feat(health): implement health endpoint (wip)

internal/endpoints/health.go

@@ -0,0 +1,48 @@
+package endpoints
+
+import (
+	"net/http"
+
+	"github.com/massix/chaos-monkey/internal/watcher"
+)
+
+type HealthEndpoint struct {
+	mainWatcher *watcher.NamespaceWatcher
+}
+
+func NewHealthEndpoint(w *watcher.NamespaceWatcher) *HealthEndpoint {
+	return &HealthEndpoint{
+		mainWatcher: w,
+	}
+}
+
+func (e *HealthEndpoint) CountWatchers() int {
+	var allWatchers func(r watcher.Watcher, acc *[]watcher.Watcher) *[]watcher.Watcher
+	allWatchers = func(w watcher.Watcher, acc *[]watcher.Watcher) *[]watcher.Watcher {
+		*acc = append(*acc, w)
+
+		if w, ok := w.(*watcher.NamespaceWatcher); ok {
+			for _, child := range w.CrdWatchers {
+				allWatchers(child, acc)
+			}
+		}
+
+		if w, ok := w.(*watcher.CrdWatcher); ok {
+			for _, child := range w.DeploymentWatchers {
+				allWatchers(child.Watcher, acc)
+			}
+		}
+
+		return acc
+	}
+
+	return len(*allWatchers(e.mainWatcher, &[]watcher.Watcher{}))
+}
+
+// ServeHTTP implements http.Handler.
+func (e *HealthEndpoint) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	w.Header()["x-server-type"] = []string{"golang"}
+	w.WriteHeader(http.StatusOK)
+}
+
+var _ = (http.Handler)((*HealthEndpoint)(nil))

internal/endpoints/health_test.go

@@ -0,0 +1,58 @@
+package endpoints_test
+
+import (
+	"fmt"
+	"math/rand"
+	"testing"
+
+	"github.com/massix/chaos-monkey/internal/endpoints"
+	"github.com/massix/chaos-monkey/internal/watcher"
+)
+
+func setup(crdWatchers, deployWatchers int) (*watcher.NamespaceWatcher, int) {
+	mainWatcher := &watcher.NamespaceWatcher{
+		CrdWatchers: map[string]watcher.Watcher{},
+	}
+	created := 1
+
+	for i := 0; i < crdWatchers; i++ {
+		crdWatcher := &watcher.CrdWatcher{DeploymentWatchers: map[string]*watcher.WatcherConfiguration{}}
+		mainWatcher.CrdWatchers[fmt.Sprintf("%d", i)] = crdWatcher
+		created++
+
+		for j := 0; j < deployWatchers; j++ {
+			var target watcher.ConfigurableWatcher
+			if rand.Intn(2) == 0 {
+				target = &watcher.PodWatcher{}
+			} else {
+				target = &watcher.DeploymentWatcher{}
+			}
+			crdWatcher.DeploymentWatchers[fmt.Sprintf("%d", j)] = &watcher.WatcherConfiguration{
+				Watcher: target,
+			}
+			created++
+		}
+	}
+
+	return mainWatcher, created
+}
+
+func TestHealthEndpoint_CountWatchers(t *testing.T) {
+	mw, created := setup(10, 15)
+	ep := endpoints.NewHealthEndpoint(mw)
+	if cnt := ep.CountWatchers(); cnt != (10*15)+10+1 {
+		t.Fatalf("wrong count: %d (expecting: %d)", cnt, created)
+	}
+}
+
+func BenchmarkHealthEndpoint_CountWatchers(b *testing.B) {
+	b.RunParallel(func(p *testing.PB) {
+		for p.Next() {
+			mw, _ := setup(rand.Intn(9000)+1, rand.Intn(500)+1)
+			ep := endpoints.NewHealthEndpoint(mw)
+			b.StartTimer()
+			ep.CountWatchers()
+			b.StopTimer()
+		}
+	})
+}