Observability/metrics update (#1962)

* Removing logging from the NOOP implementatino

* Simplifying the percentiles option

* Simple logging implementation

Co-authored-by: chris <chris@Profanity.local>

metrics/logging/reporter.go

@@ -0,0 +1,53 @@
+package logging
+
+import (
+	"time"
+
+	log "github.com/micro/go-micro/v3/logger"
+	"github.com/micro/go-micro/v3/metrics"
+)
+
+// Reporter is an implementation of metrics.Reporter:
+type Reporter struct {
+	logger  log.Logger
+	options metrics.Options
+}
+
+// New returns a configured noop reporter:
+func New(opts ...metrics.Option) *Reporter {
+	options := metrics.NewOptions(opts...)
+	logger := log.NewLogger(log.WithFields(convertTags(options.DefaultTags)))
+	logger.Log(log.InfoLevel, "Metrics/Logging - metrics will be logged (at TRACE level)")
+
+	return &Reporter{
+		logger:  logger,
+		options: metrics.NewOptions(opts...),
+	}
+}
+
+// Count implements the metrics.Reporter interface Count method:
+func (r *Reporter) Count(metricName string, value int64, tags metrics.Tags) error {
+	r.logger.Logf(log.TraceLevel, "Count metric: %s", tags)
+	return nil
+}
+
+// Gauge implements the metrics.Reporter interface Gauge method:
+func (r *Reporter) Gauge(metricName string, value float64, tags metrics.Tags) error {
+	r.logger.Logf(log.TraceLevel, "Gauge metric: %s", tags)
+	return nil
+}
+
+// Timing implements the metrics.Reporter interface Timing method:
+func (r *Reporter) Timing(metricName string, value time.Duration, tags metrics.Tags) error {
+	r.logger.Logf(log.TraceLevel, "Timing metric: %s", tags)
+	return nil
+}
+
+// convertTags turns Tags into prometheus labels:
+func convertTags(tags metrics.Tags) map[string]interface{} {
+	labels := make(map[string]interface{})
+	for key, value := range tags {
+		labels[key] = value
+	}
+	return labels
+}