Excluding rules from certain platforms about buck2

[zjturner]

Try this:

In your .buckconfig file:

[gsoyka]
is_ci = false

In a BUCK file somewhere:

build_go_binary = not read_config("gsoyka", "is_ci", false)

go_binary(
    name = "hello",
    srcs = glob(["*.go"]),
    deps = [
        "//go/hello/greeting:greeting",
    ],
) if build_go_binary else None

[gsoyka]

Thanks, that's helpful, and I think that can be made to work for my use case. If I have a rule defined, eg. my_rule(), is it possible to generalize that logic to apply to all my_rule instances within a project when the config value is set to true?

[zjturner]

You could make a macro. From a bzl file somewhere:

build_go_binary = not read_config("gsoyka", "is_ci", false)

def my_rule_macro(name, srcs, deps):
    go_binary(
        name = "hello",
        srcs = glob(["*.go"]),
        deps = [
            "//go/hello/greeting:greeting",
        ],
    ) if build_go_binary else None

and have people call your macro instead of your rule.

[gsoyka]

That makes sense to me, when I tried the example I'm seeing the behavior I want, but am getting an error about a missing symbol. Is there something the macro can return that isn't None that still does nothing?

[zjturner]

Try:

if build_go_binary:
go_binary(…)

hard to say without seeing your error

[cjhopman]

Reading the docs, it seems like constraints added to our platform should work

Yeah, marking it target incompatible will cause it to be skipped without error when resolved in a pattern like //... or //foo: (but error when used explicitly like //foo:xyz).

You could actually still use the config value to set things up if you wanted, somethign like this could work:

constraint_setting(
  name = "none",
)

my_rule(
  ...
  target_compatible_with = [] if read_config("foo", "is_ci", False) else [":none"]
)