https://nalar.dev/tags/context-variables/ Recent content in Context Variables on Nalar Hugo en-us Tue, 08 Sep 2026 00:00:00 +0700 https://nalar.dev/keep-request-state-local-with-contextvars/ Tue, 08 Sep 2026 00:00:00 +0700 https://nalar.dev/keep-request-state-local-with-contextvars/ <p>Passing a request ID through every function is explicit, but after a few layers it can become noise. Logging is the example I keep running into: the logger needs the request ID, while most business functions do not actually care about it.</p> <p>A global variable looks tempting until two requests run concurrently. <code>threading.local()</code> fixes a different problem, but one event-loop thread can execute many asyncio tasks. Python&rsquo;s <code>contextvars</code> module is designed for this kind of context-local state.</p>