Added some probe count boundaries.

cmd/probe.go

@@ -48,14 +48,17 @@ func PollFan(cfg *mffp.Config) (*mffp.FanData, error) {
 
 // ProbeFan runs continuous fan poller.
 func ProbeFan(cfg *mffp.Config) {
-	for probeCount := 1; ; probeCount++ {
+	var probeCount, failCount int
+
+	for probeCount = 1; ; probeCount++ {
 		fd, err := PollFan(cfg)
 		switch err != nil {
 		case true:
 			{
+				failCount++
 				log.SetOutput(os.Stderr)
 				log.Printf("Probe #%d: error reading fan information from %q: %v.", probeCount, cfg.Host, err)
-				if cfg.ExitOnError {
+				if cfg.ExitOnError && failCount > cfg.MaxFail {
 					os.Exit(42)
 				}
 				log.SetOutput(os.Stdout)
@@ -66,6 +69,9 @@ func ProbeFan(cfg *mffp.Config) {
 					log.Printf("Probe #%d: %s", probeCount, fd)
 				}
 			}
+			if cfg.MaxCount > 0 && probeCount >= cfg.MaxCount {
+				continue
+			}
 			time.Sleep(cfg.Interval)
 		}
 	}

main/main.go

@@ -28,6 +28,8 @@ func init() {
 	flag.BoolVar(&cfg.ExitOnError, "exit-on-error", true, "Exit polling loop on error")
 	flag.BoolVar(&cfg.Quiet, "quiet", false, "Log only polling errors")
 	flag.DurationVar(&cfg.Timeout, "timeout", 1*time.Second, "Polling probe timeout in seconds")
+	flag.IntVar(&cfg.MaxCount, "maxcount", 0, "Maximum number of probes (0 means unlimited)")
+	flag.IntVar(&cfg.MaxFail, "maxfail", 0, "Maximum number of failed probes")
 	flag.BoolVar(&v, "version", false, "Show version")
 	flag.Parse()
 
@@ -36,6 +38,14 @@ func init() {
 		os.Exit(42)
 	}
 
+	if cfg.MaxCount < 0 {
+		log.Fatalf("Maximum probe count must be greater or equal to 0.")
+	}
+
+	if cfg.MaxFail < 0 {
+		log.Fatalf("Maximum probe number of failed probes be greater or equal to 0.")
+	}
+
 	if cfg.Host == "" {
 		log.Fatalf("Target host must be specified.")
 	}

mffprober.go

@@ -17,11 +17,12 @@ const (
 
 // Config holds the configuration parameters used throughout the prober.
 type Config struct {
-	Host        string
-	Interval    time.Duration
-	ExitOnError bool
-	Quiet       bool
-	Timeout     time.Duration
+	Host              string
+	Interval          time.Duration
+	ExitOnError       bool
+	Quiet             bool
+	Timeout           time.Duration
+	MaxCount, MaxFail int
 }
 
 func (cfg Config) String() string {
@@ -32,6 +33,8 @@ func (cfg Config) String() string {
 	s.WriteString(fmt.Sprintf("Timeout: %s; ", cfg.Timeout))
 	s.WriteString(fmt.Sprintf("Exit on error: %v; ", cfg.ExitOnError))
 	s.WriteString(fmt.Sprintf("Quiet mode: %v", cfg.Quiet))
+	s.WriteString(fmt.Sprintf("Max probes: %v", cfg.MaxCount))
+	s.WriteString(fmt.Sprintf("Max failed probes: %v", cfg.MaxFail))
 
 	return s.String()
 }