AgentSkillsCN

acc-create-retry-pattern

为 PHP 8.5 生成重试模式。通过指数退避、抖动机制以及可配置的重试策略,打造韧性组件,并附带单元测试。

SKILL.md
--- frontmatter
name: acc-create-retry-pattern
description: Generates Retry pattern for PHP 8.5. Creates resilience component with exponential backoff, jitter, and configurable retry strategies. Includes unit tests.

Retry Pattern Generator

Creates Retry pattern infrastructure for handling transient failures.

When to Use

ScenarioExample
Transient failuresNetwork timeouts, temporary unavailability
External API callsHTTP requests to third-party services
Database operationsDeadlock recovery, connection issues
Message processingQueue message handling with retries

Component Characteristics

RetryPolicy

  • Configures retry behavior
  • Maximum attempts
  • Delay strategy (fixed, exponential, linear)
  • Jitter support to prevent thundering herd

RetryExecutor

  • Executes operations with retry logic
  • Tracks attempt count
  • Applies delay between retries
  • Logs retry attempts

Backoff Strategies

  • Fixed: Same delay every time
  • Linear: Delay increases linearly
  • Exponential: Delay doubles (with optional jitter)

Generation Process

Step 1: Generate Core Components

Path: src/Infrastructure/Resilience/Retry/

  1. BackoffStrategy.php — Enum for delay strategies
  2. RetryPolicy.php — Configuration with shouldRetry/calculateDelay
  3. RetryContext.php — Attempt context value object
  4. RetryException.php — Exception with attempt history

Step 2: Generate Executor

Path: src/Infrastructure/Resilience/Retry/

  1. RetryExecutor.php — Main retry logic with callbacks
  2. SleepInterface.php — For testability

Step 3: Generate Tests

  1. RetryPolicyTest.php — Policy behavior tests
  2. RetryExecutorTest.php — Executor tests

File Placement

ComponentPath
All Classessrc/Infrastructure/Resilience/Retry/
Unit Teststests/Unit/Infrastructure/Resilience/Retry/

Naming Conventions

ComponentPatternExample
PolicyRetryPolicyRetryPolicy
Strategy EnumBackoffStrategyBackoffStrategy
ExecutorRetryExecutorRetryExecutor
ContextRetryContextRetryContext
ExceptionRetryExceptionRetryException
Test{ClassName}TestRetryExecutorTest

Quick Template Reference

RetryPolicy

php
final readonly class RetryPolicy
{
    public function __construct(
        public int $maxAttempts = 3,
        public int $baseDelayMs = 100,
        public int $maxDelayMs = 10000,
        public float $multiplier = 2.0,
        public bool $useJitter = true,
        public BackoffStrategy $strategy = BackoffStrategy::Exponential,
        public array $retryableExceptions = [],
        public array $nonRetryableExceptions = []
    ) {}

    public static function exponential(int $maxAttempts = 5, int $baseDelayMs = 100): self;
    public static function linear(int $maxAttempts = 5, int $baseDelayMs = 500): self;
    public function shouldRetry(\Throwable $e, int $attempt): bool;
    public function calculateDelay(int $attempt): int;
}

RetryExecutor

php
final readonly class RetryExecutor
{
    public function execute(
        callable $operation,
        RetryPolicy $policy,
        ?callable $onRetry = null
    ): mixed;
}

Usage Example

php
$policy = new RetryPolicy(
    maxAttempts: 3,
    baseDelayMs: 200,
    retryableExceptions: [
        ConnectionException::class,
        TimeoutException::class,
    ],
    nonRetryableExceptions: [
        ClientException::class,
    ]
);

try {
    $result = $retryExecutor->execute(
        operation: fn() => $httpClient->get($url),
        policy: $policy,
        onRetry: fn($e, $ctx) => $logger->warning('Retrying...', ['attempt' => $ctx->attempt])
    );
} catch (RetryException $e) {
    // All retries exhausted
    $deadLetter->send($message, $e);
}

Anti-patterns to Avoid

Anti-patternProblemSolution
No Max AttemptsInfinite retriesAlways set maxAttempts
No BackoffHammering serviceUse exponential backoff
Retrying All ExceptionsRetrying unrecoverable errorsSpecify retryable exceptions
No JitterThundering herdEnable jitter
Ignoring ContextCan't track attemptsUse RetryContext
Blocking ForeverThread exhaustionSet maxDelayMs cap

References

For complete PHP templates and examples, see:

  • references/templates.md — RetryPolicy, BackoffStrategy, RetryExecutor, RetryContext templates
  • references/examples.md — HTTP client, database, message consumer examples and tests