package main import ( "fmt" "io" "os" "strings" "github.com/mitchellh/panicwrap" ) // This is output if a panic happens. const panicOutput = ` !!!!!!!!!!!!!!!!!!!!!!!!!!! PACKER CRASH !!!!!!!!!!!!!!!!!!!!!!!!!!!! Packer crashed! This is always indicative of a bug within Packer. A crash log has been placed at "crash.log" relative to your current working directory. It would be immensely helpful if you could please report the crash with Packer[1] so that we can fix this. [1]: https://github.com/hashicorp/packer/issues !!!!!!!!!!!!!!!!!!!!!!!!!!! PACKER CRASH !!!!!!!!!!!!!!!!!!!!!!!!!!!! ` // panicHandler is what is called by panicwrap when a panic is encountered // within Packer. It is guaranteed to run after the resulting process has // exited so we can take the log file, add in the panic, and store it // somewhere locally. func panicHandler(logF *os.File) panicwrap.HandlerFunc { return func(m string) { // Write away just output this thing on stderr so that it gets // shown in case anything below fails. fmt.Fprintf(os.Stderr, fmt.Sprintf("%s\n", m)) // Create the crash log file where we'll write the logs f, err := os.Create("crash.log") if err != nil { fmt.Fprintf(os.Stderr, "Failed to create crash log file: %s", err) return } defer f.Close() // Seek the log file back to the beginning if _, err = logF.Seek(0, 0); err != nil { fmt.Fprintf(os.Stderr, "Failed to seek log file for crash: %s", err) return } // Copy the contents to the crash file. This will include // the panic that just happened. if _, err = io.Copy(f, logF); err != nil { fmt.Fprintf(os.Stderr, "Failed to write crash log: %s", err) return } // Tell the user a crash occurred in some helpful way that // they'll hopefully notice. fmt.Printf("\n\n") fmt.Println(strings.TrimSpace(panicOutput)) } }