Should I use log.Panic() or log.Fatal() with os.Open?

Question

when we have:

f, err := os.Open("no-file.txt")
if err != nil {
    log.Panic(err)
}
defer f.Close()

I think it would make more sense to use log.Panic(err). Right? Panic() allows defer f.Close() to execute but log.Fatal() prevents it.

Or the file doesn't get opened if not found? I supposed in that case it's irrelevant if we use Fatal or Panic. Right?

Answer 1

log.Fatal() should rarely be used in production apps–if ever–as it terminates the whole app. log.Panic() panics after performing the log, which again is rarely desired.

Many examples use them (or alternatively a single panic(err) call) to make the example code shorter (to let you focus on what the example is about), but they should be used sparingly in production apps. Instead handle the error "properly". What that means is use case-specific, you may choose to log it and return, or return a new error or do something else, but only do one thing with it (only handle it once). See Writing good Golang code.