Add support for adding arbitrary docker build flags

[kuza55]

Is your feature request related to a problem? Please describe.
Docker has a lot of different flags, most of which are not officially supported via pants, I'd like to be able to use them without needing code changes to pants.

extra_runs_args got added in #20440 but the build args version was never added.

Describe the solution you'd like
I'd like docker_image and pants.toml to get some extra parameters for extra_command_line_build_args to be passed to docker build..

Describe alternatives you've considered
Adding every flag to pants that does not need special handling seems wasteful.

[huonw]

This does seem sensible.

The hardest bit is probably deciding on a name that doesn't conflict with the existing extra_build_args field (https://www.pantsbuild.org/stable/reference/targets/docker_image#extra_build_args). Maybe extra_docker_build_args or extra_args_for_docker_build are good enough?

Would you like to contribute this?

Breadcrumbs:

• a new field like extra_run_args:

  pants/src/python/pants/backend/docker/target_types.py

  Lines 592 to 597 in c4da187

  	class DockerImageRunExtraArgsField(StringSequenceField):
  	alias: ClassVar[str] = "extra_run_args"
  	default = ()
  	help = help_text(
  	lambda: f"Extra arguments to pass into the invocation of `docker run`. These are in addition to those at the `[{DockerOptions.options_scope}].run_args`"
  	)

• maybe expand get_build_options to yield them too:

  pants/src/python/pants/backend/docker/goals/package_image.py

  Lines 313 to 378 in c4da187

  	def get_build_options(
  	context: DockerBuildContext,
  	field_set: DockerPackageFieldSet,
  	global_target_stage_option: str | None,
  	global_build_hosts_options: dict | None,
  	global_build_no_cache_option: bool | None,
  	use_buildx_option: bool,
  	target: Target,
  	) -> Iterator[str]:
  	# Build options from target fields inheriting from DockerBuildOptionFieldMixin
  	for field_type in target.field_types:
  	if issubclass(field_type, DockerBuildKitOptionField):
  	if use_buildx_option is not True:
  	if target[field_type].value != target[field_type].default:
  	raise DockerImageOptionValueError(
  	f"The {target[field_type].alias} field on the = `{target.alias}` target in `{target.address}` was set to `{target[field_type].value}`"
  	f" and buildx is not enabled. Buildx must be enabled via the Docker subsystem options in order to use this field."
  	)
  	else:
  	# Case where BuildKit option has a default value - still should not be generated
  	continue
  	if issubclass(
  	field_type,
  	(
  	DockerBuildOptionFieldMixin,
  	DockerBuildOptionFieldMultiValueDictMixin,
  	DockerBuildOptionFieldListOfMultiValueDictMixin,
  	DockerBuildOptionFieldValueMixin,
  	DockerBuildOptionFieldMultiValueMixin,
  	DockerBuildOptionFlagFieldMixin,
  	),
  	):
  	source = InterpolationContext.TextSource(
  	address=target.address, target_alias=target.alias, field_alias=field_type.alias
  	)
  	format = partial(
  	context.interpolation_context.format,
  	source=source,
  	error_cls=DockerImageOptionValueError,
  	)
  	yield from target[field_type].options(format, global_build_hosts_options=global_build_hosts_options) # type: ignore[attr-defined]
  	# Target stage
  	target_stage = None
  	if global_target_stage_option in context.stages:
  	target_stage = global_target_stage_option
  	elif field_set.target_stage.value:
  	target_stage = field_set.target_stage.value
  	if target_stage not in context.stages:
  	raise DockerBuildTargetStageError(
  	f"The {field_set.target_stage.alias!r} field in `{target.alias}` "
  	f"{field_set.address} was set to {target_stage!r}"
  	+ (
  	f", but there is no such stage in `{context.dockerfile}`. "
  	f"Available stages: {', '.join(context.stages)}."
  	if context.stages
  	else f", but there are no named stages in `{context.dockerfile}`."
  	)
  	)
  	if target_stage:
  	yield from ("--target", target_stage)
  	if global_build_no_cache_option:
  	yield "--no-cache"