Allow selectively turn off prometheus metrics and/or stats poller

Signed-off-by: Vladimir Lavor <vlavor@cisco.com>

plugins/telemetry/config.go

@@ -27,8 +27,10 @@ const (
 type Config struct {
 	// Custom polling interval, default value is 30s
 	PollingInterval time.Duration `json:"polling-interval"`
-	// Allows to disable plugin
-	Disabled bool `json:"disabled"`
+	// Allows to disable prometheus in telemetry plugin
+	PrometheusDisabled bool `json:"prometheus-disabled"`
+	// Allows to disable stats poller in telemetry plugin
+	StatsPollerDisabled bool `json:"stats-poller-disabled"`
 	// Skip collecting some of the metrics:
 	// 	runtime, memory, buffers, nodes, interfaces
 	Skipped []string `json:"skipped"`

plugins/telemetry/telemetry.conf

@@ -1,8 +1,11 @@
 # Interval of data read procedure from the vpp. Default value is 30 seconds.
 polling-interval: 30s
 
-# If set to true, telemetry plugin is disabled.
-disabled: false
+# If set to true, prometheus in telemetry plugin is disabled.
+prometheus-disabled: false
+
+# If set to true, stats poller in telemetry plugin is disabled.
+stats-poller-disabled: false
 
 # Skip collecting some of the metrics.
 # 	runtime, memory, buffers, nodes, interfaces

plugins/telemetry/telemetry.go

@@ -55,9 +55,10 @@ type Plugin struct {
 	prometheusMetrics
 
 	// From config file
-	updatePeriod time.Duration
-	disabled     bool
-	skipped      map[string]bool
+	updatePeriod        time.Duration
+	prometheusDisabled  bool
+	statsPollerDisabled bool
+	skipped             map[string]bool
 
 	wg   sync.WaitGroup
 	quit chan struct{}
@@ -83,13 +84,14 @@ func (p *Plugin) Init() error {
 	if err != nil {
 		return err
 	}
-	if config != nil {
-		// If telemetry is not enabled, skip plugin initialization
-		if config.Disabled {
-			p.Log.Info("Telemetry plugin disabled via config file")
-			p.disabled = true
-			return nil
-		}
+
+	// Prometheus metrics
+	if config == nil {
+		p.updatePeriod = defaultUpdatePeriod
+	} else if config.PrometheusDisabled {
+		p.prometheusDisabled = true
+		p.Log.Infof("Prometheus metrics disabled")
+	} else {
 		// This prevents setting the update period to less than 5 seconds,
 		// which can have significant performance hit.
 		if config.PollingInterval > minimumUpdatePeriod {
@@ -103,23 +105,25 @@ func (p *Plugin) Init() error {
 		for _, skip := range config.Skipped {
 			p.skipped[skip] = true
 		}
-	}
-	// This serves as fallback if the config was not found or if the value is not set in config.
-	if p.updatePeriod == 0 {
-		p.updatePeriod = defaultUpdatePeriod
-	}
 
-	if err := p.registerPrometheus(); err != nil {
-		return err
-	}
+		if err := p.registerPrometheus(); err != nil {
+			return err
+		}
 
-	p.statsPollerServer.log = p.Log.NewLogger("stats-poller")
-	if err := p.setupStatsPoller(); err != nil {
-		return err
+		if p.HTTPHandlers != nil {
+			p.HTTPHandlers.RegisterHTTPHandler("/metrics/{metric}", metricsHandler, "GET")
+		}
 	}
 
-	if p.HTTPHandlers != nil {
-		p.HTTPHandlers.RegisterHTTPHandler("/metrics/{metric}", metricsHandler, "GET")
+	// Stats poller
+	if config == nil || !config.StatsPollerDisabled {
+		p.statsPollerServer.log = p.Log.NewLogger("stats-poller")
+		if err := p.setupStatsPoller(); err != nil {
+			return err
+		}
+	} else {
+		p.statsPollerDisabled = true
+		p.Log.Infof("Stats poller disabled")
 	}
 
 	return nil
@@ -128,12 +132,10 @@ func (p *Plugin) Init() error {
 // AfterInit executes after initializion of Telemetry Plugin
 func (p *Plugin) AfterInit() error {
 	// Do not start polling if telemetry is disabled
-	if p.disabled {
-		return nil
+	if !p.prometheusDisabled {
+		p.startPeriodicUpdates()
 	}
 
-	p.startPeriodicUpdates()
-
 	return nil
 }