Re: [PATCH RFC] docker: automatic dependencies for dockerfiles

["Alex Bennée" <alex.bennee@linaro.org>]

John Snow <jsnow@redhat.com> writes:

> This is a demo for using makefile dependencies for image requisites.
> Honestly, I don't like it -- Makefile sorcery is a bit beyond my
> comprehension.
>
> This is as near as I could stab, and it has the unfortunate requisite
> that it will generate all of the *.d files at first run and not in an
> on-demand way. Boo.
>
> But, I wanted to raise the point that manually managing the variables
> is not long-term viable -- we should manage them automatically if we
> can.

I think this gets more complicated when we want to handle multiple host
architectures as well. We might for example have a final image that is
based of a native docker base in one case and a linux-user docker base
in another.

> As far as "partial" images vs "full" images, we should manage this
> too; perhaps by subdirectory on the dockerfiles -- that way these
> won't get out of date, either.

I'll have an experiment with different layouts and see.

>
> Signed-off-by: John Snow <jsnow@redhat.com>
> ---
>  tests/docker/Makefile.include | 37 ++++++++-------------------------
>  tests/docker/deputil.py       | 39 +++++++++++++++++++++++++++++++++++
>  2 files changed, 48 insertions(+), 28 deletions(-)
>  create mode 100755 tests/docker/deputil.py
>
> diff --git a/tests/docker/Makefile.include b/tests/docker/Makefile.include
> index 50a400b573..266395d927 100644
> --- a/tests/docker/Makefile.include
> +++ b/tests/docker/Makefile.include
> @@ -21,6 +21,7 @@ DOCKER_TOOLS := travis
>  ENGINE := auto
>
>  DOCKER_SCRIPT=$(SRC_PATH)/tests/docker/docker.py --engine $(ENGINE)
> +DEPTOOL=$(SRC_PATH)/tests/docker/deputil.py
>
>  TESTS ?= %
>  IMAGES ?= %
> @@ -47,12 +48,12 @@ docker-image: ${DOCKER_TARGETS}
>  # invoked with SKIP_DOCKER_BUILD we still check the image is up to date
>  # though
>  ifdef SKIP_DOCKER_BUILD
> -docker-image-%: $(DOCKER_FILES_DIR)/%.docker
> +docker-image-%: $(DOCKER_FILES_DIR)/%.docker %.d
>  	$(call quiet-command, \
>  		$(DOCKER_SCRIPT) check --quiet qemu:$* $<, \
>  		"CHECK", "$*")
>  else
> -docker-image-%: $(DOCKER_FILES_DIR)/%.docker
> +docker-image-%: $(DOCKER_FILES_DIR)/%.docker %.d
>  	$(call quiet-command,\
>  		$(DOCKER_SCRIPT) build qemu:$* $< \
>  		$(if $V,,--quiet) $(if $(NOCACHE),--no-cache) \
> @@ -88,23 +89,17 @@ docker-binfmt-image-debian-%: $(DOCKER_FILES_DIR)/debian-bootstrap.docker
>  endif
>
>  # Enforce dependencies for composite images
> -docker-image-debian9-mxe: docker-image-debian9
> +%.d: $(DOCKER_FILES_DIR)/%.docker
> +	$(call quiet-command, $(DEPTOOL) $(DOCKER_FILES_DIR)/$*.docker > $@)
> +
> +DEPFILES := $(DOCKER_IMAGES:%=%.d)
> +include $(DEPFILES)
> +
>  ifeq ($(ARCH),x86_64)
> -docker-image-debian-amd64: docker-image-debian9
>  DOCKER_PARTIAL_IMAGES += debian-amd64-cross
>  else
> -docker-image-debian-amd64-cross: docker-image-debian10
>  DOCKER_PARTIAL_IMAGES += debian-amd64
>  endif
> -docker-image-debian-armel-cross: docker-image-debian9
> -docker-image-debian-armhf-cross: docker-image-debian9
> -docker-image-debian-mips-cross: docker-image-debian9
> -docker-image-debian-mipsel-cross: docker-image-debian9
> -docker-image-debian-mips64el-cross: docker-image-debian9
> -docker-image-debian-ppc64el-cross: docker-image-debian9
> -docker-image-debian-s390x-cross: docker-image-debian9
> -docker-image-debian-win32-cross: docker-image-debian9-mxe
> -docker-image-debian-win64-cross: docker-image-debian9-mxe
>
>  # For non-x86 hosts not all cross-compilers have been packaged
>  ifneq ($(ARCH),x86_64)
> @@ -115,22 +110,8 @@ DOCKER_PARTIAL_IMAGES += debian-win32-cross debian-win64-cross
>  DOCKER_PARTIAL_IMAGES += fedora travis
>  endif
>
> -docker-image-debian-alpha-cross: docker-image-debian10
> -docker-image-debian-arm64-cross: docker-image-debian10
> -docker-image-debian-hppa-cross: docker-image-debian10
> -docker-image-debian-m68k-cross: docker-image-debian10
> -docker-image-debian-mips64-cross: docker-image-debian10
> -docker-image-debian-powerpc-cross: docker-image-debian10
> -docker-image-debian-ppc64-cross: docker-image-debian10
> -docker-image-debian-riscv64-cross: docker-image-debian10
> -docker-image-debian-sh4-cross: docker-image-debian10
> -docker-image-debian-sparc64-cross: docker-image-debian10
> -
>  docker-image-travis: NOUSER=1
>
> -# Specialist build images, sometimes very limited tools
> -docker-image-tricore-cross: docker-image-debian9
> -
>  # These images may be good enough for building tests but not for test builds
>  DOCKER_PARTIAL_IMAGES += debian-alpha-cross
>  DOCKER_PARTIAL_IMAGES += debian-hppa-cross
> diff --git a/tests/docker/deputil.py b/tests/docker/deputil.py
> new file mode 100755
> index 0000000000..69711cf85e
> --- /dev/null
> +++ b/tests/docker/deputil.py
> @@ -0,0 +1,39 @@
> +#!/usr/bin/env python3
> +import os
> +import re
> +import sys
> +from typing import IO, Optional
> +
> +def get_dep(infile: IO[str]) -> Optional[str]:
> +    """Get a dependency as a string from a dockerfile."""
> +    for line in infile:
> +        match = re.match(r'FROM (.+)', line)
> +        if match:
> +            return match[1]
> +    return None
> +
> +def get_qemu_dep(infile: IO[str]) -> Optional[str]:
> +    """Get a dependency on the qemu: namespace from a dockerfile."""
> +    dep = get_dep(infile) or ''
> +    match = re.match(r'qemu:(.+)', dep)
> +    return match[1] if match else None
> +
> +def main() -> None:
> +    filename = sys.argv[1]
> +    basefile = os.path.basename(filename)
> +    base = os.path.splitext(basefile)[0]
> +    depfile = f"{base}.d"
> +    deps = [filename]
> +
> +    print(f"{depfile}: {filename}")
> +    with open(filename, "r") as infile:
> +        match = get_qemu_dep(infile) or ''
> +        if match:
> +            deps.append(f"docker-image-{match}")
> +    print("{}: {}".format(
> +        f"docker-image-{base}",
> +        " ".join(deps)
> +    ))
> +
> +if __name__ == '__main__':
> +    main()


--
Alex Bennée