Provide more interesting metrics.

cmd/internal/determine-sync-images/lister.go

@@ -9,6 +9,7 @@ import (
 
 	"github.com/aws/aws-sdk-go/service/s3"
 	metalgo "github.com/metal-stack/metal-go"
+	"github.com/metal-stack/metal-image-cache-sync/cmd/internal/metrics"
 	"github.com/metal-stack/metal-image-cache-sync/pkg/api"
 	"github.com/metal-stack/metal-image-cache-sync/pkg/utils"
 	"github.com/pkg/errors"
@@ -21,15 +22,17 @@ type SyncLister struct {
 	config       *api.Config
 	s3           *s3.S3
 	excludePaths []string
+	collector    *metrics.Collector
 }
 
-func NewSyncLister(logger *zap.SugaredLogger, driver *metalgo.Driver, s3 *s3.S3, config *api.Config) *SyncLister {
+func NewSyncLister(logger *zap.SugaredLogger, driver *metalgo.Driver, s3 *s3.S3, collector *metrics.Collector, config *api.Config) *SyncLister {
 	return &SyncLister{
 		logger:       logger,
 		driver:       driver,
 		config:       config,
 		s3:           s3,
 		excludePaths: config.ExcludePaths,
+		collector:    collector,
 	}
 }
 
@@ -39,13 +42,15 @@ func (s *SyncLister) DetermineSyncList() ([]api.OS, error) {
 		return nil, errors.Wrap(err, "error listing images in s3")
 	}
 
-	apiImages, err := s.driver.ImageList()
+	resp, err := s.driver.ImageList()
 	if err != nil {
 		return nil, errors.Wrap(err, "error listing images")
 	}
 
+	s.collector.SetMetalAPIImageCount(len(resp.Image))
+
 	images := api.OSImagesByOS{}
-	for _, img := range apiImages.Image {
+	for _, img := range resp.Image {
 		skip := false
 		for _, exclude := range s.excludePaths {
 			if strings.Contains(img.URL, exclude) {
@@ -146,6 +151,8 @@ func (s *SyncLister) DetermineSyncList() ([]api.OS, error) {
 		}
 	}
 
+	s.collector.SetUnsyncedImageCount(len(resp.Image) - len(syncImages))
+
 	return syncImages, nil
 }
 

cmd/internal/metrics/metrics.go

@@ -3,6 +3,7 @@ package metrics
 import (
 	"os"
 	"path/filepath"
+	"strings"
 
 	"github.com/metal-stack/metal-image-cache-sync/pkg/api"
 	"github.com/prometheus/client_golang/prometheus"
@@ -16,6 +17,8 @@ type Collector struct {
 	cacheSyncDownloadBytesAdd func(float64)
 	cacheSyncDownloadInc      func()
 	cacheImageDownloadsInc    func()
+	cacheUnsyncedImageCount   func(float64)
+	metalAPIImageCount        func(float64)
 }
 
 func MustMetrics(logger *zap.SugaredLogger, config *api.Config) *Collector {
@@ -29,36 +32,57 @@ func MustMetrics(logger *zap.SugaredLogger, config *api.Config) *Collector {
 		Help: "Current size of the cache directory in bytes",
 	}, c.cacheDirSize)
 
+	cacheImageCount := prometheus.NewGaugeFunc(prometheus.GaugeOpts{
+		Name: "cache_image_count",
+		Help: "Current amount of images in the cache (amount of files in cache directory excluding checksums)",
+	}, c.cacheImageCount)
+
+	cacheUnsyncedImageCount := prometheus.NewGauge(prometheus.GaugeOpts{
+		Name: "cache_unsynced_image_count",
+		Help: "Amount of images from the metal-api not synced into the cache (due to expiration, cache size constraints, ...)",
+	})
+	c.cacheUnsyncedImageCount = cacheUnsyncedImageCount.Set
+
+	metalImageCount := prometheus.NewGauge(prometheus.GaugeOpts{
+		Name: "metal_api_image_count",
+		Help: "Amount of images configured in the metal-api",
+	})
+	c.metalAPIImageCount = metalImageCount.Set
+
 	cacheMisses := prometheus.NewGauge(prometheus.GaugeOpts{
 		Name: "cache_misses",
-		Help: "Amount of cache misses",
+		Help: "Amount of cache misses during instance lifetime",
 	})
 	c.cacheMissInc = cacheMisses.Inc
 
 	cacheSyncDownloadBytes := prometheus.NewGauge(prometheus.GaugeOpts{
 		Name: "cache_sync_downloaded_image_bytes",
-		Help: "Amount of bytes downloaded by the image cache",
+		Help: "Amount of bytes downloaded by the image cache during instance lifetime",
 	})
 	c.cacheSyncDownloadBytesAdd = cacheSyncDownloadBytes.Add
 
 	cacheSyncDownloadCount := prometheus.NewGauge(prometheus.GaugeOpts{
 		Name: "cache_sync_downloaded_image_count",
-		Help: "Amount of images downloaded by the image cache",
+		Help: "Amount of images downloaded by the image cache during instance lifetime",
 	})
 	c.cacheSyncDownloadInc = cacheSyncDownloadCount.Inc
 
 	cacheImageDownloads := prometheus.NewGauge(prometheus.GaugeOpts{
 		Name: "cache_image_downloads",
-		Help: "Amount of images downloaded from the image cache",
+		Help: "Amount of images downloaded from the image cache during instance lifetime",
 	})
 	c.cacheImageDownloadsInc = cacheImageDownloads.Inc
 
 	prometheus.MustRegister(cacheSize)
+	prometheus.MustRegister(cacheImageCount)
+	prometheus.MustRegister(cacheUnsyncedImageCount)
 	prometheus.MustRegister(cacheMisses)
 	prometheus.MustRegister(cacheSyncDownloadBytes)
 	prometheus.MustRegister(cacheSyncDownloadCount)
 	prometheus.MustRegister(cacheImageDownloads)
 
+	prometheus.MustRegister(metalImageCount)
+
 	return c
 }
 
@@ -71,7 +95,7 @@ func (c *Collector) cacheDirSize() float64 {
 		if !info.IsDir() {
 			size += info.Size()
 		}
-		return err
+		return nil
 	})
 
 	if err != nil {
@@ -81,6 +105,25 @@ func (c *Collector) cacheDirSize() float64 {
 	return float64(size)
 }
 
+func (c *Collector) cacheImageCount() float64 {
+	var count int64
+	err := filepath.Walk(c.config.ImageCacheRootPath, func(_ string, info os.FileInfo, err error) error {
+		if err != nil {
+			return err
+		}
+		if !info.IsDir() && !strings.HasSuffix(info.Name(), ".md5") {
+			count += 1
+		}
+		return nil
+	})
+
+	if err != nil {
+		c.logger.Errorw("error collecting image cache count metric", "error", err)
+	}
+
+	return float64(count)
+}
+
 func (c *Collector) IncrementCacheMiss() {
 	c.cacheMissInc()
 }
@@ -93,6 +136,14 @@ func (c *Collector) IncrementSyncDownloadImageCount() {
 	c.cacheSyncDownloadInc()
 }
 
+func (c *Collector) SetUnsyncedImageCount(b int) {
+	c.cacheUnsyncedImageCount(float64(b))
+}
+
 func (c *Collector) IncrementDownloadedImages() {
 	c.cacheImageDownloadsInc()
 }
+
+func (c *Collector) SetMetalAPIImageCount(b int) {
+	c.metalAPIImageCount(float64(b))
+}

cmd/main.go

@@ -168,14 +168,14 @@ func run() error {
 		return err
 	}
 
-	collector := metrics.MustMetrics(logger.Named("metrics"), c)
-
 	driver, err := metalgo.NewDriver(c.MetalAPIEndpoint, "", c.MetalAPIHMAC, metalgo.AuthType("Metal-View"))
 	if err != nil {
 		logger.Errorw("cannot create metal-api client", "error", err)
 		return err
 	}
 
+	collector := metrics.MustMetrics(logger.Named("metrics"), c)
+
 	dummyRegion := "dummy" // we don't use AWS S3, we don't need a proper region
 	ss, err := session.NewSession(&aws.Config{
 		Endpoint:    &c.ImageStore,
@@ -194,7 +194,7 @@ func run() error {
 	s3Client := s3.New(ss)
 	s3Downloader := s3manager.NewDownloader(ss)
 
-	lister = synclister.NewSyncLister(logger.Named("sync-lister"), driver, s3Client, c)
+	lister = synclister.NewSyncLister(logger.Named("sync-lister"), driver, s3Client, collector, c)
 
 	syncer, err = sync.NewSyncer(logger.Named("syncer"), fs, s3Downloader, c, collector, stop)
 	if err != nil {