I'd benefit tremendously from having a private Cargo registry on the cheap. Most solutions I have found require either a live local filesystem or a database such as Postgres.
Since this is for personal use, I'm trying to find a solution which is serverless and without the need for local filesystem persistence. A couple ideas come to mind:
I could build an AWS lambda function with API Gateway to provide a serverless http service, and store data in S3, and wrap an API key system around it for restricting access.
If a database is explicitly required, I could use DynamoDB, which is pay-as-you-go.
If local filesystem persistence is absolutely needed, I could use an EFS shared filesystem, which IIRC is pay as you go.
Although it lacks official support for Rust, AWS CodeArtifact may be an option, as you can store arbitrary tarballs, but I am not sure what actual compute is needed for the registry.
I don't think such a thing exists and I may consider actually building it. The main question I have is whether this is even theoretically possible in the first place. Hopefully some of you know more about how the registry works.
I've built a small registry myself a while ago (might want to revisit it though...), which doesn't use the database, only filesystem. It's probably possible to do without filesystem, but it'll be highly problematic, since Cargo registry must expose a Git repository as index, and I'm not sure whether it's feasible to do this without storing this repository on disk.
I guess now I need to research Git and whether it could be done for blob storage. If it can, it's likely somebody already has done this, but I probably would have heard about it. If filesystem is mandatory, that's totally fine, AWS API Gateway to Lambda in a VPC with an attached EFS mount would do the trick in that case. Seems like a lot of infrastructure for a registry, but it is what it is, I'd rather pay $0 per month if I'm not using it than have fixed costs on it.
IIRC running a private registry only became an option fairly recently within the last few years or so. Hopefully AWS will add a Cargo registry to CodeArtifact, that would put private registries within the hands of engineers with only a few lines of code. No kidding, it was around 10 lines of Terraform to create a pull-through NPM registry.
Git doesn't include a transport for most blob stores' native protocols, but if your blob store exposes (possibly authenticated) plain HTTP/HTTPS, Git (and thus Git-based tools) can probably talk to it.