https://nalar.dev/tags/errgroup/ Recent content in Errgroup on Nalar Hugo en-us Wed, 16 Sep 2026 00:00:00 +0700 https://nalar.dev/go-errgroup-setlimit-blocks-submitters-at-concurrency-cap/ Wed, 16 Sep 2026 00:00:00 +0700 https://nalar.dev/go-errgroup-setlimit-blocks-submitters-at-concurrency-cap/ <p><code>errgroup.Group.SetLimit</code> can block the goroutine that calls <code>Group.Go</code>. The limit is enforced before a new worker goroutine starts, so a full group applies backpressure at task submission rather than building an internal queue.</p> <p>That behavior matters when submission is part of another control path. A loop that appears to launch work asynchronously can itself stop at <code>g.Go(...)</code> until one active function returns.</p> <h2 id="the-limit-sits-on-admission">The limit sits on admission</h2> <p>A zero-value <code>errgroup.Group</code> has no concurrency limit. After <code>SetLimit(n)</code>, at most <code>n</code> functions started by <code>Go</code> are active at once. A negative limit restores unlimited admission, while a zero limit prevents every later <code>Go</code> call from starting a function.</p>