import os import sys import json import uuid import functools import subprocess # NOTE: The multiprocessing module is not compatible with SCons due to conflict on cPickle JSON_SERIALIZABLE_TYPES = (bool, int, float, str) def run_in_subprocess(builder_function): @functools.wraps(builder_function) def wrapper(target, source, env): # Convert SCons Node instances to absolute paths target = [node.srcnode().abspath for node in target] source = [node.srcnode().abspath for node in source] # Short circuit on non-Windows platforms, no need to run in subprocess if sys.platform not in ("win32", "cygwin"): return builder_function(target, source, env) # Identify module module_name = builder_function.__module__ function_name = builder_function.__name__ module_path = sys.modules[module_name].__file__ if module_path.endswith(".pyc") or module_path.endswith(".pyo"): module_path = module_path[:-1] # Subprocess environment subprocess_env = os.environ.copy() subprocess_env["PYTHONPATH"] = os.pathsep.join([os.getcwd()] + sys.path) # Keep only JSON serializable environment items filtered_env = dict((key, value) for key, value in env.items() if isinstance(value, JSON_SERIALIZABLE_TYPES)) # Save parameters args = (target, source, filtered_env) data = dict(fn=function_name, args=args) json_path = os.path.join(os.environ["TMP"], uuid.uuid4().hex + ".json") with open(json_path, "wt") as json_file: json.dump(data, json_file, indent=2) json_file_size = os.stat(json_path).st_size print( "Executing builder function in subprocess: " "module_path=%r, parameter_file=%r, parameter_file_size=%r, target=%r, source=%r" % (module_path, json_path, json_file_size, target, source) ) try: exit_code = subprocess.call([sys.executable, module_path, json_path], env=subprocess_env) finally: try: os.remove(json_path) except (OSError, IOError) as e: # Do not fail the entire build if it cannot delete a temporary file print( "WARNING: Could not delete temporary file: path=%r; [%s] %s" % (json_path, e.__class__.__name__, e) ) # Must succeed if exit_code: raise RuntimeError( "Failed to run builder function in subprocess: module_path=%r; data=%r" % (module_path, data) ) return wrapper def subprocess_main(namespace): with open(sys.argv[1]) as json_file: data = json.load(json_file) fn = namespace[data["fn"]] fn(*data["args"])