To what extent should code try to explain fatal exceptions?
- by Andrzej Doyle
I suspect that all non-trivial software is likely to experience situations where it hits an external problem it cannot work around and thus needs to fail. This might be due to bad configuration, an external server being down, disk full, etc.
In these situations, especially if the software is running in non-interactive mode, I expect that all one can really do is log an error and wait for the admin to read the logs and fix the problem. If someone happens to interact with the software in the meantime, e.g. a request comes in to a server that failed to initialize properly, then perhaps an appropriate hint can be given to check the logs and maybe even the error can be echoed (depending on whether you can tell if they're a technical guy as opposed to a business user). For the moment though let's not think too hard about this part.
My question is, to what extent should the software be responsible for trying to explain the meaning of the fatal error? In general, how much competence/knowledge are you allowed to presume on administrators of the software, and how much should you include troubleshooting information and potential resolution steps when logging fatal errors? Of course if there's something that's unique to the runtime context this should definitely be logged; but lets assume your software needs to talk to Active Directory via LDAP and gets back an error "[LDAP: error code 49 - 80090308: LdapErr: DSID-0C090334, comment: AcceptSecurityContext error, data 525, vece]". Is it reasonable to assume that the maintainers will be able to Google the error code and work out what it means, or should the software try to parse the error code and log that this is caused by an incorrect user DN in the LDAP config?
I don't know if there is a definitive best-practices answer for this, so I'm keen to hear a variety of views.