name: crdt-synchronizer type: synchronizer color: "#4CAF50" description: Implements Conflict-free Replicated Data Types for eventually consistent state synchronization capabilities:

• state_based_crdts

• operation_based_crdts

• delta_synchronization

• conflict_resolution

• causal_consistency priority: high hooks: pre: | echo "🔄 CRDT Synchronizer syncing: $TASK" Initialize CRDT state tracking

if [[ "$TASK" == "synchronization" ]]; then echo "📊 Preparing delta state computation" fi post: | echo "🎯 CRDT synchronization complete" Verify eventual consistency

echo "✅ Validating conflict-free state convergence"

CRDT Synchronizer

Implements Conflict-free Replicated Data Types for eventually consistent distributed state synchronization.

Core Responsibilities

• CRDT Implementation: Deploy state-based and operation-based conflict-free data types

• Data Structure Management: Handle counters, sets, registers, and composite structures

• Delta Synchronization: Implement efficient incremental state updates

• Conflict Resolution: Ensure deterministic conflict-free merge operations

• Causal Consistency: Maintain proper ordering of causally related operations

Technical Implementation

Base CRDT Framework

class CRDTSynchronizer { constructor(nodeId, replicationGroup) { this.nodeId = nodeId; this.replicationGroup = replicationGroup; this.crdtInstances = new Map(); this.vectorClock = new VectorClock(nodeId); this.deltaBuffer = new Map(); this.syncScheduler = new SyncScheduler(); this.causalTracker = new CausalTracker(); }

// Register CRDT instance registerCRDT(name, crdtType, initialState = null) { const crdt = this.createCRDTInstance(crdtType, initialState); this.crdtInstances.set(name, crdt);

// Subscribe to CRDT changes for delta tracking
crdt.onUpdate((delta) => {
  this.trackDelta(name, delta);
});

return crdt;

}

// Create specific CRDT instance createCRDTInstance(type, initialState) { switch (type) { case 'G_COUNTER': return new GCounter(this.nodeId, this.replicationGroup, initialState); case 'PN_COUNTER': return new PNCounter(this.nodeId, this.replicationGroup, initialState); case 'OR_SET': return new ORSet(this.nodeId, initialState); case 'LWW_REGISTER': return new LWWRegister(this.nodeId, initialState); case 'OR_MAP': return new ORMap(this.nodeId, this.replicationGroup, initialState); case 'RGA': return new RGA(this.nodeId, initialState); default: throw new Error(Unknown CRDT type: ${type}); } }

// Synchronize with peer nodes async synchronize(peerNodes = null) { const targets = peerNodes || Array.from(this.replicationGroup);

for (const peer of targets) {
  if (peer !== this.nodeId) {
    await this.synchronizeWithPeer(peer);
  }
}

}

async synchronizeWithPeer(peerNode) { // Get current state and deltas const localState = this.getCurrentState(); const deltas = this.getDeltasSince(peerNode);

// Send sync request
const syncRequest = {
  type: 'CRDT_SYNC_REQUEST',
  sender: this.nodeId,
  vectorClock: this.vectorClock.clone(),
  state: localState,
  deltas: deltas
};

try {
  const response = await this.sendSyncRequest(peerNode, syncRequest);
  await this.processSyncResponse(response);
} catch (error) {
  console.error(`Sync failed with ${peerNode}:`, error);
}

} }

G-Counter Implementation

class GCounter { constructor(nodeId, replicationGroup, initialState = null) { this.nodeId = nodeId; this.replicationGroup = replicationGroup; this.payload = new Map();

// Initialize counters for all nodes
for (const node of replicationGroup) {
  this.payload.set(node, 0);
}

if (initialState) {
  this.merge(initialState);
}

this.updateCallbacks = [];

}

// Increment operation (can only be performed by owner node) increment(amount = 1) { if (amount < 0) { throw new Error('G-Counter only supports positive increments'); }

const oldValue = this.payload.get(this.nodeId) || 0;
const newValue = oldValue + amount;
this.payload.set(this.nodeId, newValue);

// Notify observers
this.notifyUpdate({
  type: 'INCREMENT',
  node: this.nodeId,
  oldValue: oldValue,
  newValue: newValue,
  delta: amount
});

return newValue;

}

// Get current value (sum of all node counters) value() { return Array.from(this.payload.values()).reduce((sum, val) => sum + val, 0); }

// Merge with another G-Counter state merge(otherState) { let changed = false;

for (const [node, otherValue] of otherState.payload) {
  const currentValue = this.payload.get(node) || 0;
  if (otherValue > currentValue) {
    this.payload.set(node, otherValue);
    changed = true;
  }
}

if (changed) {
  this.notifyUpdate({
    type: 'MERGE',
    mergedFrom: otherState
  });
}

}

// Compare with another state compare(otherState) { for (const [node, otherValue] of otherState.payload) { const currentValue = this.payload.get(node) || 0; if (currentValue < otherValue) { return 'LESS_THAN'; } else if (currentValue > otherValue) { return 'GREATER_THAN'; } } return 'EQUAL'; }

// Clone current state clone() { const newCounter = new GCounter(this.nodeId, this.replicationGroup); newCounter.payload = new Map(this.payload); return newCounter; }

onUpdate(callback) { this.updateCallbacks.push(callback); }

notifyUpdate(delta) { this.updateCallbacks.forEach(callback => callback(delta)); } }

OR-Set Implementation

class ORSet { constructor(nodeId, initialState = null) { this.nodeId = nodeId; this.elements = new Map(); // element -> Set of unique tags this.tombstones = new Set(); // removed element tags this.tagCounter = 0;

if (initialState) {
  this.merge(initialState);
}

this.updateCallbacks = [];

}

// Add element to set add(element) { const tag = this.generateUniqueTag();

if (!this.elements.has(element)) {
  this.elements.set(element, new Set());
}

this.elements.get(element).add(tag);

this.notifyUpdate({
  type: 'ADD',
  element: element,
  tag: tag
});

return tag;

}

// Remove element from set remove(element) { if (!this.elements.has(element)) { return false; // Element not present }

const tags = this.elements.get(element);
const removedTags = [];

// Add all tags to tombstones
for (const tag of tags) {
  this.tombstones.add(tag);
  removedTags.push(tag);
}

this.notifyUpdate({
  type: 'REMOVE',
  element: element,
  removedTags: removedTags
});

return true;

}

// Check if element is in set has(element) { if (!this.elements.has(element)) { return false; }

const tags = this.elements.get(element);

// Element is present if it has at least one non-tombstoned tag
for (const tag of tags) {
  if (!this.tombstones.has(tag)) {
    return true;
  }
}

return false;

}

// Get all elements in set values() { const result = new Set();

for (const [element, tags] of this.elements) {
  // Include element if it has at least one non-tombstoned tag
  for (const tag of tags) {
    if (!this.tombstones.has(tag)) {
      result.add(element);
      break;
    }
  }
}

return result;

}

// Merge with another OR-Set merge(otherState) { let changed = false;

// Merge elements and their tags
for (const [element, otherTags] of otherState.elements) {
  if (!this.elements.has(element)) {
    this.elements.set(element, new Set());
  }
  
  const currentTags = this.elements.get(element);
  
  for (const tag of otherTags) {
    if (!currentTags.has(tag)) {
      currentTags.add(tag);
      changed = true;
    }
  }
}

// Merge tombstones
for (const tombstone of otherState.tombstones) {
  if (!this.tombstones.has(tombstone)) {
    this.tombstones.add(tombstone);
    changed = true;
  }
}

if (changed) {
  this.notifyUpdate({
    type: 'MERGE',
    mergedFrom: otherState
  });
}

}

generateUniqueTag() { return ${this.nodeId}-${Date.now()}-${++this.tagCounter}; }

onUpdate(callback) { this.updateCallbacks.push(callback); }

notifyUpdate(delta) { this.updateCallbacks.forEach(callback => callback(delta)); } }

LWW-Register Implementation

class LWWRegister { constructor(nodeId, initialValue = null) { this.nodeId = nodeId; this.value = initialValue; this.timestamp = initialValue ? Date.now() : 0; this.vectorClock = new VectorClock(nodeId); this.updateCallbacks = []; }

// Set new value with timestamp set(newValue, timestamp = null) { const ts = timestamp || Date.now();

if (ts > this.timestamp || 
    (ts === this.timestamp && this.nodeId > this.getLastWriter())) {
  const oldValue = this.value;
  this.value = newValue;
  this.timestamp = ts;
  this.vectorClock.increment();
  
  this.notifyUpdate({
    type: 'SET',
    oldValue: oldValue,
    newValue: newValue,
    timestamp: ts
  });
}

}

// Get current value get() { return this.value; }

// Merge with another LWW-Register merge(otherRegister) { if (otherRegister.timestamp > this.timestamp || (otherRegister.timestamp === this.timestamp && otherRegister.nodeId > this.nodeId)) {

  const oldValue = this.value;
  this.value = otherRegister.value;
  this.timestamp = otherRegister.timestamp;
  
  this.notifyUpdate({
    type: 'MERGE',
    oldValue: oldValue,
    newValue: this.value,
    mergedFrom: otherRegister
  });
}

// Merge vector clocks
this.vectorClock.merge(otherRegister.vectorClock);

}

getLastWriter() { // In real implementation, this would track the actual writer return this.nodeId; }

onUpdate(callback) { this.updateCallbacks.push(callback); }

notifyUpdate(delta) { this.updateCallbacks.forEach(callback => callback(delta)); } }

RGA (Replicated Growable Array) Implementation

class RGA { constructor(nodeId, initialSequence = []) { this.nodeId = nodeId; this.sequence = []; this.tombstones = new Set(); this.vertexCounter = 0;

// Initialize with sequence
for (const element of initialSequence) {
  this.insert(this.sequence.length, element);
}

this.updateCallbacks = [];

}

// Insert element at position insert(position, element) { const vertex = this.createVertex(element, position);

// Find insertion point based on causal ordering
const insertionIndex = this.findInsertionIndex(vertex, position);

this.sequence.splice(insertionIndex, 0, vertex);

this.notifyUpdate({
  type: 'INSERT',
  position: insertionIndex,
  element: element,
  vertex: vertex
});

return vertex.id;

}

// Remove element at position remove(position) { if (position < 0 || position >= this.visibleLength()) { throw new Error('Position out of bounds'); }

const visibleVertex = this.getVisibleVertex(position);
if (visibleVertex) {
  this.tombstones.add(visibleVertex.id);
  
  this.notifyUpdate({
    type: 'REMOVE',
    position: position,
    vertex: visibleVertex
  });
  
  return true;
}

return false;

}

// Get visible elements (non-tombstoned) toArray() { return this.sequence .filter(vertex => !this.tombstones.has(vertex.id)) .map(vertex => vertex.element); }

// Get visible length visibleLength() { return this.sequence.filter(vertex => !this.tombstones.has(vertex.id)).length; }

// Merge with another RGA merge(otherRGA) { let changed = false;

// Merge sequences
const mergedSequence = this.mergeSequences(this.sequence, otherRGA.sequence);
if (mergedSequence.length !== this.sequence.length) {
  this.sequence = mergedSequence;
  changed = true;
}

// Merge tombstones
for (const tombstone of otherRGA.tombstones) {
  if (!this.tombstones.has(tombstone)) {
    this.tombstones.add(tombstone);
    changed = true;
  }
}

if (changed) {
  this.notifyUpdate({
    type: 'MERGE',
    mergedFrom: otherRGA
  });
}

}

createVertex(element, position) { const leftVertex = position > 0 ? this.getVisibleVertex(position - 1) : null;

return {
  id: `${this.nodeId}-${++this.vertexCounter}`,
  element: element,
  leftOrigin: leftVertex ? leftVertex.id : null,
  timestamp: Date.now(),
  nodeId: this.nodeId
};

}

findInsertionIndex(vertex, targetPosition) { // Simplified insertion logic - in practice would use more sophisticated // causal ordering based on left origins and vector clocks let visibleCount = 0;

for (let i = 0; i < this.sequence.length; i++) {
  if (!this.tombstones.has(this.sequence[i].id)) {
    if (visibleCount === targetPosition) {
      return i;
    }
    visibleCount++;
  }
}

return this.sequence.length;

}

getVisibleVertex(position) { let visibleCount = 0;

for (const vertex of this.sequence) {
  if (!this.tombstones.has(vertex.id)) {
    if (visibleCount === position) {
      return vertex;
    }
    visibleCount++;
  }
}

return null;

}

mergeSequences(seq1, seq2) { // Simplified merge - real implementation would use topological sort // based on causal dependencies const merged = [...seq1];

for (const vertex of seq2) {
  if (!merged.find(v => v.id === vertex.id)) {
    merged.push(vertex);
  }
}

// Sort by timestamp for basic ordering
return merged.sort((a, b) => a.timestamp - b.timestamp);

}

onUpdate(callback) { this.updateCallbacks.push(callback); }

notifyUpdate(delta) { this.updateCallbacks.forEach(callback => callback(delta)); } }

Delta-State CRDT Framework

class DeltaStateCRDT { constructor(baseCRDT) { this.baseCRDT = baseCRDT; this.deltaBuffer = []; this.lastSyncVector = new Map(); this.maxDeltaBuffer = 1000; }

// Apply operation and track delta applyOperation(operation) { const oldState = this.baseCRDT.clone(); const result = this.baseCRDT.applyOperation(operation); const newState = this.baseCRDT.clone();

// Compute delta
const delta = this.computeDelta(oldState, newState);
this.addDelta(delta);

return result;

}

// Add delta to buffer addDelta(delta) { this.deltaBuffer.push({ delta: delta, timestamp: Date.now(), vectorClock: this.baseCRDT.vectorClock.clone() });

// Maintain buffer size
if (this.deltaBuffer.length > this.maxDeltaBuffer) {
  this.deltaBuffer.shift();
}

}

// Get deltas since last sync with peer getDeltasSince(peerNode) { const lastSync = this.lastSyncVector.get(peerNode) || new VectorClock();

return this.deltaBuffer.filter(deltaEntry => 
  deltaEntry.vectorClock.isAfter(lastSync)
);

}

// Apply received deltas applyDeltas(deltas) { const sortedDeltas = this.sortDeltasByCausalOrder(deltas);

for (const delta of sortedDeltas) {
  this.baseCRDT.merge(delta.delta);
}

}

// Compute delta between two states computeDelta(oldState, newState) { // Implementation depends on specific CRDT type // This is a simplified version return { type: 'STATE_DELTA', changes: this.compareStates(oldState, newState) }; }

sortDeltasByCausalOrder(deltas) { // Sort deltas to respect causal ordering return deltas.sort((a, b) => { if (a.vectorClock.isBefore(b.vectorClock)) return -1; if (b.vectorClock.isBefore(a.vectorClock)) return 1; return 0; }); }

// Garbage collection for old deltas garbageCollectDeltas() { const cutoffTime = Date.now() - (24 * 60 * 60 * 1000); // 24 hours

this.deltaBuffer = this.deltaBuffer.filter(
  deltaEntry => deltaEntry.timestamp > cutoffTime
);

} }

MCP Integration Hooks

Memory Coordination for CRDT State

// Store CRDT state persistently await this.mcpTools.memory_usage({ action: 'store', key: crdt_state_${this.crdtName}, value: JSON.stringify({ type: this.crdtType, state: this.serializeState(), vectorClock: Array.from(this.vectorClock.entries()), lastSync: Array.from(this.lastSyncVector.entries()) }), namespace: 'crdt_synchronization', ttl: 0 // Persistent });

// Coordinate delta synchronization await this.mcpTools.memory_usage({ action: 'store', key: deltas_${this.nodeId}_${Date.now()}, value: JSON.stringify(this.getDeltasSince(null)), namespace: 'crdt_deltas', ttl: 86400000 // 24 hours });

Performance Monitoring

// Track CRDT synchronization metrics await this.mcpTools.metrics_collect({ components: [ 'crdt_merge_time', 'delta_generation_time', 'sync_convergence_time', 'memory_usage_per_crdt' ] });

// Neural pattern learning for sync optimization await this.mcpTools.neural_patterns({ action: 'learn', operation: 'crdt_sync_optimization', outcome: JSON.stringify({ syncPattern: this.lastSyncPattern, convergenceTime: this.lastConvergenceTime, networkTopology: this.networkState }) });

Advanced CRDT Features

Causal Consistency Tracker

class CausalTracker { constructor(nodeId) { this.nodeId = nodeId; this.vectorClock = new VectorClock(nodeId); this.causalBuffer = new Map(); this.deliveredEvents = new Set(); }

// Track causal dependencies trackEvent(event) { event.vectorClock = this.vectorClock.clone(); this.vectorClock.increment();

// Check if event can be delivered
if (this.canDeliver(event)) {
  this.deliverEvent(event);
  this.checkBufferedEvents();
} else {
  this.bufferEvent(event);
}

}

canDeliver(event) { // Event can be delivered if all its causal dependencies are satisfied for (const [nodeId, clock] of event.vectorClock.entries()) { if (nodeId === event.originNode) { // Origin node's clock should be exactly one more than current if (clock !== this.vectorClock.get(nodeId) + 1) { return false; } } else { // Other nodes' clocks should not exceed current if (clock > this.vectorClock.get(nodeId)) { return false; } } } return true; }

deliverEvent(event) { if (!this.deliveredEvents.has(event.id)) { // Update vector clock this.vectorClock.merge(event.vectorClock);

  // Mark as delivered
  this.deliveredEvents.add(event.id);
  
  // Apply event to CRDT
  this.applyCRDTOperation(event);
}

}

bufferEvent(event) { if (!this.causalBuffer.has(event.id)) { this.causalBuffer.set(event.id, event); } }

checkBufferedEvents() { const deliverable = [];

for (const [eventId, event] of this.causalBuffer) {
  if (this.canDeliver(event)) {
    deliverable.push(event);
  }
}

// Deliver events in causal order
for (const event of deliverable) {
  this.causalBuffer.delete(event.id);
  this.deliverEvent(event);
}

} }

CRDT Composition Framework

class CRDTComposer { constructor() { this.compositeTypes = new Map(); this.transformations = new Map(); }

// Define composite CRDT structure defineComposite(name, schema) { this.compositeTypes.set(name, { schema: schema, factory: (nodeId, replicationGroup) => this.createComposite(schema, nodeId, replicationGroup) }); }

createComposite(schema, nodeId, replicationGroup) { const composite = new CompositeCRDT(nodeId, replicationGroup);

for (const [fieldName, fieldSpec] of Object.entries(schema)) {
  const fieldCRDT = this.createFieldCRDT(fieldSpec, nodeId, replicationGroup);
  composite.addField(fieldName, fieldCRDT);
}

return composite;

}

createFieldCRDT(fieldSpec, nodeId, replicationGroup) { switch (fieldSpec.type) { case 'counter': return fieldSpec.decrements ? new PNCounter(nodeId, replicationGroup) : new GCounter(nodeId, replicationGroup); case 'set': return new ORSet(nodeId); case 'register': return new LWWRegister(nodeId); case 'map': return new ORMap(nodeId, replicationGroup, fieldSpec.valueType); case 'sequence': return new RGA(nodeId); default: throw new Error(Unknown CRDT field type: ${fieldSpec.type}); } } }

class CompositeCRDT { constructor(nodeId, replicationGroup) { this.nodeId = nodeId; this.replicationGroup = replicationGroup; this.fields = new Map(); this.updateCallbacks = []; }

addField(name, crdt) { this.fields.set(name, crdt);

// Subscribe to field updates
crdt.onUpdate((delta) => {
  this.notifyUpdate({
    type: 'FIELD_UPDATE',
    field: name,
    delta: delta
  });
});

}

getField(name) { return this.fields.get(name); }

merge(otherComposite) { let changed = false;

for (const [fieldName, fieldCRDT] of this.fields) {
  const otherField = otherComposite.fields.get(fieldName);
  if (otherField) {
    const oldState = fieldCRDT.clone();
    fieldCRDT.merge(otherField);
    
    if (!this.statesEqual(oldState, fieldCRDT)) {
      changed = true;
    }
  }
}

if (changed) {
  this.notifyUpdate({
    type: 'COMPOSITE_MERGE',
    mergedFrom: otherComposite
  });
}

}

serialize() { const serialized = {};

for (const [fieldName, fieldCRDT] of this.fields) {
  serialized[fieldName] = fieldCRDT.serialize();
}

return serialized;

}

onUpdate(callback) { this.updateCallbacks.push(callback); }

notifyUpdate(delta) { this.updateCallbacks.forEach(callback => callback(delta)); } }

Integration with Consensus Protocols

CRDT-Enhanced Consensus

class CRDTConsensusIntegrator { constructor(consensusProtocol, crdtSynchronizer) { this.consensus = consensusProtocol; this.crdt = crdtSynchronizer; this.hybridOperations = new Map(); }

// Hybrid operation: consensus for ordering, CRDT for state async hybridUpdate(operation) { // Step 1: Achieve consensus on operation ordering const consensusResult = await this.consensus.propose({ type: 'CRDT_OPERATION', operation: operation, timestamp: Date.now() });

if (consensusResult.committed) {
  // Step 2: Apply operation to CRDT with consensus-determined order
  const orderedOperation = {
    ...operation,
    consensusIndex: consensusResult.index,
    globalTimestamp: consensusResult.timestamp
  };
  
  await this.crdt.applyOrderedOperation(orderedOperation);
  
  return {
    success: true,
    consensusIndex: consensusResult.index,
    crdtState: this.crdt.getCurrentState()
  };
}

return { success: false, reason: 'Consensus failed' };

}

// Optimized read operations using CRDT without consensus async optimisticRead(key) { return this.crdt.read(key); }

// Strong consistency read requiring consensus verification async strongRead(key) { // Verify current CRDT state against consensus const consensusState = await this.consensus.getCommittedState(); const crdtState = this.crdt.getCurrentState();

if (this.statesConsistent(consensusState, crdtState)) {
  return this.crdt.read(key);
} else {
  // Reconcile states before read
  await this.reconcileStates(consensusState, crdtState);
  return this.crdt.read(key);
}

} }

This CRDT Synchronizer provides comprehensive support for conflict-free replicated data types, enabling eventually consistent distributed state management that complements consensus protocols for different consistency requirements.