Client from worker context

The River client is made available to workers on the context, making it easy to enqueue additional jobs from within a job.

The River client working a job is stored in a value on the context provided to workers. The client can be retrieved from the context (or any contexts derived from it) using the ClientFromContext helper:

func (w *MyWorker) Work(ctx context.Context, job *river.Job[MyArgs]) error {
    client := river.ClientFromContext(ctx)

    ...
}

If ClientFromContext is called on a context which isn't derived from the work context, it will panic. This situation indicates a programming error so most users will find the panic more convenient, although a non-panicking version is also available:

func (w *MyWorker) Work(ctx context.Context, job *river.Job[MyArgs]) error {
    client, err := river.ClientFromContextSafely(ctx)
    if err != nil {
        return fmt.Errorf("error getting client from context: %w", err)
    }

    ...
}