severance-processor

Severance Processor

The severance processor Lambda function automatically detects federation relationship severances by monitoring DynamoDB streams for:

1. Domain Blocks: When a domain is blocked, all relationships with users from that domain are severed
2. Federation Issues: When critical federation issues are detected (unreachable instances, timeouts)
3. Instance Health: When an instance becomes unhealthy based on federation metrics

Event Flow

1. DynamoDB stream event triggers Lambda
2. Processor examines the event for severance indicators
3. If a severance is detected, affected relationships are counted
4. A severance record is created with:
   • Remote instance
   • Reason (domain block, instance down, etc.)
   • Affected followers/following counts
   • Auto-detection flag
   • Severity based on impact
5. Event is emitted to streaming system for real-time notifications

Severity Levels

• High: > 1000 affected relationships
• Medium: 100-1000 affected relationships
• Low: < 100 affected relationships

Integration

The processor integrates with:

• Severance Service: Creates and manages severance records
• Event Bus: Publishes SEVERANCE_DETECTED events
• Federation Service: Monitors federation health
• Relationship Storage: Counts affected relationships

Deployment

Built and deployed as part of the CDK infrastructure stack:

• Triggered by DynamoDB stream events
• IAM permissions for DynamoDB, CloudWatch
• Environment variables from CDK config