node_exporter/vendor/github.com/mdlayher/netlink/debug.go

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package netlink
import (
"fmt"
"log"
"os"
"strconv"
"strings"
)
var (
// Arguments used to create a debugger.
debugArgs []string
)
func init() {
// Is netlink debugging enabled?
s := os.Getenv("NLDEBUG")
if s == "" {
return
}
debugArgs = strings.Split(s, ",")
}
// A debugger is used to provide debugging information about a netlink connection.
type debugger struct {
Log *log.Logger
Level int
}
// newDebugger creates a debugger by parsing key=value arguments.
func newDebugger(args []string) *debugger {
d := &debugger{
Log: log.New(os.Stderr, "nl: ", 0),
Level: 1,
}
for _, a := range args {
kv := strings.Split(a, "=")
if len(kv) != 2 {
// Ignore malformed pairs and assume callers wants defaults.
continue
}
switch kv[0] {
// Select the log level for the debugger.
case "level":
level, err := strconv.Atoi(kv[1])
if err != nil {
panicf("netlink: invalid NLDEBUG level: %q", a)
}
d.Level = level
}
}
return d
}
// debugf prints debugging information at the specified level, if d.Level is
// high enough to print the message.
func (d *debugger) debugf(level int, format string, v ...interface{}) {
if d.Level >= level {
d.Log.Printf(format, v...)
}
}
func panicf(format string, a ...interface{}) {
panic(fmt.Sprintf(format, a...))
}