package healthcheck import ( "context" "net/http" "net/url" "sync" "time" "github.com/containous/traefik/log" "github.com/containous/traefik/safe" "github.com/vulcand/oxy/roundrobin" ) var singleton *HealthCheck var once sync.Once // GetHealthCheck Get HealtchCheck Singleton func GetHealthCheck() *HealthCheck { once.Do(func() { singleton = newHealthCheck() }) return singleton } // BackendHealthCheck HealthCheck configuration for a backend type BackendHealthCheck struct { Path string Interval time.Duration DisabledURLs []*url.URL requestTimeout time.Duration lb loadBalancer } var launch = false //HealthCheck struct type HealthCheck struct { Backends map[string]*BackendHealthCheck cancel context.CancelFunc } type loadBalancer interface { RemoveServer(u *url.URL) error UpsertServer(u *url.URL, options ...roundrobin.ServerOption) error Servers() []*url.URL } func newHealthCheck() *HealthCheck { return &HealthCheck{ Backends: make(map[string]*BackendHealthCheck), } } // NewBackendHealthCheck Instantiate a new BackendHealthCheck func NewBackendHealthCheck(Path string, interval time.Duration, lb loadBalancer) *BackendHealthCheck { return &BackendHealthCheck{ Path: Path, Interval: interval, requestTimeout: 5 * time.Second, lb: lb, } } //SetBackendsConfiguration set backends configuration func (hc *HealthCheck) SetBackendsConfiguration(parentCtx context.Context, backends map[string]*BackendHealthCheck) { hc.Backends = backends if hc.cancel != nil { hc.cancel() } ctx, cancel := context.WithCancel(parentCtx) hc.cancel = cancel for backendID, backend := range hc.Backends { currentBackendID := backendID currentBackend := backend safe.Go(func() { hc.execute(ctx, currentBackendID, currentBackend) }) } } func (hc *HealthCheck) execute(ctx context.Context, backendID string, backend *BackendHealthCheck) { log.Debugf("Initial healthcheck for currentBackend %s ", backendID) checkBackend(backend) ticker := time.NewTicker(backend.Interval) defer ticker.Stop() for { select { case <-ctx.Done(): log.Debugf("Stopping all current Healthcheck goroutines") return case <-ticker.C: log.Debugf("Refreshing healthcheck for currentBackend %s ", backendID) checkBackend(backend) } } } func checkBackend(currentBackend *BackendHealthCheck) { enabledURLs := currentBackend.lb.Servers() var newDisabledURLs []*url.URL for _, url := range currentBackend.DisabledURLs { if checkHealth(url, currentBackend) { log.Debugf("HealthCheck is up [%s]: Upsert in server list", url.String()) currentBackend.lb.UpsertServer(url, roundrobin.Weight(1)) } else { log.Warnf("HealthCheck is still failing [%s]", url.String()) newDisabledURLs = append(newDisabledURLs, url) } } currentBackend.DisabledURLs = newDisabledURLs for _, url := range enabledURLs { if !checkHealth(url, currentBackend) { log.Warnf("HealthCheck has failed [%s]: Remove from server list", url.String()) currentBackend.lb.RemoveServer(url) currentBackend.DisabledURLs = append(currentBackend.DisabledURLs, url) } } } func checkHealth(serverURL *url.URL, backend *BackendHealthCheck) bool { client := http.Client{ Timeout: backend.requestTimeout, } resp, err := client.Get(serverURL.String() + backend.Path) if err == nil { defer resp.Body.Close() } return err == nil && resp.StatusCode == 200 }