Add config options for metrics

metrics/api.go

@@ -90,7 +90,7 @@ func writeMetricsTo(ctx context.Context, url string) error {
 	}
 
 	// Create request
-	req, err := http.NewRequestWithContext(ctx, http.MethodPut, url, buf)
+	req, err := http.NewRequestWithContext(ctx, http.MethodPost, url, buf)
 	if err != nil {
 		return fmt.Errorf("failed to create request: %w", err)
 	}
@@ -118,6 +118,7 @@ func writeMetricsTo(ctx context.Context, url string) error {
 }
 
 func metricsWriter(ctx context.Context) error {
+	pushURL := pushOption()
 	ticker := time.NewTicker(10 * time.Second)
 	defer ticker.Stop()
 

metrics/config.go

@@ -0,0 +1,69 @@
+package metrics
+
+import (
+	"flag"
+
+	"github.com/safing/portbase/config"
+)
+
+// Configuration Keys
+var (
+	CfgOptionInstanceKey   = "core/metrics/instance"
+	instanceOption         config.StringOption
+	cfgOptionInstanceOrder = 0
+
+	CfgOptionPushKey   = "core/metrics/push"
+	pushOption         config.StringOption
+	cfgOptionPushOrder = 0
+
+	pushFlag     string
+	instanceFlag string
+)
+
+func init() {
+	flag.StringVar(&pushFlag, "push-metrics", "", "Set default URL to push prometheus metrics to.")
+	flag.StringVar(&instanceFlag, "metrics-instance", "", "Set the default global instance label.")
+}
+
+func prepConfig() error {
+	err := config.Register(&config.Option{
+		Name:            "Metrics Instance Name",
+		Key:             CfgOptionInstanceKey,
+		Description:     "Define the prometheus instance label for exported metrics. Please note that changing the instance name will reset persisted metrics.",
+		OptType:         config.OptTypeString,
+		ExpertiseLevel:  config.ExpertiseLevelExpert,
+		ReleaseLevel:    config.ReleaseLevelStable,
+		DefaultValue:    instanceFlag,
+		RequiresRestart: true,
+		Annotations: config.Annotations{
+			config.DisplayOrderAnnotation: cfgOptionInstanceOrder,
+			config.CategoryAnnotation:     "Metrics",
+		},
+		ValidationRegex: "^(" + prometheusBaseFormt + ")?$",
+	})
+	if err != nil {
+		return err
+	}
+	instanceOption = config.Concurrent.GetAsString(CfgOptionInstanceKey, instanceFlag)
+
+	err = config.Register(&config.Option{
+		Name:            "Push Metrics",
+		Key:             CfgOptionPushKey,
+		Description:     "Push metrics to this URL in the prometheus format.",
+		OptType:         config.OptTypeString,
+		ExpertiseLevel:  config.ExpertiseLevelExpert,
+		ReleaseLevel:    config.ReleaseLevelStable,
+		DefaultValue:    pushFlag,
+		RequiresRestart: true,
+		Annotations: config.Annotations{
+			config.DisplayOrderAnnotation: cfgOptionPushOrder,
+			config.CategoryAnnotation:     "Metrics",
+		},
+	})
+	if err != nil {
+		return err
+	}
+	pushOption = config.Concurrent.GetAsString(CfgOptionPushKey, pushFlag)
+
+	return nil
+}

metrics/metric.go

@@ -15,7 +15,8 @@ import (
 
 // PrometheusFormatRequirement is required format defined by prometheus for
 // metric and label names.
-const PrometheusFormatRequirement = "[a-zA-Z_][a-zA-Z0-9_]*"
+const prometheusBaseFormt = "[a-zA-Z_][a-zA-Z0-9_]*"
+const PrometheusFormatRequirement = "^" + prometheusBaseFormt + "$"
 
 var prometheusFormat = regexp.MustCompile(PrometheusFormatRequirement)
 
@@ -60,7 +61,7 @@ type Options struct {
 
 func newMetricBase(id string, labels map[string]string, opts Options) (*metricBase, error) {
 	// Check formats.
-	if !prometheusFormat.MatchString(id) {
+	if !prometheusFormat.MatchString(strings.ReplaceAll(id, "/", "_")) {
 		return nil, fmt.Errorf("metric name %q must match %s", id, PrometheusFormatRequirement)
 	}
 	for labelName := range labels {
@@ -75,6 +76,11 @@ func newMetricBase(id string, labels map[string]string, opts Options) (*metricBa
 		opts.Permission = api.PermitUser
 	}
 
+	// Ensure that labels is a map.
+	if labels == nil {
+		labels = make(map[string]string)
+	}
+
 	// Create metric base.
 	base := &metricBase{
 		Identifier: id,

metrics/module.go

@@ -2,7 +2,6 @@ package metrics
 
 import (
 	"errors"
-	"flag"
 	"fmt"
 	"sort"
 	"sync"
@@ -20,9 +19,6 @@ var (
 	metricNamespace       string
 	globalLabels          = make(map[string]string)
 
-	pushURL        string
-	metricInstance string
-
 	// ErrAlreadyStarted is returned when an operation is only valid before the
 	// first metric is registered, and is called after.
 	ErrAlreadyStarted = errors.New("can only be changed before first metric is registered")
@@ -36,29 +32,30 @@ var (
 )
 
 func init() {
-	flag.StringVar(&pushURL, "push-metrics", "", "URL to push prometheus metrics to")
-	flag.StringVar(&metricInstance, "metrics-instance", "", "Set the global instance label")
-
 	module = modules.Register("metrics", prep, start, stop, "database", "api")
 }
 
 func prep() error {
+	return prepConfig()
+}
+
+func start() error {
 	// Add metric instance name as global variable if set.
-	if metricInstance != "" {
-		if err := AddGlobalLabel("instance", metricInstance); err != nil {
+	if instanceOption() != "" {
+		if err := AddGlobalLabel("instance", instanceOption()); err != nil {
 			return err
 		}
 	}
 
-	return registerInfoMetric()
-}
+	if err := registerInfoMetric(); err != nil {
+		return err
+	}
 
-func start() error {
 	if err := registerAPI(); err != nil {
 		return err
 	}
 
-	if pushURL != "" {
+	if pushOption() != "" {
 		module.StartServiceWorker("metric pusher", 0, metricsWriter)
 	}