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Advanced Configuration

Master advanced FLOPY-NET configuration techniques for complex federated learning experiments, including custom algorithms, advanced networking, and sophisticated policy management.

Overview

This tutorial covers advanced configuration topics:

  • Custom FL Algorithms: Implement and configure custom federated learning algorithms
  • Advanced Network Configuration: Complex topology and traffic shaping
  • Sophisticated Policy Management: Multi-layer policies and dynamic rule systems
  • Performance Optimization: Resource allocation and system tuning
  • Integration Patterns: Advanced service integration and data flow

Custom Federated Learning Algorithms

Implementing FedProx

Create a custom FedProx implementation with configurable proximal term:

# src/fl/algorithms/fedprox.py
from src.fl.algorithms.base_algorithm import BaseFLAlgorithm
import torch
import torch.nn.functional as F
from typing import Dict, List, Any

class FedProxAlgorithm(BaseFLAlgorithm):
"""
FedProx algorithm implementation with proximal term for handling
heterogeneous client capabilities and data distributions.
"""

def __init__(self, config: Dict[str, Any]):
super().__init__(config)
self.algorithm_name = "FedProx"
self.mu = config.get("mu", 0.1) # Proximal term coefficient
self.adaptive_mu = config.get("adaptive_mu", False)
self.mu_adaptation_strategy = config.get("mu_adaptation_strategy", "divergence_based")

def local_training(self, client_id: str, local_model: torch.nn.Module,
global_model: torch.nn.Module, train_loader: torch.utils.data.DataLoader,
local_epochs: int, learning_rate: float) -> Dict[str, Any]:
"""
Perform local training with proximal term.
"""
local_model.train()
optimizer = torch.optim.SGD(local_model.parameters(), lr=learning_rate)

# Store global model parameters for proximal term
global_params = {name: param.clone().detach()
for name, param in global_model.named_parameters()}

training_loss = 0.0
proximal_loss = 0.0

for epoch in range(local_epochs):
epoch_loss = 0.0
epoch_proximal = 0.0

for batch_idx, (data, target) in enumerate(train_loader):
optimizer.zero_grad()

# Forward pass
output = local_model(data)
classification_loss = F.cross_entropy(output, target)

# Calculate proximal term
prox_term = 0.0
for name, param in local_model.named_parameters():
if name in global_params:
prox_term += torch.norm(param - global_params[name])**2

# Total loss with proximal regularization
total_loss = classification_loss + (self.mu / 2) * prox_term

# Backward pass
total_loss.backward()
optimizer.step()

# Track losses
epoch_loss += classification_loss.item()
epoch_proximal += prox_term.item()

training_loss += epoch_loss / len(train_loader)
proximal_loss += epoch_proximal / len(train_loader)

# Adapt mu based on training dynamics
if self.adaptive_mu:
self.mu = self.adapt_mu(client_id, training_loss, proximal_loss)

return {
"client_id": client_id,
"training_loss": training_loss / local_epochs,
"proximal_loss": proximal_loss / local_epochs,
"mu_used": self.mu,
"model_parameters": {name: param.data.clone()
for name, param in local_model.named_parameters()},
"num_samples": len(train_loader.dataset)
}

def adapt_mu(self, client_id: str, training_loss: float, proximal_loss: float) -> float:
"""
Adaptively adjust the proximal term coefficient.
"""
if self.mu_adaptation_strategy == "divergence_based":
# Increase mu if model is diverging too much from global model
divergence_ratio = proximal_loss / (training_loss + 1e-8)

if divergence_ratio > 1.0:
new_mu = min(self.mu * 1.1, 1.0) # Increase mu, cap at 1.0
elif divergence_ratio < 0.1:
new_mu = max(self.mu * 0.9, 0.01) # Decrease mu, floor at 0.01
else:
new_mu = self.mu

elif self.mu_adaptation_strategy == "loss_based":
# Adapt based on training loss progression
if training_loss > self.previous_losses.get(client_id, float('inf')):
new_mu = min(self.mu * 1.05, 1.0)
else:
new_mu = max(self.mu * 0.95, 0.01)
else:
new_mu = self.mu

return new_mu

def aggregate_models(self, client_updates: List[Dict[str, Any]]) -> Dict[str, Any]:
"""
Aggregate model updates with weighted averaging.
"""
total_samples = sum(update["num_samples"] for update in client_updates)

# Initialize aggregated parameters
aggregated_params = {}

for update in client_updates:
weight = update["num_samples"] / total_samples

for param_name, param_value in update["model_parameters"].items():
if param_name not in aggregated_params:
aggregated_params[param_name] = torch.zeros_like(param_value)

aggregated_params[param_name] += weight * param_value

# Calculate aggregation statistics
avg_training_loss = sum(update["training_loss"] for update in client_updates) / len(client_updates)
avg_proximal_loss = sum(update["proximal_loss"] for update in client_updates) / len(client_updates)

return {
"aggregated_parameters": aggregated_params,
"participating_clients": len(client_updates),
"total_samples": total_samples,
"average_training_loss": avg_training_loss,
"average_proximal_loss": avg_proximal_loss,
"mu_values": {update["client_id"]: update["mu_used"] for update in client_updates}
}

Algorithm Configuration

{
"fl_algorithm": {
"name": "FedProx",
"class": "src.fl.algorithms.fedprox.FedProxAlgorithm",
"parameters": {
"mu": 0.1,
"adaptive_mu": true,
"mu_adaptation_strategy": "divergence_based",
"mu_bounds": [0.01, 1.0],
"adaptation_frequency": 1
}
},
"training_config": {
"local_epochs": 5,
"learning_rate": 0.01,
"batch_size": 32,
"convergence_threshold": 0.001,
"max_rounds": 50
}
}

Advanced Network Configuration

Complex Network Topologies

Define sophisticated network architectures:

# scenarios/network_topologies/hierarchical_edge.py
class HierarchicalEdgeTopology:
"""
Multi-tier hierarchical topology with edge computing layers.
"""

def __init__(self, config: Dict[str, Any]):
self.config = config
self.topology = self.build_topology()

def build_topology(self) -> Dict[str, Any]:
"""
Build a hierarchical edge computing topology.

Architecture:
- Core Cloud (FL Server)
- Regional Edge Nodes (Aggregation)
- Local Edge Nodes (Client Clusters)
- End Devices (FL Clients)
"""

topology = {
"topology_type": "hierarchical_edge",
"layers": {
"core": {
"nodes": [
{
"node_id": "cloud-core-1",
"type": "fl_server",
"resources": {
"cpu_cores": 32,
"memory_gb": 128,
"storage_gb": 2000,
"network_bandwidth_gbps": 10
},
"location": {"region": "us-east-1", "zone": "a"}
}
]
},
"regional_edge": {
"nodes": [
{
"node_id": f"regional-edge-{i}",
"type": "edge_aggregator",
"resources": {
"cpu_cores": 16,
"memory_gb": 64,
"storage_gb": 500,
"network_bandwidth_gbps": 1
},
"location": {"region": f"region-{i}", "zone": "edge"},
"served_areas": [f"area-{i}-{j}" for j in range(3)]
}
for i in range(4)
]
},
"local_edge": {
"nodes": [
{
"node_id": f"local-edge-{i}-{j}",
"type": "local_aggregator",
"resources": {
"cpu_cores": 8,
"memory_gb": 32,
"storage_gb": 200,
"network_bandwidth_mbps": 500
},
"location": {"region": f"region-{i}", "area": f"area-{i}-{j}"},
"client_capacity": 10
}
for i in range(4) for j in range(3)
]
},
"end_devices": {
"node_templates": [
{
"template_id": "high_end_device",
"count": 20,
"type": "fl_client",
"resources": {
"cpu_cores": 4,
"memory_gb": 8,
"storage_gb": 100,
"battery_capacity_wh": 50
},
"network_profile": "wifi_6"
},
{
"template_id": "mid_range_device",
"count": 40,
"type": "fl_client",
"resources": {
"cpu_cores": 2,
"memory_gb": 4,
"storage_gb": 50,
"battery_capacity_wh": 30
},
"network_profile": "wifi_5"
},
{
"template_id": "iot_device",
"count": 20,
"type": "fl_client",
"resources": {
"cpu_cores": 1,
"memory_gb": 1,
"storage_gb": 16,
"battery_capacity_wh": 10
},
"network_profile": "lte_cat_m"
}
]
}
}
}

# Define connections between layers
topology["connections"] = self.define_layer_connections()

# Define network characteristics
topology["network_profiles"] = self.define_network_profiles()

return topology

def define_layer_connections(self) -> List[Dict[str, Any]]:
"""Define connections between topology layers."""
connections = []

# Core to Regional Edge connections
for i in range(4):
connections.append({
"from": "cloud-core-1",
"to": f"regional-edge-{i}",
"connection_type": "fiber_backbone",
"characteristics": {
"bandwidth_gbps": 1,
"latency_ms": 10,
"reliability": 0.999,
"cost_per_gb": 0.001
}
})

# Regional Edge to Local Edge connections
for i in range(4):
for j in range(3):
connections.append({
"from": f"regional-edge-{i}",
"to": f"local-edge-{i}-{j}",
"connection_type": "metro_ethernet",
"characteristics": {
"bandwidth_mbps": 500,
"latency_ms": 5,
"reliability": 0.99,
"cost_per_gb": 0.01
}
})

return connections

def define_network_profiles(self) -> Dict[str, Any]:
"""Define network profiles for different connection types."""
return {
"wifi_6": {
"bandwidth_mbps": 100,
"latency_ms": [5, 15],
"reliability": 0.95,
"power_consumption_w": 2
},
"wifi_5": {
"bandwidth_mbps": 50,
"latency_ms": [10, 25],
"reliability": 0.90,
"power_consumption_w": 3
},
"lte_cat_m": {
"bandwidth_mbps": 1,
"latency_ms": [50, 200],
"reliability": 0.85,
"power_consumption_w": 0.5
}
}

Traffic Shaping and QoS

Implement advanced traffic management:

# src/networking/traffic_manager.py
class AdvancedTrafficManager:
"""
Advanced traffic management with QoS, traffic shaping, and
adaptive bandwidth allocation.
"""

def __init__(self, config: Dict[str, Any]):
self.config = config
self.traffic_classes = self.define_traffic_classes()
self.adaptive_policies = self.setup_adaptive_policies()

def define_traffic_classes(self) -> Dict[str, Any]:
"""Define traffic classes with different QoS requirements."""
return {
"fl_control": {
"priority": 1, # Highest priority
"bandwidth_allocation": "guaranteed",
"min_bandwidth_mbps": 10,
"max_latency_ms": 50,
"jitter_tolerance_ms": 5,
"packet_loss_tolerance": 0.001
},
"fl_model_updates": {
"priority": 2,
"bandwidth_allocation": "adaptive",
"min_bandwidth_mbps": 50,
"max_latency_ms": 200,
"jitter_tolerance_ms": 20,
"packet_loss_tolerance": 0.01,
"compression_enabled": True
},
"fl_data_transfer": {
"priority": 3,
"bandwidth_allocation": "best_effort",
"min_bandwidth_mbps": 1,
"max_latency_ms": 1000,
"jitter_tolerance_ms": 100,
"packet_loss_tolerance": 0.05
},
"monitoring_metrics": {
"priority": 4,
"bandwidth_allocation": "background",
"min_bandwidth_mbps": 0.1,
"max_latency_ms": 5000,
"compression_enabled": True,
"aggregation_enabled": True
}
}

def setup_adaptive_policies(self) -> List[Dict[str, Any]]:
"""Setup adaptive traffic management policies."""
return [
{
"name": "congestion_control",
"trigger": "network_utilization > 0.8",
"actions": [
{
"type": "reduce_background_traffic",
"parameters": {"reduction_factor": 0.5}
},
{
"type": "enable_compression",
"parameters": {"traffic_classes": ["fl_model_updates", "monitoring_metrics"]}
},
{
"type": "increase_buffer_size",
"parameters": {"buffer_multiplier": 1.5}
}
]
},
{
"name": "latency_optimization",
"trigger": "average_latency > 100ms",
"actions": [
{
"type": "prioritize_control_traffic",
"parameters": {"priority_boost": 1}
},
{
"type": "route_optimization",
"parameters": {"algorithm": "shortest_path"}
}
]
},
{
"name": "client_adaptation",
"trigger": "client_type == 'mobile' and battery_level < 0.3",
"actions": [
{
"type": "reduce_transmission_power",
"parameters": {"power_reduction": 0.3}
},
{
"type": "increase_compression",
"parameters": {"compression_level": "high"}
}
]
}
]

Sophisticated Policy Management

Multi-Layer Policy Architecture

Implement a hierarchical policy system:

# src/policy_engine/advanced_policies.py
class MultiLayerPolicyEngine:
"""
Advanced policy engine with multiple policy layers and
context-aware decision making.
"""

def __init__(self, config: Dict[str, Any]):
self.config = config
self.policy_layers = self.initialize_policy_layers()
self.context_manager = ContextManager()
self.policy_cache = PolicyCache()

def initialize_policy_layers(self) -> Dict[str, Any]:
"""Initialize different policy layers."""
return {
"system_policies": SystemPolicyLayer(self.config.get("system_policies", {})),
"experiment_policies": ExperimentPolicyLayer(self.config.get("experiment_policies", {})),
"client_policies": ClientPolicyLayer(self.config.get("client_policies", {})),
"network_policies": NetworkPolicyLayer(self.config.get("network_policies", {})),
"security_policies": SecurityPolicyLayer(self.config.get("security_policies", {}))
}

def evaluate_request(self, request: Dict[str, Any]) -> Dict[str, Any]:
"""
Evaluate a request against all policy layers with context awareness.
"""
# Get current context
context = self.context_manager.get_current_context()

# Check policy cache first
cache_key = self.generate_cache_key(request, context)
cached_result = self.policy_cache.get(cache_key)
if cached_result and not cached_result.is_expired():
return cached_result.decision

# Evaluate through policy layers
evaluation_result = {
"request_id": request.get("request_id"),
"timestamp": time.time(),
"context": context,
"layer_results": {},
"final_decision": "allow",
"applied_policies": [],
"confidence_score": 1.0
}

# Process through each layer
for layer_name, layer in self.policy_layers.items():
layer_result = layer.evaluate(request, context)
evaluation_result["layer_results"][layer_name] = layer_result

# Update final decision based on layer result
if layer_result["decision"] == "deny":
evaluation_result["final_decision"] = "deny"
evaluation_result["confidence_score"] *= layer_result.get("confidence", 1.0)
elif layer_result["decision"] == "conditional":
evaluation_result["final_decision"] = "conditional"
evaluation_result["conditions"] = evaluation_result.get("conditions", [])
evaluation_result["conditions"].extend(layer_result.get("conditions", []))

# Cache the result
self.policy_cache.put(cache_key, evaluation_result, ttl=300) # 5-minute TTL

return evaluation_result

class SystemPolicyLayer(BasePolicyLayer):
"""System-level policies for resource management and system integrity."""

def __init__(self, config: Dict[str, Any]):
super().__init__(config)
self.resource_policies = self.load_resource_policies()
self.security_policies = self.load_security_policies()

def evaluate(self, request: Dict[str, Any], context: Dict[str, Any]) -> Dict[str, Any]:
"""Evaluate system-level policies."""
result = {
"layer": "system",
"decision": "allow",
"policies_evaluated": [],
"violations": [],
"recommendations": []
}

# Check resource availability
if request.get("resource_request"):
resource_result = self.evaluate_resource_policies(request["resource_request"], context)
result["policies_evaluated"].append("resource_management")

if not resource_result["allowed"]:
result["decision"] = "deny"
result["violations"].append({
"policy": "resource_limits",
"violation": resource_result["violation"],
"current_usage": resource_result["current_usage"],
"requested": resource_result["requested"],
"limit": resource_result["limit"]
})

# Check system security policies
security_result = self.evaluate_security_policies(request, context)
result["policies_evaluated"].append("system_security")

if not security_result["allowed"]:
result["decision"] = "deny"
result["violations"].extend(security_result["violations"])

return result

def evaluate_resource_policies(self, resource_request: Dict[str, Any],
context: Dict[str, Any]) -> Dict[str, Any]:
"""Evaluate resource allocation policies."""
current_usage = context.get("system_resources", {})

for resource_type, requested_amount in resource_request.items():
current_amount = current_usage.get(resource_type, 0)
limit = self.resource_policies.get(resource_type, {}).get("max_allocation", float('inf'))

if current_amount + requested_amount > limit:
return {
"allowed": False,
"violation": f"Resource limit exceeded for {resource_type}",
"current_usage": current_amount,
"requested": requested_amount,
"limit": limit
}

return {"allowed": True}

class ExperimentPolicyLayer(BasePolicyLayer):
"""Experiment-specific policies for FL training governance."""

def evaluate(self, request: Dict[str, Any], context: Dict[str, Any]) -> Dict[str, Any]:
"""Evaluate experiment-level policies."""
result = {
"layer": "experiment",
"decision": "allow",
"policies_evaluated": [],
"conditions": []
}

experiment_context = context.get("current_experiment", {})

# Evaluate training policies
if request.get("action") == "start_training":
training_result = self.evaluate_training_policies(request, experiment_context)
result["policies_evaluated"].append("training_governance")

if training_result["conditions"]:
result["decision"] = "conditional"
result["conditions"].extend(training_result["conditions"])

# Evaluate data policies
if request.get("data_access"):
data_result = self.evaluate_data_policies(request["data_access"], experiment_context)
result["policies_evaluated"].append("data_governance")

if not data_result["allowed"]:
result["decision"] = "deny"
result["violations"] = data_result["violations"]

return result

Dynamic Policy Adaptation

Implement policies that adapt based on system state:

class AdaptivePolicyManager:
"""
Manager for policies that adapt based on system state and learning.
"""

def __init__(self, config: Dict[str, Any]):
self.config = config
self.adaptive_policies = {}
self.learning_history = {}
self.adaptation_strategies = self.load_adaptation_strategies()

def register_adaptive_policy(self, policy_id: str, policy_config: Dict[str, Any]):
"""Register a new adaptive policy."""
self.adaptive_policies[policy_id] = AdaptivePolicy(policy_config)
self.learning_history[policy_id] = []

def update_policy_based_on_feedback(self, policy_id: str,
decision_context: Dict[str, Any],
outcome: Dict[str, Any]):
"""Update policy parameters based on decision outcomes."""
if policy_id not in self.adaptive_policies:
return

policy = self.adaptive_policies[policy_id]

# Record the decision and its outcome
feedback_record = {
"timestamp": time.time(),
"context": decision_context,
"decision": decision_context.get("decision"),
"outcome": outcome,
"success": outcome.get("success", False)
}

self.learning_history[policy_id].append(feedback_record)

# Adapt policy if enough feedback is available
if len(self.learning_history[policy_id]) >= policy.min_feedback_samples:
self.adapt_policy_parameters(policy_id)

def adapt_policy_parameters(self, policy_id: str):
"""Adapt policy parameters based on historical feedback."""
policy = self.adaptive_policies[policy_id]
history = self.learning_history[policy_id]

# Calculate success rate for different parameter ranges
parameter_performance = {}

for record in history[-policy.adaptation_window:]:
param_key = self.discretize_parameters(record["context"]["parameters"])
if param_key not in parameter_performance:
parameter_performance[param_key] = {"successes": 0, "total": 0}

parameter_performance[param_key]["total"] += 1
if record["success"]:
parameter_performance[param_key]["successes"] += 1

# Find best performing parameters
best_params = max(parameter_performance.items(),
key=lambda x: x[1]["successes"] / x[1]["total"] if x[1]["total"] > 0 else 0)

# Update policy parameters
new_params = self.undiscretize_parameters(best_params[0])
policy.update_parameters(new_params)

logger.info(f"Adapted policy {policy_id} parameters: {new_params}")

Performance Optimization

Resource Allocation Strategies

Implement sophisticated resource allocation:

class ResourceAllocationOptimizer:
"""
Optimize resource allocation across the federated learning system.
"""

def __init__(self, config: Dict[str, Any]):
self.config = config
self.allocation_strategies = {
"fair_share": FairShareStrategy(),
"performance_based": PerformanceBasedStrategy(),
"priority_based": PriorityBasedStrategy(),
"adaptive": AdaptiveStrategy()
}
self.current_strategy = config.get("default_strategy", "adaptive")

def optimize_allocation(self, clients: List[Dict[str, Any]],
available_resources: Dict[str, Any]) -> Dict[str, Any]:
"""
Optimize resource allocation across clients.
"""
strategy = self.allocation_strategies[self.current_strategy]

allocation_plan = strategy.allocate(clients, available_resources)

# Validate allocation plan
if self.validate_allocation(allocation_plan, available_resources):
return allocation_plan
else:
# Fallback to fair share if allocation is invalid
return self.allocation_strategies["fair_share"].allocate(clients, available_resources)

def validate_allocation(self, allocation_plan: Dict[str, Any],
available_resources: Dict[str, Any]) -> bool:
"""Validate that allocation plan doesn't exceed available resources."""
total_allocated = {}

for client_id, allocation in allocation_plan["allocations"].items():
for resource_type, amount in allocation.items():
total_allocated[resource_type] = total_allocated.get(resource_type, 0) + amount

for resource_type, total_amount in total_allocated.items():
if total_amount > available_resources.get(resource_type, 0):
return False

return True

class AdaptiveStrategy:
"""Adaptive resource allocation based on client performance and needs."""

def allocate(self, clients: List[Dict[str, Any]],
available_resources: Dict[str, Any]) -> Dict[str, Any]:
"""
Allocate resources adaptively based on client characteristics.
"""
allocation_plan = {
"strategy": "adaptive",
"timestamp": time.time(),
"allocations": {},
"optimization_objective": "maximize_system_efficiency"
}

# Calculate client scores based on multiple factors
client_scores = []
for client in clients:
score = self.calculate_client_score(client)
client_scores.append((client["client_id"], score))

# Sort clients by score (highest first)
client_scores.sort(key=lambda x: x[1], reverse=True)

# Allocate resources proportionally to scores
total_score = sum(score for _, score in client_scores)

for client_id, score in client_scores:
allocation_ratio = score / total_score
client_allocation = {}

for resource_type, total_amount in available_resources.items():
allocated_amount = total_amount * allocation_ratio
client_allocation[resource_type] = allocated_amount

allocation_plan["allocations"][client_id] = client_allocation

return allocation_plan

def calculate_client_score(self, client: Dict[str, Any]) -> float:
"""Calculate a composite score for client resource allocation priority."""
# Factors: performance history, data quality, reliability, resource efficiency

performance_score = client.get("historical_performance", {}).get("average_accuracy", 0.5)
data_quality_score = client.get("data_profile", {}).get("quality_score", 0.5)
reliability_score = client.get("reliability_metrics", {}).get("uptime_ratio", 0.8)
efficiency_score = client.get("resource_efficiency", {}).get("computation_per_watt", 0.5)

# Weighted combination
composite_score = (
0.3 * performance_score +
0.25 * data_quality_score +
0.25 * reliability_score +
0.2 * efficiency_score
)

return composite_score

System Tuning

Implement comprehensive system tuning:

# configs/advanced/system_tuning.yaml
system_optimization:
# Memory management
memory:
garbage_collection:
strategy: "generational"
gc_threshold: 0.8
max_heap_size: "4g"

caching:
model_cache_size: "1g"
data_cache_size: "2g"
policy_cache_ttl: 300

# Network optimization
network:
connection_pooling:
max_connections: 100
connection_timeout: 30
keepalive_timeout: 60

compression:
enabled: true
algorithm: "lz4"
compression_level: 3

buffering:
send_buffer_size: "64k"
receive_buffer_size: "64k"

# Computation optimization
computation:
thread_pool_size: 16
async_workers: 8
batch_processing:
enabled: true
batch_size: 32
max_wait_time: 100

# Storage optimization
storage:
database:
connection_pool_size: 20
query_timeout: 30
batch_insert_size: 1000

file_system:
io_buffer_size: "1m"
async_io: true
compression: "gzip"

Integration Patterns

Event-Driven Architecture

Implement sophisticated event-driven patterns:

class EventDrivenIntegrationManager:
"""
Manage event-driven integration between FLOPY-NET components.
"""

def __init__(self, config: Dict[str, Any]):
self.config = config
self.event_bus = EventBus()
self.event_handlers = {}
self.event_filters = {}
self.integration_patterns = self.setup_integration_patterns()

def setup_integration_patterns(self) -> Dict[str, Any]:
"""Setup different integration patterns."""
return {
"publish_subscribe": PublishSubscribePattern(self.event_bus),
"event_sourcing": EventSourcingPattern(self.event_bus),
"saga_pattern": SagaPattern(self.event_bus),
"circuit_breaker": CircuitBreakerPattern(self.event_bus)
}

def register_event_handler(self, event_type: str, handler: callable,
filter_conditions: Dict[str, Any] = None):
"""Register an event handler with optional filtering."""
if event_type not in self.event_handlers:
self.event_handlers[event_type] = []

self.event_handlers[event_type].append(handler)

if filter_conditions:
self.event_filters[f"{event_type}_{len(self.event_handlers[event_type])}"] = filter_conditions

def publish_event(self, event: Dict[str, Any]):
"""Publish an event to the system."""
event_type = event.get("type")

# Apply filters and route to appropriate handlers
for handler in self.event_handlers.get(event_type, []):
if self.should_handle_event(event, handler):
try:
handler(event)
except Exception as e:
logger.error(f"Error handling event {event_type}: {e}")

def should_handle_event(self, event: Dict[str, Any], handler: callable) -> bool:
"""Determine if a handler should process an event based on filters."""
# Implementation of event filtering logic
return True # Simplified for brevity

# Example: FL Training Event Handler
class FLTrainingEventHandler:
"""Handle FL training-related events."""

def __init__(self, fl_server, policy_engine, collector):
self.fl_server = fl_server
self.policy_engine = policy_engine
self.collector = collector

def handle_round_started(self, event: Dict[str, Any]):
"""Handle FL round started event."""
round_number = event["round_number"]
experiment_id = event["experiment_id"]

# Notify policy engine
self.policy_engine.notify_round_started(experiment_id, round_number)

# Start metrics collection
self.collector.start_round_metrics_collection(experiment_id, round_number)

# Log the event
logger.info(f"FL round {round_number} started for experiment {experiment_id}")

def handle_client_joined(self, event: Dict[str, Any]):
"""Handle client joined event."""
client_id = event["client_id"]
client_info = event["client_info"]

# Policy compliance check
compliance_result = self.policy_engine.check_client_compliance(client_id, client_info)

if not compliance_result["compliant"]:
# Reject client
self.fl_server.reject_client(client_id, compliance_result["violations"])
else:
# Accept client and start monitoring
self.collector.start_client_monitoring(client_id)
logger.info(f"Client {client_id} joined and monitoring started")

Configuration Management

Hierarchical Configuration System

class HierarchicalConfigManager:
"""
Manage hierarchical configuration with inheritance and overrides.
"""

def __init__(self, config_paths: List[str]):
self.config_hierarchy = self.load_config_hierarchy(config_paths)
self.resolved_config = self.resolve_configuration()

def load_config_hierarchy(self, config_paths: List[str]) -> List[Dict[str, Any]]:
"""Load configuration files in hierarchical order."""
configs = []

for config_path in config_paths:
if os.path.exists(config_path):
with open(config_path, 'r') as f:
if config_path.endswith('.yaml') or config_path.endswith('.yml'):
config = yaml.safe_load(f)
else:
config = json.load(f)
configs.append(config)

return configs

def resolve_configuration(self) -> Dict[str, Any]:
"""Resolve configuration hierarchy with proper inheritance."""
resolved = {}

# Apply configurations in order (later configs override earlier ones)
for config in self.config_hierarchy:
resolved = self.deep_merge(resolved, config)

# Apply environment variable overrides
resolved = self.apply_env_overrides(resolved)

return resolved

def deep_merge(self, base: Dict[str, Any], override: Dict[str, Any]) -> Dict[str, Any]:
"""Deep merge two configuration dictionaries."""
result = base.copy()

for key, value in override.items():
if key in result and isinstance(result[key], dict) and isinstance(value, dict):
result[key] = self.deep_merge(result[key], value)
else:
result[key] = value

return result

This advanced configuration tutorial demonstrates sophisticated techniques for:

  1. Custom FL Algorithms: Implementing complex algorithms like FedProx with adaptive parameters
  2. Advanced Networking: Multi-tier topologies and sophisticated traffic management
  3. Sophisticated Policies: Multi-layer policies with adaptive behavior
  4. Performance Optimization: Resource allocation and system tuning
  5. Integration Patterns: Event-driven architectures and complex service coordination

These techniques enable researchers to create highly customized and optimized federated learning experiments that closely match real-world deployment scenarios.