Add support to optionally opt-in on System metrics (#82)

Closes #79

Co-authored-by: Lucas Medeiros <[email protected]>

_examples/server.go

@@ -13,7 +13,7 @@ import (
 )
 
 func main() {
-	h, _ := health.New()
+	h, _ := health.New(health.WithSystemInfo())
 	// custom health check example (fail)
 	h.Register(health.Config{
 		Name:      "some-custom-check-fail",

health.go

@@ -51,7 +51,7 @@ type (
 		// Failures holds the failed checks along with their messages.
 		Failures map[string]string `json:"failures,omitempty"`
 		// System holds information of the go process.
-		System `json:"system"`
+		*System `json:"system,omitempty"`
 		// Component holds information on the component for which checks are made
 		Component `json:"component"`
 	}
@@ -88,6 +88,8 @@ type (
 		instrumentationName string
 
 		component Component
+
+		systemInfoEnabled bool
 	}
 )
 
@@ -232,24 +234,29 @@ func (h *Health) Measure(ctx context.Context) Check {
 	wg.Wait()
 	span.SetAttributes(attribute.String("status", string(status)))
 
-	return newCheck(h.component, status, failures)
+	var systemMetrics *System
+	if h.systemInfoEnabled {
+		systemMetrics = newSystemMetrics()
+	}
+
+	return newCheck(h.component, status, systemMetrics, failures)
 }
 
-func newCheck(c Component, s Status, failures map[string]string) Check {
+func newCheck(c Component, s Status, system *System, failures map[string]string) Check {
 	return Check{
 		Status:    s,
 		Timestamp: time.Now(),
 		Failures:  failures,
-		System:    newSystemMetrics(),
+		System:    system,
 		Component: c,
 	}
 }
 
-func newSystemMetrics() System {
+func newSystemMetrics() *System {
 	s := runtime.MemStats{}
 	runtime.ReadMemStats(&s)
 
-	return System{
+	return &System{
 		Version:          runtime.Version(),
 		GoroutinesCount:  runtime.NumGoroutine(),
 		TotalAllocBytes:  int(s.TotalAlloc),

health_test.go

@@ -143,4 +143,11 @@ func TestHealth_Measure(t *testing.T) {
 	assert.Equal(t, StatusUnavailable, result.Status)
 	assert.Equal(t, string(StatusTimeout), result.Failures["check1"])
 	assert.Equal(t, string(StatusTimeout), result.Failures["check2"])
+	assert.Nil(t, result.System)
+
+	h, err = New(WithSystemInfo())
+	require.NoError(t, err)
+	result = h.Measure(context.Background())
+
+	assert.NotNil(t, result.System)
 }

options.go

@@ -50,3 +50,11 @@ func WithMaxConcurrent(n int) Option {
 		return nil
 	}
 }
+
+// WithSystemInfo enables the option to return system information about the go process.
+func WithSystemInfo() Option {
+	return func(h *Health) error {
+		h.systemInfoEnabled = true
+		return nil
+	}
+}

options_test.go

@@ -85,3 +85,13 @@ func TestWithMaxConcurrent(t *testing.T) {
 	require.NoError(t, err)
 	assert.Equal(t, 13, h2.maxConcurrent)
 }
+
+func TestWithSystemInfo(t *testing.T) {
+	h1, err := New()
+	require.NoError(t, err)
+	assert.False(t, h1.systemInfoEnabled)
+
+	h2, err := New(WithSystemInfo())
+	require.NoError(t, err)
+	assert.True(t, h2.systemInfoEnabled)
+}