[bazel] Use exec_tools instead of tools for better RBE compatibility

The tools in genrules [1] correspond to the HOST's version, which
is a problem if we are doing cross-platform builds. In this case,
when I was using my M1 Mac to run on a Linux RBE platform, the
Mac's python binaries (e.g. python3_9_aarch64-apple-darwin/bin/python3)
were being uploaded to RBE and attempted to be used, which resulted
in OSError: [Errno 8] Exec format error because the won't run
on the Linux RBE machine.

Thanks to tjgq@, I learned about exec_tools [2], which will use
the version of the tools for the EXECUTION platform, which
is exactly what we want.

While debugging this, I added a minimal reproduction case in
//experimental/bazel_test and updated the py_tools version
in an effort to diagnose the issue further.

We will need to contribute similar fixes to @spirv_tools

[1] https://bazel.build/reference/be/general#genrule.tools
[2] https://bazel.build/reference/be/general#genrule.exec_tools
Bug: skia:12541
Change-Id: Ib14deb4e326d3103fd08c21e93afe342d751c17a
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/554518
Reviewed-by: Jorge Betancourt <jmbetancourt@google.com>

WORKSPACE.bazel

@@ -61,12 +61,12 @@ bazel_toolchains_repositories()
 # https://github.com/bazelbuild/rules_python
 http_archive(
     name = "rules_python",
-    sha256 = "9fcf91dbcc31fde6d1edb15f117246d912c33c36f44cf681976bd886538deba6",
-    strip_prefix = "rules_python-0.8.0",
+    sha256 = "5fa3c738d33acca3b97622a13a741129f67ef43f5fdfcec63b29374cc0574c29",
+    strip_prefix = "rules_python-0.9.0",
     urls = [
-        "https://github.com/bazelbuild/rules_python/archive/refs/tags/0.8.0.tar.gz",
-        "https://storage.googleapis.com/skia-world-readable/bazel/9fcf91dbcc31fde6d1edb15f117246d912c33c36f44cf681976bd886538deba6.tar.gz",
-    ],
+    "https://github.com/bazelbuild/rules_python/archive/refs/tags/0.9.0.tar.gz",
+    "https://storage.googleapis.com/skia-world-readable/bazel/5fa3c738d33acca3b97622a13a741129f67ef43f5fdfcec63b29374cc0574c29.tar.gz",
+    ]
 )
 
 # This sets up a hermetic python3, rather than depending on what is installed.

bazel/external/dawn/BUILD.bazel

@@ -46,7 +46,7 @@ genrule(
           "--template-dir $$(dirname $(location generator/templates/api_cpp.h)) " +
           "--targets cpp_headers " +
           "--output-dir $(RULEDIR)",
-    tools = [":dawn_json_generator"],
+    exec_tools = [":dawn_json_generator"],
 )
 
 genrule(
@@ -68,7 +68,7 @@ genrule(
           "--template-dir $$(dirname $(location generator/templates/api.h)) " +
           "--targets headers " +
           "--output-dir $(RULEDIR)",
-    tools = [":dawn_json_generator"],
+    exec_tools = [":dawn_json_generator"],
 )
 
 genrule(
@@ -90,7 +90,7 @@ genrule(
           "--template-dir $$(dirname $(location generator/templates/BSD_LICENSE)) " +
           "--targets proc " +
           "--output-dir $(RULEDIR)",
-    tools = [":dawn_json_generator"],
+    exec_tools = [":dawn_json_generator"],
 )
 
 genrule(
@@ -110,7 +110,7 @@ genrule(
           "--template-dir $$(dirname $(location generator/templates/BSD_LICENSE)) " +
           "--targets cpp " +
           "--output-dir $(RULEDIR)",
-    tools = [":dawn_json_generator"],
+    exec_tools = [":dawn_json_generator"],
 )
 
 genrule(
@@ -154,7 +154,7 @@ genrule(
           "--template-dir $$(dirname $(location generator/templates/BSD_LICENSE)) " +
           "--targets native_utils " +
           "--output-dir $(RULEDIR)",
-    tools = [":dawn_json_generator"],
+    exec_tools = [":dawn_json_generator"],
 )
 
 py_binary(
@@ -187,7 +187,7 @@ genrule(
           "--gpu-info-json $(location src/dawn/gpu_info.json) " +
           "--template-dir $$(dirname $(location generator/templates/BSD_LICENSE)) " +
           "--output-dir $(RULEDIR)",
-    tools = [":dawn_gpu_info_generator"],
+    exec_tools = [":dawn_gpu_info_generator"],
 )
 
 py_binary(
@@ -222,7 +222,7 @@ genrule(
           "--template-dir $$(dirname $(location generator/templates/BSD_LICENSE)) " +
           "--dawn-dir $$(dirname $(location generator/templates/BSD_LICENSE)) " +
           "--output-dir $(RULEDIR) 2> /dev/null",
-    tools = [":dawn_version_generator"],
+    exec_tools = [":dawn_version_generator"],
 )
 
 DAWN_HDRS = [

experimental/bazel_test/BUILD.bazel

@@ -1,5 +1,6 @@
 load("//bazel:macros.bzl", "cc_binary", "exports_files_legacy", "go_binary", "go_library")
 load("//bazel:cc_library_with_flags.bzl", "cc_library_with_flags")
+load("@rules_python//python:defs.bzl", "py_binary")
 
 licenses(["notice"])
 
@@ -36,3 +37,18 @@ go_library(
     importpath = "go.skia.org/skia/experimental/bazel_test",
     visibility = ["//visibility:private"],
 )
+
+py_binary(
+    name = "print_os",
+    srcs = ["print_os.py"],
+)
+
+genrule(
+    name = "generate_file",
+    srcs = [],
+    outs = [
+        "some_file.txt",
+    ],
+    cmd = "$(location :print_os) $@",
+    exec_tools = [":print_os"],
+)

experimental/bazel_test/print_os.py

@@ -0,0 +1,23 @@
+#!/usr/bin/python3
+
+'''
+Copyright 2022 Google LLC
+
+Use of this source code is governed by a BSD-style license that can be
+found in the LICENSE file.
+'''
+
+import os
+import platform
+import sys
+
+def main():
+  print("hello", sys.argv)
+  print(os.name, platform.system(), platform.release())
+  if len(sys.argv) > 1:
+    with open(sys.argv[1], "w") as f:
+      f.write("created")
+
+
+if __name__ == "__main__":
+  main()

modules/canvaskit/BUILD.bazel

@@ -58,7 +58,7 @@ genrule(
           # in the fonts/ subdirectory as if it had been there all along.
           "--output=$@ " +
           "--align=4",
-    tools = ["//tools:embed_resources"],
+    exec_tools = ["//tools:embed_resources"],
 )
 
 # Note: These are defines that only impact the _bindings.cpp files in this folder.

third_party/BUILD.bazel

@@ -1355,7 +1355,7 @@ genrule(
           # The $@ means substitute in the one and only output location, which will be located
           # in //bazel-out.
           "$@",
-    tools = [":make_data_cpp"],
+    exec_tools = [":make_data_cpp"],
 )
 
 # We need to make a separate genrule per input because cmd cannot be based on a select()
@@ -1369,7 +1369,7 @@ genrule(
           # The $@ means substitute in the one and only output location, which will be located
           # in //bazel-out.
           "$@",
-    tools = [":make_data_assembly"],
+    exec_tools = [":make_data_assembly"],
 )
 
 genrule(
@@ -1382,7 +1382,7 @@ genrule(
           # The $@ means substitute in the one and only output location, which will be located
           # in //bazel-out.
           "$@",
-    tools = [":make_data_assembly"],
+    exec_tools = [":make_data_assembly"],
 )
 
 genrule(
@@ -1395,7 +1395,7 @@ genrule(
           # The $@ means substitute in the one and only output location, which will be located
           # in //bazel-out.
           "$@",
-    tools = [":make_data_assembly"],
+    exec_tools = [":make_data_assembly"],
 )
 
 py_binary(