rust-musl-builder/README.md

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# `rust-musl-builder`: Docker container for easily building static Rust binaries
Do you want to compile a completely static Rust binary with no external
dependencies? If so, try:
```sh
alias rust-musl-builder='docker run --rm -it -v "$(pwd)":/home/rust/src ekidd/rust-musl-builder'
rust-musl-builder cargo build --rebase
```
This command assumes that `$(pwd)` is readable and writable by uid 1000,
gid 1000. It will output binaries in
`target/x86_64-unknown-linux-musl/release`. At the moment, it doesn't
attempt to cache libraries between builds, so this is best reserved for
making final release builds.
## Deploying your Rust application
With a bit of luck, you should be able to just copy your application binary
from `target/x86_64-unknown-linux-musl/release`, and install it directly on
any reasonably modern x86_64 Linux machine. In particular, you should be
able to copy your Rust application into an
[Alpine Linux container][].
## How it works
`rust-musl-builder` uses [musl-libc][], [musl-gcc][], and the new
[rustup][] `target` support. It includes static versions of several
libraries:
- The standard `musl-libc` libraries.
- OpenSSL, which is needed by many Rust applications.
## Adding more C libraries
If you're using Docker crates which require specific C libraries to be
installed, you can create a Dockerfile based on this one, and use
`musl-gcc` to compile the libraries you need. For example:
```Dockerfile
FROM ekidd/rust-musl-builder:stable
RUN VERS=1.2.8 && \
mkdir -p /home/rust/libs && cd /home/rust/libs && \
curl -LO http://zlib.net/zlib-$VERS.tar.gz && \
tar xzf zlib-$VERS.tar.gz && cd zlib-$VERS && \
CC=musl-gcc ./configure --static --prefix=/usr/local/musl && \
make && sudo make install && \
rm -rf /home/rust/libs/zlib-$VERS.tar.gz /home/rust/libs/zlib-$VERS
```
This usually involves a bit of experimentation for each new library, but it
seems to work well for most simple, standalone libraries.
If you need an especially common library, please feel free to submit a pull
request adding it to the main `Dockerfile`! We'd like to support popular
Rust crates out of the box.
[Alpine Linux container]: https://hub.docker.com/_/alpine/
[musl-libc]: http://www.musl-libc.org/
[musl-gcc]: http://www.musl-libc.org/how.html
[rustup]: https://www.rustup.rs/