Merge branch 'feature/gb/domains-source-caching-metrics' into 'master'

Add GitLab API domains source caching metrics

Closes #279

See merge request gitlab-org/gitlab-pages!213

2 files changed, 18 insertions, 0 deletions

diff --git a/internal/source/gitlab/cache/cache.go b/internal/source/gitlab/cache/cache.go
index 492a52a9..3d518ff0 100644
--- a/internal/source/gitlab/cache/cache.go
+++ b/internal/source/gitlab/cache/cache.go
@@ -4,6 +4,7 @@ import (
 	"context"
 
 	"gitlab.com/gitlab-org/gitlab-pages/internal/source/gitlab/api"
+	"gitlab.com/gitlab-org/gitlab-pages/metrics"
 )
 
 // Cache is a short and long caching mechanism for GitLab source
@@ -73,14 +74,17 @@ func (c *Cache) Resolve(ctx context.Context, domain string) *api.Lookup {
 	entry := c.store.LoadOrCreate(domain)
 
 	if entry.IsUpToDate() {
+		metrics.DomainsSourceCacheHit.Inc()
 		return entry.Lookup()
 	}
 
 	if entry.NeedsRefresh() {
 		entry.Refresh(c.client, c.store)
 
+		metrics.DomainsSourceCacheHit.Inc()
 		return entry.Lookup()
 	}
 
+	metrics.DomainsSourceCacheMiss.Inc()
 	return entry.Retrieve(ctx, c.client)
 }
diff --git a/metrics/metrics.go b/metrics/metrics.go
index 18fd3fdd..e65d87b1 100644
--- a/metrics/metrics.go
+++ b/metrics/metrics.go
@@ -28,10 +28,24 @@ var (
 		Name: "gitlab_pages_last_domain_update_seconds",
 		Help: "UNIX timestamp of the last update",
 	})
+
+	// DomainsSourceCacheHit is the number of GitLab API call cache hits
+	DomainsSourceCacheHit = prometheus.NewCounter(prometheus.CounterOpts{
+		Name: "gitlab_pages_domains_source_cache_hit",
+		Help: "The number of GitLab domains API cache hits",
+	})
+
+	// DomainsSourceCacheMiss is the number of GitLab API call cache misses
+	DomainsSourceCacheMiss = prometheus.NewCounter(prometheus.CounterOpts{
+		Name: "gitlab_pages_domains_source_cache_miss",
+		Help: "The number of GitLab domains API cache misses",
+	})
 )
 
 func init() {
 	prometheus.MustRegister(DomainsServed)
 	prometheus.MustRegister(DomainUpdates)
 	prometheus.MustRegister(DomainLastUpdateTime)
+	prometheus.MustRegister(DomainsSourceCacheHit)
+	prometheus.MustRegister(DomainsSourceCacheMiss)
 }