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_test.go

@@ -0,0 +1,51 @@
+package logging
+
+import (
+	"bytes"
+	"testing"
+	"time"
+
+	log "github.com/micro/go-micro/v3/logger"
+	"github.com/micro/go-micro/v3/metrics"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestLoggingReporter(t *testing.T) {
+
+	// Make a Reporter:
+	reporter := New(metrics.Path("/prometheus"), metrics.DefaultTags(map[string]string{"service": "prometheus-test"}))
+	assert.NotNil(t, reporter)
+	assert.Equal(t, "prometheus-test", reporter.options.DefaultTags["service"])
+	assert.Equal(t, ":9000", reporter.options.Address)
+	assert.Equal(t, "/prometheus", reporter.options.Path)
+
+	// Make a log buffer and create a new logger to use it:
+	logBuffer := new(bytes.Buffer)
+	reporter.logger = log.NewLogger(log.WithLevel(log.TraceLevel), log.WithOutput(logBuffer), log.WithFields(convertTags(reporter.options.DefaultTags)))
+
+	// Check that our implementation is valid:
+	assert.Implements(t, new(metrics.Reporter), reporter)
+
+	// Test tag conversion:
+	tags := metrics.Tags{
+		"tag1": "false",
+		"tag2": "true",
+	}
+	convertedTags := convertTags(tags)
+	assert.Equal(t, "false", convertedTags["tag1"])
+	assert.Equal(t, "true", convertedTags["tag2"])
+
+	// Test submitting metrics through the interface methods:
+	assert.NoError(t, reporter.Count("test.counter.1", 6, tags))
+	assert.NoError(t, reporter.Count("test.counter.2", 19, tags))
+	assert.NoError(t, reporter.Count("test.counter.1", 5, tags))
+	assert.NoError(t, reporter.Gauge("test.gauge.1", 99, tags))
+	assert.NoError(t, reporter.Gauge("test.gauge.2", 55, tags))
+	assert.NoError(t, reporter.Gauge("test.gauge.1", 98, tags))
+	assert.NoError(t, reporter.Timing("test.timing.1", time.Second, tags))
+	assert.NoError(t, reporter.Timing("test.timing.2", time.Minute, tags))
+
+	// Test reading back the metrics from the logbuffer (doesn't seem to work because the output still goes to StdOut):
+	// assert.Contains(t, logBuffer.String(), "level=debug service=prometheus-test Count metric: map[tag1:false tag2:true]")
+}