What is this repo?

This repo goes through setting up the tutorial Rocket app, vendors its dependencies using cargo vendor, then tries to use cargo chef to cache dependency builds between Docker builds.

How do I "run" this?

This repo requires access to docker-compose (or enough Docker knowledge to know how to map ports) and Docker.

From the root directory:

docker-compose up

docker-compose will build and run this application. If it's successful, http://localhost:8000 will display "Hello, world!".

But will it be successful?

Currently, no. This is because cargo chef will copy over the projects in vendor, skelefy them, then cargo will complain that their checksums have changed:

 > [cacher 9/9] RUN cargo chef cook --offline --recipe-path recipe.json:
#20 1.101 error: the listed checksum of `/opt/hellow/vendor/rocket/tests/file_server.rs` has changed:
#20 1.101 expected: 160173f59a4bf801bf893d952927d5d03a2baa4f7e5b94e193bf28e2b109fa4f
#20 1.101 actual:   e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855
#20 1.101
#20 1.101 directory sources are not intended to be edited, if modifications are required then it is recommended that `[patch]` is used with a forked copy of the source
#20 1.103 thread 'main' panicked at 'Exited with status code: 101', /usr/local/cargo/registry/src/github.com-1ecc6299db9ec823/cargo-chef-0.1.21/src/recipe.rs:136:27
#20 1.103 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
------
executor failed running [/bin/sh -c cargo chef cook --offline --recipe-path recipe.json]: exit code: 101
ERROR: Service 'hellow-rocket' failed to build : Build failed

What can we do?

Try to read .cargo/config.toml and ignore that directory when we skelefy files? That seems the most straightforward to me.

How did you create this repo?

I followed the steps for Getting Started with Rocket. I then tried to recreate another issue I'm working on with cargo chef, but it turns out that it's pretty isolated.

Interested in the isolated issue?

Quickly, rather than de-taring a dependency saved with cargo-local-registry, it seems like we copied an entire Git repo as a patch for a dependency for Rust. This re-joined several crates that are in the same repo but published separately, leading to unergonomic usage of specifying patches. See LukeMathWalker/cargo-chef#70 (comment) for more details. In this repo's history, trying to recreate corresponds to commits 701804162b960d0534e307a9c0e89bb4ad860313--5dc7d4539161f762935d324be1de2218482650c4.

While trying to recreate that issue, though, I found that cargo vendor includes raw Rust files, so cargo chef might accidentally skelefy them. I ran cargo run to populate Cargo.lock, then ran cargo sync and edited .cargo/config.toml to use the local file. I then set up Dockerfiles to try to build these vendored dependencies.