> A) Why async in the user code? Is it really necessary?
It's not a requirement, but it's simpler to default to one and mention the other. You can see an example of sync code in https://github.com/helderco/dagger-examples/blob/main/say_sy... and we'll add a guide in the docs website to explain the difference.
Why async?
It's more inclusive. If you want to run dagger from an async environment (say FastAPI), you don't want to run blocking code. You can run the whole pipeline in a thread, but not really taking advantage of the event loop. It's simpler to do the opposite because if you run in a sync environment (like all our examples, running from CLI), it's much easier to just spin an event loop with `anyio.run`.
It's more powerful. For most examples probably the difference is small, unless you're using a lot of async features. Just remove async/await keywords and the event loop. But you can easily reach for concurrency if there's benefit. While the dagger engine ensures most of the parallelism and efficiency, some pipelines can benefit from doing this at the language level. See this example where I'm testing a library (FastAPI) with multiple Python versions: https://github.com/helderco/dagger-examples/blob/main/test_c.... It has an obvious performance benefit compared to running "synchronously": https://github.com/helderco/dagger-examples/blob/main/test_m...
Dagger has a client and a server architecture, so you're sending requests through the network. This is an especially common use case for using async.
Async Python is on the rise. More and more libraries are supporting it, more users are getting to know it, and sometimes it feels very transitional. It's very hard to maintain both async and sync code. There's a lot of duplication because you need blocking and non-blocking versions for a lot of things like network requests, file operations and running subprocesses. But I've made quite an effort to support both and meet you where you're at. I especially took great care to hide the sync/async classes and methods behind common names so it's easy to change from one to another.
I'm very interested to know the community's adoption or preference of one vs the other. :)