Leverage <a target="_blank" href="https://docs.celeryq.dev/en/stable/userguide/canvas.html#chains">Celery Chains</a> to execute sequential tasks. But it wasn't clear from the documentation on how to add a delay in-between executions.
The initial (reasonable) attempt:
<pre><code class="lang-python">result = (
 add.s(1,1) |
 mul.s(3) | 
 mul.s(4)
).apply_async(countdown=5) # 24
</code></pre>
resulted in the task completing immediately.
However setting the <code>countdown</code> for each signature* worked.
<pre><code class="lang-python">result = (
 add.s(1,1) | 
 mul.s(3).set(countdown=5) | 
 mul.s(4).set(countdown=5)
) # 24
</code></pre>
<blockquote>
*use <a target="_blank" href="https://docs.celeryq.dev/en/stable/userguide/canvas.html#immutability">immutable signatures</a> (shortcut: si) so the next task doesn't require the return value of the previous one who's result is implicitly passed as the first argument
</blockquote>

Leverage [Celery Chains](https://docs.celeryq.dev/en/stable/userguide/canvas.html#chains) to execute sequential tasks. But it wasn't clear from the documentation on how to add a delay in-between executions.

The initial (reasonable) attempt:

```python
result = (
  add.s(1,1) |
  mul.s(3) | 
  mul.s(4)
).apply_async(countdown=5)  # 24
```

resulted in the task completing immediately.

However setting the `countdown` for each signature\* worked.

```python
result = (
  add.s(1,1) | 
  mul.s(3).set(countdown=5) | 
  mul.s(4).set(countdown=5)
) # 24
```

> \*use [immutable signatures](https://docs.celeryq.dev/en/stable/userguide/canvas.html#immutability) (shortcut: si) so the next task doesn't require the return value of the previous one who's result is implicitly passed as the first argument

Chained celery tasks with delay