Wire Ctrl-C / SIGTERM via signal.NotifyContext in main

byob-lifecycle.2 concurrencycontextlifecycle

Problem: users hit Ctrl-C and expect the CLI to stop. Naive implementations either ignore the signal (process gets killed uncleanly, orphaning subprocesses and DB connections) or reach for channels, goroutines, and shutdown flags — all of which have to be plumbed into every blocking call.

Idea: use signal.NotifyContext(ctx, os.Interrupt, syscall.SIGTERM) at the top of main(). It returns a context.Context that cancels when either signal fires. Thread that context into root.ExecuteContext(ctx), and every downstream HTTP call, DB query, or subprocess that accepts a context.Context cancels automatically — no channels, no goroutines, no shutdown flags.

Defer cancel() immediately after to release the signal handler on clean exit. A second Ctrl-C then reverts to the default handler and force-exits, which is the right behavior: the first one asks politely; the second kills.

Tradeoffs: the catch is that your runFuncs and everything they call must actually thread ctx through (see byob-lifecycle.1). If they don't, the context cancels but nobody listens. That's a one-time audit.

When not to use: never for a production CLI. Every CLI should exit cleanly on Ctrl-C.

Design

func main() {
    ctx, cancel := signal.NotifyContext(
        context.Background(), os.Interrupt, syscall.SIGTERM,
    )
    defer cancel()

    root := pkgcmd.NewCmdRoot(factory.New())
    if err := root.ExecuteContext(ctx); err != nil {
        os.Exit(exitCodeFor(err))
    }
}