Add no_prelude remote execution to github actions

Enabling testing of remote execution on github actions for `no_prelude`

* Create github action that generates .buckconfig.local using `NATIVELINK_HEADER_RW_KEY` from gha secrets.
* Set `container-image` used for remote execution specific to setup of buck2.
* Update .gitignore to include .buckconfig.local.
* Include a `platforms` configuration for the `no_prelude` example.
* Update `go_toolchain.bzl` to be remote enabled friendly,
  no need to download a toolchain when remote worker has one.

Open question:
* Was the downloading of go toolchain to be remote execution
  compatible prior to this change?

Author: Adam Singer

.github/actions/build_example_nativelink_no_prelude/action.yml

@@ -0,0 +1,27 @@
+name: build_example_nativelink_no_prelude
+inputs:
+  NATIVELINK_HEADER_RW_KEY_SECRET:
+    description: ''
+    required: true
+runs:
+  using: composite
+  steps:
+  - name: Build example/no_prelude directory using remote execution
+    run: |-
+      {
+      echo "[buck2_re_client]
+      engine_address       = grpc://scheduler-buck2.build-faster.nativelink.net:443
+      action_cache_address = grpc://cas-buck2.build-faster.nativelink.net:443
+      cas_address          = grpc://cas-buck2.build-faster.nativelink.net:443
+      http_headers         = x-nativelink-api-key:${NATIVELINK_HEADER_RW_KEY}
+      tls = true
+      instance_name = main
+      enabled = true
+      [build]
+        execution_platforms = root//platforms:platforms"
+      } > examples/no_prelude/.buckconfig.local
+      cd examples/no_prelude
+      $RUNNER_TEMP/artifacts/buck2 build //... -v 4
+    env:
+      NATIVELINK_HEADER_RW_KEY: ${{ inputs.NATIVELINK_HEADER_RW_KEY_SECRET }}
+    shell: bash

.github/workflows/build-and-test.yml

@@ -48,6 +48,9 @@ jobs:
         $RUNNER_TEMP/artifacts/buck2 build //... -v 2
         $RUNNER_TEMP/artifacts/buck2 test //... -v 2
     - uses: ./.github/actions/build_example_no_prelude
+    - uses: ./.github/actions/build_example_nativelink_no_prelude
+      with:
+        NATIVELINK_HEADER_RW_KEY_SECRET: ${{ secrets.NATIVELINK_HEADER_RW_KEY_SECRET }}
     - uses: ./.github/actions/setup_reindeer
     - uses: ./.github/actions/build_bootstrap
   linux-build-examples:

.gitignore

@@ -2,6 +2,7 @@
 Cargo.lock
 buck-out
 /.direnv
+.buckconfig.local
 
 # symlinks
 /examples/with_prelude/prelude

examples/no_prelude/go/rules.bzl

@@ -14,7 +14,7 @@ def _go_binary_impl(ctx: AnalysisContext) -> list[Provider]:
 
     cmd = cmd_args([ctx.attrs.toolchain[GoCompilerInfo].compiler_path, "build", "-o", out.as_output()] + sources)
 
-    ctx.actions.run(cmd, category = "compile")
+    ctx.actions.run(cmd, env = {"GOCACHE":ctx.attrs.toolchain[GoCompilerInfo].GOCACHE}, category = "compile")
 
     return [
         DefaultInfo(default_output = out),

examples/no_prelude/platforms/BUCK

@@ -0,0 +1,3 @@
+load(":defs.bzl", "platforms")
+
+platforms(name = "platforms")

examples/no_prelude/platforms/defs.bzl

@@ -0,0 +1,33 @@
+# Copyright (c) Meta Platforms, Inc. and affiliates.
+#
+# This source code is licensed under both the MIT license found in the
+# LICENSE-MIT file in the root directory of this source tree and the Apache
+# License, Version 2.0 found in the LICENSE-APACHE file in the root directory
+# of this source tree.
+
+def _platforms(ctx):
+    configuration = ConfigurationInfo(
+        constraints = {},
+        values = {},
+    )
+
+    platform = ExecutionPlatformInfo(
+        label = ctx.label.raw_target(),
+        configuration = configuration,
+        executor_config = CommandExecutorConfig(
+            local_enabled = True,
+            remote_enabled = True,
+            use_limited_hybrid = True,
+            # Set those up based on what workers you've registered with NativeLink.
+            remote_execution_properties = {
+                "OSFamily": "linux",
+                "container-image": "docker://buck2-github:latest",
+            },
+            remote_execution_use_case = "buck2-default",
+            remote_output_paths = "output_paths",
+        ),
+    )
+
+    return [DefaultInfo(), ExecutionPlatformRegistrationInfo(platforms = [platform])]
+
+platforms = rule(attrs = {}, impl = _platforms)

examples/no_prelude/toolchains/go_toolchain.bzl

@@ -7,24 +7,33 @@
 
 GoCompilerInfo = provider(
     doc = "Information about how to invoke the go compiler.",
-    fields = ["compiler_path", "GOROOT"],
+    fields = ["compiler_path", "GOROOT", "GOCACHE"],
 )
 
+def is_remote_enabled() -> bool:
+    re_enabled = read_root_config("buck2_re_client", "enabled", "false")
+    return re_enabled == "true"
+
 def _go_toolchain_impl(ctx):
-    download = _download_toolchain(ctx)
+    is_re_enabled = is_remote_enabled()
+    gocache="/tmp/gocache"
+    if is_re_enabled:
+        return [DefaultInfo(), GoCompilerInfo(compiler_path = "go", GOROOT = "", GOCACHE=gocache)]
+    else:
+        download = _download_toolchain(ctx)
 
-    compiler_dst = ctx.actions.declare_output("compiler.exe" if host_info().os.is_windows else "compiler")
+        compiler_dst = ctx.actions.declare_output("compiler.exe" if host_info().os.is_windows else "compiler")
 
-    cmd = cmd_args()
-    if host_info().os.is_windows:
-        compiler_src = cmd_args(download, format = "{}\\go\\bin\\go.exe", relative_to = (compiler_dst, 1))
-        cmd.add([ctx.attrs._symlink_bat, compiler_dst.as_output(), compiler_src])
-    else:
-        compiler_src = cmd_args(download, format = "{}/go/bin/go", relative_to = (compiler_dst, 1))
-        cmd.add(["ln", "-sf", compiler_src, compiler_dst.as_output()])
+        cmd = cmd_args()
+        if host_info().os.is_windows:
+            compiler_src = cmd_args(download, format = "{}\\go\\bin\\go.exe", relative_to = (compiler_dst, 1))
+            cmd.add([ctx.attrs._symlink_bat, compiler_dst.as_output(), compiler_src])
+        else:
+            compiler_src = cmd_args(download, format = "{}/go/bin/go", relative_to = (compiler_dst, 1))
+            cmd.add(["ln", "-sf", compiler_src, compiler_dst.as_output()])
 
-    ctx.actions.run(cmd, category = "cp_compiler")
-    return [DefaultInfo(default_output = download), GoCompilerInfo(compiler_path = compiler_dst, GOROOT = "")]
+        ctx.actions.run(cmd, category = "cp_compiler")
+        return [DefaultInfo(default_output = download), GoCompilerInfo(compiler_path = compiler_dst, GOROOT = "", GOCACHE=gocache)]
 
 go_toolchain = rule(
     impl = _go_toolchain_impl,