Fix bugs + add tests

Signed-off-by: Justin Jung <jungjust@amazon.com>

Author: justinjung04

pkg/cortex/modules.go

@@ -781,16 +781,20 @@ func (t *Cortex) initResourceMonitor() (services.Service, error) {
 			containerLimits[resource.Type(res)] = float64(runtime.GOMAXPROCS(0))
 		case resource.Heap:
 			containerLimits[resource.Type(res)] = float64(debug.SetMemoryLimit(-1))
+		default:
+			level.Warn(util_log.Logger).Log("msg", fmt.Sprintf("skipping unsupported resource [%s]", res))
 		}
 	}
 
 	var err error
 	t.ResourceMonitor, err = resource.NewMonitor(containerLimits, prometheus.DefaultRegisterer)
-	if t.ResourceMonitor != nil {
-		util_log.WarnExperimentalUse("resource monitor")
+	if err != nil {
+		level.Warn(util_log.Logger).Log("msg", "skipping resource monitor; failed to initialize.", "err", err)
+		return nil, nil
 	}
 
-	return t.ResourceMonitor, err
+	util_log.WarnExperimentalUse("resource monitor")
+	return t.ResourceMonitor, nil
 }
 
 func (t *Cortex) setupModuleManager() error {

pkg/cortex/modules_test.go

@@ -232,3 +232,16 @@ func Test_setupModuleManager(t *testing.T) {
 		}
 	}
 }
+
+func Test_initResourceMonitor_shouldNotFailOnInvalidResource(t *testing.T) {
+	cortex := &Cortex{
+		Server: &server.Server{},
+		Cfg: Config{
+			MonitoredResources: []string{"invalid"},
+		},
+	}
+
+	// log warning message and spin up other cortex services
+	_, err := cortex.initResourceMonitor()
+	require.NoError(t, err)
+}

pkg/util/resource/monitor.go

@@ -50,6 +50,7 @@ func NewMonitor(limits map[Type]float64, registerer prometheus.Registerer) (*Mon
 	m := &Monitor{
 		containerLimit: limits,
 		scanners:       make(map[Type]scanner),
+		utilization:    make(map[Type]float64),
 
 		cpuRates:     [dataPointsToAvg]float64{},
 		cpuIntervals: [dataPointsToAvg]float64{},

pkg/util/resource/monitor_test.go

@@ -0,0 +1,18 @@
+package resource
+
+import (
+	"testing"
+
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/stretchr/testify/require"
+)
+
+func Test_Monitor(t *testing.T) {
+	m, err := NewMonitor(map[Type]float64{}, prometheus.DefaultRegisterer)
+
+	m.scanners[CPU] = &noopScanner{}
+	m.containerLimit[CPU] = 1
+	m.utilization[CPU] = 0.5
+
+	require.NoError(t, err)
+}

pkg/util/resource/scanner.go

@@ -6,7 +6,7 @@ import (
 )
 
 const (
-	heapMetricName = "/memory/classes/Heap/objects:bytes"
+	heapMetricName = "/memory/classes/heap/objects:bytes"
 )
 
 type scanner interface {

pkg/util/resource/scanner_test.go

@@ -12,3 +12,8 @@ func Test_NoopScanner(t *testing.T) {
 	require.NoError(t, err)
 	require.Zero(t, val)
 }
+
+func Test_HeapScanner(t *testing.T) {
+	_, err := newHeapScanner()
+	require.NoError(t, err)
+}