Github user tliron commented on a diff in the pull request:
https://github.com/apache/incubator-ariatosca/pull/188#discussion_r131703940
--- Diff: aria/orchestrator/execution_plugin/ctx_proxy/server.py ---
@@ -170,101 +178,59 @@ def _process_ctx_request(ctx, args): # pylint:
disable=too-many-branches,too-man
modifying_key = None
modifying_value = None
- num_args = len(args)
-
- while index < num_args:
- arg = args[index]
-
- # Object attribute
- attr = _desugar_attr(current, arg)
- if attr is not None:
- current = getattr(current, attr)
-
- # List entry
- elif isinstance(current, list) and _is_int(arg):
- current = current[int(arg)]
-
- # Dict (or dict-like object) value
- elif hasattr(current, '__getitem__'):
- if modifying and (not arg in current):
- current[arg] = {}
- current = current[arg]
-
- # Call
- elif callable(current):
- if isinstance(current, functools.partial):
- argspec = inspect.getargspec(current.func)
- # Don't count initial args fulfilled by the partial
- spec_args = argspec.args[len(current.args):]
- # Don't count keyword args fulfilled by the partial
- spec_args = tuple(a for a in spec_args if a not in
current.keywords)
- else:
- argspec = inspect.getargspec(current)
- spec_args = argspec.args
-
- callable_kwargs = {}
- if isinstance(arg, dict):
- # If the first arg is a dict, treat it as our kwargs
- # TODO: what if the first argument really needs to be a
dict?
- callable_kwargs = arg
- index += 1
-
- if argspec.varargs is not None:
- # Gobble the rest of the args
- callable_args = args[index:]
- else:
- # Take only what we need
- spec_args = tuple(a for a in spec_args if a not in
callable_kwargs)
- spec_args_count = len(spec_args)
- if inspect.ismethod(current):
- # Don't count "self" argument
- spec_args_count -= 1
- callable_args = args[index:index + spec_args_count]
- # Note: we might actually have fewer args than the
args_count, but that could be OK
- # if the user expects subsequent args to have default
values
-
- args_count = len(callable_args)
- if args_count > 1:
- index += args_count - 1
-
- current = current(*callable_args, **callable_kwargs)
-
- else:
- raise RuntimeError('`{0}` cannot be processed in
{1}'.format(arg, args))
-
- index += 1
-
- if callable(current):
- current = current()
+ # Parse all arguments
+ while len(args) > 0:
+ obj, args = _parse_argument(obj, args, modifying)
if modifying:
- if hasattr(current, '__setitem__'):
- # Modify dict value
- current[modifying_key] = modifying_value
- else:
+ if hasattr(obj, '__setitem__'):
+ # Modify item value (dict, list, and similar)
+ if isinstance(obj, (list, tuple)):
+ modifying_key = int(modifying_key)
+ obj[modifying_key] = modifying_value
+ elif hasattr(obj, modifying_key):
# Modify object attribute
- setattr(current, modifying_key, modifying_value)
-
- return current
+ setattr(obj, modifying_key, modifying_value)
+ else:
+ raise ProcessingError('Cannot modify `{0}` of `{1!r}`'
+ .format(modifying_key, obj))
+ return obj
-def _desugar_attr(obj, attr):
- if not isinstance(attr, basestring):
- return None
- if hasattr(obj, attr):
- return attr
- attr = attr.replace('-', '_')
- if hasattr(obj, attr):
- return attr
- return None
+def _parse_argument(obj, args, modifying):
+ args = list(args)
+ arg = args.pop(0)
-def _is_int(arg):
- try:
- int(arg)
- except ValueError:
- return False
- return True
+ # Call?
+ if arg == '[':
+ # TODO: should there be a way to escape "[" and "]" in case they
are needed as real
+ # arguments?
+ try:
+ closing_index = args.index(']')
+ except ValueError:
+ raise ParsingError('Opening "[" without a closing "]')
+ callable_args = args[:closing_index]
+ args = args[closing_index + 1:]
+ if not callable(obj):
+ raise ProcessingError('Used "[" and "] on an object that is
not callable')
+ return obj(*callable_args), args
+
+ # Attribute?
+ if isinstance(arg, basestring):
+ if hasattr(obj, arg):
+ return getattr(obj, arg), args
+ arg_sugared = arg.replace('-', '_')
+ if hasattr(obj, arg_sugared):
+ return getattr(obj, arg_sugared), args
+
+ # Item? (dict, lists, and similar)
+ if hasattr(obj, '__getitem__'):
+ if modifying and hasattr(obj, 'has_key') and (not
obj.has_key(arg)):
+ obj[arg] = {}
--- End diff --
I think it's non-trivial and not useful to set nested lists that have no
value. Consider this:
```
x = ['a','b','c']
ctx x 10 name = 2
```
What is to be done with indexes between 3 and 9 of the list? Fill them with
None? With empty dicts? It is unclear what would be best. I think it is best in
such situations for ARIA to fail with an error message. Only let users modify
existing index values.
I recommend leaving it as is.
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