Helicon Zoo glues together bunch of very different technologies and applications, therefore it provides number of ways to inform customer of possible errors or problems.
Helicon Zoo 500 error page
This error happens when backend application failed to execute or failed to handle its error state gracefully. In terms of Helicon Zoo Module “backend application” means engine, i.e. Perl, Ruby, Node.js, etc. This error normally looks like this:
Here are the fields explained:
This field shows last error state set by application. It does not necessarily indicate a real error source as some backend applications never set Windows error state.
Internal module error
This information may be useful for Helicon Tech support service.
Probably the most informative part of the message. Many backend engines send various error messages to the console STDERR stream. Helicon Zoo collects these data and show last lines of log output here. Reviewing STDERR in most situations may provide useful information about the error:
Other fields indicate actual settings of environment and other request specific data that may help identify error cause.
Sometimes error is gracefully handled by backend application and error message is returned to the user as a normal HTTP response. In this situation Helicon Zoo is not involved into error handling process. If you see anything that does not look like “Helicon Zoo 500 error page” above, the error was returned by application itself. For example this is how Django application error message may look like:
The application specific errors are handled and investigated using application specific tools and Helicon Tech usually does not provide support for third-party applications that are executed with our environment. In this situation you may get better help if you contact corresponding application or engine community.
Helicon Zoo error logs
Another thing you can do to learn about the error is enable logging in web.config using the following line:
The ‘value’ is a relative path to the logs directory. Write permissions should be enabled for this
directory in order for Helicon Zoo to be able to write log files.
Contacting Helicon Tech support
Helicon Tech provides commercial support for our free products. You can reach support service here: http://support.helicontech.com/
We definitely wish as few errors as possible but if you come across some, we believe that the hints in this article will help you out.