Human-readable metric emit logs

Rather than dumping metrics on a single line, nearly unrelated textproto, print
them in alphabetical order, each on their own line.

e.g.,

D0108 17:42:42.198216  3382465 metric.go:253] Emitting metrics:
D0108 17:42:42.198240  3382465 metric.go:255] /fs/opens: &{Uint64Value:22}
D0108 17:42:42.198271  3382465 metric.go:255] /fs/read_wait: &{Uint64Value:0}
D0108 17:42:42.198294  3382465 metric.go:255] /fs/reads: &{Uint64Value:26}
D0108 17:42:42.198319  3382465 metric.go:255] /gofer/opened_write_execute_file: &{Uint64Value:0}
D0108 17:42:42.198327  3382465 metric.go:255] /gofer/opens_9p: &{Uint64Value:0}
D0108 17:42:42.198340  3382465 metric.go:255] /gofer/opens_host: &{Uint64Value:20}
...

PiperOrigin-RevId: 351590340

1 files changed, 17 insertions, 4 deletions

diff --git a/pkg/metric/metric.go b/pkg/metric/metric.go
index d012c5734..c9f9357de 100644
--- a/pkg/metric/metric.go
+++ b/pkg/metric/metric.go
@@ -18,6 +18,7 @@ package metric
 import (
 	"errors"
 	"fmt"
+	"sort"
 	"sync/atomic"
 
 	"gvisor.dev/gvisor/pkg/eventchannel"
@@ -139,7 +140,8 @@ func MustRegisterCustomUint64Metric(name string, cumulative, sync bool, descript
 	}
 }
 
-// NewUint64Metric creates and registers a new cumulative metric with the given name.
+// NewUint64Metric creates and registers a new cumulative metric with the given
+// name.
 //
 // Metrics must be statically defined (i.e., at init).
 func NewUint64Metric(name string, sync bool, units pb.MetricMetadata_Units, description string) (*Uint64Metric, error) {
@@ -147,7 +149,8 @@ func NewUint64Metric(name string, sync bool, units pb.MetricMetadata_Units, desc
 	return &m, RegisterCustomUint64Metric(name, true /* cumulative */, sync, units, description, m.Value)
 }
 
-// MustCreateNewUint64Metric calls NewUint64Metric and panics if it returns an error.
+// MustCreateNewUint64Metric calls NewUint64Metric and panics if it returns an
+// error.
 func MustCreateNewUint64Metric(name string, sync bool, description string) *Uint64Metric {
 	m, err := NewUint64Metric(name, sync, pb.MetricMetadata_UNITS_NONE, description)
 	if err != nil {
@@ -156,7 +159,8 @@ func MustCreateNewUint64Metric(name string, sync bool, description string) *Uint
 	return m
 }
 
-// MustCreateNewUint64NanosecondsMetric calls NewUint64Metric and panics if it returns an error.
+// MustCreateNewUint64NanosecondsMetric calls NewUint64Metric and panics if it
+// returns an error.
 func MustCreateNewUint64NanosecondsMetric(name string, sync bool, description string) *Uint64Metric {
 	m, err := NewUint64Metric(name, sync, pb.MetricMetadata_UNITS_NANOSECONDS, description)
 	if err != nil {
@@ -245,6 +249,15 @@ func EmitMetricUpdate() {
 		return
 	}
 
-	log.Debugf("Emitting metrics: %v", &m)
+	if log.IsLogging(log.Debug) {
+		sort.Slice(m.Metrics, func(i, j int) bool {
+			return m.Metrics[i].Name < m.Metrics[j].Name
+		})
+		log.Debugf("Emitting metrics:")
+		for _, metric := range m.Metrics {
+			log.Debugf("%s: %+v", metric.Name, metric.Value)
+		}
+	}
+
 	eventchannel.Emit(&m)
 }