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