getKey and getKeyEnv silently default.

[gregwebs]

There is a problem with the getKey and getKeyEnv from clientsession: they both silently default to generating a new key when one is missing.

Can we change these functions (actually add new ones) that essentially return an Either? Left would be a default, and in that case a warning can be logged for the user.

I would suggest as new function names keyFromFile and keyFromEnv.
However, this points to the fact that some kind of generic key generator is needed. Also, Either may not be descriptive enough.

data KeyGenerator = KeyGenerator { gatherKey :: IO ByteString, writeKey :: ByteString -> IO () }


data KeyInit = KeyGenerated Text Key -- ^ no key was found, generated and recorded a new one
                   | KeyFound Key -- ^ found the existing key

keyFrom :: KeyGenerator -> KeyInit
keyFromDef :: KeyGenerator -> Key

[gregwebs]

This would also get rid of the need for to use putStrLn for generating the env key and defer that action to the library user.

[meteficha]

If I understand correctly, you're suggesting that the functions should:

• Keep their current behaviour: creating a new key out of thin air if necessary.
• Have a variant that returns whether a key was created or not.

That sounds like a good idea.

[pbrisbin]

Yup, 👍 on pushing the putStrLn to the caller.

[gregwebs]

@meteficha yes, that is a perfect summary