A panic should always be a last resort, and even then consider a better option!
- Logging errors with context (cause and message)
- Expose errors as metrics
- Expose errors as events
So after all the long talk, when is it okay to panic?
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Panics are somewhat okay when the error state needs attention and there’s no going forward from there.
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An example would be starting an application with a missing environment variable or having an invalid configuration (this could also be hot reloaded).
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No amount of error handling would fit a case of this, panic as needed and let the user know their attention is needed. A failed write to a store could be worth a panic as the application not writing will lead to a fatal inconsistent state etc.
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A lot of the time, panics are needed only when you have a fatal end and need to stop to save yourself, rather than shoot yourself in the foot for some fancy stack trace.
To end this, I say:
With great power comes great responsibility, but even Spiderman knew better than to panic unless needed.
The end!