cmd: beacon alarm tool to monitor boot nodes agreeing on beacon values (

#4704)

## Motivation

This tool is intended to be used to monitor if the bootnodes agree on the beacon value for the next epoch. It queries the central Mimir server for the metrics of all nodes of a given namespace and pushes its own metric to indicate if the bootnodes agree or not.

**NOTE:** The tool itself has been added to the internal tools repository. This PR now only includes some minor code changes (mostly exporting non-exported functions) that are needed for the tool to work properly.

beacon/metrics/prometheus.go

@@ -37,6 +37,12 @@ type BeaconMetricsCollector struct {
 	calculatedBeaconWeight *prometheus.Desc
 }
 
+var nameCalculatedWeight = prometheus.BuildFQName(metrics.Namespace, subsystem, "beacon_calculated_weight")
+
+func MetricNameCalculatedWeight() string {
+	return nameCalculatedWeight
+}
+
 // NewBeaconMetricsCollector creates a prometheus Collector for beacons.
 func NewBeaconMetricsCollector(cb GatherCB, logger log.Logger) *BeaconMetricsCollector {
 	bmc := &BeaconMetricsCollector{
@@ -51,7 +57,7 @@ func NewBeaconMetricsCollector(cb GatherCB, logger log.Logger) *BeaconMetricsCol
 			"Weight of beacons collected from blocks for each epoch and value",
 			[]string{labelEpoch, labelBeacon}, nil),
 		calculatedBeaconWeight: prometheus.NewDesc(
-			prometheus.BuildFQName(metrics.Namespace, subsystem, "beacon_calculated_weight"),
+			nameCalculatedWeight,
 			"Weight of the beacon calculated by the node for each epoch",
 			[]string{labelEpoch, labelBeacon}, nil),
 	}

log/logtest/log.go

@@ -31,7 +31,7 @@ func New(tb testing.TB, override ...zapcore.Level) log.Log {
 			panic(err)
 		}
 	}
-	return log.NewFromLog(zaptest.NewLogger(tb, zaptest.Level(level)))
+	return log.NewFromLog(zaptest.NewLogger(tb, zaptest.Level(level))).Named(tb.Name())
 }
 
 // SetupGlobal updates AppLog to the instance of test-specific logger.

log/zap.go

@@ -85,6 +85,11 @@ func String(name, val string) Field {
 	return Field(zap.String(name, val))
 }
 
+// Strings returns a strings Field.
+func Strings(name string, val []string) Field {
+	return Field(zap.Strings(name, val))
+}
+
 // Stringer returns an fmt.Sringer Field.
 func Stringer(name string, val fmt.Stringer) Field {
 	return Field(zap.Stringer(name, val))

node/node.go

@@ -323,7 +323,7 @@ func loadConfig(cfg *config.Config, preset, path string) error {
 		viper.DecodeHook(hook),
 		WithZeroFields(),
 		WithIgnoreUntagged(),
-		withErrorUnused(),
+		WithErrorUnused(),
 	}
 
 	// load config if it was loaded to the viper
@@ -345,7 +345,7 @@ func WithIgnoreUntagged() viper.DecoderConfigOption {
 	}
 }
 
-func withErrorUnused() viper.DecoderConfigOption {
+func WithErrorUnused() viper.DecoderConfigOption {
 	return func(cfg *mapstructure.DecoderConfig) {
 		cfg.ErrorUnused = true
 	}