Spectral cli doesn't work in alpine docker image

[slamdev]

Describe the bug
spectral binary doesn't work in alpine docker image

To Reproduce

1. Install spectral via install.sh script
2. Run spectral --help
3. See error

Expected behavior
Help info is displayed.

Additional context

$ docker run -ti alpine
$ apk add curl
$ curl -L https://raw.githack.com/stoplightio/spectral/master/scripts/install.sh | sh
Spectral was installed to: /usr/local/bin/spectral
$ spectral --help
/bin/sh: spectral: not found
$ ls -la /usr/local/bin/spectral
-rwxr-xr-x    1 root     root      57092527 Oct  4 22:12 /usr/local/bin/spectral

[drmmr763]

I'm also having this issue

[DenialAdams]

Hi, I ran into this issue this afternoon and investigated it a bit.

Alpine is a very lightweight linux distribution (as it's intended for use in Docker), and one of the ways that they achieve their lightweight status is by shipping with musl libc instead of the more ubiquitous glibc. However, the spectral-cli binary depends on glibc in order to run. You can see this by looking at the dynamic dependencies:

/usr/local/bin # ldd ./spectral
        /lib64/ld-linux-x86-64.so.2 (0x7fe49baa9000)
        libdl.so.2 => /lib64/ld-linux-x86-64.so.2 (0x7fe49baa9000)
        librt.so.1 => /lib64/ld-linux-x86-64.so.2 (0x7fe49baa9000)
        libstdc++.so.6 => /usr/lib/libstdc++.so.6 (0x7fe49b907000)
        libm.so.6 => /lib64/ld-linux-x86-64.so.2 (0x7fe49baa9000)
        libgcc_s.so.1 => /usr/lib/libgcc_s.so.1 (0x7fe49b8ed000)
        libpthread.so.0 => /lib64/ld-linux-x86-64.so.2 (0x7fe49baa9000)
        libc.so.6 => /lib64/ld-linux-x86-64.so.2 (0x7fe49baa9000)
Error relocating ./spectral: gnu_get_libc_version: symbol not found
Error relocating ./spectral: __register_atfork: symbol not found
Error relocating ./spectral: __strdup: symbol not found
Error relocating ./spectral: setcontext: symbol not found
Error relocating ./spectral: makecontext: symbol not found
Error relocating ./spectral: backtrace: symbol not found
Error relocating ./spectral: getcontext: symbol not found

NOTE - I had to install "libgcc" and "libstdc++" by running:

apk add libstdc++
apk add libgcc

I believe that all of the remaining relocation errors are due to the missing glibc.

So, ideally we'd be able to build the spectral-cli without this dependency on glibc --- the good news is that I took a look at pkg (which is used to build the spectral-cli binary) and it seems like they have an alpine linux target! (which I believe would compile with musl and not require glibc)

https://www.npmjs.com/package/pkg

I'm thinking that we could update the CI configuration to also build the alpine linux binaries (leveraging the --targets flag of pkg), and then include those binaries when cutting a release. I'm not sure exactly what the next steps for that are, but I would love to see that happen so that embedding spectral in docker containers becomes easier!

Also want to note that even after this I think that installing libstdc++ and libgcc to your container will be necessary (see vercel/pkg#726), but that's at least very easy to do with the commands listed above.

[P0lip]

We adjusted the process to include the alpine builds and they're attached to each new release now.