Prometheus support on v1/sys/metrics endpoint

command/server.go

@@ -472,7 +472,6 @@ func (c *ServerCommand) Run(args []string) int {
 		c.UI.Error(fmt.Sprintf("Error initializing telemetry: %s", err))
 		return 1
 	}
-	prometheusEnabled := config.Telemetry != nil && config.Telemetry.PrometheusRetentionTime > 0
 
 	// Initialize the backend
 	factory, exists := c.PhysicalBackends[config.Storage.Type]
@@ -565,7 +564,6 @@ func (c *ServerCommand) Run(args []string) int {
 		BuiltinRegistry:           builtinplugins.Registry,
 		DisableKeyEncodingChecks:  config.DisablePrintableCheck,
 		InMemSink:                 inMemMetrics,
-		PrometheusEnabled:         prometheusEnabled,
 	}
 	if c.flagDev {
 		coreConfig.DevToken = c.flagDevRootTokenID
@@ -1692,6 +1690,23 @@ func (c *ServerCommand) setupTelemetry(config *server.Config) (*metrics.InmemSin
 
 	// Configure the statsite sink
 	var fanout metrics.FanoutSink
+
+	// Configure the Prometheus sink
+	if telConfig.PrometheusRetentionTime == 0 {
+		return nil, fmt.Errorf("telemetry.prometheus_retention_time must be > 0")
+	}
+
+	prometheusOpts := prometheus.PrometheusOpts{
+		Expiration: telConfig.PrometheusRetentionTime,
+	}
+
+	sink, err := prometheus.NewPrometheusSinkFrom(prometheusOpts)
+	if err != nil {
+		return nil, err
+	}
+
+	fanout = append(fanout, sink)
+
 	if telConfig.StatsiteAddr != "" {
 		sink, err := metrics.NewStatsiteSink(telConfig.StatsiteAddr)
 		if err != nil {
@@ -1746,23 +1761,6 @@ func (c *ServerCommand) setupTelemetry(config *server.Config) (*metrics.InmemSin
 		fanout = append(fanout, sink)
 	}
 
-	// Configure the Prometheus sink
-	if telConfig.PrometheusRetentionTime.Nanoseconds() > 0 {
-		prometheusOpts := prometheus.PrometheusOpts{
-			Expiration: telConfig.PrometheusRetentionTime,
-		}
-		sink, err := prometheus.NewPrometheusSinkFrom(prometheusOpts)
-		if err != nil {
-			return nil, err
-		}
-		// Hostname enabled will create poor quality metrics name
-		if !telConfig.DisableHostname {
-			c.UI.Warn("telemetry.disable_hostname has been set to false. Recommended setting is true for Prometheus to avoid poorly named metrics.")
-
-		}
-		fanout = append(fanout, sink)
-	}
-
 	if telConfig.DogStatsDAddr != "" {
 		var tags []string
 
@@ -1779,13 +1777,16 @@ func (c *ServerCommand) setupTelemetry(config *server.Config) (*metrics.InmemSin
 	}
 
 	// Initialize the global sink
-	if len(fanout) > 0 {
-		fanout = append(fanout, inm)
-		metrics.NewGlobal(metricsConf, fanout)
+	if len(fanout) > 1 {
+		// Hostname enabled will create poor quality metrics name for prometheus
+		if !telConfig.DisableHostname {
+			c.UI.Warn("telemetry.disable_hostname has been set to false. Recommended setting is true for Prometheus to avoid poorly named metrics.")
+		}
 	} else {
 		metricsConf.EnableHostname = false
-		metrics.NewGlobal(metricsConf, inm)
 	}
+	fanout = append(fanout, inm)
+	metrics.NewGlobal(metricsConf, fanout)
 	return inm, nil
 }
 

command/server/config.go

@@ -19,6 +19,10 @@ import (
 	"github.com/hashicorp/vault/helper/parseutil"
 )
 
+const (
+	prometheusDefaultRetentionTime = 24 * time.Hour
+)
+
 // Config is the configuration for the vault server.
 type Config struct {
 	Listeners []*Listener `hcl:"-"`
@@ -99,7 +103,7 @@ func DevConfig(ha, transactional bool) *Config {
 		EnableUI: true,
 
 		Telemetry: &Telemetry{
-			PrometheusRetentionTime: 24 * time.Hour,
+			PrometheusRetentionTime: prometheusDefaultRetentionTime,
 			DisableHostname:         true,
 		},
 	}
@@ -239,8 +243,7 @@ type Telemetry struct {
 
 	// Prometheus:
 	// PrometheusRetentionTime is the retention time for prometheus metrics if greater than 0.
-	// A value of 0 disable Prometheus support.
-	// Default: 0
+	// Default: 24h
 	PrometheusRetentionTime    time.Duration `hcl:-`
 	PrometheusRetentionTimeRaw interface{}   `hcl:"prometheus_retention_time"`
 }
@@ -832,6 +835,8 @@ func parseTelemetry(result *Config, list *ast.ObjectList) error {
 		if result.Telemetry.PrometheusRetentionTime, err = parseutil.ParseDurationSecond(result.Telemetry.PrometheusRetentionTimeRaw); err != nil {
 			return err
 		}
+	} else {
+		result.Telemetry.PrometheusRetentionTime = prometheusDefaultRetentionTime
 	}
 
 	return nil

vault/core.go

@@ -405,7 +405,6 @@ type Core struct {
 
 	// Telemetry objects
 	inMemSink         *metrics.InmemSink
-	prometheusEnabled bool
 }
 
 // CoreConfig is used to parameterize a core
@@ -477,7 +476,6 @@ type CoreConfig struct {
 
 	// Telemetry objects
 	InMemSink         *metrics.InmemSink
-	PrometheusEnabled bool
 }
 
 func (c *CoreConfig) Clone() *CoreConfig {
@@ -585,7 +583,6 @@ func NewCore(conf *CoreConfig) (*Core, error) {
 		allLoggers:                       conf.AllLoggers,
 		builtinRegistry:                  conf.BuiltinRegistry,
 		inMemSink:                        conf.InMemSink,
-		prometheusEnabled:                conf.PrometheusEnabled,
 	}
 
 	atomic.StoreUint32(c.sealed, 1)

vault/logical_system.go

@@ -2484,10 +2484,6 @@ func (b *SystemBackend) handleMetrics(ctx context.Context, req *logical.Request,
 
 	acceptHeaders := req.Headers["Accept"]
 	if format == "prometheus" || (len(acceptHeaders) > 0 && strings.HasPrefix(acceptHeaders[0], "application/openmetrics-text")) {
-		if !b.Core.prometheusEnabled {
-			err := "prometheus support is not enabled"
-			return nil, fmt.Errorf(err)
-		}
 
 		metricsFamilies, err := prometheus.DefaultGatherer.Gather()
 		if err != nil && len(metricsFamilies) == 0 {