https://cassiobotaro.dev/en/tags/broadcast/Recent content in Broadcast on cassiobotaroHugoenThu, 15 Oct 2026 08:39:11 -0300https://cassiobotaro.dev/en/posts/go-concurrency-tee/Thu, 15 Oct 2026 00:00:00 +0000https://cassiobotaro.dev/en/posts/go-concurrency-tee/<video src="https://cassiobotaro.dev/videos/tee.mp4" title="Each value of a channel copied to every output" aria-label="Each value of a channel copied to every output" autoplay loop muted playsinline controls preload="metadata" style="width: 100%; height: auto;"> </video> <p>In the <a href="https://cassiobotaro.dev/en/posts/go-concurrency-fan-out/" >fan-out</a> each value went to only one worker.</p> <p>But what if both need to see everything? One writes to the log and the other updates a metric, for example. Neither of them can miss a value.</p> <h2 id="what-a-tee-is"> What a tee is <a class="heading-link" href="#what-a-tee-is"> <i class="fa-solid fa-link" aria-hidden="true" title="Link to heading"></i> <span class="sr-only">Link to heading</span> </a> </h2> <p>A tee copies each value of an input channel to all the output channels. The name comes from the Unix <code>tee</code> command, which duplicates whatever it receives.</p>