nits

buck2/rust/BUCK

@@ -74,4 +74,4 @@ rust_test(
         "//platforms:engflow": "//platforms:remote_execution_action_keys",
         "DEFAULT": None,
     }),
-)
+)

buck2/rust/README.md

@@ -11,7 +11,7 @@ It is based on two existing samples in the Buck2 upstream repo:
 
 In the `platforms` cell we specify:
 In the `platforms` cell we specify:
-* The platform used for remote execution in this project `root//platforms:remote_platform`, which includes the definition of the Docker image used for remote execution, and that defines constraints for targets to run in the remote execution environment. This platform provides an `ExecutionPlatformRegistrationInfo` a `ConfigurationInfo` and a `PlatformInfo` to be able to be used in the `.buckconfig`, and in the `exec_compatible_with` and `default_target_platform` of `rust_*` rules. Note since rust rules depend on C++ linking this is needed similarly to the Buck2 cpp example in this repo.
+* The platform used for remote execution in this project `root//platforms:remote_platform`, which includes the definition of the Docker image used for remote execution, and that defines constraints for targets to run in the remote execution environment. This platform provides an `ExecutionPlatformRegistrationInfo` a `ConfigurationInfo` and a `PlatformInfo` to be able to be used in the `.buckconfig`, in the `--target-platforms` flag, and in the `exec_compatible_with` of `rust_*` rules. Note since rust rules depend on C++ linking this is needed similarly to the Buck2 cpp example in this repo.
 * The action keys `root//platforms:remote_execution_action_keys`, which provides a default `BuildModeInfo` that is needed for RE of tests to function properly.
 * The platform `image` configured in `platforms/defs.bzl`, notably, uses a different image than other Buck2 samples in this repo. Specifically, it uses a public AWS image that has `rust` preinstalled. This is because Buck2 rust rules do not include a hermetic rust toolchain.
 
@@ -40,6 +40,8 @@ You can also build the `main` for this sample by running:
 buck2 build --target-platforms //platforms:remote_platform //:main
 ```
 
+Note the use of `--target-platforms` to select the remote platform as part of the build / test command.
+
 ### Relevant configs in `.buckconfig`
 
 The EngFlow endpoint and certificate should be configured as the

buck2/rust/platforms/BUCK

@@ -39,4 +39,4 @@ action_keys(
     cell = "standard",
     mode = "standard",
     visibility = ["PUBLIC"],
-)
+)

buck2/rust/platforms/defs.bzl

@@ -73,4 +73,4 @@ action_keys = rule(
         "mode": attrs.string(),
      },
      impl = _action_keys
-)
+)