https://kevinwang930.github.io/tags/flow-control/Recent content in Flow-Control on Kevin wang's blogHugoen-USMon, 24 Aug 2026 22:00:00 +0200https://kevinwang930.github.io/post/java/spring-cloud/sentinel/Mon, 24 Aug 2026 22:00:00 +0200https://kevinwang930.github.io/post/java/spring-cloud/sentinel/<p><strong>Sentinel</strong> is Alibaba&rsquo;s library for flow control, concurrency limiting, circuit breaking, and system protection. An application protects a named <strong>resource</strong> by entering it through <code>SphU.entry</code>. A processor slot chain records statistics for that resource and applies the rules loaded at runtime.</p> <hr> <h2 id="1-overview">1. Overview</h2> <p>A resource is a string chosen by the caller: an HTTP path, a service method, or any other name. <code>SphU.entry(resourceName)</code> opens the resource and <code>entry.exit()</code> closes it. Between those two calls, Sentinel runs a <code>ProcessorSlotChain</code> built once per resource.</p>