generate-lockfiles without updating registry

[brson]

Cargobomb has a step where it calls generate-lockfiles 9000 times. Each one of these hits the network to update the registry, which causes a whole lot of latency. I'd like to be able to tell the generate-lockfiles command not to update the registry. Accordingly, I also would need some way to update the registry immediately before generate-lockfiles.

[alexcrichton]

This may actually be relatively easy to do with Cargo's API-as-a-crate rather than Cargo itself on the command line. I wonder if that'd suffice here? It'd certainly be even faster than spawning 9000 cargos

[brson]

Thanks for the advice. I'll look into the api.

[brson]

Here's another request for the feature https://users.rust-lang.org/t/generating-lockfile-without-network-access/9007

[aidanhs]

Related to #1882 - if you can generate a lockfile offline, that's ~equivalent to ignoring registry lookup failures.

[tomprince]

Because of #4066 to run this in a subprocess, so we can time things out.

[Eh2406]

What would be involved in doing this? With some good guidance I myte eavan give this a try.

[alexcrichton]

@Eh2406 I think nowadays this may be mostly covered by #4686, but it'd be good to kick the tires on that and make sure it works!

[Eh2406]

I am a little confused, #4686 is open, but #4770 is merged. Trying to kick the tyres.

>cargo -V
cargo 0.25.0-nightly (a88fbace4 2017-12-29)
>cargo generate-lockfile --manifest-path Cargo.toml
    Updating git repository `https://github.com/Eh2406/average`
    Updating registry `https://github.com/rust-lang/crates.io-index`
    Updating git repository `https://github.com/Eh2406/preferences-rs`
>cargo generate-lockfile --manifest-path Cargo.toml -Z offline
error: unknown `-Z` flag specified: offline

How is this supposed to be used?

[alexcrichton]

Ah that's actually because cargo in rust-lang/rust hasn't been updated yet, although hopefully that should happen soon!

[Eh2406]

Yes that apres to work now! I think this can be closed!

[Eh2406]

Well actually, when I went to use this for crater @aidanhs found a problem.
rust-lang/crater#178 (comment)

So Z offline does not work for this issue. The crater team could use advice on how best to proceed.

[Eh2406]

-Z no-index-update is merged. Move to close.