node: add neofs_node_engine_capacity metric

Expose metric for shard's capacity.

Closes #1794.

Signed-off-by: Andrey Butusov <[email protected]>

CHANGELOG.md

@@ -22,6 +22,7 @@ attribute, which is used for container domain name in NNS contracts (#2954)
 - New `peapod-to-fstree` tool providing peapod-to-fstree data migration (#3013)
 - Reloading node attributes with SIGHUP (#3005)
 - Reloading pool sizes (#3018)
+- Add metrics for shard's capacity (#3021)
 
 ### Fixed
 - Do not search for tombstones when handling their expiration, use local indexes instead (#2929)

cmd/neofs-node/main.go

@@ -61,6 +61,9 @@ func main() {
 
 	initApp(c)
 
+	err = c.setShardsCapacity()
+	fatalOnErr(err)
+
 	c.setHealthStatus(control.HealthStatus_STARTING)
 
 	bootUp(c)

cmd/neofs-node/metrics.go

@@ -1,6 +1,12 @@
 package main
 
 import (
+	"errors"
+	"fmt"
+	"io/fs"
+	"os"
+	"path/filepath"
+
 	metricsconfig "github.com/nspcc-dev/neofs-node/cmd/neofs-node/config/metrics"
 	httputil "github.com/nspcc-dev/neofs-node/pkg/util/http"
 	"github.com/prometheus/client_golang/prometheus/promhttp"
@@ -25,3 +31,34 @@ func initMetrics(c *cfg) *httputil.Server {
 
 	return srv
 }
+
+func (c *cfg) setShardsCapacity() error {
+	for _, sh := range c.cfgObject.cfgLocalStorage.localStorage.DumpInfo().Shards {
+		paths := make([]string, 0, len(sh.BlobStorInfo.SubStorages))
+		for _, subStorage := range sh.BlobStorInfo.SubStorages {
+			path := subStorage.Path
+
+			for len(path) > 1 { // Dir returns / or . if nothing else left.
+				fi, err := os.Stat(path)
+				if err == nil && fi.IsDir() {
+					break
+				}
+				if err != nil && !errors.Is(err, fs.ErrNotExist) {
+					return fmt.Errorf("accessing %q: %w", path, err)
+				}
+				path = filepath.Dir(path)
+			}
+
+			paths = append(paths, path)
+		}
+
+		capacity, err := totalBytes(paths)
+		if err != nil {
+			return fmt.Errorf("calculating capacity on shard %s: %w", sh.ID.String(), err)
+		}
+
+		c.metricsCollector.SetCapacitySize(sh.ID.String(), capacity/(1<<30))
+	}
+
+	return nil
+}

pkg/metrics/engine.go

@@ -22,6 +22,7 @@ type (
 
 		containerSize prometheus.GaugeVec
 		payloadSize   prometheus.GaugeVec
+		capacitySize  prometheus.GaugeVec
 	}
 )
 
@@ -121,6 +122,13 @@ func newEngineMetrics() engineMetrics {
 			Name:      "payload_size",
 			Help:      "Accumulated size of all objects in a shard",
 		}, []string{shardIDLabelKey})
+
+		capacitySize = prometheus.NewGaugeVec(prometheus.GaugeOpts{
+			Namespace: storageNodeNameSpace,
+			Subsystem: engineSubsystem,
+			Name:      "capacity",
+			Help:      "Contains the shard's capacity, GB",
+		}, []string{shardIDLabelKey})
 	)
 
 	return engineMetrics{
@@ -137,6 +145,7 @@ func newEngineMetrics() engineMetrics {
 		listObjectsDuration:           listObjectsDuration,
 		containerSize:                 *containerSize,
 		payloadSize:                   *payloadSize,
+		capacitySize:                  *capacitySize,
 	}
 }
 
@@ -154,6 +163,7 @@ func (m engineMetrics) register() {
 	prometheus.MustRegister(m.listObjectsDuration)
 	prometheus.MustRegister(m.containerSize)
 	prometheus.MustRegister(m.payloadSize)
+	prometheus.MustRegister(m.capacitySize)
 }
 
 func (m engineMetrics) AddListContainersDuration(d time.Duration) {
@@ -211,3 +221,7 @@ func (m engineMetrics) AddToContainerSize(cnrID string, size int64) {
 func (m engineMetrics) AddToPayloadCounter(shardID string, size int64) {
 	m.payloadSize.With(prometheus.Labels{shardIDLabelKey: shardID}).Add(float64(size))
 }
+
+func (m engineMetrics) SetCapacitySize(shardID string, capacity uint64) {
+	m.capacitySize.With(prometheus.Labels{shardIDLabelKey: shardID}).Set(float64(capacity))
+}