refactor(bazel): extract repository rule helpers

MODULE.bazel.lock

@@ -93,7 +93,7 @@
   "moduleExtensions": {
     "//bazel:rust_toolchain.bzl%rust": {
       "general": {
-        "bzlTransitiveDigest": "fQj9CTS2ItcWLOd4VcpBs75mepI/nRwLQOA3c7X5QG4=",
+        "bzlTransitiveDigest": "dVDpuhw0j4+nz6zvC0CHD8HwV8sSxepnzuFdoOftyBk=",
         "usagesDigest": "SQP3kWaLgKBHOdfxAvAWSUMuSfW8zC/274pBGhq2FlQ=",
         "recordedFileInputs": {},
         "recordedDirentsInputs": {},

bazel/BUILD

@@ -1 +1,4 @@
-exports_files(["rust_toolchain.bzl"])
+exports_files([
+    "rust_toolchain.bzl",
+    "utils.bzl",
+])

bazel/rust_toolchain.bzl

@@ -1,3 +1,6 @@
+load("//bazel:utils.bzl", _execute = "execute", _require = "require")
+
+
 def _rust_repository_impl(repository_ctx):
     rustc = _require(repository_ctx, "rustc")
     rustdoc = _require(repository_ctx, "rustdoc")
@@ -36,20 +39,6 @@ def _rust_repository_impl(repository_ctx):
     repository_ctx.file("BUILD.bazel", _build_file(host_triple, release))
 
 
-def _require(repository_ctx, executable):
-    path = repository_ctx.which(executable)
-    if path == None:
-        fail("{} must be available in PATH.".format(executable))
-    return path
-
-
-def _execute(repository_ctx, arguments):
-    result = repository_ctx.execute(arguments)
-    if result.return_code != 0:
-        fail("command failed: {}\n{}".format(" ".join(arguments), result.stderr))
-    return result.stdout.strip()
-
-
 def _build_file(host_triple, release):
     return """
 filegroup(

bazel/utils.bzl

@@ -0,0 +1,12 @@
+def require(repository_ctx, executable):
+    path = repository_ctx.which(executable)
+    if path == None:
+        fail("{} must be available in PATH.".format(executable))
+    return path
+
+
+def execute(repository_ctx, arguments):
+    result = repository_ctx.execute(arguments)
+    if result.return_code != 0:
+        fail("command failed: {}\n{}".format(" ".join(arguments), result.stderr))
+    return result.stdout.strip()