Function recoverPanic

stack/example_test.go:236–288

()

}

func recoverPanic() {
	if v := recover(); v != nil {
		// Collect the stack and process it.
		rawStack := append(debug.Stack(), '\n', '\n')
		st, _, err := stack.ScanSnapshot(bytes.NewReader(rawStack), io.Discard, stack.DefaultOpts())

		if err != nil || len(st.Goroutines) != 1 {
			// Processing failed. Print out the raw stack.
			fmt.Fprintf(os.Stdout, "recovered: %q\nStack processing failed: %v\nRaw stack:\n%s", v, err, rawStack)
			return
		}

		// Calculate alignment.
		srcLen := 0
		pkgLen := 0
		for _, line := range st.Goroutines[0].Stack.Calls {
			if l := len(fmt.Sprintf("%s:%d", line.SrcName, line.Line)); l > srcLen {
				srcLen = l
			}
			if l := len(filepath.Base(line.Func.ImportPath)); l > pkgLen {
				pkgLen = l
			}
		}
		buf := bytes.Buffer{}
		// Reduce memory allocation.
		buf.Grow(len(st.Goroutines[0].Stack.Calls) * (40 + srcLen + pkgLen))
		for _, line := range st.Goroutines[0].Stack.Calls {

			// REMOVE: Skip the standard library in this test since it would
			// make it Go version dependent.
			if line.Location == stack.Stdlib {
				continue
			}

			// REMOVE: Not printing args here to make the test deterministic.
			args := "<args>"
			//args := line.Args.String()

			fmt.Fprintf(
				&buf,
				"    %-*s %-*s %s(%s)\n",
				pkgLen, line.Func.DirName, srcLen,
				fmt.Sprintf("%s:%d", line.SrcName, line.Line),
				line.Func.Name,
				args)
		}
		if st.Goroutines[0].Stack.Elided {
			io.WriteString(&buf, "    (...)\n")
		}
		// Print out the formatted stack.
		fmt.Fprintf(os.Stdout, "recovered: %q\nParsed stack:\n%s", v, buf.String())
	}
}

// wrapPanic is a http.Handler middleware that traps panics and print it out to
// os.Stdout.