Debug Build Container Image for GitHub Packages

2024年9月3日(火) 10:35 Ben Ramsey ramsey@php.net:

Hi Internals.

PHP currently does not provide official container images. Given that
DockerHub adequately maintains these and considering the maintenance costs,
we haven't felt the need to change the status quo.

However, the official DockerHub images lack debug builds, which can
be somewhat inconvenient when trying to report bugs or reproduce issues.

What if we were to provide debug build container images that are
compatible with the official DockerHub images? Fortunately, we already
conduct most of our development on GitHub, which has a container registry
called Packages.

This could be achieved simply by creating a single repository under
the php organization on GitHub. What are your thoughts on this?

Best Regards.
Go Kudo

Since the folks who do the DockerHub builds already have all the
infrastructure set up to maintain the images, I think it might be easier to
work with them to have them provide debug builds.

Perhaps there’s someone from that team on this list who can speak to
that?

Cheers,
Ben

Hey Ben,

what I'd really like to see is not debug-builds, but debug symbols.

Basically, you'd have a docker image "php:8.3" and a docker image
"php:8.3-dbgsym". The former image then just has a gnu_debuglink. The
latter has the actual symbols file included and is based on the former.

Thanks,

Bob

I think the team who manages the Docker builds could also provide
images with debug symbols. Since they’re already equipped for it and have
the experience, why don’t we partner with them to provide these images to
the community?

Cheers,
Ben
Yes. Absolutely.
The problem, however, if you want to provide a build with debug symbols
and one without, the primary value for me would be being able to take a
core dump produced in an image without debug symbols and then simply open
the image with debug symbols and inspect it there.
To the best of my knowledge however, it isn't trivially possible to
build two docker images with the same docker build invocation. Basically
you'd need an intermediary image, from which you then create both (so, 3
different docker builds - one base image which has the build and the
symbols but is not uploaded. And two images where the base images files are
copied into.). I believe this would not be compatible with the way
docker-library/php is built currently.
So, yes, please reach out to them what they are willing to do.

Thanks,
Bob

I opened an issue on their GitHub tracker to gauge their interest:
https://github.com/docker-library/php/issues/1538

Cheers,
Ben

Hi.

I think it's great that drop-in replacement images are being provided on
DockerHub. Thank you for the suggestion!

However, I believe it would be beneficial to have image variants as well.
For instance, providing images with LLVM MemorySanitizer enabled builds
would allow us to easily conduct various tests using our local PHP code.
This would also be useful for testing third-party extensions.

For safely developing PHP extensions, I primarily use the following build
variants:

• The build provided by DockerHub
• GCC debug build
• GCC debug with gcov build
• GCC Valgrind build
• Clang MSan build
• Clang ASan build
• Clang UBSan build

These images are intended for development purposes, and it might be
challenging to host them on DockerHub, which typically hosts images for
general use. That said, I already maintain these [1], and I think it could
be beneficial to offer them as official PHP images. Of course, I plan to
continue maintaining them if we decide to do so.

Additionally, I'd like to point out that we could utilize the existing
GitHub infrastructure for both the build environment and hosting
environment when publishing these images.

[1] https://github.com/colopl/pskel

Best Regards,
Go Kudo