditions.

**Acceptance Criteria:**

1. Container provides perfect isolation between instances with zero global variables
2. Async lifecycle management with proper initialization and cleanup
3. Component dependency injection through async factory methods
4. Thread-safe component management with async locks
5. Memory efficient without global registry or shared state
6. Context manager support for scoped access and automatic cleanup
7. Factory methods for clean instantiation with async configuration
8. Explicit dependency passing (pure DI) for testability and safety

### Story 1.2: Async Component Registry

As a developer,
I want an async component registry that manages plugin discovery and loading,
so that I can dynamically load and manage plugins with proper lifecycle isolation.

**Acceptance Criteria:**

1. Async component registry with plugin discovery and loading
2. Thread-safe component management with lifecycle isolation
3. Plugin versioning and compatibility validation
4. Component lifecycle management with async initialization and cleanup
5. Type-safe component creation with dependency injection
6. Plugin discovery from marketplace and local plugins
7. Component isolation between different container instances
8. Memory leak prevention with proper cleanup mechanisms

### Story 1.3: Async Error Handling Hierarchy

As a developer,
I want comprehensive async error handling with circuit breakers and context preservation,
so that errors are handled gracefully with proper recovery mechanisms and audit trails.

**Acceptance Criteria:**

1. Standardized error types with context preservation in async context
2. Graceful degradation with fallback mechanisms for async operations
3. Retry with exponential backoff for transient failures in async operations
4. Safe execution wrappers for error isolation with async patterns
5. Comprehensive error categorization for different failure types
6. Circuit breaker patterns for preventing cascading failures
7. Plugin error isolation to prevent plugin failures from affecting core system
8. Enterprise compliance error handling with audit trails

### Story 1.4: Async Configuration and Validation

As a developer,
I want async configuration loading with comprehensive validation and plugin marketplace integration,
so that I can configure the library with confidence and easily integrate plugins.

**Acceptance Criteria:**

1. Async configuration loading with environment variable support
2. Pydantic validation excellence with async field validation patterns
3. Plugin configuration validation recreating quality gates
4. Plugin marketplace configuration recreating ecosystem growth
5. Enterprise compliance validation when compliance features are enabled
6. Data handling configuration validation for sensitive data controls
7. Observability configuration validation for enterprise standards
8. Security configuration validation for encryption and access control

## Epic 2: Performance Revolution

**Epic Goal**: Achieve revolutionary performance improvements through zero-copy operations, parallel processing, and async-first optimizations while maintaining architectural excellence and perfect container isolation.

**Integration Requirements**: All performance optimizations must recreate the excellent v2 patterns while achieving revolutionary throughput improvement and latency reduction.

### Story 2.1: Zero-Copy Operations

As a developer,
I want zero-copy serialization and processing throughout the pipeline,
so that I can achieve maximum memory efficiency and performance without data copying overhead.

**Acceptance Criteria:**

1. Zero-copy serialization recreating event structure and metadata
2. Memory-mapped persistence recreating sink patterns for file operations
3. Plugin zero-copy operations recreating plugin performance within 10% of core
4. Plugin performance benchmarks recreating quality standards
5. Memory views for efficient data access without copying
6. Efficient serialization formats (JSON, Protobuf, custom) with zero-copy
7. Batch processing with zero-copy operations for maximum throughput
8. Memory usage monitoring and optimization throughout pipeline

### Story 2.2: Parallel Processing Pipeline

As a developer,
I want parallel processing throughout the async pipeline with controlled concurrency,
so that I can achieve 500K-2M events/second throughput with optimal resource utilization.

**Acceptance Criteria:**

1. Parallel enrichment with async gather for multiple enrichers
2. Parallel processing with async gather for multiple processors
3. Zero-copy serialization and async sink delivery
4. Controlled concurrency to prevent resource exhaustion
5. Adaptive batch sizing recreating batching excellence
6. Adaptive backpressure recreating error handling patterns
7. Plugin parallel processing recreating plugin performance
8. Performance monitoring with real-time metrics collection

### Story 2.3: Async Resource Management

As a developer,
I want async connection pooling and resource cleanup,
so that I can achieve optimal performance for HTTP sinks and other external services.

**Acceptance Criteria:**

1. Async connection pooling recreating HTTP sink patterns
2. Async resource cleanup recreating lifecycle management
3. Plugin resource management recreating plugin lifecycle
4. Plugin resource monitoring recreating observability
5. Connection pooling for database sinks and external APIs
6. Automatic resource cleanup with async context managers
7. Resource monitoring and alerting for resource exhaustion
8. Graceful degradation when resources are limited

### Story 2.4: High-Performance Features

As a developer,
I want lock-free data structures and async work stealing,
so that I can achieve maximum concurrency and performance without blocking operations.

**Acceptance Criteria:**

1. Lock-free data structures recreating thread safety
2. Async work stealing recreating concurrency patterns
3. Plugin high-performance features recreating plugin excellence
4. Plugin performance optimization recreating marketplace quality
5. Non-blocking queue operations with async patterns
6. Efficient memory allocation and deallocation
7. CPU cache-friendly data structures and algorithms
8. Performance profiling and optimization tools

## Epic 3: Plugin Ecosystem Foundation

**Epic Goal**: Create a universal plugin ecosystem that enables community-driven growth while maintaining architectural excellence and providing both developer-friendly and enterprise-ready plugins.

**Integration Requirements**: Plugin architecture must recreate all v2 extensibility patterns while adding ecosystem support and marketplace integration.

### Story 3.1: Universal Plugin Architecture

As a developer,
I want a simple plugin interface for creating custom sinks, processors, and enrichers,
so that I can extend the library's functionality with my own custom logic.

**Acceptance Criteria:**

1. Async plugin interfaces for sinks, processors, enrichers, and future alerting
2. Simple plugin development with clear documentation and examples
3. Plugin discovery and loading system with version compatibility
4. Plugin validation and quality gates for marketplace inclusion
5. Plugin testing framework recreating test excellence
6. Plugin documentation standards recreating clarity
7. Plugin CI/CD pipeline recreating quality gates
8. Plugin marketplace infrastructure for ecosystem growth

### Story 3.2: Plugin Marketplace Infrastructure

As a developer,
I want a plugin marketplace for discovering and installing plugins,
so that I can easily find and use community-developed plugins for common use cases.

**Acceptance Criteria:**

1. Plugin marketplace with search and discovery capabilities
2. Plugin installation and update mechanisms
3. Plugin ratings and reviews for quality assurance
4. Performance benchmarks for plugin comparison
5. Enterprise support for commercial plugins
6. Plugin monetization for community developers
7. Compliance validation for enterprise plugins
8. Security scanning for all plugins

### Story 3.3: Developer Plugin Experience

As a developer,
I want excellent tools and documentation for creating custom plugins,
so that I can contribute to the ecosystem and share my solutions with the community.

**Acceptance Criteria:**

1. Plugin development guidelines recreating code quality
2. Plugin scaffolding tools for rapid development
3. Plugin testing utilities recreating test coverage
4. Plugin documentation generation recreating clarity
5. Plugin examples and tutorials for common use cases
6. Plugin development environment with hot reloading
7. Plugin debugging tools and error reporting
8. Plugin performance profiling and optimization tools

### Story 3.4: Enterprise Plugin Ecosystem

As an enterprise developer,
I want enterprise-ready plugins for compliance and platform integration,
so that I can meet regulatory requirements and integrate with enterprise observability platforms.

**Acceptance Criteria:**

1. Enterprise compliance plugins (PCI-DSS, HIPAA, SOX)
2. Enterprise platform integration plugins (SIEM, Splunk, ELK)
3. Enterprise plugin validation for compliance and security
4. Enterprise plugin testing framework recreating test excellence
5. Enterprise plugin documentation recreating clarity
6. Enterprise plugin support and consulting services
7. Enterprise plugin marketplace with compliance validation
8. Enterprise plugin performance benchmarks and guarantees

## Epic 4: Enterprise Compliance & Observability

**Epic Goal**: Implement comprehensive enterprise compliance and observability standards that enable enterprise adoption while maintaining the library's performance and developer experience excellence.

**Integration Requirements**: Enterprise features must recreate all v2 security and audit patterns while adding comprehensive compliance and observability capabilities.

### Story 4.1: Enterprise Compliance Architecture

As an enterprise developer,
I want built-in compliance schema enforcement and immutable log storage,
so that I can meet regulatory requirements for PCI-DSS, HIPAA, and SOX compliance.

**Acceptance Criteria:**

1. Compliance schema enforcement recreating validation excellence
2. Immutable log storage recreating audit trail patterns
3. Enterprise data handling recreating security patterns
4. Compliance plugin architecture recreating extensibility
5. PCI-DSS compliance validation passing
6. HIPAA compliance validation passing
7. SOX compliance validation passing
8. Data handling controls testable and validated

### Story 4.2: Enterprise Observability Standards

As an enterprise developer,
I want canonical log formats and enterprise correlation,
so that I can integrate with enterprise observability platforms and maintain operational standards.

**Acceptance Criteria:**

1. Canonical log formats recreating format excellence
2. Enterprise correlation recreating trace patterns
3. Enterprise platform integration recreating sink patterns
4. Enterprise testing framework recreating test excellence
5. SIEM platform integration working
6. Splunk platform integration working
7. ELK stack integration working
8. Enterprise correlation functioning across systems

### Story 4.3: Enterprise Data Handling

As an enterprise developer,
I want data minimization and value-level redaction,
so that I can handle sensitive data according to enterprise security requirements.

**Acceptance Criteria:**

1. Data minimization with allow-list schemas
2. Value-level redaction beyond regex-based approaches
3. Audit trails for all data handling operations
4. Testable controls around sensitive data logging
5. Encryption for sensitive data at rest and in transit
6. Access control for log access and modification
7. Retention policies for data lifecycle management
8. Data integrity verification and monitoring

### Story 4.4: Enterprise Platform Integration

As an enterprise developer,
I want seamless integration with enterprise observability platforms,
so that I can leverage existing enterprise infrastructure and tools.

**Acceptance Criteria:**

1. SIEM platform integration with real-time event streaming
2. Splunk platform integration with optimized data formats
3. ELK stack integration with Elasticsearch compatibility
4. Enterprise platform validation and testing
5. Platform-specific optimizations for performance
6. Enterprise platform authentication and authorization
7. Enterprise platform monitoring and alerting
8. Enterprise platform support and documentation

## Epic 5: Developer Experience & Documentation

**Epic Goal**: Create comprehensive developer experience with async documentation, excellent type safety, and intuitive async-first API design that enables immediate productivity.

**Integration Requirements**: Developer experience must recreate v2 usability patterns while adding comprehensive async-first idioms and type safety.

### Story 5.1: Async-First API Design

As a developer,
I want an intuitive async-first API that feels natural and powerful,
so that I can be immediately productive with the library without learning complex patterns.

**Acceptance Criteria:**

1. Simple async logger with immediate productivity
2. Async context managers for automatic resource management
3. FastAPI middleware and lifecycle integration
4. Depends-based logger injection for FastAPI endpoints
5. Plugin development experience recreating ecosystem growth
6. Plugin marketplace UX recreating user experience
7. Comprehensive type safety with 100% async type coverage
8. Intuitive error messages and debugging information
9. Zero configuration for basic use cases
10. Rich documentation with real-world examples

### Story 5.2: Comprehensive Type Safety

As a developer,
I want comprehensive async type annotations throughout the codebase,
so that I can get excellent IDE support and catch errors at development time.

**Acceptance Criteria:**

1. Comprehensive async type annotations recreating type safety
2. Generic async interfaces recreating extensibility
3. Plugin type safety recreating plugin quality
4. Plugin type checking recreating marketplace quality
5. 100% type coverage for all async operations
6. Type-safe plugin interfaces and implementations
7. IDE support for async patterns and plugins
8. Type validation for configuration and plugins

### Story 5.3: Documentation Excellence

As a developer,
I want comprehensive documentation with async examples and enterprise deployment guides,
so that I can quickly understand and implement the library in any environment.

**Acceptance Criteria:**

1. Async-first documentation recreating clarity
2. Async usage examples recreating usability
3. FastAPI-specific guides and examples for middleware setup, lifecycle registration, plugin usage, exception logging, and testing
4. Plugin documentation recreating ecosystem growth
5. Plugin marketplace documentation recreating user experience
6. Enterprise deployment guides for compliance and integration
7. Performance tuning guides for high-throughput applications
8. Plugin development guides for community contributors
9. Troubleshooting guides for common issues and solutions

### Story 5.4: Testing Excellence

As a developer,
I want comprehensive async testing framework with plugin testing utilities,
so that I can ensure code quality and reliability in async environments.

**Acceptance Criteria:**

1. Async testing framework recreating test coverage
2. Async performance testing recreating benchmark excellence
3. Plugin testing excellence recreating plugin quality
4. Plugin testing automation recreating marketplace quality
5. 90%+ test coverage with async testing patterns
6. Performance benchmarks for all components
7. Plugin testing utilities and examples
8. Enterprise compliance testing framework

## Epic 6: Testing & Quality Assurance

**Epic Goal**: Build comprehensive async testing framework with enterprise compliance testing that ensures code quality and reliability while maintaining the library's performance and architectural excellence.

**Integration Requirements**: Testing framework must recreate v2 testing excellence while adding comprehensive async testing and enterprise compliance validation.

### Story 6.1: Async Testing Framework

As a developer,
I want comprehensive async testing utilities and mock components,
so that I can thoroughly test async code and ensure reliability.

**Acceptance Criteria:**

1. Async testing framework recreating v2 testing excellence
2. Async mock sinks recreating test utilities
3. Plugin testing utilities recreating test coverage
4. Async performance testing recreating benchmark excellence
5. Async test runners and utilities
6. Mock components for sinks, processors, and enrichers
7. Performance testing utilities and benchmarks
8. Integration testing framework for end-to-end scenarios

### Story 6.2: Plugin Testing Framework

As a plugin developer,
I want comprehensive testing utilities for developing and validating plugins,
so that I can ensure plugin quality and compatibility with the core library.

**Acceptance Criteria:**

1. Plugin testing framework recreating test excellence
2. Plugin validation tools for quality assurance
3. Plugin performance testing recreating benchmark standards
4. Plugin compatibility testing across versions
5. Plugin security scanning and vulnerability assessment
6. Plugin documentation generation and validation
7. Plugin CI/CD pipeline with automated testing
8. Plugin marketplace quality gates and validation

### Story 6.3: Enterprise Compliance Testing

As an enterprise developer,
I want comprehensive testing for enterprise compliance and platform integration,
so that I can validate compliance requirements and platform compatibility.

**Acceptance Criteria:**

1. Enterprise compliance testing framework recreating test excellence
2. PCI-DSS compliance validation testing
3. HIPAA compliance validation testing
4. SOX compliance validation testing
5. Enterprise platform integration testing
6. Data handling controls testing and validation
7. Security testing for encryption and access control
8. Performance testing for enterprise workloads

### Story 6.4: Performance Testing & Benchmarks

As a developer,
I want comprehensive performance testing and benchmarking tools,
so that I can validate performance improvements and optimize for high-throughput scenarios.

**Acceptance Criteria:**

1. Performance testing framework recreating benchmark excellence
2. Throughput testing for 500K-2M events/second targets
3. Latency testing for <1ms per event requirements
4. Memory usage testing for 80% reduction targets
5. Plugin performance testing within 10% of core performance
6. Enterprise compliance performance testing within 20% of core
7. Scalability testing for linear performance improvements
8. Performance profiling and optimization tools

## Epic 7: Community & Ecosystem Growth

**Epic Goal**: Establish community contribution framework and plugin marketplace that enables ecosystem-driven growth while maintaining code quality and architectural excellence.

**Integration Requirements**: Community framework must recreate v2 code quality standards while enabling ecosystem growth and community-driven innovation.

### Story 7.1: Community Contribution Framework

As a community contributor,
I want clear guidelines and tools for contributing to the ecosystem,
so that I can easily contribute plugins and improvements while maintaining quality standards.

**Acceptance Criteria:**

1. Plugin development guidelines recreating code quality
2. Plugin testing framework recreating test excellence
3. Plugin documentation standards recreating clarity
4. Plugin CI/CD pipeline recreating quality gates
5. Community governance and transparent development
6. Contributor recognition and support programs
7. Cross-platform compatibility and testing
8. Community engagement through GitHub discussions and forums

### Story 7.2: Plugin Marketplace

As a developer,
I want a plugin marketplace for discovering and installing community plugins,
so that I can leverage community solutions and contribute to ecosystem growth.

**Acceptance Criteria:**

1. Plugin marketplace with search and discovery capabilities
2. Plugin installation and update mechanisms
3. Plugin ratings and reviews for quality assurance
4. Performance benchmarks for plugin comparison
5. Enterprise support for commercial plugins
6. Plugin monetization for community developers
7. Compliance validation for enterprise plugins
8. Security scanning for all plugins

### Story 7.3: Ecosystem Growth Metrics

As a project maintainer,
I want comprehensive metrics and monitoring for ecosystem growth,
so that I can track adoption and guide ecosystem development.

**Acceptance Criteria:**

1. Developer adoption metrics (1000+ individual developers by v3.1)
2. Plugin ecosystem metrics (100+ plugins by v3.1)
3. Community contribution metrics (50+ contributors by v3.1)
4. GitHub engagement metrics (1000+ stars by v3.1)
5. Plugin download metrics (10K+ downloads by v3.1)
6. Enterprise adoption metrics (10+ enterprise customers by v3.1)
7. Compliance plugin metrics (10+ compliance plugins by v3.1)
8. Enterprise platform plugin metrics (10+ platform plugins by v3.1)

### Story 7.4: Educational Content & Support

As a developer,
I want comprehensive educational content and community support,
so that I can learn the library quickly and get help when needed.

**Acceptance Criteria:**

1. Tutorials and examples for common use cases
2. Best practices guides for async-first development
3. Performance optimization guides for high-throughput applications
4. Enterprise deployment guides for compliance and integration
5. Plugin development tutorials and examples
6. Community support through GitHub discussions and Discord
7. Conference and meetup presence with developer-focused demos
8. Educational content with real-world examples and best practices

## Epic 8: Production Excellence

**Epic Goal**: Implement production-ready features with comprehensive monitoring, deployment tools, and enterprise-grade reliability while maintaining the library's performance and developer experience excellence.

**Integration Requirements**: Production features must recreate v2 reliability patterns while adding comprehensive monitoring and deployment capabilities.

### Story 8.1: Production Monitoring & Observability

As a production engineer,
I want comprehensive monitoring and observability for production deployments,
so that I can ensure reliability and performance in production environments.

**Acceptance Criteria:**

1. Async metrics collection recreating monitoring patterns
2. Async tracing support recreating correlation excellence
3. Plugin observability recreating plugin monitoring
4. Plugin marketplace observability recreating enterprise compliance
5. Real-time performance monitoring and alerting
6. Health checks and status endpoints
7. Log aggregation and analysis tools
8. Performance dashboards and reporting

### Story 8.2: Production Deployment Tools

As a production engineer,
I want comprehensive deployment tools and automation,
so that I can deploy and manage the library in production environments.

**Acceptance Criteria:**

1. Async deployment tools recreating deployment patterns
2. Async monitoring dashboards recreating monitoring excellence
3. Plugin production readiness recreating plugin enterprise
4. Plugin marketplace production recreating enterprise adoption
5. Container deployment support (Docker, Kubernetes)
6. Infrastructure as Code (IaC) templates and examples
7. CI/CD pipeline integration and automation
8. Rollback and disaster recovery procedures

### Story 8.3: Enterprise Production Support

As an enterprise production engineer,
I want enterprise-grade production support and reliability,
so that I can deploy the library in enterprise environments with confidence.

**Acceptance Criteria:**

1. Enterprise support and consulting services
2. Enterprise deployment guides and best practices
3. Enterprise compliance validation in production
4. Enterprise platform integration in production
5. Enterprise security and access control
6. Enterprise monitoring and alerting
7. Enterprise backup and disaster recovery
8. Enterprise performance optimization and tuning

### Story 8.4: Production Quality Assurance

As a quality assurance engineer,
I want comprehensive quality assurance tools and processes,
so that I can ensure production readiness and reliability.

**Acceptance Criteria:**

1. Automated testing in production-like environments
2. Performance regression testing and monitoring
3. Security vulnerability scanning and assessment
4. Compliance validation in production environments
5. Load testing and stress testing tools
6. Chaos engineering and resilience testing
7. Quality gates and release validation
8. Production incident response and resolution

## Epic 9: FastAPI Integration Layer

**Epic Goal**: Provide native FastAPI integration tools that enhance developer productivity, request-level observability, and testability, while preserving Fapilog's async-first, plugin-driven architecture.

**Integration Requirements**: All FastAPI integrations must follow existing Fapilog architecture (plugin-based, zero global state, container isolation) and must be optional and non-intrusive to core library behavior.

### Story 9.1: FastAPI Middleware for Request Context Logging

As a FastAPI developer,
I want middleware that injects a Fapilog logger and correlation ID per request,
so that I can trace logs easily without boilerplate.

**Acceptance Criteria:**

1. Middleware automatically creates isolated logger instance per request
2. Correlation ID generation and propagation across all async operations
3. Logger injection into request context for endpoint access
4. Zero global state - each request gets independent logger instance
5. Optional configuration for correlation ID header names
6. Async context preservation across middleware chain
7. Performance impact <1ms per request initialization
8. Compatible with FastAPI dependency injection system

### Story 9.2: Request/Response Logging Plugin

As a FastAPI developer,
I want a plugin that logs HTTP requests/responses with optional body redaction,
so that I can observe access patterns and debug issues in production.

**Acceptance Criteria:**

1. Automatic request/response logging with configurable detail levels
2. Optional request/response body logging with size limits
3. PII redaction capabilities for sensitive request data
4. Configurable exclusion patterns for health checks and static files
5. Structured logging format compatible with Fapilog pipeline
6. Performance optimization for high-throughput APIs
7. Integration with existing Fapilog processors and sinks
8. Support for custom request/response enrichment

### Story 9.3: FastAPI Lifecycle Hook Registration

As a FastAPI developer,
I want a helper to auto-register logger lifecycle with startup and shutdown,
so that I can cleanly manage the logger within my app lifecycle.

**Acceptance Criteria:**

1. Automatic logger initialization during FastAPI startup
2. Graceful logger shutdown during FastAPI shutdown
3. Container isolation - multiple FastAPI apps can coexist
4. Configuration loading from environment variables or files
5. Plugin discovery and loading during startup
6. Health check endpoints for logger status
7. Zero global state - logger bound to FastAPI app instance
8. Support for multiple logger configurations per app

### Story 9.4: FastAPI-Aware Exception Handling

As a FastAPI developer,
I want to log unhandled exceptions and validation errors using Fapilog,
so that I can catch production issues with full context.

**Acceptance Criteria:**

1. Automatic exception logging with full context preservation
2. FastAPI validation error logging with request details
3. Correlation ID preservation in exception logs
4. Structured exception data compatible with Fapilog processors
5. Optional exception response formatting
6. Integration with FastAPI exception handlers
7. Support for custom exception enrichment
8. Performance isolation - exceptions don't impact healthy requests

### Story 9.5: FastAPI Logger DI via Depends

As a FastAPI developer,
I want to inject a logger into endpoints using Depends,
so that I can maintain clean and testable route functions.

**Acceptance Criteria:**

1. Depends-based logger injection for FastAPI endpoints
2. Request-scoped logger with automatic correlation ID
3. Type-safe dependency injection with proper annotations
4. Compatible with FastAPI testing framework
5. Support for custom logger configuration per endpoint
6. Thread-safe and async-safe dependency resolution
7. Optional caching for performance optimization
8. Integration with existing FastAPI security dependencies

### Story 9.6: FastAPI Test Fixtures for Logger Verification

As a developer,
I want to use a test fixture that captures Fapilog events in FastAPI tests,
so that I can assert logging behavior reliably.

**Acceptance Criteria:**

1. pytest fixtures for capturing Fapilog events in tests
2. Integration with FastAPI TestClient for end-to-end testing
3. Mock sinks for verifying log output without side effects
4. Assertion helpers for common logging verification patterns
5. Support for async test functions
6. Correlation ID verification in test scenarios
7. Performance testing utilities for logging overhead
8. Documentation and examples for testing best practices

## Checklist Results Report

_This section will be populated after running the PM checklist validation._

## Next Steps

### UX Expert Prompt

Create comprehensive UX/UI design for fapilog v3 that emphasizes the async-first, performance-focused, and enterprise-ready nature of the library. Focus on developer experience, plugin marketplace interface, and enterprise compliance dashboard design.

### Architect Prompt

Design the async-first architecture for fapilog v3 that recreates the 9 critical architectural patterns from v2 excellence while achieving revolutionary performance improvements. Focus on zero-copy operations, parallel processing, plugin ecosystem, and enterprise compliance integration.
