Add OpenDAL as another kind of storage adapter

[Xuanwo]

Description

Hi, OpenDAL is another widely used storage abstraction in the Rust ecosystem and offers many more storage integrations.

I'm willing to add an OpendalAdapter so that users can choose based on their own needs or existing dependencies.

Do you think it's a good idea?

[jondot]

We currently use object store and kind of wrapped it.

Do you think we should replace object store with this? Will that work better? Im not against replacing as long as we pick a leading store abstraction and keep with it.

[Xuanwo]

Hi @jondot, thank you so much for your swift response!

As an OpenDAL maintainer and object_store contributor, I must acknowledge that my perspective might be somewhat biased.

However, I believe OpenDAL is particularly well-suited for Loco, not just because it offers extensive storage support, but also because it seamlessly integrates with the Rust ecosystem. This includes native logging, tracing, metrics, retry mechanisms, concurrent limits, and speed limit support, all of which are crucial for a robust framework like Loco. All of those features can be enabled by feature flags which compiling.

I'm happy to contribute to this part of the project and take responsibility for further maintenance of the storage component.

[Xuanwo]

Hi, @jondot. I would be happy to implement this change to replace it with opendal. OpenDAL hasn't reached version 1.0 yet (we are working on it: apache/opendal#5189). I will take responsibility for helping upgrade OpenDAL as breaking changes occur, if you want.

I also plan to completely hide opendal and make it purely an implementation detail. This will address the following concern and allow us to switch from opendal easily in the worst-case scenario.

loco/src/storage/drivers/mod.rs

Lines 24 to 26 in 9879c2c

	// TODO: need to properly abstract the object_store type in order to not
	// strongly depend on it
	pub type GetResponse = object_store::GetResult;

[jondot]

@Xuanwo please feel free to submit PR, it sounds good!