Implement --log.prober

Signed-off-by: Jan-Otto Kröpke <[email protected]>

main.go

@@ -50,7 +50,7 @@ var (
 	configFile     = kingpin.Flag("config.file", "Blackbox exporter configuration file.").Default("blackbox.yml").String()
 	timeoutOffset  = kingpin.Flag("timeout-offset", "Offset to subtract from timeout in seconds.").Default("0.5").Float64()
 	configCheck    = kingpin.Flag("config.check", "If true validate the config file and then exit.").Default().Bool()
-	logProbeErrors = kingpin.Flag("log.probe-errors", "Log error from probe requests").Default().Bool()
+	logLevelProber = kingpin.Flag("log.prober", "Log level from probe requests. One of: [debug, info, warn, error, none]").Default("none").String()
 	historyLimit   = kingpin.Flag("history.limit", "The maximum amount of items to keep in the history.").Default("100").Uint()
 	externalURL    = kingpin.Flag("web.external-url", "The URL under which Blackbox exporter is externally reachable (for example, if Blackbox exporter is served via a reverse proxy). Used for generating relative and absolute links back to Blackbox exporter itself. If the URL has a path portion, it will be used to prefix all HTTP endpoints served by Blackbox exporter. If omitted, relevant URL components will be derived automatically.").PlaceHolder("<url>").String()
 	routePrefix    = kingpin.Flag("web.route-prefix", "Prefix for the internal routes of web endpoints. Defaults to path of --web.external-url.").PlaceHolder("<path>").String()
@@ -80,6 +80,9 @@ func run() int {
 	logger := promlog.New(promlogConfig)
 	rh := &prober.ResultHistory{MaxResults: *historyLimit}
 
+	logLevelProberValue, _ := level.Parse(*logLevelProber)
+	logLevelProber := level.Allow(logLevelProberValue)
+
 	level.Info(logger).Log("msg", "Starting blackbox_exporter", "version", version.Info())
 	level.Info(logger).Log("build_context", version.BuildContext())
 
@@ -183,7 +186,7 @@ func run() int {
 		sc.Lock()
 		conf := sc.C
 		sc.Unlock()
-		prober.Handler(w, r, conf, logger, rh, *timeoutOffset, nil, moduleUnknownCounter, *logProbeErrors)
+		prober.Handler(w, r, conf, logger, rh, *timeoutOffset, nil, moduleUnknownCounter, logLevelProber)
 	})
 	http.HandleFunc(*routePrefix, func(w http.ResponseWriter, r *http.Request) {
 		w.Header().Set("Content-Type", "text/html")

prober/handler.go

@@ -42,9 +42,9 @@ var (
 	}
 )
 
-func Handler(w http.ResponseWriter, r *http.Request, c *config.Config, logger log.Logger,
-	rh *ResultHistory, timeoutOffset float64, params url.Values, moduleUnknownCounter prometheus.Counter,
-	logProbeErrors bool) {
+func Handler(w http.ResponseWriter, r *http.Request, c *config.Config, logger log.Logger, rh *ResultHistory, timeoutOffset float64, params url.Values,
+	moduleUnknownCounter prometheus.Counter,
+	logLevelProber level.Option) {
 
 	if params == nil {
 		params = r.URL.Query()
@@ -109,7 +109,7 @@ func Handler(w http.ResponseWriter, r *http.Request, c *config.Config, logger lo
 		}
 	}
 
-	sl := newScrapeLogger(logger, moduleName, target, logProbeErrors)
+	sl := newScrapeLogger(logger, moduleName, target, logLevelProber)
 	level.Info(sl).Log("msg", "Beginning probe", "probe", module.Prober, "timeout_seconds", timeoutSeconds)
 
 	start := time.Now()
@@ -160,15 +160,15 @@ type scrapeLogger struct {
 	next         log.Logger
 	buffer       bytes.Buffer
 	bufferLogger log.Logger
-	logErrors    bool
+	logLevel     level.Option
 }
 
-func newScrapeLogger(logger log.Logger, module string, target string, logProbeErrors bool) *scrapeLogger {
+func newScrapeLogger(logger log.Logger, module string, target string, logLevel level.Option) *scrapeLogger {
 	logger = log.With(logger, "module", module, "target", target)
 	sl := &scrapeLogger{
-		next:      logger,
-		buffer:    bytes.Buffer{},
-		logErrors: logProbeErrors,
+		next:     logger,
+		buffer:   bytes.Buffer{},
+		logLevel: logLevel,
 	}
 	bl := log.NewLogfmtLogger(&sl.buffer)
 	sl.bufferLogger = log.With(bl, "ts", log.DefaultTimestampUTC, "caller", log.Caller(6), "module", module, "target", target)
@@ -177,24 +177,8 @@ func newScrapeLogger(logger log.Logger, module string, target string, logProbeEr
 
 func (sl scrapeLogger) Log(keyvals ...interface{}) error {
 	sl.bufferLogger.Log(keyvals...)
-	kvs := make([]interface{}, len(keyvals))
-	copy(kvs, keyvals)
 
-	if sl.logErrors {
-		for i := 0; i < len(kvs); i += 2 {
-			if kvs[i] == level.Key() && kvs[i+1] == level.ErrorValue() {
-				return sl.next.Log(kvs...)
-			}
-		}
-	}
-
-	// Switch level to debug for application output.
-	for i := 0; i < len(kvs); i += 2 {
-		if kvs[i] == level.Key() {
-			kvs[i+1] = level.DebugValue()
-		}
-	}
-	return sl.next.Log(kvs...)
+	return level.NewFilter(sl.next, sl.logLevel).Log(keyvals...)
 }
 
 // DebugOutput returns plaintext debug output for a probe.