facebook
Document mixed/heterogeneous builds across different operating systems
Is it possible to have a BUILD step automatically run on a remote host if the local OS is not target_compatible without having to use --fake-host?
E.g I want to make something like this to work:
genrule(
name = "hello_windows",
out = "hello_windows.txt",
cmd = "echo Hello from Windows >> $OUT",
target_compatible_with = ["config//os:windows"],
)
genrule(
name = "hello_linux",
out = "hello_linux.txt",
cmd = "sha1sum $(location :hello_windows) >> $OUT",
target_compatible_with = ["config//os:linux"],
)
This is similar to the following bazel issues:
- https://github.com/bazelbuild/bazel/issues/19587
- https://github.com/bazelbuild/bazel/issues/19209
- https://github.com/bazelbuild/bazel/issues/5309
buck2 build root//:from_linux --out=- --prefer-local does now work with the following example but I hoped that buck2 would fallback to local execution if the remote_execution_properties could not be satisfied.
For now I am required to use --prefer-local.
buck2 build root//:from_linux --out=- --prefer-local
File changed: root//BUCK
Build ID: f7875f28-00da-483e-82e9-1d5e1e5bc5b8
Network: (GRPC-SESSION-ID)
Jobs completed: 14. Time elapsed: 0.2s.
Cache hits: 0%. Commands: 2 (cached: 0, remote: 1, local: 1)
BUILD SUCCEEDED
Hello from Windows!!!
Microsoft Windows [Version 10.0.22000.2538]
Linux 6.6.1-arch1-1 #1 SMP PREEMPT_DYNAMIC Wed, 08 Nov 2023 16:05:38 +0000
genrule(
name = "hello_from_windows",
out = "hello_from_windows.txt",
cmd = "echo Hello from Windows!!! >> $OUT & ver >> $OUT",
exec_compatible_with = ["config//os:windows"],
)
genrule(
name = "from_linux",
out = "hello_linux.txt",
cmd = "cat $(location :hello_from_windows) >> $OUT; uname -svr >> $OUT;",
exec_compatible_with = ["config//os:linux"],
)
def _platforms(ctx: AnalysisContext) -> list[Provider]:
name = ctx.label.raw_target()
constraints_windows = dict()
constraints_windows.update(ctx.attrs.os_configuration_windows[ConfigurationInfo].constraints)
platform_windows = ExecutionPlatformInfo(
label = name,
configuration = ConfigurationInfo(
constraints = constraints_windows,
values = {},
),
executor_config = CommandExecutorConfig(
local_enabled = host_info().os.is_windows,
remote_enabled = True,
use_limited_hybrid = True,
remote_execution_properties = {
"OSFamily": "Windows",
},
remote_execution_use_case = "buck2-default",
use_windows_path_separators = True,
),
)
constraints2 = dict()
constraints2.update(ctx.attrs.os_configuration_linux[ConfigurationInfo].constraints)
platform1 = ExecutionPlatformInfo(
label = name,
configuration = ConfigurationInfo(
constraints = constraints2,
values = {},
),
executor_config = CommandExecutorConfig(
local_enabled = host_info().os.is_linux,
remote_enabled = True,
use_limited_hybrid = True,
remote_execution_properties = {
"OSFamily": "Linux",
},
remote_execution_use_case = "buck2-default",
use_windows_path_separators = False,
),
)
return [
DefaultInfo(),
ExecutionPlatformRegistrationInfo(platforms = [platform_windows, platform1]),
]
platforms = rule(
impl = _platforms,
attrs = {
"use_windows_path_separators": attrs.bool(default = False),
"os_configuration_windows": attrs.dep(
providers = [ConfigurationInfo],
default = "config//os:windows",
),
"os_configuration_linux": attrs.dep(
providers = [ConfigurationInfo],
default = "config//os:linux",
),
},
)
So this does work and it is a feature that bazel does not have today.
I am keeping this issue open for now because this feature deserves a bit more documentation / examples:
- exec_compatible_with
- ExecutionPlatformRegistrationInfo with more that one platform
