1import os
2import inspect
3
4
5def trace_function(function, log_calls, log_results, label=''):
6    def wrapper(*args, **kwargs):
7        kwarg_strs = ['{}={}'.format(k, v) for (k, v) in kwargs]
8        arg_str = ', '.join([str(a) for a in args] + kwarg_strs)
9        call_str = '{}({})'.format(function.func_name, arg_str)
10
11        # Perform the call itself, logging before, after, and anything thrown.
12        try:
13            if log_calls:
14                print '{}: Calling {}'.format(label, call_str)
15            res = function(*args, **kwargs)
16            if log_results:
17                print '{}: {} -> {}'.format(label, call_str, res)
18            return res
19        except Exception as ex:
20            if log_results:
21                print '{}: {} raised {}'.format(label, call_str, type(ex))
22            raise ex
23
24    return wrapper
25
26
27def trace_object(obj, log_calls, log_results, label=''):
28    for name, member in inspect.getmembers(obj):
29        if inspect.ismethod(member):
30            # Skip meta-functions, decorate everything else
31            if not member.func_name.startswith('__'):
32                setattr(obj, name, trace_function(member, log_calls,
33                                                  log_results, label))
34    return obj
35