Tidying up the new Metrics implementations (#1974)

* Unit tests to check tagging and aggregation of Prometheus metrics

* Removing the logger output routing (because it doesn't actually work in the logger implementation)

* Emitting values with the logging reporter

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

metrics/logging/reporter.go

@@ -3,43 +3,43 @@ package logging
 import (
 	"time"
 
-	log "github.com/micro/go-micro/v3/logger"
+	"github.com/micro/go-micro/v3/logger"
 	"github.com/micro/go-micro/v3/metrics"
 )
 
+const (
+	defaultLoggingLevel = logger.TraceLevel
+)
+
 // Reporter is an implementation of metrics.Reporter:
 type Reporter struct {
-	logger  log.Logger
 	options metrics.Options
 }
 
-// New returns a configured noop reporter:
+// New returns a configured logging 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)")
+	logger.Logf(logger.InfoLevel, "Metrics/Logging - metrics will be logged (at %s level)", defaultLoggingLevel.String())
 
 	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)
+	logger.Logf(defaultLoggingLevel, "Count metric: (%s: %d) %s", metricName, value, 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)
+	logger.Logf(defaultLoggingLevel, "Gauge metric: (%s: %f) %s", metricName, value, 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)
+	logger.Logf(defaultLoggingLevel, "Timing metric: (%s: %s) %s", metricName, value.String(), tags)
 	return nil
 }