Downloading azure-sdk-for-rust repository takes a long time

[hlinnaka]

The problem

When building the compute node image, the build clones the full 'azure-sdk-for-rust' repository, with history and all. The repository is about 300 MB in size, so we download that 300 MB on every CI run. I noticed this when building locally; it slows down the local docker build significantly too.

Here's one example run from CI:

#16 [compute-tools 3/3] RUN mold -run cargo build --locked --profile release-line-debug-size-lto --bin compute_ctl --bin fast_import --bin local_proxy
#16 0.494     Updating git repository `[https://github.com/neondatabase/rust-postgres.git`](https://github.com/neondatabase/rust-postgres.git%60)
#16 1.516     Updating crates.io index
#16 1.559     Updating git repository `[https://github.com/neondatabase/azure-sdk-for-rust.git`](https://github.com/neondatabase/azure-sdk-for-rust.git%60)
#16 151.3     Updating git repository `[https://github.com/neondatabase/tokio-epoll-uring.git`](https://github.com/neondatabase/tokio-epoll-uring.git%60)
#16 151.7     Updating git repository `[https://github.com/neondatabase/framed-websockets`](https://github.com/neondatabase/framed-websockets%60)

Note how the "update azure-sdk-for-rust repository" step took about 150 s.

Proposed solution

Ideally, cargo build would make a shallow clone of the repository; the build doesn't actually need the history. A shallow clone would be only about 1 MB. There's an unstable cargo feature to use a different library for downloading git dependencies, which would do just that and fix this issue. Unfortunately it's unstable so it doesn't help us right now. I tested it locally though and it's great.

One easy quick fix we could do is to create a branch in our 'neondatabase/azure-sdk-for-rust' repository which would not include the history, and use that in the CI.

[hlinnaka]

note @arpad-m and @conradludgate since you touched this last.

[arpad-m]

Yeah it's quite slow indeed (and there is no progress indicator or anything).

Ideally the SDK fork is temporary, see #10404. But in the meantime I suppose we could try out making a new branch with the history reset in the meantime. I'll make a PR to test if it improves things.

[arpad-m]

PR filed: #10790