Error Handling and Logging Strategy Designer

You are a reliability engineer who designs robust error handling systems. Design an error handling and logging strategy for this application.

Application type: [WEB APP / API / MICROSERVICE / CLI]
Language/Framework: [STACK]
Current error handling: [DESCRIBE OR PASTE EXAMPLES]
Logging infrastructure: [CLOUDWATCH / DATADOG / ELK / OTHER]
Environments: [DEV / STAGING / PROD]

Design:

**Error Classification**
```
Operational Errors (expected, recoverable):
- Network timeouts
- Validation failures
- Rate limits

Programmer Errors (bugs):
- Type errors
- Null references
- Logic errors
```

**Error Response Format**
```json
{
  "error": {
    "code": "ERROR_CODE",
    "message": "User-friendly message",
    "details": {},
    "requestId": "uuid",
    "documentation": "url"
  }
}
```

**Error Codes Catalog**
| Code | HTTP Status | Description | User Message |
|------|-------------|-------------|-------------|

**Custom Error Classes**
```[language]
class AppError extends Error {
  // Implementation with proper inheritance
}
```

**Logging Strategy**

Log Levels:
- ERROR: [When to use]
- WARN: [When to use]
- INFO: [When to use]
- DEBUG: [When to use]

Structured Log Format:
```json
{
  "timestamp": "",
  "level": "",
  "message": "",
  "context": {},
  "requestId": ""
}
```

**Sensitive Data Handling**
- Fields to redact
- Redaction patterns
- PII handling

**Monitoring & Alerting**
- Error rate thresholds
- Alert conditions
- Runbook triggers
- Dashboard requirements

**Recovery Patterns**
- Retry strategies
- Circuit breakers
- Fallbacks
- Graceful degradation

You are a reliability engineer who designs robust error handling systems. Design an error handling and logging strategy for this application.

Application type: [WEB APP / API / MICROSERVICE / CLI]
Language/Framework: [STACK]
Current error handling: [DESCRIBE OR PASTE EXAMPLES]
Logging infrastructure: [CLOUDWATCH / DATADOG / ELK / OTHER]
Environments: [DEV / STAGING / PROD]

Design:

**Error Classification**
```
Operational Errors (expected, recoverable):
- Network timeouts
- Validation failures
- Rate limits

Programmer Errors (bugs):
- Type errors
- Null references
- Logic errors
```

**Error Response Format**
```json
{
  "error": {
    "code": "ERROR_CODE",
    "message": "User-friendly message",
    "details": {},
    "requestId": "uuid",
    "documentation": "url"
  }
}
```

**Error Codes Catalog**
| Code | HTTP Status | Description | User Message |
|------|-------------|-------------|-------------|

**Custom Error Classes**
```[language]
class AppError extends Error {
  // Implementation with proper inheritance
}
```

**Logging Strategy**

Log Levels:
- ERROR: [When to use]
- WARN: [When to use]
- INFO: [When to use]
- DEBUG: [When to use]

Structured Log Format:
```json
{
  "timestamp": "",
  "level": "",
  "message": "",
  "context": {},
  "requestId": ""
}
```

**Sensitive Data Handling**
- Fields to redact
- Redaction patterns
- PII handling

**Monitoring & Alerting**
- Error rate thresholds
- Alert conditions
- Runbook triggers
- Dashboard requirements

**Recovery Patterns**
- Retry strategies
- Circuit breakers
- Fallbacks
- Graceful degradation