utility-components_skill

Overview

This skill provides a compact guide to four utility component families used in CI/CD services: JWT security, expression parsing, thread-pool looping utilities, and the chain-of-responsibility pattern. It focuses on practical usage, code snippets, and decision guidance for applying these tools in Kotlin/Java microservice contexts. The content helps engineers choose the right utility for authentication, dynamic evaluations, concurrent processing, and request interception chains.

How this skill works

The skill explains what each component inspects and does: JWT utilities generate, verify, and refresh tokens and integrate with OAuth2; the expression parser evaluates variable and conditional expressions with custom functions and caching; thread-pool and loop utilities manage concurrent batch tasks, retries, and backoff; the responsibility chain composes interceptors to process requests sequentially. Each section includes quick-start examples and recommended configuration patterns for production safety and performance.

When to use it

• Implement stateless authentication, token refresh, or OAuth2 flows for APIs
• Evaluate or expand pipeline variables and conditional logic at runtime
• Process large batches or concurrent jobs with controlled thread pools and retry loops
• Compose request handling, validation, logging, or plugin pipelines using interceptor chains
• Choose tool-level solutions when the need is a focused utility rather than a framework-wide cross-cutting concern

Best practices

• Keep JWT secrets and signing keys in a secure vault and rotate periodically
• Cache parsed expressions and limit dynamic function exposure to avoid injection risks
• Tune thread-pool sizes based on CPU, IO characteristics, and observed latency; use bounded queues
• Use exponential backoff and max-retry limits for external calls to avoid cascading failures
• Design interceptors to be idempotent and fail-fast; keep chain handlers small and single-responsibility

Example use cases

• Protect CI API endpoints with JWT tokens and token refresh flows
• Evaluate pipeline expressions like ${buildId}_${status} with custom functions for formatting
• Run thousands of small tasks concurrently using a configured thread pool and loop utilities for batching
• Implement an interceptor chain for auth, validation, and audit logging in request pipelines
• Wrap external service calls with LoopUtil.loopWithRetry to add resilient retry behavior