Module Resilience 

Resilience Patterns Module

Provides robust resilience patterns for external service calls:

• Exponential backoff retry logic with jitter
• Circuit breaker pattern for fault isolation
• Bulkhead pattern for resource isolation
• Timeout management with cascading deadlines

Responsibilities

Retry Patterns

• Exponential backoff with jitter for distributed systems
• Adaptive retry policies based on error classification
• Retry budget management for service rate limiting
• Panic recovery for background retry tasks

Circuit Breaker

• Automatic fault detection and isolation
• State consistency validation across transitions
• Event publishing for telemetry integration
• Half-open state monitoring for recovery testing

Bulkhead Pattern

• Concurrent request limiting for resource protection
• Queue management with overflow protection
• Load monitoring and metrics collection
• Timeout validation for all operations

Timeout Management

• Cascading deadline propagation
• Global deadline coordination
• Operation timeout enforcement
• Panic-safe timeout cancellation

Integration with Mountain

Resilience patterns directly support Mountain’s stability by:

• preventing cascading failures through circuit breaker isolation
• managing load through bulkhead resource limits
• providing event publishing for Mountain’s telemetry dashboard
• enabling adaptive retry behavior for improved service availability

VSCode Stability References

Similar patterns used in VSCode for:

• External service resilience (telemetry, updates, extensions)
• Editor process isolation and recovery
• Background task fault tolerance

Reference: vs/base/common/errors

TODOs

• [DISTRIBUTED TRACING] Integrate with Tracing module for retry/circuit span correlation
• [CUSTOM METRICS] Add detailed bulkhead load metrics to Metrics module
• [EVENT PUBLISHING] Extend circuit breaker events with OpenTelemetry support
• [ADAPTIVE POLICIES] Enhance retry policies with machine learning-based error prediction
• [METRICS INTEGRATION] Export resilience metrics to Mountain’s telemetry UI

Sensitive Data Handling

This module does not process sensitive data directly but should:

• Redact error messages before logging/event publishing
• Avoid including request payloads in resilience events
• Sanitize service names before publishing to telemetry

Structs

BulkheadConfig

Bulkhead configuration

BulkheadExecutor

Bulkhead semaphore for resource isolation with metrics and panic recovery

BulkheadStatistics

Bulkhead statistics for metrics export

CircuitBreaker

Circuit breaker for fault isolation with state consistency validation and event publishing

CircuitBreakerConfig

Circuit breaker configuration

CircuitEvent

Circuit breaker events for metrics and telemetry integration

CircuitStatistics

Circuit breaker statistics for metrics export

ResilienceOrchestrator

Resilience orchestrator combining all patterns

RetryEvent

Events published by retry operations for metrics and telemetry integration

RetryManager

Retry manager with budget tracking and adaptive policies

RetryPolicy

Retry policy configuration

TimeoutManager

Timeout manager for cascading deadlines with validation

Enums

CircuitState

Circuit breaker states

ErrorClass

Error classification for adaptive retry policies