Core Build: Full Orchestration System

Build a complete orchestration system with parallel execution, monitoring, and control in 50 minutes

Part 1: Orchestrator Design (15 minutes)

Task Decomposition Strategy

The orchestrator must intelligently split complex tasks into agent-specific subtasks.

Decomposition Patterns:

By Task Type:

  • Analysis tasks → Research agents
  • Writing tasks → Content agents
  • Data tasks → Processing agents

By Data Scope:

  • Split large datasets into chunks
  • Assign chunks to parallel agents
  • Merge results at the end

By Priority:

  • Critical path tasks execute first
  • Non-blocking tasks run in parallel
  • Dependencies determine order

Example decomposition logic:

tasks = [Task(type="research", data=chunk, priority=1)
         for chunk in split_data(input_data)]
agent_map = {"research": ResearchAgent, "write": WriterAgent}

Agent Registry and Discovery

The orchestrator maintains a registry of available agents and their capabilities.

Registry Structure:

Agent Metadata:

  • Agent ID and type
  • Capabilities (tasks it can handle)
  • Current status (idle, busy, failed)
  • Resource requirements

Discovery Process:

  • Register agents on startup
  • Query capabilities for task matching
  • Load balance across available agents
  • Handle agent failures gracefully

Example registry implementation:

registry = {agent.id: {"type": agent.type, "status": "idle"}
            for agent in available_agents}

Task Queue Management

Efficient task queuing ensures optimal resource utilization.

Queue Mechanics:

Priority Queue:

  • High priority tasks execute first
  • FIFO within same priority level
  • Dynamic priority adjustment

Task States:

  • Pending: In queue waiting
  • Running: Currently executing
  • Completed: Finished successfully
  • Failed: Encountered error

Queue Operations:

queue.put((priority, timestamp, task))
task = await queue.get()  # Blocks until task available
queue.task_done()

Result Aggregation Patterns

Collecting and synthesizing results from multiple agents requires careful design.

Aggregation Strategies:

Merge Pattern:

  • Combine similar outputs
  • Remove duplicates
  • Sort by relevance

Reduce Pattern:

  • Fold results into single output
  • Apply transformations
  • Maintain consistency

Example aggregation:

final = reduce(lambda a,b: merge(a,b), results)
return {"status": "complete", "data": final}

Design Principle: Always design for partial failures. Agents may fail individually without bringing down the entire workflow.

Part 2: Parallel Execution (15 minutes)

Concurrent Agent Execution with Asyncio

Python's asyncio enables efficient parallel execution for I/O-bound agent tasks.

Asyncio Fundamentals:

Event Loop:

  • Single thread manages multiple coroutines
  • Switches between tasks at await points
  • Ideal for network calls and API requests

Coroutines:

  • Functions defined with async def
  • Use await to yield control
  • Run concurrently, not in parallel

Example concurrent execution:

results = await asyncio.gather(
    agent1.process(task1), agent2.process(task2))

Gathers results from multiple agents running concurrently.

Thread Pool vs Async/Await Patterns

Choose the right concurrency model based on task characteristics.

Async/Await (I/O-bound):

  • Best for: API calls, file I/O, database queries
  • Single thread, event-driven
  • Low overhead, high throughput
  • Example: Web scraping, data fetching

Thread Pool (CPU-bound):

  • Best for: Data processing, calculations, transformations
  • True parallelism on multi-core CPUs
  • Higher overhead, limited by GIL
  • Example: Image processing, statistical analysis

Hybrid Approach:

loop = asyncio.get_event_loop()
cpu_result = await loop.run_in_executor(pool, cpu_task)

Run CPU-bound tasks in thread pool while maintaining async interface.

Synchronization Points

Coordinate agent execution at critical workflow stages.

Synchronization Patterns:

Barrier Pattern:

  • All agents must reach checkpoint
  • Wait for slowest agent
  • Proceed together after sync

Semaphore Pattern:

  • Limit concurrent resource access
  • Control rate of execution
  • Prevent resource exhaustion

Lock Pattern:

  • Ensure exclusive access to shared state
  • Prevent race conditions
  • Use sparingly to avoid deadlocks

Example synchronization:

async with semaphore:  # Limit to N concurrent agents
    result = await agent.process(task)

Error Handling in Parallel Workflows

Robust error handling prevents cascade failures in parallel execution.

Error Strategies:

Retry with Backoff:

  • Retry failed tasks automatically
  • Exponential backoff prevents overload
  • Maximum retry limit

Fallback Agents:

  • Switch to backup agent on failure
  • Maintain workflow continuity
  • Log original failure

Partial Success:

  • Continue with available results
  • Mark failed tasks explicitly
  • Allow graceful degradation

Example error handling:

try:
    result = await agent.process(task)
except AgentError:
    result = await fallback_agent.process(task)

Performance Tip: Use async/await for I/O-bound tasks (API calls, file operations). Use thread pools for CPU-bound tasks (data processing, calculations). Mixing the two requires run_in_executor().

Part 3: Workflow Control (10 minutes)

Start/Stop/Restart Workflow

Implement lifecycle management for orchestrated workflows.

Workflow States:

Start:

  • Initialize agent registry
  • Load task queue
  • Begin execution loop
  • Return workflow ID

Stop:

  • Cancel pending tasks
  • Wait for running tasks to complete
  • Save state for resume
  • Release resources

Restart:

  • Load saved state
  • Re-register agents
  • Resume from checkpoint
  • Handle failed tasks

Example workflow control:

workflow.start()  # Begin execution
workflow.stop()   # Graceful shutdown
workflow.restart(checkpoint_id)  # Resume

Pause and Resume

Support workflow suspension for maintenance or resource constraints.

Pause Mechanism:

Checkpoint Creation:

  • Save current task queue
  • Record agent states
  • Persist partial results
  • Generate resume token

Resume Process:

  • Load checkpoint data
  • Restore agent states
  • Continue from last task
  • Validate consistency

Use Cases:

  • System maintenance windows
  • Resource quota management
  • User-initiated suspension
  • Error investigation

Example pause/resume:

checkpoint = workflow.pause()
# Later...
workflow.resume(checkpoint)

Cancel Individual Tasks

Allow granular task cancellation without disrupting the entire workflow.

Cancellation Process:

Task Selection:

  • Cancel by task ID
  • Cancel by agent ID
  • Cancel by priority range
  • Cancel by task type

Cleanup:

  • Stop task execution immediately
  • Release allocated resources
  • Remove from queue
  • Update status to cancelled

Dependencies:

  • Check for dependent tasks
  • Cancel dependents or reassign
  • Maintain workflow integrity

Example cancellation:

workflow.cancel_task(task_id)
# Returns: {"status": "cancelled", "dependents": []}

Monitor Progress

Real-time monitoring provides visibility into workflow execution.

Monitoring Metrics:

Task Metrics:

  • Total tasks: pending, running, completed, failed
  • Average execution time
  • Throughput (tasks per second)
  • Error rate

Agent Metrics:

  • Active agents count
  • Idle vs busy distribution
  • Agent failure rate
  • Resource utilization

Workflow Metrics:

  • Overall progress percentage
  • Estimated completion time
  • Bottleneck identification
  • Critical path status

Example progress query:

status = workflow.get_status()
# {"progress": 65, "active": 8, "completed": 130}

Part 4: Result Aggregation (10 minutes)

Collect Results from Multiple Agents

Gather outputs from parallel agents efficiently.

Collection Strategies:

Streaming Collection:

  • Collect results as they arrive
  • Process incrementally
  • Reduce memory footprint
  • Enable early termination

Batch Collection:

  • Wait for all agents to complete
  • Collect results together
  • Simplify synchronization
  • Higher latency

Hybrid Collection:

  • Process available results immediately
  • Wait for critical results
  • Balance throughput and latency

Example result collection:

async for result in workflow.results_stream():
    process_result(result)  # Handle as available

Handle Partial Failures

Gracefully manage scenarios where some agents fail.

Failure Handling:

Mark Failed Tasks:

  • Tag results with success/failure status
  • Include error messages
  • Preserve partial outputs
  • Enable retry decision

Threshold-Based Decisions:

  • Proceed if N% of tasks succeed
  • Fail workflow if critical tasks fail
  • Retry failed tasks automatically
  • Escalate to human if threshold not met

Fallback Values:

  • Use default values for failed tasks
  • Interpolate from successful results
  • Mark missing data explicitly

Example partial failure handling:

if success_rate > 0.8:
    return merge_results(successful_results)
else:
    retry_failed_tasks()

Synthesize Final Output

Combine individual agent outputs into coherent final result.

Synthesis Strategies:

Merge Strategy:

  • Combine similar outputs (e.g., concatenate text)
  • Remove duplicates
  • Sort by relevance or timestamp

Reduce Strategy:

  • Apply reduction function across results
  • Example: sum, average, max, min
  • Preserve metadata

Transform Strategy:

  • Convert results to target format
  • Apply post-processing rules
  • Add computed fields

Example synthesis:

final = {"summary": merge([r.text for r in results]),
         "confidence": avg([r.score for r in results])}

Return Structured Results

Provide well-formatted output with metadata.

Result Structure:

Core Fields:

  • status: "success" | "partial" | "failed"
  • data: Aggregated output
  • metadata: Execution statistics
  • errors: List of failures if any

Metadata Fields:

  • Execution time
  • Number of agents used
  • Success rate
  • Resource consumption

Error Information:

  • Failed task IDs
  • Error messages
  • Suggested remediation
  • Retry recommendations

Example structured result:

return {"status": "success", "data": final_output,
        "metadata": {"time": elapsed, "agents": 12}}

Critical Pattern: Always handle partial failures in parallel workflows. Design aggregation logic to work with incomplete result sets. Never assume all agents will succeed.

Final Verification

System Completeness Check:

Orchestrator Capabilities:

  • Manages 4+ agents simultaneously
  • Decomposes tasks intelligently
  • Executes agents in parallel
  • Handles individual agent failures

Execution Verification:

  • Parallel execution completes faster than sequential
  • Results aggregated correctly
  • Partial failures handled gracefully
  • Control panel responds to commands

Testing Commands:

# Test parallel execution
orchestrator.run(task_count=10, parallel=True)

# Verify aggregation
results = orchestrator.get_results()
assert results["status"] == "success"

# Test failure handling
orchestrator.simulate_agent_failure(agent_id=3)
assert orchestrator.recovery_status() == "recovered"

Expected Output:

  • All 10 tasks complete
  • Execution time < 50% of sequential
  • Failed agent replaced with fallback
  • Final results valid and complete

Success Criteria:

  • Orchestrator launches successfully
  • Parallel execution 2x faster than sequential
  • Aggregation produces valid output
  • Control panel functional (start/stop/pause)

Next Steps