feat: HealthCheck

healthcheck/healthcheck.go

@@ -0,0 +1,94 @@
+package healthcheck
+
+import (
+	"github.com/containous/traefik/log"
+	"github.com/vulcand/oxy/roundrobin"
+	"net/http"
+	"net/url"
+	"sync"
+	"time"
+)
+
+var singleton *HealthCheck
+var once sync.Once
+
+// GetHealthCheck Get HealtchCheck Singleton
+func GetHealthCheck() *HealthCheck {
+	once.Do(func() {
+		singleton = newHealthCheck()
+		singleton.execute()
+	})
+	return singleton
+}
+
+// BackendHealthCheck HealthCheck configuration for a backend
+type BackendHealthCheck struct {
+	URL          string
+	DisabledURLs []*url.URL
+	lb           loadBalancer
+}
+
+var launch = false
+
+//HealthCheck struct
+type HealthCheck struct {
+	Backends map[string]*BackendHealthCheck
+}
+
+type loadBalancer interface {
+	RemoveServer(u *url.URL) error
+	UpsertServer(u *url.URL, options ...roundrobin.ServerOption) error
+	Servers() []*url.URL
+}
+
+func newHealthCheck() *HealthCheck {
+	return &HealthCheck{make(map[string]*BackendHealthCheck)}
+}
+
+// NewBackendHealthCheck Instantiate a new BackendHealthCheck
+func NewBackendHealthCheck(URL string, lb loadBalancer) *BackendHealthCheck {
+	return &BackendHealthCheck{URL, nil, lb}
+}
+
+//SetBackends set backends configuration
+func (hc *HealthCheck) SetBackendsConfiguration(backends map[string]*BackendHealthCheck) {
+	hc.Backends = backends
+}
+
+func (hc *HealthCheck) execute() {
+	ticker := time.NewTicker(time.Second * 30)
+	go func() {
+		for t := range ticker.C {
+			for backendID, backend := range hc.Backends {
+				log.Debugf("Refreshing Healthcheck %s for backend %s ", t.String(), backendID)
+				enabledURLs := backend.lb.Servers()
+				var newDisabledURLs []*url.URL
+				for _, url := range backend.DisabledURLs {
+					if testHealth(url, backend.URL) {
+						log.Debugf("Upsert %s", url.String())
+						backend.lb.UpsertServer(url, roundrobin.Weight(1))
+					} else {
+						newDisabledURLs = append(newDisabledURLs, url)
+					}
+				}
+				backend.DisabledURLs = newDisabledURLs
+
+				for _, url := range enabledURLs {
+					if !testHealth(url, backend.URL) {
+						log.Debugf("Remove %s", url.String())
+						backend.lb.RemoveServer(url)
+						backend.DisabledURLs = append(backend.DisabledURLs, url)
+					}
+				}
+			}
+		}
+	}()
+}
+
+func testHealth(serverURL *url.URL, checkURL string) bool {
+	resp, err := http.Get(serverURL.String() + checkURL)
+	if err != nil || resp.StatusCode != 200 {
+		return false
+	}
+	return true
+}