Fix serialization of CalledProcessError

bootstrapvz/common/tools.py

@@ -3,9 +3,14 @@ import os
 
 def log_check_call(command, stdin=None, env=None, shell=False, cwd=None):
 	status, stdout, stderr = log_call(command, stdin, env, shell, cwd)
+	from subprocess import CalledProcessError
 	if status != 0:
-		from subprocess import CalledProcessError
-		raise CalledProcessError(status, ' '.join(command), '\n'.join(stderr))
+		e = CalledProcessError(status, ' '.join(command), '\n'.join(stderr))
+		# Fix Pyro4's fixIronPythonExceptionForPickle() by setting the args property,
+		# even though we use our own serialization (at least I think that's the problem).
+		# See bootstrapvz.remote.serialize_called_process_error for more info.
+		setattr(e, 'args', (status, ' '.join(command), '\n'.join(stderr)))
+		raise e
 	return stdout
 
 

bootstrapvz/remote/__init__.py

@@ -33,6 +33,7 @@ supported_exceptions = ['bootstrapvz.common.exceptions.ManifestError',
                         'bootstrapvz.base.pkg.exceptions.SourceError',
                         'bootstrapvz.common.exceptions.UnitError',
                         'bootstrapvz.common.fsm_proxy.FSMProxyError',
+                        'subprocess.CalledProcessError',
                         ]
 
 
@@ -41,6 +42,8 @@ def register_deserialization_handlers():
 		SerializerBase.register_dict_to_class(supported_class, deserialize)
 	for supported_exc in supported_exceptions:
 		SerializerBase.register_dict_to_class(supported_exc, deserialize_exception)
+	import subprocess
+	SerializerBase.register_class_to_dict(subprocess.CalledProcessError, serialize_called_process_error)
 
 
 def unregister_deserialization_handlers():
@@ -73,6 +76,28 @@ def deserialize(fq_classname, data):
 	return instance
 
 
+def serialize_called_process_error(obj):
+	# This is by far the weirdest exception serialization.
+	# There is a bug in both Pyro4 and the Python subprocess module.
+	# CalledProcessError does not populate its args property,
+	# although according to https://docs.python.org/2/library/exceptions.html#exceptions.BaseException.args
+	# it should...
+	# So we populate that property during serialization instead
+	# (the code is grabbed directly from Pyro4's class_to_dict())
+	# However, Pyro4 still cannot figure out to call the deserializer
+	# unless we also use setattr() on the exception to set the args below
+	# (before throwing it).
+	# Mind you, the error "__init__() takes at least 3 arguments (2 given)"
+	# is thrown *on the server* if we don't use setattr().
+	# It's all very confusing to me and I'm not entirely
+	# sure what the exact problem is. Regardless - it works, so there.
+	return {'__class__': obj.__class__.__module__ + '.' + obj.__class__.__name__,
+	        '__exception__': True,
+	        'args': (obj.returncode, obj.cmd, obj.output),
+	        'attributes': vars(obj)  # add custom exception attributes
+	        }
+
+
 def get_class_object(fq_classname):
 	parts = fq_classname.split('.')
 	module_name = '.'.join(parts[:-1])