Error handling resilience

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Error Handling & Resilience Deep Dive

Overview

Network errors are inevitable. Handle gracefully.

Core Concepts

Error categories: - No connectivity (offline) - Timeout - 4xx client error (retry-safe: only 429) - 5xx server error (retry-safe) - Parse error (non-retriable)

Code Examples

// Error classification
sealed class Result<T> {
    data class Success<T>(val data: T) : Result<T>()
    data class NetworkError<T>(val ex: IOException) : Result<T>()
    data class HttpError<T>(val code: Int) : Result<T>()
    data class ParseError<T>(val ex: Exception) : Result<T>()
}
// Retry decision
fun shouldRetry(result: Result<*>): Boolean {
    return result is Result.NetworkError || 
           result is Result.HttpError && result.code >= 500
}

Senior-Level Insights

• Classify errors for metrics
• Fallback to cached data
• Expose errors to user appropriately