Hello!
a rust rookie here, I'm trying to generate a smaller docker images for a rust projects. I want to be able to do code changes from a shared volume to make development and reload of these projects much faster or automated. I followed a couple of the guides but got errors. Is there a working guide on how to create such images?
To be clear, you’re trying to create a “development” time image, not the “ship it to production” image?
Can you share your dockerfile?
yes that's correct, I have multiple projects that I want to create containers for and manage them with a docker-compose file. This is my docker file, I'm using a demo app to make this work first:
FROM rust AS build
WORKDIR /usr/src
# Download the target for static linking.
RUN rustup target add x86_64-unknown-linux-musl
RUN USER=root cargo new my-app
WORKDIR /usr/src/my-app
COPY Cargo.toml Cargo.lock ./
RUN cargo build --release
# Copy the source and build the application.
COPY src ./src
RUN cargo install --target x86_64-unknown-linux-musl --path .
# Copy the statically-linked binary into a scratch container.
FROM scratch
COPY --from=build /usr/local/cargo/bin/my-app .
USER 1000
CMD ["./my-app"]
the result:
build failed
The command '/bin/sh -c cargo install --target x86_64-unknown-linux-musl --path .' returned a non-zero code: 101
new error now
error occurred: Failed to find tool. Is musl-gcc installed? I couldn't find this as a brew or a cask formula. any idea how to install this on a Mac?
Why on Mac? Don't you need it in the docker?
I'm using my MacBook as a dev machine. I don't have a linux box. I have docker desktop installed with Kubernetes enabled and a VMware image running for the docker machine.
I'm now trying to test creating two rust containers. Trying to figure out how the workflow of dev / build / publish to Kubernetes works!!
I can always run VMware and install docker on the linux virtual to do the development if that resolve some issues. Would that be more ideal?
I thought you want to build inside of docker, so the Mac is irrelevant... Also you are already running docker in a virtualized Linux, that's how docker on Mac and Windows works for non Mac/Windows containers...
yes that's correct this is why I'm reaching out for help. What am I missing?
The build happens inside the “build” Docker container. You likely need to install musl-gcc.
RUN apt update && apt-get install -y musl-gcc && rm -rf /var/lib/apt/lists/*
Note that the last step removes apt files that are not necessary after installation in order to reduce image size. Although, I wouldn’t worry about image size until after you have a working container.
I've been looking into static builds and docker size, you can check my experiences Static Build of Rust Executables | Ivanovo
Few generals comments:
I added this now getting this error
E: Unable to locate package musl-gcc
The command '/bin/sh -c apt-get update && apt-get install -y musl-gcc && rm -rf /var/lib/apt/lists/*' returned a non-zero code: 100
I'll check the link thanks
According to Debian -- Error, the musl-gcc compiler is provided by the package musl-tools. You probably want to install that.
I changed the install to musl-tools and that solved it but now the original error:
error: no binaries are available for install using the selected features
The command '/bin/sh -c cargo install --target x86_64-unknown-linux-musl --path .' returned a non-zero code: 101
This command tells Cargo to look in the current directory for your own project, and install binaries from it in ~/.cargo/bin.
Do you need this? Do you actually have binaries? Do you use required-features to disable them?
I thought the project gets outputted as one binary that would need to be copied to that directory!! isn't that the case? I was following the guide I saw online from a couple of posts!
When you run cargo build (or run/test/bench), the project is built in ./target, and all results sit there.
You never need to call cargo install to build a project, unless you want to actually install the produced binary as a system-wide developer tool living in Cargo's bin directory.
If your project is a library, then cargo install doesn't make any sense and serves no purpose.
my project is an api that runs a web server
If you want to deploy the binary on the server, then copying from ./target to some other "deployment" destination OK-ish. cargo install does basically the same thing.
For slightly better deployment, if you use Debian/Ubuntu, I suggest running cargo deb or cargo deb --install, which will properly install the binary on the system.
