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 if sys.version_info[0] < 3: JSON_SERIALIZABLE_TYPES = (bool, int, long, float, basestring) else: JSON_SERIALIZABLE_TYPES = (bool, int, float, str) def run_in_subprocess(builder_function): # Run in subprocess only while running the build on Windows if sys.platform not in ('win32', 'cygwin'): return 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] # 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'])