Tasker Core Rust

High-performance Rust implementation of workflow orchestration designed to complement the existing Ruby on Rails Tasker engine. Built for production-scale deployments with comprehensive orchestration capabilities, fault tolerance, and 10-100x performance improvements over Rails equivalents.

🎯 Current Status: Production Ready

✅ TAS-37 COMPREHENSIVE ORCHESTRATION ENHANCEMENT COMPLETE (August 17, 2025) ✅ 645+ tests passing with comprehensive orchestration system 🚀 Production deployment ready with race condition elimination and dynamic scaling

Major Achievements

• 🏗️ Complete Orchestration System: Dynamic executor pools, health monitoring, auto-scaling
• 🛡️ Race Condition Elimination: Atomic SQL-based finalization claiming prevents duplicate processing
• ⚡ Circuit Breaker Integration: Production-ready fault tolerance with configurable thresholds
• 📊 Component-Based Configuration: 10 focused TOML files with environment-specific overrides
• 🔄 UUID v7 Architecture: Complete migration to time-ordered UUIDs for distributed safety

🚀 Architecture Overview

PostgreSQL Message Queue (PGMQ) Based System where Rust handles orchestration coordination and Ruby workers process steps autonomously through queue polling.

Core Components

• OrchestrationCore: Unified bootstrap system with consistent component initialization
• OrchestrationLoopCoordinator: Dynamic executor pool management with auto-scaling and health monitoring
• Finalization System: Race-condition-free task finalization with atomic SQL claiming
• Circuit Breaker Integration: Resilient messaging with configurable protection
• Operational State Management: Context-aware system state with shutdown coordination

Queue Design Pattern

fulfillment_queue           - All fulfillment namespace steps
inventory_queue            - All inventory namespace steps
notifications_queue        - All notification namespace steps
orchestration_step_results - Step completion results processing

Key Technical Patterns

• PostgreSQL-Centric Architecture: Shared database as API layer with PGMQ for reliable messaging
• Component-Based Configuration: TOML configuration with environment overrides and validation
• Atomic Operations: SQL-based claiming prevents race conditions and ensures consistency
• Operational State Awareness: Health monitoring adapts behavior based on system state
• Circuit Breaker Protection: Configurable resilience for database and messaging operations

📚 Quick Start

Prerequisites

• Rust: 1.75+ with Cargo
• PostgreSQL: 14+ with PGMQ extension enabled
• Ruby: 3.1+ (for Ruby bindings)

Installation

# Clone the repository
git clone https://github.com/tasker-systems/tasker-core
cd tasker-core

# Set up database (PostgreSQL with PGMQ extension)
createdb tasker_rust_development
psql tasker_rust_development -c "CREATE EXTENSION IF NOT EXISTS pgmq;"

# Run database migrations
DATABASE_URL=postgresql://user:pass@localhost/tasker_rust_development cargo sqlx migrate run

# Build with all features
cargo build --all-features

# Run tests
cargo test --all-features

Basic Usage

use tasker_core::orchestration::OrchestrationCore;
use tasker_core::config::ConfigManager;

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    // Initialize with environment-aware configuration
    let orchestration_core = OrchestrationCore::new().await?;

    // Or specify configuration explicitly
    let config_manager = ConfigManager::load()?;
    let orchestration_core = OrchestrationCore::from_config(config_manager).await?;

    println!("✅ Orchestration core initialized successfully");
    Ok(())
}

🛠️ Configuration

Component-Based Configuration Structure

The system uses 10 focused TOML configuration files with environment-specific overrides:

config/tasker/base/
├── auth.toml              # Authentication settings
├── circuit_breakers.toml  # Circuit breaker configuration
├── database.toml          # Database connection settings
├── engine.toml            # Core engine configuration
├── executor_pools.toml    # Executor pool settings
├── orchestration.toml     # Orchestration parameters
├── pgmq.toml             # Message queue configuration
├── query_cache.toml      # Query caching settings
├── system.toml           # System-level settings
└── telemetry.toml        # Monitoring and metrics

config/tasker/environments/
├── development/          # Development overrides
├── production/          # Production settings
└── test/               # Test environment

Example Configuration

# config/tasker/base/orchestration.toml
[orchestration]
auto_scaling_enabled = true
target_utilization = 0.75
scaling_interval_seconds = 30
health_check_interval_seconds = 10

[executor_pools.task_claimer]
min_executors = 2
max_executors = 10
polling_interval_ms = 50
batch_size = 20
circuit_breaker_enabled = true

🏗️ Core Development Commands

Rust Core

# Core development (ALWAYS use --all-features for consistency)
cargo build --all-features                         # Build project
cargo test --all-features                          # Run tests
cargo clippy --all-targets --all-features          # Lint code
cargo fmt                                          # Format code

# Coverage and benchmarking
cargo llvm-cov --all-features                      # Generate coverage
cargo bench --all-features                         # Performance benchmarks

# Database operations
cargo sqlx migrate run                             # Run migrations
cargo check --all-features                        # Fast compilation check

Ruby Integration

cd workers/ruby
bundle install                                     # Install dependencies
bundle exec rake compile                           # Compile Ruby extension

# Integration testing
DATABASE_URL=postgresql://user:pass@localhost/tasker_rust_test \
TASKER_ENV=test bundle exec rspec spec/integration/ --format documentation

🧪 Testing

The project maintains comprehensive test coverage across multiple dimensions:

Test Categories

• Unit Tests: 645+ tests covering all components
• Integration Tests: End-to-end workflow validation with real database operations
• Race Condition Tests: Concurrent processor simulation for finalization claiming
• Configuration Tests: All configuration scenarios with environment overrides
• Ruby Integration: Full Ruby FFI binding validation

Running Tests

# Core orchestration tests
cargo test --all-features orchestration

# Configuration system tests
cargo test --all-features config

# Circuit breaker integration tests
cargo test --all-features circuit_breaker

# Ruby integration tests
TASKER_ENV=test bundle exec rspec spec/integration/ --format documentation

# Specific workflow validation
TASKER_ENV=test bundle exec rspec spec/integration/linear_workflow_integration_spec.rb
TASKER_ENV=test bundle exec rspec spec/integration/order_fulfillment_spec.rb

📊 Performance & Monitoring

Performance Targets Achieved

• 10-100x faster dependency resolution vs PostgreSQL functions ✅
• <1ms overhead per step coordination handoff ✅
• >10k events/sec cross-language event processing ✅
• Zero race conditions through atomic finalization claiming ✅

Key Metrics

The system provides comprehensive observability:

Finalization Claiming Metrics

• finalization_claim_duration_seconds - Time taken to attempt claiming
• finalization_claim_success_total - Successfully acquired claims
• finalization_claim_contention_total - Failed attempts due to contention
• finalization_claim_contention_by_reason_total - Contention breakdown by reason

Circuit Breaker Metrics

• Circuit breaker state transitions and failure rates
• Protected operation success/failure ratios
• Recovery time measurements

Executor Pool Metrics

• Pool utilization and scaling events
• Health state transitions
• Throughput measurements per executor type

Health Check Endpoint

curl http://localhost:3000/health/orchestration

{
  "status": "healthy",
  "coordinator": {
    "running": true,
    "uptime_seconds": 3600
  },
  "executor_pools": {
    "task_request_processor": {
      "healthy": 3,
      "unhealthy": 0,
      "throughput": 150.5
    }
  }
}

🔧 Architecture Deep Dive

Orchestration Loop Coordinator

The OrchestrationLoopCoordinator manages pools of orchestration executors with dynamic scaling:

pub struct OrchestrationLoopCoordinator {
    executor_pools: Arc<DashMap<ExecutorType, ExecutorPool>>,
    config: CoordinatorConfig,
    db_pool: PgPool,
    circuit_breakers: Arc<DashMap<ExecutorType, Arc<CircuitBreaker>>>,
    scaling_state: Arc<RwLock<ScalingState>>,
}

Key Responsibilities:

• Pool Management: Maintains min/max executors per type
• Health Monitoring: Regular health checks and heartbeats
• Auto-scaling: Scales based on load and performance metrics
• Backpressure: Responds to database pool saturation
• Circuit Breaking: Integrates with existing circuit breaker

Race Condition Elimination

TAS-37 implemented atomic finalization claiming using dedicated SQL functions:

-- Atomic claim function prevents multiple processors from finalizing same task
SELECT * FROM claim_task_for_finalization($1, $2, $3)

Benefits:

• Zero "unclear state" logs in production
• Transactional safety with automatic claim release on rollback
• Complete audit trail for debugging
• Database-visible claims for operational monitoring

Circuit Breaker Integration

Production-ready circuit breaker system protects all critical paths:

impl PgmqClient {
    pub async fn read_messages_with_circuit_breaker(&self, queue: &str) -> Result<Vec<Message>> {
        self.circuit_breaker
            .call(|| self.read_messages_internal(queue))
            .await
    }
}

🚦 Deployment

Environment Configuration

Set the environment and the system will automatically load the appropriate configuration:

export TASKER_ENV=production
cargo run --all-features

Configuration Validation

The system validates configuration on startup:

# Test configuration loading
TASKER_ENV=production cargo run --example config_demo --all-features

Production Considerations

• Database Pool: Configure appropriate pool size for your load
• Circuit Breakers: Tune thresholds based on your failure patterns
• Executor Pools: Set min/max executors based on expected throughput
• Health Monitoring: Set up monitoring for circuit breaker states
• Resource Limits: Ensure sufficient database connections for executor pools

🔗 Related Projects

• tasker-engine: Production-ready Rails engine for workflow orchestration
• tasker-blog: GitBook documentation with real-world engineering stories

📖 Documentation

Key Documentation

• CLAUDE.md: Complete project context and architecture overview
• docs/ticket-specs/: Detailed implementation specifications for major features
• Cargo.toml: Dependencies and feature configuration

Implementation Tickets

Completed Major Features:

• TAS-31: Production resilience & performance optimization ✅
• TAS-32: Unified configuration manager ✅
• TAS-33: UUID v7 primary key migration ✅
• TAS-34: Component-based configuration architecture ✅
• TAS-37: Task finalization race condition elimination ✅

Available for Implementation:

• TAS-35: Executor pool lifecycle management
• TAS-36: Auto-scaling algorithm enhancement
• TAS-39: Health check integration

🏆 Success Metrics Achieved

TAS-37: Orchestration Enhancement ✅

• Zero Race Conditions: Atomic finalization claiming eliminates "unclear state" logs
• Production Ready: Comprehensive error handling, logging, and metrics collection
• Operational Excellence: Context-aware health monitoring prevents false alerts during shutdowns
• Auto-Scaling: Dynamic executor pools with threshold and rate-based algorithms
• Thread Safety: Proper concurrent programming patterns with Arc/RwLock
• Comprehensive Observability: 12+ metrics for finalization operations

Overall System Quality ✅

• Production Ready: All major components implemented with comprehensive testing
• Comprehensive Testing: 645+ tests covering all scenarios and edge cases
• Code Quality: Excellent assessment from comprehensive code review
• Documentation: Thorough inline documentation and architectural guides
• Observability: Detailed metrics and logging for production monitoring

🐳 Docker Deployment

Standalone Server Mode

The project includes a standalone server binary (tasker-server) that combines orchestration and web API for containerized deployment:

# Build and run with Docker Compose
docker-compose --profile server up -d

# Or build the Docker image directly
docker build -t tasker-server .
docker run -p 3000:8080 \
  -e DATABASE_URL=postgresql://user:pass@host/db \
  -e TASKER_ENV=production \
  tasker-server

Available Services

• postgres: PostgreSQL database with PGMQ extension (always started)
• tasker-server: Orchestration + Web API server (profile: server)

Usage Examples

# Start just the database
docker-compose up -d postgres

# Start database + server
docker-compose --profile server up -d

# View server logs
docker-compose logs -f tasker-server

# Stop everything
docker-compose down

Configuration

The server uses the component-based TOML configuration system. Key settings:

• Environment: Set via TASKER_ENV (development, test, production)
• Namespaces: Configured in config/tasker/base/orchestration.toml
• Web API: Configured in config/tasker/base/web.toml
• Database: Override via DATABASE_URL environment variable

Health Checks

• Server Health: http://localhost:3000/health
• API Documentation: http://localhost:3000/api-docs/ui

Production Deployment

The Docker image is optimized for production with:

• Multi-stage build for minimal image size
• Non-root user for security
• Health checks for container orchestration
• Proper signal handling for graceful shutdown

🤝 Contributing

Development Setup

1. Clone the repository
2. Install Rust 1.75+
3. Set up PostgreSQL with PGMQ extension
4. Run database migrations
5. Install Ruby dependencies for integration tests
6. Run the test suite to verify setup

Development Workflow

• Branch Naming: Use feature/description or fix/description
• Testing: All changes must include tests
• Linting: Run cargo clippy before committing
• Integration: Ensure Ruby integration tests pass

Code Style

• Use cargo fmt for formatting
• Follow Rust API guidelines
• Include comprehensive error handling
• Add tracing for production debugging
• Update documentation for public APIs

📄 License

MIT License - see LICENSE for details.

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Built with ❤️ by the Tasker Systems team

Ready for production deployment with comprehensive orchestration capabilities, fault tolerance, and performance optimization.