Compilation error : failed to run custom build command for 'ring v0.16.20'

[albanducos87]

Hello everyone
I hava an issue when I want to execute this command : serverless deploy

My terminal show me an error and after many and many attempts, I don't know what to do.

Here's the error :

[demeringo]

Hello @albanducos87, thank you for openning the issue.

I did not test (yet) the compilation or serverless deployment from Windows, as I do all the development from Linux.

But I suspect that the error is related to cross-compiling (from a windows machine to produce a binary suitable for lambda deployment). Something may be need to be installed for the cross compilation to work from Windows.

I really do not have much experience with such setup, but solution may be related to something like:

• https://github.com/briansmith/ring/blob/main/BUILDING.md#supported-toolchains
• https://users.rust-lang.org/t/how-to-cross-compile-linux-binaries-with-rust-from-windows-hosts/15218/4
• Cross compiling from Windows to Linux japaric/rust-cross#33 (comment)

Posssible workaround:

If setting up a Rust + serverless environment on Windows is too much complication, a simpler workaroound could be either to

• run the commands from WSL (The Windows Subsystem for Linux)
  or
• use a temporary AWS or Azure Linux instance (Ubuntu or Debian) and use it to checkout / compile / deploy the lambdas.

Sadly, I may not be able to give you much support in the coming days, because I'm traveling and do not have a Windows laptop with me to do the tests.

[jfaixo]

Hi,

I reproduced the problem. This is a problem related to cross compilation of the ring crate while targetting linux-musl (the target that is set in serverless) from windows.

I don't know serverless very well, but it might be more robust to compile the rust part inside a linux container with the proper toolchain (musl & co :) )

See for example: briansmith/ring/#1472

The workaround seems to be to use WSL when you want to cross-compile...

[demeringo]

Thanks @jfaixo, I realize that I used the dockerless=true setting in the serverless.yml file:

cloud-scanner/serverless.yml

Line 26 in 5ace291

dockerless: true

According to serverless-rust plugin doc, it means that I had to add the x86_64-unknown-linux-musl target https://github.com/softprops/serverless-rust#-experimental-local-builds.

I probably did this initially with the following command: rustup target add x86_64-unknown-linux-musl

[jfaixo]

Rust is usually very good at cross compilation, but the ring crate embeds C code I think, which require to have a fully blown toolchain for compiling C for the target platform, so it's becoming way more complex.. containerizing is the way !

[demeringo]

I finally tested building or deploying the serverless app from Windows using WSL2 + Ubuntu. It works ⚡,
You can use this way until we provide a simpler building container for windows....

Added procedure here: https://boavizta.github.io/cloud-scanner/how-to/building-cli.html and https://boavizta.github.io/cloud-scanner/how-to/deploy-sls.html.

[demeringo]

Long story short,:

1. we need to install musl development packages in Linux.
2. add x86_64-unknown-linux-musl as a target for the Rust compiler .

1. Check availability and install if needed musl

#  Warning: musl-gcc may be missing, wich results in error: 
#    error: failed to run custom build command for `ring v0.16.20`
# it can be verified by trying to call musl-gcc on command prompt
# $ musl-gcc
# Which results in:
#    Command 'musl-gcc' not found, but can be installed with:
# This musl-gcc is not available (preventing cross compilation)

# On linux  Need to install musl-gcc
sudo apt update && sudo apt install -y musl-tools musl-dev

2. Install x86_64-unknown-linux-musl as rustup target

# Add Linux musl target (needed for cross compilation for aws lambda)
rustup target add x86_64-unknown-linux-musl

[demeringo]

Not yet mentionned in the docs but I published a docker image to use Rust + Serverless in CI:
https://github.com/demeringo/rust-serverless-ci

# get image
docker pull ghcr.io/demeringo/rust-serverless-ci:latest