Importing an optional module

Question

This is my file structure:

[mylibrary]
    __init__.py 

    [codecs]
        __init__.py < this is the file that we're talking about
        optional.py

Now I have this code in the marked __init__.py:

def load_optional_codecs():
    try:
        from mylibrary.codecs import optional
        # do stuff with optional
    except ImportError:
        pass

There is one problem with this. If the optional module contains an import exception itself it will silently fail. Is there a way to import an optional module without silencing any exception from the module?

---

This might seem like an obscure scenario, but I have gotten a nasty error because of the silenced exception and I would like to prevent that from happening in the future.

Answer 1

This is a bit hacky, but you could check the message on the exception to determine what failed:

try:
    from mylibrary.codecs import optional
except ImportError, e:
    if e.message != 'No module named optional':
        raise

With this code, if importing the optional module fails, it is ignored, but if anything else raises an exception (importing another module, syntax errors, etc), it will get raised.