Service Accounts: Implement basic usage stats (#46619)

* Stats: do not count SAs as users

* Stats: implement basic service account metrics

* Stats: do not count service account tokens as api keys

* Stats: fix metric names

* Stats: add SA stats test

* rename user to sa

pkg/services/serviceaccounts/database/stats_test.go

@@ -0,0 +1,41 @@
+package database
+
+import (
+	"context"
+	"testing"
+
+	"github.com/grafana/grafana/pkg/components/apikeygen"
+	"github.com/grafana/grafana/pkg/models"
+	"github.com/grafana/grafana/pkg/services/serviceaccounts/tests"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestStore_UsageStats(t *testing.T) {
+	saToCreate := tests.TestUser{Login: "servicetestwithTeam@admin", IsServiceAccount: true}
+	db, store := setupTestDatabase(t)
+	sa := tests.SetupUserServiceAccount(t, db, saToCreate)
+
+	keyName := t.Name()
+	key, err := apikeygen.New(sa.OrgId, keyName)
+	require.NoError(t, err)
+
+	cmd := models.AddApiKeyCommand{
+		Name:          keyName,
+		Role:          "Viewer",
+		OrgId:         sa.OrgId,
+		Key:           key.HashedKey,
+		SecondsToLive: 0,
+		Result:        &models.ApiKey{},
+	}
+
+	err = store.AddServiceAccountToken(context.Background(), sa.Id, &cmd)
+	require.NoError(t, err)
+
+	stats, err := store.GetUsageMetrics(context.Background())
+	require.NoError(t, err)
+
+	assert.Equal(t, int64(1), stats["stats.serviceaccounts.count"].(int64))
+	assert.Equal(t, int64(1), stats["stats.serviceaccounts.tokens.count"].(int64))
+	assert.Equal(t, int64(1), stats["stats.serviceaccounts.enabled.count"].(int64))
+}