Re: [Buildroot] [[Next]RFC] sdk-docker: new make target using Dockcross

[Joachim Wiberg <troglobit@gmail.com>]

Hi,

sorry for the late review:

On Sun, Feb 14, 2021 at 23:32, Matt Weber <matt@thewebers.ws> wrote:
> This patch adds a new make target for building a Docker with
> an SDK installed. This patch has not been broken up and is for
> RFC only to get feedback on the technical approach.
>
>  - `make sdk-docker` first sets up the dockcross package and
>    the environment-setup script to stage the environment.
>
>  - The dockcross package in Buildroot includes a folder with
>    a custom Dockerfile and pre-exec setup scripts which are
>    copied into the dockcross build folder at configure time.
>    This Dockerfile uses the Buildroot base and sets up other
>    tools to allow a project to completely execute a build flow
>    with make / cmake / meson / scons.
>
>  - Within the Dockcross package, the entrypoint and sudo
>    scripting are reused but a new standard image/custom image
>    is not defined.  Instead this patchset duplicates the
>    docker build step in the Buildroot top-level Makefile.
>    The entrypoint / sudo scripting were reused because it
>    handles seamless mapping of the calling user into the
>    container for the build and back with all the files uid/gid
>    intacted.
>
>  - One of the best advantages of this environment is the
>    fact it resets on each new lauch and is clean for a new
>    build.  I.e. just the PWD which is mapped as /work inside
>    is maintained after the container tears down.
>
>  - I'm unsure if it makes sense to use dockcross or just pull
>    over the concepts they use into Buildroot directly....
>    I think I found a good balance considering each Buildroot
>    defconfig build is unique so it doesn't seem like there is
>    a chance to upstream a Buildroot configuration to dockcross.
>
>  - TODO: Add a manual section that includes usage notes
>
>  - How to test
>    make qemu_aarch64_virt_defconfig
>    make sdk-docker
>    # Usage from https://github.com/dockcross/dockcross
>    # Setup container launch script
>    docker run --rm dockcross/buildroot-sdk-aarch64-buildroot-linux-gnu  > ./dockcross
>    # This dockcross script maps the pwd into the container as /work
>    # as well as the current users $HOME as $HOME inside.
>    # Executing the script to dump the env, should list all the
>    # environment-setup exported values for use
>    ./dockcross bash -c 'export'
>    # Check that the cross toolchain executes
>    ./dockcross bash -c '$CC -version'
>
> Signed-off-by: Matt Weber <matt@thewebers.ws>

This looks *really* interesting!  At $DAYJOB we currently have locally
maintained docker containers to get reproducible build environments on
developer laptops.  Having it integrated in Buildroot would be great!

I've tested your patch using latest Buildroot and qemu_x86_64_defconfig
but it failed with the following, which turned out to be a too old
buildroot/base.  When I bumped to 20211120.1925 it worked fine.  Turns
out GitHub dropped insecure cryptos last summer and the old Debian base
had a bit too old curl:

Downloading https://github.com/tianon/gosu/releases/download/1.10/gosu-amd64
######################################################################## 100.0%
curl: (35) Unknown SSL protocol error in connection to objects.githubusercontent.com:443 
The command '/bin/sh -c set -x &&   /buildscripts/install-gosu-binary.sh &&   /buildscripts/install-gosu-binary-wrapper.sh &&   rm -rf /buildscripts' returned a non-zero code: 35
make[1]: *** [Makefile:629: sdk-docker] Error 35

Only two things that stick out to me are:

 1. might need to have some small check in the top Makefile to verify
    that 'docker' is available on the host system -- maybe obvious to
    experienced users, but it would help reduce the support burden for
    the mailing list, I think
 2. the dockcross project apparently doesn't do releases, or even tags,
    so it might be a bit of a hassle to track changes and do updates?
    Maybe we could reach out to them and ask for tags, at least

Can't give better technical feedback than that, maybe Mr Petazzoni can
chime in here wrt the actual integration.

Reviewed-by: Joachim Wiberg <troglobit@gmail.com>

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